energy thrift and thermal comfort in public houses

Energy thrift and thermal comfort inpublic houses

M.A. Bond *, S.D. Probert

Department of Applied Energy, Cran®eld University, Bedfordshire MK43 0AL, UK

Abstract

To contribute to achieving improved energy-e�ectiveness of future designs of public housesand the equipment employed therein, energy usage and wastages have been examined for two

``pubs'', one of modern and the other of traditional construction. The use of pertinent energy-consuming equipment was surveyed and the associated patterns of operation assessed. Energytari�s in force are analysed with respect to their in¯uence upon demands. Thermal conditions

within the public areas of the public houses were also monitored, and the proportion ofenergy used for space heating determined. Pub managers and sta� were involved with thesurvey. Refrigeration equipment was particularly energy consuming, owing to the conditions

under which it was required to operate. Despite the availability of more e�cient alternatives,tungsten lighting is still in common use in bars, and accounted for up to a quarter of theelectricity used in the public houses considered. There, controls for the heating systems arebasic but ill-devised, so leading to extreme thermal conditions in some areas of the pubs:

consequently there are signi®cant opportunities for savings. Ventilation controls were over-looked, so large rates of heat loss occurred via the exhaust air. The potential for achievingsigni®cant energy-savings through the introduction of waste-heat recovery equipment is

hampered by (i) the brewery's requirement for a payback period for such investments of 1 yearor less, and (ii) the reality that energy bills amount only to �3% of turnover at present unit-energy prices and are therefore of less importance than customer comfort. Values of the

recommended `energy indices' are calculated in order to assess the pubs' overall performances:according to these nationally-accepted benchmarks for these concepts, both assessed pubs areclassi®ed as `good', despite the shortcomings of each enterprise identi®ed in the present

research. # 1999 Published by Elsevier Science Ltd. All rights reserved.

Applied Energy 62 (1999) 1±65

0306-2619/99/$ - see front matter # 1999 Published by Elsevier Science Ltd. All rights reserved.

PII: S0306-2619(98)00044-0

* Corresponding author. Tel.:+44-(0)1923-664738; e-mail:[email protected] (M.A. Bond)

Glossary

Availability charge: a theoretical maximum rate of electrical-power consumption fora premises, set by the supply company, which if exceeded will trigger penalty charges.Bain±Marie hot cupboard: an electrically-heated water-bath unit which maintains

food at the appropriate serving temperature. It also contains heated cupboards anda serving shelf heated by infra-red lamps.Line coolers: refrigeration units that cool the beer as it ¯ows through delivery

pipes from cellar to the bar.Post mix: a unit which mixes syrups with carbonated water to produce soft drinks.Treated ¯oor area: any ¯oor area that is arti®cially heated or cooled, and so includes

all occupied areas and the cellar, but excludes unheated areas such as plant rooms.

1. Energy usage in public houses

1.1. The cost of wasting energy

Everyone is aware to some extent of the need to practise energy thrift. The valueof a reliable, cheap energy-supply was brought home to the public by the unit-energy price `crises' of the 1970s. Today, fossil fuels are once more seen as cheap andplentiful, but the perception that this will continue inde®nitely is false. The hiddencosts of energy provision, namely pollution and its many associated impacts (e.g.upon human health), are not presently passed on directly to the individual con-sumer. The `internalisation' of these e�ects would lead to the imposition of the fullcost of energy upon consumers, and so then environmental conservation willbecome far more acceptable for economic reasons with all individuals than it istoday. There is the eventual likelihood that internalisation will become a reality, inthe form of carbon, toxic and noxious pollutant or energy taxes.Unfortunately, misleading signals are at present being sent to the domestic con-

sumer, suggesting that plentiful cheap supplies of energy will always be available:e.g. the 1997 reduction of VAT for domestic fuel; a one-o� rebate following the saleof the nuclear-electricity industry to the private sector; excessive competition madepossible by the deregulation of the supply market; and repeated demands by theenergy regulators for reduced domestic bills. Commercial users pay VAT at the fullrate of 17.5%, but, through bulk buying, often have access to energy which ischeaper per kWh than even the domestic tari�.It is demonstrable that the inclusion of energy-thrift features at the design stage of

a new building is more cost e�ective than retro®tting those same measures, sub-sequent to the erection of the building. Additional insulation, for example, is dis-ruptive and hence costly to introduce as an afterthought, and with this in mind theUK building regulations have demanded progressively higher standards of thermalinsulation for new buildings.The same is true of individual items of energy-consuming equipment, but most of

these have relatively short lifespans compared with those for buildings, and so are

2 M.A. Bond, S.D. Probert/Applied Energy 62 (1999) 1±65

usually replaced quite frequently with higher-e�ciency models. However, it willoften be the case that a refrigerator (for example) will be outdated shortly after itspurchase by a more energy-e�cient model, but clearly it would be uneconomic toreplace it immediately. The age of the equipment, its remaining operational lifespan,its purchase cost and its higher running cost (compared with those of the potentialreplacements) must all be considered. The running cost depends on the rate ofenergy consumption, the pattern of use, and the unit cost of energy employed.In the commercial world, investments in such measures are likely to be made only

if it can be shown that the simple pay-back period, i.e. capital investment requireddivided by the savings recouped per year as a result of making that investment, isshorter than 3 years: some organisations only favour measures with payback periodsof less than 1 year.High rates of energy usage in pubs have been accepted in the past as an unavoid-

able necessity. The main aim of each business is to attract customers, and once theyare inside the pub, to make them so comfortable that they will return, bringing othercustomers. If this means keeping them warm, and their beer cold, then so be it.Necessarily, the pub landlord is exposed to many stresses, and hence traditionallyenergy e�ciency has remained a low priority. This is especially so when the pub ismanaged on behalf of a brewery: the pub's energy bills, which form such a smallproportion of running costs, are sent directly to the brewery for payment. However,in a `free house', the energy bills tend to receive greater attention and concern,because they are paid by the landlord.The all-embracing handbook `Running Your Own Pub' [1] is more concerned with

the comfort conditions that are deemed desirable for the customers than with thecost incurred in providing that thermal environment: the energy consumptions ande�ciencies of equipment other than heating are not discussed. The pub must becomfortable throughout opening hours, whether the pub is busy, or entertaining justa single customer. The automatic systems to achieve occupancy-related control,which are employed frequently in o�ces and commercial premises, are only rarelyemployed in pubs.Currently, approximately 65,000 pubs in the UK share an annual energy bill of

about £500 million [2]. It is now recognised that it is possible to reduce this costsigni®cantly without adversely a�ecting customer comfort. Indeed, the clients mayeven be more comfortable as a result of the implementation of energy-thrift mea-sures. However, modern refurbishments of pubs can lead to increased annual energycosts, if new facilities or heating systems are installed without expert advice beingacted upon.This report describes the rates of energy usage and room-temperature variations

from winter to summer, for two quite di�erent pubs. One is a recently-built pub-restaurant and the other is a traditional village pub.Liaison with the pubs' managers allowed information concerning equipment

usage, cold areas, and other relevant issues, to be gathered. The observations andconclusions arising from the monitoring, and other on-site observations, are used toassess ways in which the rates of energy consumption could be reduced in the mon-itored pubs, as well as in pubs in general.

M.A. Bond, S.D. Probert/Applied Energy 62 (1999) 1±65 3

New-build pubs are often constructed to a standard design-speci®cation, and so itis then particularly bene®cial that the design should have been optimised for severaldi�erent purposes. Breweries, that intend to build many such pubs, may in thefuture for instance wish to maximise their energy performances.The energy demands of the two considered pubs, and the temperatures in zones such

as the saloon and lounge bars, were monitored using data-logging equipment with (i)current clamps to assess the electricity consumptions, and (ii) thermoprobes for tem-perature measurement. Observing critically the rate of natural-gas usage involvedmonthly meter-readings. To gain a comprehensive understanding of the buildings'thermal behaviours, temperature data from the coldest to the warmest parts of the yearwere obtained. Electricity monitoring was undertaken from mid-December to mid-August. However, it were felt that Christmas decorations would obstruct the thermop-robewiring, and, in any case, the pubs'managers did notwelcomeour disruption at theirbusiest time of the year, so detailed temperature monitoring started in mid-January.For the traditional pub, which has had full central-heating system installed since

we undertook our ®rst annual audit in 1981, a direct `before and after' comparisoncan be made to evaluate its e�ectiveness.

1.1.1. Energy auditThis considers the energy sources, ¯ows and sinks for each pub. Fig. 1 illustrates

that most of the energy delivered will eventually ®nd its way to the environment asheat, with small contributions due to light and sound. In the case of public houses,sundry energy gains from people are considerable, however, high levels of ventila-tion are often required to remove smoke. Tungsten lighting converts �96% of itsinput power to heat, and only �4% to light; ¯uorescent lighting contributes �80%as heat, and so consumes commensurately less input power in the provision of thesame light output. Electricity consumption in pubs is dominated by cooking andrefrigeration, which radically a�ect the thermal conditions `backstage' but not in thepublic areas. The processes involved include the preparation of food, which is con-sumed by people, and thus contributes slightly to sundry gains via personal heatloss. Natural gains occur when sunlight enters through windows.

1.1.2. Central-heating system and hot waterBoth considered pubs are equipped with full gas-®red central-heating supplying

water-®lled `radiators', most of the heat being convected away from them. Theheating controls employed are simple mechanical time-switches; zoned areas havingindividual thermostats. Unfortunately the latter are poorly sited. Commendably, noelectrical space-heating is employed.Separate gas-®red heaters for combined heating and storage of domestic hot-water

are in continual operation, with simple manual switches: the temperatures are regu-lated by thermostats ®tted to the burner valves, which permit settings ranging from41 to 66�C. The appropriate pipes are lagged, in order to reduce `wild' heat-losses.Convector radiators are mounted both in the open and enclosed behind the seating.

The latter method cuts down considerably on the e�ectiveness of the radiator. Theradiative component of heat emission, around 30% of the total heat output, is lost


completely into the seat enclosure and the wall; as a result, the room fabric cannotbene®t directly from radiated heat. The remaining �70% of heat output is by con-vection, which is also inhibited as no inlet grilles are provided beneath the seats, andthe gaps in the upper outlet-grilles are too small.

Fig. 1. Energy supplies and losses for the pub.


1.2. Ventilation to the ambient environment

This is required in order to extract smoke and odours arising from food, as well asto introduce su�cient fresh air from the ambient environment. Outside air contains�0.035% CO2, which is therefore the least concentration which can be feasiblyachieved, whilst 0.1% is acceptable for an occupied space; the increase being due tohuman respiration. In addition, for rooms containing fuel-burning appliances, anadditional fresh-air supply is necessary (and required by the Building Regulations)to replace the oxygen used for combustion.Ventilation is normally achieved by mechanical means for expelling the stale air.

Typical licensing authority requirements for air-changes per hour are rates of 10 to12 for public rooms, 14 to 16 for toilets and 18 to 22 for kitchens: CIBSE recom-mends a supply of fresh outdoor air of 16 litres/s per sedentary person wheresmoking is permitted [3]. As the quantity of food served in pubs is increasing, evenhigher ventilation rates are likely to be required in the future.Much heat is lost to the ambient environment during winter by the ventilation of

warm high-humidity air naturally and forcibly leaving the building; this lost heatmust then be replaced by the central-heating system. Also, in summer, solar-heatedair is brought into the building, so requiring arti®cial cooling and hence energyexpenditure for this purpose.Extractor fans, with manual dual-speed controls, were ®tted to the public-bar

rooms of both monitored pubs, and were used continuously during opening hours.The expelled air is replaced by air from outside the buildings: it in®ltrates throughcracks and gaps or via open doors and windows, or comes unfortunately from otherparts of the building, such as the kitchen or toilets. In one of the considered pubs,the entire building could become so depressurized, that when an external door wasopened, a sudden rush of outside air would enter the building. No attempt was madein either pub to provide lower rates of ventilation in non-smoking areas.

1.2.1. Kitchen and refrigerationThe amounts of energy used in the storage and preparation of food are con-

siderable. For a pub restaurant with an extensive menu, the overall cost of energyper meal (including refrigeration, cooking, dishwashing, and heating and venti-lating the space in which it is cooked and eaten) may amount to 10 to 15 kWh,costing around 50p [2]. Using an estimate of the number of meals provided, theenergy involved in catering may be as much as 50% of the total energy usage inthe building.It is widely recognised that kitchens should be heated by purpose-suited space-

heating means, rather than by their cooking appliances, as any item of equipmentused for an unintended purpose is unlikely to be energy e�ective. Neither of thekitchens considered was equipped with space heaters, but, as things are, these arenot necessary. Both kitchens are e�ectively kept warm overnight by the waste heatfrom refrigerators under worktops, and cooled mechanically by extractor hoods.Bulk refrigeration is located nearby. All free-standing refrigeration equipment issubject to high local-air temperatures, so leading to frequent safety cut-outs of the


hot compressors. Sta� arrive mid-morning to begin preparations for lunch, so longhours of unnecessary use of other cooking equipment are avoided.Dishwashers and washing machines are connected to hot and cold water supplies,

with the dishwasher supplies connected via water softeners. Both pubs also useconventional domestic electric tumble-driers, with the exhaust vented to the ambientenvironment without any attempt to achieve heat recovery.The bar chillers are left on continuously, and are restocked at the end of the

evening, and after lunch if necessary. These are of the self-contained type, withcondensers at the rear, often encased within the bar with little room for air to cir-culate, so leading to a raised-temperature immediate environment, and henceincreased rate of energy dissipation.

1.2.2. CellarBreweries publish guidance notes for the designs of pub cellars and temperature-

control installations. These suggest that a cellar temperature of 11.1�C be maintained,for an ambient temperature of 32�C, with the building fabric U-values, air changerates, and beer throughputs all speci®ed: to achieve this, the equipment may berequired to run for no more than 16 h per 24 h day. This allows for some `emergency'capacity, and cuts down on compressor running hours and energy use. Energy thrift isaddressed via the insulation requirements, given for ceilings, roofs, walls, and accessdoors: inadequate insulation will cause prolonged plant-running. A heatermay also bespeci®ed in the cellar for winter use, although neither pub in this study has one; giventhe proximity of heated rooms, this would probably be unnecessary for most pubs.It is possible to reduce the rate of energy consumption of the cellar chiller by the

more careful use of the room. This involves minimising several factors: e.g. (i) thenumber of cellar-door openings per day and the duration for which it is left openeach time, (ii) the amount of unchilled stock loaded into the cellar at any one time,and (iii) the ease with which stock can lose its chill when exposed to warmer airwhen the cellar door is open.The cellar's temperature control speci®cation gives data for the average number n

of air-changes per day for storage rooms at above 0�C. The actual ®gure for anyparticular room of volume Vm3 will depend on the frequency and duration of dooropening as well as the e�ectiveness of the shut cellar-door's draughtproo®ng. The®gure permits the rate of heat losses _Q kWh per day through the escape of chilled airto be calculated, and this will assist with the determination of the chiller capacityrequired. The equation usually used is:

_Q � ��cnV� 24

3600

� �TC ÿ TA

1000� 8nV�TC ÿ TN�

1000

��where � = density of air = 1.2 kg/m3, c = speci®c heat of air &1000 J/kgK, TC =temperature of lost chilled air, and TA = temperature of incoming ambient air. Thevolume is calculated from the room dimensions and does not account for parts ofthat space which are occupied. The calculated ®gure should therefore be used onlyas a guide. It does not account for the heat entering the chilled space via the walls,


¯oor and ceiling, or via the replenishment of stock (e.g. beer barrels). It is alsolikely that an equivalent amount of energy is used by other services outside thecellar, such as post-mix and line coolers.

1.2.3. Electrical-load managementElectricity supply companies seek to reduce peak demands through imposing

smaller preferential-time tari�s during national low-demand periods. These presentsigni®cant opportunities for both considered premises for ®nancial savings by usingelectricity at night rather than during the day. Penalties are also imposed for peakuse, either by charging for the highest peak reached during the month, or by raisingthe tari� considerably during certain periods. Neither pub attempted to manage itsdemand optimally to achieve the lowest overall tari�Ðeven though the refrigerators wererun throughout the night. Dishwashers, clothes-washing machines and driers could alsobe used then. However, daytime peaks are hard to avoid when the main consideration iscustomer service. Minor tasks such as the laundry tend to be carried out during themorning and there is resistance to change with respect to cooking and dishwashinghabits: this tends to frustrate conscious attempts to spread demand to avoid peaks.The easier way to reduce high electrical-demand peaks will be to use equipment

with higher energy-e�ciencies, but this will incur greater capital expenditures.

1.3. Lighting

Previous studies [2] have found that �25% of a pub's electricity is used for light-ing. The lighting provision in the public areas of a pub should be designed to con-tribute to the welcoming ambience, and as such, its aesthetics are regarded as moreimportant than how e�cient it is (i.e. in terms of light output in lumens per watt).The `colour' of the light emitted is a vital feature in the eyes of interior designers.This has often prevented the use of sources other than the conventional tungstenlight-bulb. Interior designers tend to mix a variety of light sources to provideattractive localised lighting (e.g. in alcoves).To date, the use of ¯uorescent lighting, with its long, unshaded tubes with their cold,

harsh glare, in the trading areas has been unpopular. Nevertheless, during the last decade,there have been dramatic improvements with the development of tri-phosphor coatingswith high-quality colour rendering, high-frequency (�40kHz) operation, and miniatur-isation of the tube into a variety of compact shapes. The new lamps should usually be anacceptable replacement for standard light-bulbs, using �80% less energy for the samelight output and giving a lifetime of at least 10,000h (i.e. many times that of a tungstenlight bulb), but with some restrictions, such as their inability to be dimmed. This is onlypossible for lamps with a separate electronic ballast, which is preferable in any case, as ito�ers even larger energy-savings, longer life, and no lamp ¯icker. Ballasts built into thelight ®ttings reduce costs further, as only the actual lamp is replaced at the end of its life,unlike self-contained, internal-ballast types, which are replaced entirely. Theft would alsobe discouraged by the non-standard lamp cap of the `separate ballast' type.The use of compact ¯uorescent lamps (CFLs) is becoming more popular in many

commercial establishments where localised `point' lighting is required, even in public


houses, but not in the two assessed in this investigation. CFLs are relegated to amenitylighting in toilets, sta� areas, and outside sign lighting, with the trading areas lit entirelywith tungsten lamps, in use all day under manual control, from 9am to 11.30 pm, aslittle daylight comes into many public houses. Tungsten lamps emit 96% of their ratedpower as waste heat. This adds considerably to the heat load in summer, and must bedispersed. In winter, admittedly it provides some space-heating to the upper air strata,but this could be achieved more e�ectively, and at lower cost, by the central-heatingsystem.Some interior designers still claim that the colour of CFLs is unacceptable. How-

ever, when used within a shade, or as indirect light re¯ected o� another surface, thedi�erence from tungsten lighting is relatively small. Tinted varieties are now available:these have apparently been tried and rejected by some interior designers, even whenused in conjunction with gel ®lters. Sylvania `Mini-Lynx' CFLs, available in apricotand rose colours aimed at the home and `displaced residential' markets, such as pubsand restaurants, have been tested in the two assessed pubs. The apricot version, to theauthors' eyes, closely resembled the colour of light emitted from a ®lament lamp.Mixtures of standard and compact ¯uorescent lighting have proved to be accep-

table in the kitchen and other non-public areas of both pubs.

1.4. Monitoring

Electricity consumption was monitored continuously, using a Sension Hawk data-logger attached to the 3-phase electricity supply to each of the considered premises.This device uses a current clamp, which senses the current in a single cable without theneed to break into the circuit. When one is attached to each mains phase, the totalpower consumption can be measured. By averaging the demand over each half-hourperiod and then multiplying this by 0.5, the total energy consumed in kWh, during thehalf-hour, can be determined. Knowledge of what equipment is connected to eachphase can make it easier to identify the loads corresponding to each demand.The monitored data reveal a systematic pattern of electrical usage. Electricity is

employed to power mainly non-seasonal loads, such as produced by refrigeration,cooking and lighting. Although the refrigeration load is higher in summer, thethermal problems outlined earlier cause the demand in winter to remain above whatmight be expected. Most lighting is in continual daily use, so no signi®cant load-reduction is achieved during the summer.The temperatures in various zones of each pub were monitored once per hour by

a battery-powered Squirrel datalogger, installed above the bar service-area. Eachdatalogger has several channels connected to remote sensors, which were mountedin truly representative locations of the pub, whilst keeping the associated obtrusivewiring to an absolute minimum. Each datalogger was also provided with a localsensor. The outside ambient-environment temperature was also monitored.

1.4.1. Data analysisThe data from the continuous monitoring are loaded into spreadsheets to facil-

itate the analysis. The pattern of electrical demand was compared with the prevail-


ing electricity-supply tari� and with the ¯uctuations of inside and outside tempera-tures, and especially with their di�erence.Various performance-rating indices have been suggested for comparing the energy

performances of public houses [4]. These are now listed here, and will be quanti®edfor each pub over all the years for which data are available:

. Energy-cost index: i.e. the fuel cost per m2 of treated ¯oor area per k£ of®nancial turnover. Less than 7.5p/m2/k£ is deemed good; more than 17p/m2/k£is regarded as poor.

. Energy cost as a percentage of turnover: this ®gure-of-merit is of most interestto the ®nancial managers and directors of breweries.

. Energy consumption index: energy used per m2 of treated ¯oor area per k£ of®nancial turnover. Less than 2.3 kWh/m2/k£ is deemed good; more than5.3 kWh/m2/k£ is regarded as poor.

Using spreadsheets, the half-hourly electricity data were multiplied by the tari�rate and summed with the standing charge to give the total bill. This was doneseparately for each pub, noting that di�erent tari�s applied. The total electricity-usage per day was determined. Also calculated was the proportion of the daily usagewhich falls into each tari� period, on a daily basis for the overnight load (which islikely to be similar for each day of the week), but also identi®ed by weekday fordaytime tari�-periods, where usage is found to vary according to the day of theweek. An average ®gure is determined for each month.The hourly temperature-readings from both pubs were entered into a spreadsheet, and

their maximum, minimum and average values calculated. The number of degree-dayswere deduced by subtracting the outside temperature readings from a base temperatureof 15.5�C, and summing all positive results (so that, when the outside temperature rises to15.5�C or above, a zero is recorded). As readings were taken hourly, the sum was thendivided by 24 to give the number of degree-days for the considered day.

1.4.2. Site visitsBoth pubs were visited on a monthly basis, in order to download the measured

data, and to experience the atmosphere in the building ®rst-hand at di�erent timesof year. Although most visits were made before opening time, a couple of longerstays occurred at each pub, in order to (i) investigate the energy usage in the kitchensand other areas, (ii) inspect the cellar and refrigeration equipment, and (iii) samplethe food and beer o�ered for sale.

2. The assessed modern-pub

2.1. Description of the premises (see Table 1)

This pub-restaurant was opened in January 1996. Inside, the public bar and foodservery cater for the restaurant, which could seat 180 people simultaneously. At oneend of the building is a children's play-room, and the outside is mainly allocated forcar parking, although there is a modest paved area with tables. Sta� ¯ats are located


upstairs, i.e. on the ®rst ¯oor. The sales are presently around k£16 per week, ofwhich approximately k£10 is for the �1800 meals served, and k£6 is for liquor. Thepub has been criticised by the brewery for its high fuel bills.

2.2. Construction

The premises are of brick-cavity-block construction, and built to satisfy modernstandards. A pitched tiled-roof contains the ¯ues for various gas-burning appliances.The windows are wooden framed (i.e. of heavy, 50mm square timbers) with 9mmsealed-unit double-glazed panels; every top panel is an opening fanlight. The win-dows rise from just 0.3m above the ¯oor to the low ceiling.

2.3. Supply tari�s

Electricity supplier: Eastern Electricity [5]�`Seasonal Time-Of-Day, Low Voltage' tari�. Standing charge per month is £18.85�Availability charge 55p per kVA up to a chargeable supply

capacity of 110 kVA�Night rate (00.30±07.30 h) 2.45p/kWh�Day rates (07.30±16.00 h) 7.18p/kWh (November, February)

(19.00±20.00 h) 7.22p/kWh (December, January)�Day rates (16.00±19.00 h) 16.5p/kWh (November, February)

26.2p/kWh (December, January)�Day rates (other times) 5.99p/kWh�A reactive-power charge: unlikely to apply as the power factor for the electricityused at the premises is around 0.9�VAT at 17.5%Natural-gas supplier: Mobil�0.7469p/kWh + VAT, all inclusive (no standing charges).

2.4. Central-heating and hot water

Three gas-®red boilers are ®tted (see Table 2). Two are in the outside plant-room:an Andrews natural-gas water storage heater (i.e. combined boiler and storage tank)

Table 1

The modern pub: ¯oor area (m2)

Trading areas (including toilets, etc.) 393

Sta� areas 80

Kitchen 62

Freezers 19

Cellar 18

Bottle store and plant room 29

First ¯oor ¯at 140

Total 741


for the hot-water supply (for the pub and sta� ¯at), and an Ideal Concord CX (aPotterton King®sher 180) for the ground-¯oor central-heating system. A smallerPotterton King®sher CF100 supplies the central-heating `radiators' in the upstairs¯at. None of these boilers is of the condensing type. All pipes are thermally insulatedwith foam sleeves, and the surface of the water-storage heater is cool to the touch.The louvred plant-room door forms a ventilation panel, facilitating the entry ofcombustion air from the outside ambient environment: the room is therefore likelyto remain only a few degrees above the ambient temperature.The central-heating water is circulated by a three-speed pump (rated at 140W), set

to its top speed. Heating in the public areas is provided by radiators of various sizes,some of which are mounted in the open and painted to achieve a `wood' appearance.Others are unfortunately encased behind ®xed seating around the outside walls, butwith convector grilles in the shelving above intended to encourage warm air to cir-culate. No corresponding air inlets are provided beneath the radiators, and theupper grilles are inadequate to facilitate convection. None is equipped with a local-control device, such as a thermostatic valve. Many areas are heated poorly or not atall, such as the non-smoking dining area, where the raised ¯oor leaves no room forradiators beneath the windows. (A new speci®cation stipulates that 50mm ®nnedtube heating coils are to be mounted there behind the seating.)One timeswitch, in the plant room, controls the entire ground-¯oor heating sys-

tem. It is set to switch on at 7 a.m. and o� at 9.15 p.m.; in winter, the manageradvances the switch-on time to 6 a.m. (A new speci®cation indicates that a controlpanel and sensors for each of four heating zones are to be installed.)There are two thermostats in the bar. One is inappropriately sited in a corner

behind the bar, just above a shelf, and hidden behind display material. The need to

Table 2

The modern pub: gas appliances in use

Appliance type Consumption or rating Location No. o� Hours of use

Andrews natural gas

water storage heater

(286 litre capacity)

Input 22.0 kW

Output 16.6 kW

�=75%

Plant room 1 24

or Potterton King®sher

2 CF180

Input 72.3 kW

Output 52.8 kW

�=73%

Plant room 1 ±

Potterton King®sher

2 CF100 central-heating

boiler (¯at CH)

Input 31±38 kW

Output 23±29kW

�=75%

Flat 1 ±

Gas Jotel no. 3 Input 7.8 kW

Output 5.45 kW

�=70%

Dining area 1 Winter, as

required

Spanish traditional ®re basket Input 13.9 kW

Output 2.8 kW

�=20%

Dining area,

bar

2 Winter, as

required

Cooker (four hobs, oven) Kitchen 1 Daily

Deep fat fryers ± Kitchen 2 Daily


prevent tampering by curious customers can be appreciated, but the use of thislocation defeats the purpose of obtaining truly representative signals concerning thetemperatures experienced by the customers. The location of this thermostat makes itinsensitive to ¯uctuations in room temperature, which in winter varies wildlydepending on whether sunshine is entering the building. The other thermostat islocated on the wall, by an alcove, opposite the food servery.In the public bar are a gas-®red coal-e�ect stove with a fan-assisted ¯ue, and two

gas-®red Spanish traditional ®re baskets: their speed-controlled fan-assisted ¯ues areexcessive consumers of electrical power. These ®res are not merely decorative: theyare deemed desirable to keep the public bars `topped-up' in winter (especially at theeastern end). However, they are not intended to provide a major contribution to theheating, and are far less e�cient than the central-heating installation. Much of the heatthey provide goes up the ¯ue, and relatively little radiant heat is emitted into the room.The stove is sited beneath an air-conditioning ceiling `cassette', although the two wouldnever be used simultaneously: the stove is reasonably e�cient as a radiator of heat,and is ®tted with a matt black ¯ue, which will emit further heat captured from thedeparting ¯ue gases. The ®re baskets, on the other hand, have a rated e�ciency ofjust 20%, but the actual ®gure is higher, as they are used beneath canopies whichcan also act as heat exchangers. The ®re basket at the eastern end of the public bar islocated against the wall of the chilled cellar. These gas-burning appliances require anair supply, which is taken from the room, thereby increasing the air in®ltrationrequired via the ventilation system, although a forced supply of air is not provided.The performance of the central-heating system in the sta� ¯at, from a dedicated

boiler in the ¯at, is said to be satisfactory. The energy consumption in the ¯at issmall (�5% of that of the main pub). A domestic programmer controls the heatingof this sta� ¯at.The pub's hot-water system has a storage capacity of 286 litres. But, by 11 a.m.,

the reserve of hot water has often been used, and a further supply may take 2 h tobecome available. Prior to this investigation, the water was too hot at the point ofdelivery: now a delivery temperature of approximately 52�C has been selected. Thisnevertheless may be inadequate for washing-up purposes, and will require top-upheating in the electrically-powered dishwasher. Furthermore, the hot water shouldbe stored at above 55�C to avoid the risk of legionnaires' disease. A recirculationloop keeps the water hot at the taps; its 80W pump runs continuously, although amanual switch is ®tted. (The new speci®cation requires a 24 h timeswitch to controlthis pump). The spur to the hot tap in the gents' toilets, for example, takes just 15 sto run hot when ®rst used. Pipe insulation is speci®ed throughout the pub, to reduceheat losses.

2.5. Ventilation

The public areas are provided with extract fans, six in the walls of the public barsfor smoke control, and two in the children's play room. Those in the public barshave individual speed controls, and are used continuously at full speed duringopening hours: four had already burnt out and been replaced by the time (1997) of


the present assessment. The raised dining area is designated a no-smoking zone, but,as it is open-plan, it su�ers smoke incursion from other areas, and is ventilated atthe same rate as the rest of the pub. These extract units cause a considerable noisedisturbance, which is particularly noticeable when the pub is otherwise quiet.The risk of drawing exhaust gases from the three gas-burning ®res into the room is

avoided as fan-assisted ¯ues are ®tted to these ®res. However, the need for an extrasupply of combustion air must be addressed.Severe draught problems are associated with the main entries: the porch has inner

and outer double swing-doors; the inner ones usually being left open so that sta�can keep an eye on customers in the porch for security reasons. High winds can blowopen the outer door, and slam it against the wall. Its frequent use leads to draughtproblems, and so the dining tables near the doors tend to be unpopular.Summer natural ventilation is inadequate, because the fanlight windows are too

small, and there is no `through' draught between the main doors. The extractor fansand air conditioning are unable to prevent the atmosphere from becoming `stu�y'.Excessively high-temperature environments are experienced by those occupying thesunny window seats.The toilets are ®tted with small extractor fans, which unfortunately run con-

tinuously during opening hours, rather than intermittently as and when required.

2.6. Air conditioning

The air-conditioning system consists of Daikin ceiling-cassettes in the bar areas.These provide extract-air temperature information to the central-heating controller,thereby preventing one system from working against the other, and eliminatingthe need for thermostats; but this link had not been made. The condenser unitsare in the rear yard, at ¯oor level. The air-conditioning system is controlledmanually by the manager, and used only in summer when the heating system isswitched o�.

2.7. Kitchen and refrigeration equipment

The kitchen is kept warm by wild heat from its refrigerators. No windows orfresh-air ventilation are provided. In cold weather, sta� keep warm by turning onthe deep-fat fryers to prepare the sta� meal, which is served at 11.30 a.m.; this wouldbe done in any case, so there is no unnecessary use of cooking equipment for pro-viding space heating.A gas cooker, comprising a four-ring hob and an oven, is in continual use. The

deep-fat fryers are also natural-gas powered. Electrical equipment (see Table 3)includes a steamer, a combination microwave oven, at least three small microwaveovens, a Bain-Marie hot-cupboard, a toaster, an ultra-violet ¯y-killer and the dish-washer, whose supply-water softener was once damaged by excessively hot water,and had to be replaced. Some refrigerators and freezers are in the kitchen to storefood for immediate use: one refrigerator is an upright type, with all the other unitshoused beneath worktops.


The kitchen is ventilated by an extractor hood above the cooking range, with amulti-speed manual control. The exhaust air is ducted to a cowl on the ¯at roof. Theextract grease-®lter is cleaned weekly on Mondays to try to ensure that the unitremains e�ective. When cooking, the kitchen soon becomes too hot for sta� tofunction e�ectivelyÐit can reach 40�C. However, it is also very noisy, and so theextractor is used at a low-speed setting, otherwise orders go unheard! The rateof waste heat being ejected from the refrigerators is so high that the extractor isleft running overnight at this slow speed, otherwise the kitchen temperature willbe too uncomfortable the following morning. A further problem is that the refrig-erator motors cut out for their own protection when their temperatures rise sig-ni®cantly, and so refrigeration is interrupted. Thus considerable challenges need tobe addressed.

Table 3

The modern pub: electrical appliances in use

Appliance type Location Number Hours of use

Lighting (see Table 4) ± ±

Microwaves Kitchen 3 ±

Combi oven Kitchen 1 ±

Steamer Kitchen 1 ±

Toaster Kitchen 1 ±

Fly killer Kitchen 1 24

Hot-water urns Kitchen ± ±

Bain-Marie Kitchen 1 9

Refrigerators Kitchen Many 24

Freezers Kitchen 1 24

Extractor hood Kitchen 1 24 (setting varies)

Walk-in refrigerator Rear corridor 1 24

Walk-in freezer Rear corridor 2 24

Co�ee makers Bar, children's play room 3 ±

Dishwashers Kitchen 1 ±

Tills Bar, children's play room 3 15

Sound system Public bars ± 12

Games equipment Public bars 4 15

Heating pumps Plant ± When heating on

Flue fans Roof 3 When gas ®res on

Extractor fans Public bars 6 15

Air conditioning Public bars 3 cass When needed

Bar chillers Public bars 5 24

Cellar chiller Cellar 1 24

Beer delivery chiller Bottle store 1 24

Post mix chiller Bottle store 1 24

Hand dryers Toilets 5 ±

Computer O�ce 1 ±

Washing machine Laundry 1 ±

Tumble drier Laundry 1 ±

Ice-slush machine Children's play room 1 ±

Ice maker ± ± ±


Outside the kitchen are a larger walk-in refrigerator and two walk-in freezers.These have sealed, insulated doors and insulated walls. Their condensers are wiselylocated on the outside surface of the north-facing wall.In the laundry, the washing machine uses the hot-water supply when a 60 or a

95�C wash is selected, but the cold ®ll alone for 20 or 40�C programmes. The un-insulated hot spur-pipe is unfortunately too close to the cold pipe, on an outsidewall, and so the water does not run signi®cantly hot in time for a single machine ®ll.The machine then has to heat the water internally by electricity.

2.8. Cellar

The `cellar' is on the north-east corner of the ground ¯oor (as opposed to theusual subterranean arrangement), with the corner of the roof void immediatelyabove. No extra thermal insulation from the outside is provided in addition to thestandard insulated block-cavity-brick wall. Through a supporting wall to the southis the public bar, with its gas basket-®re, which is in frequent use during coldweather. There is no extra thermal insulation of this wall. Through a single blockwall to the west is the bottle store. Double draughtproofed swing-doors are pro-vided, and are normally kept locked; only being left open during restocking. Theapproximately cubic cellar is of normal full ceiling height and is cooled by a dedi-cated chiller unit, mounted near the ceiling. The evaporator is ®xed on the insidesurface of the outside wall. A washbasin in one corner is fed by a short spur run ofnon-insulated hot pipe. The beer barrels are not ®tted with insulating jackets.The approximately 45m3 cellar undergoes �14 air changes per 24 h day. The

temperature di�erence between the chilled air (at 11�C) and outside air (at 21�C, inthe warm bottle store) corresponds to an average loss of 50 kWh/day or18,250 kWh/year via this air change.The cellar is used to pre-cool bottles before they are transferred to the bar chillers.

The adjacent bottle-store is used to keep spirits. Here are located separate chillersfor beer and post-mix line delivery, and the gas pressurization units. The bottle storebecomes warm due to the reject heat from the chillers (as there is no external venti-lation). The cellar cooling has to operate against this unnecessary heat source allyear round, with added ambient heat during summer.Fresh bar-stock is brought from the cellar, so it does not need to be cooled so

much by the bar chillers, which are self-contained units mounted under shelving,with little room for air to circulate around their condensers.

2.9. Children's play room

This adjunct, to the western end of the main building, has large double-glazedwindows facing south, west and north. It has a problem with temperature extremes.It is very cold in winter, but, in summer, the room behaves like a greenhouse andbecomes very hot.Heating is achieved by two fan-assisted radiators mounted high on the connecting

wall to the entrance foyer: these are fed via a pumped circuit from the main boiler.


The fans are controlled by two thermostats located behind the servery, in a recessbetween a deep partition and a chiller cabinet. These thermostats are covered withdust, and are warmed by the chiller's condenser; in practice, both are e�ectivelyover-ridden, by being set to maximum in winter and minimum in summer. Thissuggests that they are regarded as useless. Presumably in winter either the heatingsystem works ¯at-out, or the warmed thermostats prevent it from functioning atall. Either way, the control system is ine�ective. The heaters also have manualwall-switches to prevent them from running in summer, or when the room is not inuse.The room contains a climbing frame, to ceiling height. Even if the heating is

switched on at 6 a.m. in winter, at ground level it is too cold for comfort: parentsoften wear coats whilst supervising their children, or leave the doors open to thewell-heated lobby. Simultaneously, the air temperature near the top of the climbingframe is excessively high, i.e. it is again uncomfortable. In summer, despite the fully-operational extractor fans at ceiling height on all outside walls, the windows need tobe open; even so, the temperatures within the room are so high that parents havebeen known to refuse to allow their children to remain there. Thus trade is beinga�ected adversely by the frequent discomfort experienced in this room.

2.10. Lighting

A few compact ¯uorescent lamps (CFLs) are used, but the basic scheme relies ontungsten lamps and linear `white' ¯uorescent tubes (see Table 4). In the publicbars, 40 and 60W tungsten lamps are used in ceiling and wall-mounted brassbrackets with glass or fabric shades, and tungsten re¯ector lamps are recessed intothe ceiling. Lighting throughout the public-bar areas is dimmable (to four presetlevels), but this facility is rarely used (e.g. only on New-Year's Eve, when candlesare lit). The bar is illuminated by low-voltage 20 or 50W halogen dichroic re¯ectorlamps.The children's play-room, kitchen, corridors, bottle store, and cellar use white

¯uorescent lamps, and the back-yard and toilets use 16W 2D CFLs, with tungstenre¯ector lamps above the washstands.Outside, there are 70W high-pressure sodium ¯oodlamps, at ground level and on

posts. Signs are lit by 20W CFLs in open `scoop' brass luminaires. One lamp, by themain door, had already gone missing, and another had been replaced with a tung-sten re¯ector lamp. The road sign uses 20W CFLs and 30W ¯uorescent lamps.Outside lighting is on a standard mechanical timeswitch, and presently set to

operate from 6.30 p.m. to midnight. This is wasteful in summer, as dusk falls muchlater, but also presumably inadequate in winter, for which the timeswitch wouldneed to be reprogrammed. The electrical speci®cation mentions a `solar dial' time-switch, of the type that adjusts with the season, set up according to the client'swishes. This has not as yet been ®tted.There is scope for conversion to compact ¯uorescent lighting, mainly of the ceiling

and wall lights in the bars, which all use tungsten lamps at present. However, thedimming circuitry would then require modi®cation.


Table 4

The modern pub: lighting installation

Lamp type Location Existing lamps installed

Rating

(W)

Light

output

(lumens)

No. Rating

total (W)

Output

total

(lumens)

Usage

(h/day)

Consumption

(kWh/day)

Tungsten Public bars, bulkheads 60 700 10 600 7000 15 9.0

Public bars, fabric shades 60 700 36 2160 25,200 15 32.4

Public bars, glass shades 60 700 53 3180 37,100 15 47.7

Tungsten striplight Pictures 60 600 7 420 4200 15 6.3

Tungsten spot Public bars, downlighters 40 400 45 1800 18,000 15 27.0

Toilets 40 400 6 240 2400 15 3.6

Halogen low voltage Over and behind bar 20 300 40 800 12,000 15 12.0

Fluorescent 30W Road signs 40 2200 4 160 8800 5 0.8

Fluorescent 36W Back corridors, plant room 46 2800 5 230 14,000 15 3.5

Fluorescent 58W Wall signs 70 4500 4 280 18,000 15 4.2

Laundry 70 4500 1 70 4500 15 1.1

Fluorescent 70W Kitchen 85 6000 6 510 36,000 15 7.7

Back corridors 85 6000 3 255 18,000 15 3.8

Cellar and bottle store 85 6000 5 425 30,000 15 6.4

Fun factory 85 6000 24 2040 144,000 12 24.5

CFL ``2D'' 16W Toilets, back corridors 21 1050 15 315 15,750 15 4.7

Rear delivery access 21 1050 6 126 6300 5 0.6

CFL 20W Outside signs 20 1200 14 280 16,800 5 1.4

Road sign 20 1200 2 40 2400 5 0.2

HP Sodium 70W Outside on posts 85 6000 22 1870 132,000 5 9.4

Outside on ground 85 6000 7 595 42,000 5 3.0

Sta� ¯ats: unknown

Total 315 16,396 594,450 209.1

of which, tungsten lamps: 138.0

Installation load density (excluding sta� ¯at) (W/m2) 27.3

Overall installation e�ciency (lumens/W) 36.3

Lamp type Location Tungsten retro®t using energy e�cient lamps

Rating

(W)

Light

output

(lumens)

No Rating

total (W)

Output

total

(lumens)

Usage

(h/day)

Consumption

(kWh/day)

Tinted CFL Public bars, bulkheads 15 640 10 150 6400 15 2.3

Tinted CFL Public bars, fabric shades 15 640 36 540 23,040 15 8.1

Tinted CFL Public bars, glass shades 15 640 53 795 33,920 15 11.9

Tinted CFL Pictures 15 640 7 105 4480 15 1.6

Halogen low voltage Public bars, downlighters 20 300 45 900 13,500 15 13.5

Halogen low voltage Toilets 20 300 6 120 1800 15 1.8

As at present All other locations 7996 500,550 83.1

Total 10,606 583,690 122.3

Installation load density (excluding sta� ¯at) (W/m2) 17.6

E�ciency after upgrade (lumens/W) 55.0


2.11. Electrical load

The only electrical load that can be directly ascertained is for the lighting. This hasa known consumption and period of operation. A ®gure of 209 kWh per day isobtained; 138 kWh of this being due to the tungsten lamps. Lighting accounts for25% of the electricity usage, or 12% of the total purchased energy consumption(including natural gas). This result con¯icts with traditional conclusions, whichsuggest that lighting represents �25% of the total energy usage [4]. Table 4 showsthe possibilities for the retro®tting of CFLs in the existing installation: the installedload-density could then be reduced from 27 to 17W/m2, with electricity consump-tion for lighting falling from 209 to 115 kWh per day.At 9 a.m. daily (and 10 a.m. on Sundays), the electrical load on one phase jumps

from its overnight level to a daytime level, as lights and other equipment are turnedon. The other two phases also rise suddenly, but later in the morning. Around 14%of the daily electricity consumption occurs at the night rate, although this periodcovers 29% of the full 24-hour day. The night-time rate of consumption is used forthe refrigeration, the kitchen extractor fan and the hot-water loop pump. No otherequipment is used intentionally at night (i.e. when the Economy 7 cheaper tari� rateapplies). Neither is its use avoided between 4 and 7 p.m. during winter months; thesta� being unaware that this is a premium period, and as trade is then busy, usage isunavoidable. At other times of day, the situation is reversed, with larger proportionsof the day's electricity consumption occurring during periods when the tari� ishigher: for example, in winter, 17% of the load falls during the afternoon premiumperiod, which represents just 13% of the 24 h.The monthly rate of electricity consumption varies somewhat throughout the year

(see Table 5 and Fig. 2). What little variation occurs is more by weekday than byseason. This suggests that electrical loads are relatively independent of the outsideambient temperature. The refrigeration load in fact is more in¯uenced by the inter-nal temperatures within the building, which are dictated by the rate of output fromthe gas-powered central-heating system in winter. The consumption lies in the range646 to 1031 kWh per day, but is typically �830 kWh per day; being relatively low onMondays and Tuesdays, and largest at the weekends. Clearly, there is a directlink between electricity use and trade levels in the pub. The early May bank-holidayweekend, immediately following the 1997 general election, saw the highestconsumption. Those for January and February were slightly lower overall thanfor the other months. Table 6 shows the full data for two individual days, repre-senting those with the highest and lowest consumptions during the monitoredperiod.The availability charge is set at 110 kVA for this pub by the electricity supplier, and

this charge would be raised for any individual month, if demand therein inter-mittently exceeds this load. This setting however is too high for the considered pub, asthe maximum demand noted during this survey was 73 kW, occurring at a time oftypically high demand (i.e. 9.30 p.m. on Sunday 4 May 1997). Renegotiating thesupply capacity to become 75 kVA, and paying the extra charge if this level was everexceeded, would save �£271 per year. It is also possible that the tari� could be


Table

5

Themodernpub:dailyelectricityuse

andcost

Decem

ber

January

February

March

April

May

June

July

August

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Tuesday

±±

±±

±±

±±

795.5

39.96

±±

±±

878.5

44.60

±±

Wednesday

±±

907.0

87.57

±±

±±

829.0

41.14

±±

±±

858.5

43.10

±±

Thursday

±±

772.5

72.90

±±

±±

801.5

40.02

897.0

44.87

±±

847.5

42.69

±±

Friday

±±

782,5

77.81

±±

±±

814.5

41.20

1011.0

51.18

±±

890.0

45.17

975.5

49.45

Saturday

±±

622.0

41.82

885.0

45.17

901.5

45.92

874.5

43.68

957.0

48.22

±±

937.5

47.50

936.5

47.11

Sunday

±±

800.5

40.72

882.5

44.88

937.5

47.28

917.5

45.58

1031.5

51.30

914.5

46.25

1044.0

52.45

1007.5

51.06

Monday

±±

732.5

69.41

738.5

58.04

771.0

39.15

835.5

41.62

941.0

47.19

792.5

39.77

1000.5

50.55

888.0

44.82

Tuesday

±±

719.5

71.14

734.5

56.54

822.5

41.37

798.0

39.73

762.5

38.58

799.5

40.31

999.5

50.52

902.0

45.90

Wednesday

±±

744.5

69.16

742.0

57.27

800.5

40.19

815.5

40.75

809.5

40.63

887.5

44.83

1016.0

51.06

951.5

48.18

Thursday

±±

747.0

71.16

759.0

57.50

763.0

38.54

840.5

41.83

810.0

41.01

882.0

44.56

918.5

46.13

1052.0

53.68

Friday

±±

768.0

73.98

738.5

57.96

814.0

41.74

827.5

42.04

849.0

43.14

954.5

47.95

876.5

43.80

1120.0

57.51

Saturday

±±

888.5

45.40

830.5

42.13

895.0

45.41

856.0

43.74

914.0

45.98

998.5

50.642

1044.0

53.26

1185.0

60.47

Sunday

±±

867.5

44.30

837.0

42.52

995.0

50.54

896.5

45.23

920.0

46.30

996.0

50.29

1093.5

55.47

1148.5

58.38

Monday

760.0

74.64

751.5

58.48

781.5

39.46

810.0

40.74

835.5

42.02

871.5

43.75

970.0

48.80

1073.0

53.94

Tuesday

727.0

68.01

767.5

58.51

786.0

39.68

781.5

39.51

773.0

38.88

976.0

49.20

992.5

50.08

1096.5

55.30

Wednesday

857.5

81.68

752.5

73.37

784.5

60.53

775.0

38.94

787.6

39.99

816.0

41.13

857.5

43.06

878.5

43.78

1017.0

50.99

Thursday

890.0

84.13

742.5

70.45

737.5

56.61

790.0

40.08

790.0

39.57

792.0

39.92

885.5

44.06

927.5

46.54

996.0

50.29

Friday

903.0

86.38

812.6

78.95

816.0

65.10

808.5

40.67

794.0

40.63

846.5

42.32

986.5

50.18

962.0

48.34

1131.0

57.55

Saturday

914.5

46.87

863.5

44.26

891.5

45.22

905.5

45.86

846.5

42.99

942.5

47.88

945

47.726

1043.0

53.13

1146.5

57.86

Sunday

888.0

44.95

889.5

45.41

890.0

45.41

904.5

45.66

872.5

44.48

940.0

47.38

992.0

49.97

1027.0

52.11

1149.0

58.19

Monday

820.5

79.61

646.5

62.10

796.8

62.44

770.5

38.69

770.0

39.12

809.5

40.33

799.5

39.98

874.5

43.60

±±

Tuesday

881.5

84.04

759.0

70.79

770.0

58.49

792.5

39.28

765.5

38.95

853.5

43.02

846.0

42.97

995.0

50.19

±±

Wednesday

729.0

66.97

783.0

70.90

846.0

66.75

819.5

40.81

800.5

40.41

822.0

41.31

827.5

41.61

1023.0

51.90

±±

Thursday

726.0

71.13

803.5

72.80

812.5

62.62

831.0

41.03

819.0

41.12

827.5

41.71

847.5

42.47

1039.5

52.46

±±

Friday

767.5

75.49

809.0

75.25

827.5

63.58

843.4

42.01

820.0

41.48

827.5

41.88

846.5

42.52

1025.5

52.10

±±

Saturday

820.5

41.98

839.0

43.05

869.5

44.21

890.2

44.59

905.5

46.11

878.0

44.81

909.5

46.02

995.0

49.63

±±

Sunday

830.5

42.50

837.5

42.56

873.5

44.44

910.5

45.52

939.5

47.23

935.5

47.80

972.0

49.34

1136.5

57.67

±±

Monday

763.0

71.87

722.5

69.55

761.0

58.12

817.0

40.67

805.0

40.44

965.0

48.81

827.5

41.48

988.5

50.13

±±

Tuesday

831.0

78.72

736.5

71.13

807.5

62.34

810.0

40.42

860.5

42.87

856.0

43.22

835.0

41.78

1056.0

53.26

±±

(continued)


Table5Ð

(continued)

Wednesday

736.5

69.45

771.0

59.36

846.0

41.85

888.0

44.73

829.5

42.08

797.5

39.75

999.5

50.28

±±

Thursday

±±

759.5

71.10

767.5

57.73

846.5

42.19

±±

810.5

41.01

820.0

40.91

987.5

50.32

±±

Friday

±±

775.5

72.29

797.5

61.66

935.0

46.55

±±

902.5

45.83

864.5

43.38

±±

±±

Saturday

±±

±±

±±

903.0

45.59

±±

889.6

44.96

920.0

46.61

±±

±±

Sunday

±±

±±

±±

912.5

40.25

±±

±±

966.5

48.96

±±

±±

Monday

±±

±±

±±

904.5

45.58

±±

±±

836.5

42.10

±±

±±

Total

25,736

2117.58

24,308

2011.44

22,486

1553.59

26,283

1321.52

24,958

1256.8827,055

1364.6826,655

1342.45

30,326

1530.6232,414

1642.42

Average

830.2

68.31

784.1

64.89

803.1

55.49

847.8

42.63

831.9

41.90

872.7

44.02

888.5

44.75

978.2

49.37

1045.6

52.98

Includingstandingcharges:

Total

2581.391

2456.68

1918.71

1646.03

1570.07

1696.74

1670.61

1891.71

2023.08

Average

83.27

79.25

68.53

53.10

52.34

54.73

55.69

61.02

65.26

Standingcharge

£18.85

Reductionofavailabilitycharge

±

Availabilitychargeper

kVA

£0.55

Availability(kVA)

110

Recommended

availability(kVA)

75

Totalextras

£79.35

Annualsaving(£)

271.43

VAT@%

17.5


changed to the Maximum Demand Night & Day, Low-Voltage <75 kVA tari� (asused in the other surveyed pub, i.e. the traditional pub), as demand appears toremain below 75 kVA: but this does not leave much spare capacity for unforeseendemands. Also, this study has not monitored the power factor, but taking a statedvalue of 0.9 on a recent invoice as typical, the demand of 73 kW equates to 81 kVA,in which case the `>75 kVA' version of that tari� would be required.

2.12. Monitoring

The Hawk was installed in December 1996, and the Squirrel in January 1997.Three sensors were used: a chrome-rod thermistor was located in the main south-facing bar, an encapsulated-bead thermistor in the east-facing bar, both suspendedfrom ceiling ornaments, and a third sensor on the Squirrel itself.In addition, a `Thermoscript' mechanical chart-recorder was sited in the children's

play-room on a shelf beneath the two `hidden' thermostats. This may not have beenthe best place for it, as here the air is warmed by the adjacent chiller±condenser. Itwas moved to a higher shelf further from the chiller in May 1997. However, it wasstill a�ected by heat from the chiller, so causing its readings to oscillate on a two-hourcycle as the device switched on and o� during the night, and occasionally giving alarge and sudden `dip' during the day, revealing the room's true ambient tempera-ture in the absence of heat from the chiller-condenser. On hot days, when the chillermay have been running continuously, there is no `dip', so giving a totally misleadingreading. The readings from the Thermoscript chart rolls were transcribed into thetemperature spreadsheet data for analysis.

Fig. 2. The modern pub: daily electricity use.


Table 6

The modern pub: half-hourly electrical consumption data for two extreme days


3. The traditional village pub assessed

3.1. Description of the premises

This pubwas built in the 16th century, with public and saloon bars and a rear family-room extension. The building is mainly a single-storey structure, with two parallelpitched roofs, one above the public bar and cellar, and the other above the saloon bar,with a gully in between. A sta� ¯at is located in the attic rooms above the public bar,with dormer windows let into the roof. The other roof void is not used as a living space.The bar rooms have roaring open-®res, which add to the pub's attractive ambience

during the winter. Outside, the large beer-garden includes children's play facilities.The pub is extremely popular, even at lunchtimes during weekdays. Bar meals areserved, ranging from jacket potatoes to full hot-dinners. The turnover is presentlyaround £6500 per week, of which roughly half is for food and the rest for liquor.Floor areas, taken from the ¯oor plan as given in the 1981 survey, are shown in Table 7.

3.2. Construction

The pub has grown around an original timber-framed core, with solid stone wallsin the public bars. It has two ridged roofs of overlapping terracotta tiles. The pool-table area, family-room and utility-area extensions are of modern block-cavity-brickconstruction, with thermally-insulated ¯at roofs. All windows are single-glazed andtimber-framed with opening fanlights. The upstairs ¯at is in the attic rooms: theoriginal thatched roof has been retained beneath the newer tiled roof, and thus the¯at is well insulated thermally.

3.3. Supply tari�s

Electricity supplier: Eastern Electricity [5]�`Maximum Demand Night & Day, Low Voltage <75 kVA' tari�. Standing chargeper month is £12.25

Table 7

The traditional pub: ¯oor area (m2)

Public bar and entrance porch 59

Saloon bar and corridor 32

Family room 37

Toilets 13

Bar service 11

Kitchen 33

Corridor areas and o�ce 20

Cellar 9

Bottle store, plant room 12

First ¯oor ¯at 73

Total ¯oor area 299


�Availability charge 55p per kVA up to a chargeable supply capacity of 30 kVA�Maximum Demand charge £2.30 for November and February; £6.90

for December and January, per kW maxdemand made in the month

�Night rate (12 to 7 a.m. GMT) 2.45p/kWh�Day rate 5.99p/kWh�VAT at 17.5%Natural-gas supplier: Mobil�0.7469p/kWh + VAT, all inclusive (no standing charges).Wood for the open ®res is purchased at an approximate cost of £90 per monthduring the winter.

3.4. Central-heating and hot water

Since our ®rst study of this pub in 1981, a full gas-®red central-heating system hasbeen installed. The following were ®tted (see Table 8): two boilers in a cupboardwithin the bottle store adjoining the cellar, although not against the partition wall;an Andrews natural-gas water store/heater for the hot-water supply, and a PottertonKing®sher boiler for the central-heating system. Services in the sta� ¯at also rely onthese boilers. Hot and cold pipes within the cupboard are crammed together, andeach is spiral-wrapped with only thin lagging. The water store/heater casing is warmto the touch, but this is hardly surprising, given the con®ned space and inadequateair circulation within the cupboard: small ventilation-grilles are provided for entryof the combustion air. A ¯ue-gas analysis would be required to demonstrate whetherthese are su�cient for complete combustion to ensue.The central-heating system is divided (with ¯ow valves under individual thermo-

stat control) into three zones: (i) the public bar area, (ii) the family room with partof the saloon bar and (iii) the manager's ¯at. Water is circulated by a three-speedpump, set to the top speed (and rated at 115W). Heating is provided by radiators,some of which are mounted in the open; others are encased behind ®xed seatingaround the outside walls, with convector grilles in the shelving above to try toinduce the warm air to circulate. Unfortunately, no corresponding air inlet is pro-vided beneath the radiator, and the upper grilles have a total free area of only

Table 8

The traditional pub: gas appliances in use

Appliance type Consumption or rating Location Number Hours of use

Andrews natural-gas water Input 11.79 kW Bottle store 1 24

storage heater (114 litre capacity) Output 8.79 kW �=75% cupboard

Potterton King®sher central- ± Bottle store 1 24

heating boiler cupboard

Cooker (hob) ± Kitchen 6 ±

Cooker (dual oven) ± Kitchen 1 ±

Cooker (grill) ± Kitchen 1 ±


170 cm2 per radiator. None is equipped with a local-control device, such as a ther-mostatic valve. One radiator has had a fruit machine placed immediately in front ofit, so lowering its e�ectiveness still further.Two timeswitches are provided, one to control the central-heating system in the

public bar and family room, the other to control the heating of the manager's ¯at.Both these are e�ectively disabled, as the timing pegs are positioned to give maximum`on' time (for 22 h per day), and the clocks are not set to the correct time. Therefore,during colder weather, the heating system will maintain the pub at normal opera-tional temperatures virtually around the clock. There is, clearly, no attempt at opti-mised-start control.The thermostat (set at 18�C) for the public bar zone is located in an unobstructed

position on the bar, quite close to an outside door. A thermostat for the family-roomzone could not be found, even after an extended search by the sta�. It is possiblethat it was removed (and the connections shorted together) during a room redec-oration, or it could be that the heating in this zone is now linked to the public-barzone. The radiators in the family room were run even during summer: this wouldexplain why it is the warmest room in the building and often the subject of customercomplaints. Some radiators in the public bar were found to be warm during thesummer, others simultaneously were cold (including the pool-table area radiator,which was turned o� at its valve: this might explain why this area is cold in winter).However, during the August 1997 visit (in very hot weather), all the radiators wereo�. This suggests that the family room zone is no longer properly controlled. No oneat the pub could say for certain how the heating there is controlled. The only meansof turning it o�, namely via the timeswitch and thermostat, is either not functioningor absent. Overall, therefore, control of the ground-¯oor heating is inadequate, soleading to the wasteful running of the heating system in warm weather and at night,and resulting in signi®cant di�erences in temperature between the opposite ends ofthe public areas.Three open ®res have been restored to full use (having previously housed gas

®res), and are used daily to burn wood logs from November to March. Nevertheless,the northern extension to the public bar (now a pool-and-darts area) tends to becold, and the manager occasionally has to use electric fan-heaters there in winter. Anopen radiator is ®tted, but there are several single-glazed windows; the large chim-ney breast of the original outside wall inhibits the ¯ow of heat from the main bar.The remainder of the public bar is thermally comfortable, with the family roombeing the warmest, as it bene®ts from south-facing windows and is better insulatedthan the rest of the building.The upstairs ¯at is now said to be reasonably warm during winter, but can be

unbearably hot on sunny summer days.The hot-water system has a storage capacity of 114 litres. A delivery water-tem-

perature of 57�C is selected. There does not appear to be a pumped loopÐjust asingle hot draw-o� was foundÐso there can be no guarantee of hot water near thetap, thus requiring the tap to be run for a long time before su�ciently-hot wateremerges. In the gents' toilet, when tested, this took over 1min to ensue, by whenmost customers would have abandoned the attempt. Therefore, hot water is left


standing in the pipes, and the volume used from storage is replaced by cold ®ll,which then needs to be heated.

3.5. Ventilation

The public bars are provided with extract units, a 9 inch Ventaxia unit in the wallof the saloon bar, and a 12 inch unit in the public bar near the side entrance (butbehind a games machine). Manual control is achieved from behind the bar, withlow, high or boost (i.e. start) settings. No areas are designated as non-smokingzones, and these fans run continuously on a low-speed setting during opening hours.A small extractor fan, in the lobby between the family room and the kitchen, is

under manual control, but is not used. It could assist with the dispersal of unwantedheat from the kitchen.The front entrance porch and the side-entrance lobby have inner and outer doors,

the inner of which is usually left open. Double doors open from the saloon bardirectly onto the rear garden: these are usually left open in summer. The doors andwindows appear to ®t well, but are not provided with extra draught-proo®ng seals.

3.6. Kitchen and refrigeration

The kitchen is kept warm by heat rejected from its refrigerators. Two roof-lightsand a large window overlooking the covered yard permit the entry of daylight, butnevertheless electric lighting is needed at all times.The kitchen contains a six-hob gas cooker, oven and grill. All the other equipment

is electrical (see Table 9), including the twin deep-fat fryers and the hot-plate besidethe cooker. There are large and small microwave ovens, a Bain-Marie hot cupboardwith ®ve heated trays and an infra-red-lit serving shelf, and a soup tureen. The mainkitchen contains a half-height freezer and single and double-width refrigeratorcabinets, as well as the dishwasher.The kitchen is ventilated by an extractor hood over the cooking range, which is

run at full speed for 24 h per day in summer, and 12 h per day in winter. It has a 5-speed manual control. The extract grease-®lter is cleaned weekly to ensure that theunit continues to perform e�ectively.The adjoining larder room and preparation area contain two co�ee machines, a half-

height and four full-height upright freezers, a full-height upright and a half-heightrefrigerator and a microwave oven. The room was conspicuously hot, on all visits, andthis is due to the heat rejected from the refrigeration equipment, which is crowded intothe room. The natural draught, which in®ltrates through the small ventilator in thewindow, is unable to cool the room su�ciently for the satisfactory operation of therefrigerators: they cut out when the ambient temperature rises above a certain level.

3.7. Cellar

The cellar is a ground-¯oor room of head height only, fully utilised, and sur-rounded on three sides by other rooms (i.e. the bar, a corridor, and the bottle store).


The original window is shuttered and thermally insulated. The high thermal-inertiaof the large mass of masonry forming one corner (which used to contain ®replacesand ovens) acts as a temperature stabilizer. There is no insulation on the standardinternal `panel' door, which is not opened often; there are no hot pipes or items ofequipment that should not be there, although well-insulated heating pipes from thenearby boiler cupboard pass through the void above the lowered ceiling. Owing to alack of available space, the cellar is not used to pre-cool bottles before they aretransferred to the bar chillers. The evaporator is mounted on the outside surface ofthe wall facing the rear yard, but separated from the cellar by the bottle store.The 18m3 cellar undergoes approximately 35 air changes per day. For the chilled

air at 11�C and the outside air in the corridor at 18�C, an average ventilation loss of35 kWh/day or 12,775 kWh/year ensues.

Table 9

The traditional pub: electrical applicances in use

Appliance type Location Number Daily hours of use

Lighting (see Table 10) ± ±

Microwaves, small Kitchen 2±3 ±

Microwaves, large Kitchen 1 ±

Dual deep fat fries Kitchen 2 ±

Cooker hotplate Kitchen 1 ±

Bain-Marie Kitchen 1 ±

Co�ee machines Kitchen 2 ±

Dishwasher Kitchen 1 ±

Extractor hood Kitchen 1 12±24

Fly killer Kitchen 1 24

Refriaerators, half height Kitchen 4 24

Freezers, half height Kitchen 2 24

Refrigerators, full height Larder 1 24

Freezers, full height Larder 4 24

Tills Bar 2 12

Games machines Bar 3 12

Extractor fans Bar 2 12

Cigarette machine Bar 1 12

Sound system Bar 1 12

Chiller cabinets Bar 2 24

TV Family room 1 ±

Cellar cooler Cellar ± 24

Line, postmix coolers Bottle store 2 24

Ice maker Bottle store 1 24

Washing machine Bottle store 1 Twice daily

Tumble drier Bottle store 1 Twice daily

Hand dryers Toilets 2 ±

Electric fan heaters Toilets 2 ±

Computer O�ce 1 ±

Shower Flat 1 ±

Heating pump Boiler room 1 ±


In the bottle store are the cellar chiller, the washing machine and tumble drier, anicemaker, as well as the cupboard housing the boilers. The washing machine is astandard domestic model, equipped with hot and cold ®lls, rated at 2000W whenheating and 500W when only turning, and the tumble drier is correspondingly ratedat 2000 or 200W.

3.8. Lighting

Occasional spot-installations of compact ¯uorescent lamps exist in the pub, but thebasic scheme relies on tungsten lamps and linear `white' ¯uorescent tubes (see Table 10).In the public bars, 60W tungsten lamps in green glass shades supported by brass

wall-mounted brackets are used: tungsten re¯ector (R40) lamps are recessed abovethe bar. Behind the bar, `white' ¯uorescent tubes are employed.The kitchen, bottle store and cellar are lit by white ¯uorescent lamps, whereas the

toilets, corridors and back yard use 16W 2D CFLs. Outside, there are 60W re¯ectorlamps housed in brass lanterns, although one has been replaced with an 18W CFL,and a 70W high-pressure sodium ¯oodlight illuminates the garden. The road signuses 20W CFLs and 30W ¯uorescent tubes. The outside lighting is usually switchedon at dusk and o� at closing time.The lighting in the manager's ¯at is entirely via tungsten-®lament lamps.Considerable scope remains for the conversion to compact ¯uorescent lighting,

mainly for the wall lights in the bars, which at present are all 60W tungsten lamps. Theappearance and performance of a `tinted' CFL were demonstrated to the managers,compared with those of a normal tungsten lamp. The apricot version was foundacceptable, and was preferred to a `plain' CFL, which was also tried.

3.9. Electrical load

The only electrical load that can be accounted for directly is that for lighting, i.e.via the known rate of consumption and the measured hours of operation. A ®gure of49.9 kWh per day is obtained for the existing lighting installation; 33 kWh of this isdue to the tungsten lamps. This represents 17% of the electricity, and 6.5% of thetotal energy consumptions for the pub (including natural gas). This result contrastswith the established conclusion, which claims that lighting represents 25% of thetotal energy usage. Table 10 shows the possibilities for retro®tting of CFLs in theexisting installation. It is shown that the installed load-density could be reducedfrom 18 to 10W/m2, with the electricity consumption for lighting falling from 50 to26 kWh per day.At around 11.30 a.m., the electrical load on one phase doubles, as cooking equip-

ment is turned on. Around 19% of the daily electricity-consumption occurs at thenight rate, although the relevant period represents 29% of the 24 h. This load isproduced by the refrigeration and the kitchen's extractor-fan. No other equipment isintentionally used at night (i.e. on the Economy 7 tari�).As with the modern pub, the electricity consumption remains remarkably invar-

iant throughout the year (see Table 11 and Fig. 3), changing more by weekday than


Table 10

The traditional pub: lighting installation

Lamp type Location Existing lamps installed

Rating(W)

Lightoutput(lumens)

No. Ratingtotal (W)

Outputtotal

(lumens)

Usage(h/day)

Consumption(kWh/day)

Tungsten Public bar, walls 60 700 12 720 8400 14 10.1Saloon bar, walls 60 700 6 360 4200 1.4 5.0

Above bar 60 700 2 120 1400 14 1.7Family room 60 700 11 660 7700 14 9.2

Entrance porches 60 700 2 120 1400 14 1.7Toilets 60 700 2 120 1400 14 1.7

Side entrance 60 700 1 60 700 5.5 0.3Tungsten spot Above bar 40 400 4 160 1600 14 2.2

Outside lanterns 60 700 5 300 3500 5.5 1.7Fluorescent 13W Above bar 18 800 2 36 1600 1.4 0.5Fluorescent 18W Cellar 26 1100 1 26 1100 2 0.1Fluorescent 30W Road signs 40 2200 2 80 4400 5.5 0.4

Above bar 40 2200 4 160 8800 14 2.2Fluorescent 36W Cellar 46 2800 1 46 2800 2 0.1Fluorescent 58W Kitchen 70 4500 3 210 13500 14 2.9

Bottle store 70 4500 2 140 9000 14 2.0Larder, corridor 70 4500 3 210 13500 14 2.9

CFL ``PL''9W Name sign 11 600 10 110 6000 5.5 0.6CFL ``21'' 16W Toilets 21 1050 5 105 5250 14 1.5

Rear delivery access 21 1050 2 42 2100 5.5 0.2Front bay windows 21 1050 2 42 2100 14 0.6

Bottle store 21 1050 1 21 1050 14 0.3Back corridors 21 1050 4 84 4200 1.4 1.2

CFL ``SL'' 18W Outside lantern 18 900 1 18 900 5.5 0.1CFL 20W Road sign 20 1200 2 40 2400 5.5 0.2HP Sodium 7OW Garden 85 6000 1 85 6000 5.5 0.5

Sta� ¯ats: unknown

Total 1 4075 115,000 49.9of which, tungsten lamps: 33.6Installation load density (excluding sta� ¯at) (W/m2) 18.0Overall installation e�ectiveness (lumens/W) 28.2

Lamp type Location Tungsten retro®t using higher energy-e�cient lamps

Rating(W)

Lightoutput(lumens)

No Ratingtotal (W)

Outputtotal

(lumens)

Usage(h/day)

Consumption(kWh/day)

Tinted CFL Public bar, walls 15 640 12 180 7680 14 2.5Tinted CFL Saloon bar, walls 15 640 6 90 3840 14 1.3Tinted CFL Above bar 15 640 2 30 1280 14 0.4Tinted CFL Family room 15 640 11 165 7040 14 2.3CFL Entrance porches 15 900 2 30 1800 14 0.4CFL Toilets 15 900 2 30 1800 14 0.4CFL Side entrance 15 900 1 15 900 5.5 0.1Halogen low voltage Above bar 20 300 4 80 1200 14 1.1CFL Outside lanterns 15 900 5 75 4500 5.5 0.4As at present All other locations 1455 84700 109 16.3

Total 2150 114,740 25.3Installation load density (excluding sta� ¯at) (W/m2) 9.5E�ectiveness after upgrade (lumens/W) 53.4


Table

11

Thetraditionalpub:dailyelectricityuse

andcost

February

March

April

May

June

July

August

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Tuesday

±±

±±

291.9

15.54

±±

±±

279.5

14.75

±±

Wednesday

±±

±±

292.4

15.60

±±

±±

295.1

15.75

±±

Thursday

±±

±±

272.8

14.44

318.1

17.02

±±

292.1

15.58

±±

Friday

±±

±±

289.0

15.42

334.3

18.05

±±

303.5

16.26

299.9

16.05

Saturday

±±

298.1

15.81

291.1

15.61

345.1

18.51

±±

331.2

17.50

315.2

16.73

Sunday

±±

309.2

16.49

297.9

16.08

340.3

18.16

333.6

17.80

327.8

17.64

307.8

16.40

Monday

±±

288.2

15.42

294.5

15.74

317.6

16.90

298.6

15.87

305.1

16.28

289.2

15.36

Tuesday

±±

299.8

16.12

300.5

16.04

293.2

15.56

301.5

16.06

320.3

16.97

310.2

16.61

Wednesday

±±

292.1

15.50

290.2

15.56

291.9

15.57

304.5

16.32

322.8

17.19

319.8

17.15

Thursday

±±

282.2

15.06

297.5

15.86

305.6

16.46

311.7

16.68

302.6

15.97

322.2

17.17

Friday

±±

305.8

16.04

307.7

16.56

315.9

16.94

321.0

16.91

305.6

16.19

323.1

17.32

Saturday

±±

323.3

16.67

283.8

15.39

312.5

16.71

323.9

17.2

322.8

17.24

340.0

17.95

Sunday

±±

333.1

17.82

310.7

16.85

350.2

18.96

332.8

17.66

338.8

17.97

349.5

18.62

Monday

±±

284.4

15.14

295.3

15.64

313.8

16.93

309.1

16.39

279.9

14.58

325.9

17.20

Tuesday

±±

292.9

15.76

303.9

16.36

300.5

16.00

320.1

16.96

311.4

16.54

333.8

17.64

Wednesday

±±

311.3

16.39

289.8

15.58

305.2

16.49

330.7

17.61

321.1

16.81

332.1

17.45

Thursday

±±

291.7

15.41

289.3

15.60

326.6

17.52

313.8

16.66

304.3

16.11

326.4

17.30

Friday

±±

288.2

15.16

325.3

17.36

303.9

16.28

326.0

17.35

308.6

16.48

321.4

17.12

Saturday

±±

307.1

16.27

289.3

15.48

3042

16.33

305.7

16.15

314.4

16.86

333.8

17.67

Sunday

±±

311.3

16.89

310.3

16.74

311.2

16.58

314.2

16.80

325.5

17.42

335.0

17.74

Monday

±±

293.4

15.68

288.9

15.56

304.1

15.99

302.4

16.02

299.5

15.97

326.4

17.15

Tuesday

±±

300.2

15.82

291.1

15.61

290.1

15.42

301.8

16.14

308.6

16.42

±±

Wednesday

300.2

15.85

277.5

14.85

289.8

15.49

279.6

14.76

294.6

15.70

321.4

17.06

±±

Thursday

289.1

15.30

293.4

15.57

293.6

15.59

302.8

16.25

289.6

15.44

314.8

16.68

±±

Friday

302.3

15.85

306.2

16.12

309.1

16.65

304.9

16.23

271.5

14.31

317.3

16.81

±±

Saturday

298.1

15.63

299.4

15.99

304.3

16.45

289.7

15.60

310.2

16.71

313.1

16.68

±±

Sunday

319.4

16.89

298.8

16.10

322,8

17.42

301.9

16.29

314.0

16.90

333.4

17.78

±±

Monday

300.6

16.15

284.7

15.32

302.6

16.12

308.7

16.56

283.3

14.98

324.3

16.94

±±

Tuesday

320.3

16.72

291.1

15.47

305.2

16.29

305.7

16.18

285.0

15.21

314.0

16.82

±±

(continued)


Table

11Ð(continued)

February

March

April

May

June

July

August

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Energy

(kWh)

Cost

(£)

Wednesday

317.7

17.02

282.6

15.07

300.5

16.07

285.1

15.28

291.3

15.65

311.9

16.65

±±

Thursday

299.3

15.65

295.3

15.81

±±

297.7

16.10

299.7

16.00

306.1

16.45

±±

Friday

287.8

15.36

301.7

16.04

±±

326.0

17.54

306.4

16.27

±±

±±

Saturday

±±

293.2

15.74

±±

309.1

16.51

307.2

16.44

±±

±±

Sunday

±±

287.2

15.64

±±

±±

310.6

16.72

±±

±±

Monday

±±

295.8

16.12

±±

±±

280.3

14.89

±±

±±

Total

8498

449.17

9219

491.30

8931

478.69

9596

513.68

9195

489.83

9677

514.35

10,009

531.54

Average

303.5

16.04

297.4

15.85

297.7

15.96

309.5

16.57

306.5

16.33

312.2

16.59

322.9

17.15

Includingstandingcharges:

Total

626.28

611.06

596.25

637.35

609.34

638.15

658.34

Average

22.37

19.71

19.87

20.56

20.31

20.59

21.24

Standingcharge

£12.25

Availabilitychargeper

kVA

£0.55

AvailabilitykVA

30

Maxdem

ch.Novem

ber,February

£2.30

Maxdem

ch.Decem

ber,January

£6.90

VAT%

17.5

Accuracy

check

Date

18February

22March

16April

17May

17June

18July

19August

Meter

reading11a.m

.429193

438,779

446,129

455,717

465,288

474,888

484,992

Actualusage

±9586

7350

9588

9572

9409

10,294

Per

day

±300

294

309

309

304

322

Hawkreading

±11,208

8623

11,184

11,333

11,193

12,459

Per

day

±350

345

361

366

361

389

Error%

±16.9

17.3

16.6

18.4

19.0

21.0


by season. The consumption lies in the range 284 to 350 kWh per day, but is typi-cally �305 kWh per day, being least on Mondays and Tuesdays, and highest atweekends. Table 12 shows the full data for 2 days, together with the highest andlowest rates of consumption during the monitored period.The availability charge is set by the electricity supplier for 30kVA, and this is raised

during any individual month in which demand occasionally exceeds this level. This levelseems to be well chosen, as the maximum demand noted during this survey was 24kW.

3.10. Monitoring

The Hawk datalogger was installed in December 1996. After the ®rst download,its 100A current clamps were found to be giving consistently high readings (as hadbeen the case in 1995). Thus the current clamps were replaced with 250A types, andmore realistic readings were then obtained. From February 1997 onwards, reliabledata were recorded. However, a slight loss of sensitivity was su�ered, as the loadremained well below the upper limit of the 250A clamp. After several months ofoperation, the summed Hawk data were compared with the monthly electricitymeter readings: it was found that the Hawk was still over-reading by around 18%.So, all Hawk data were divided by a correction factor, to ensure that it corre-sponded with the monthly total from the utility meter. This correction factor wasdetermined over each monthly monitoring period.The Squirrel datalogger was installed in January 1997. Three sensors were used. A

black globe sensor was mounted outside above the pub's front-door; a chrome-rodthermistor was located in the public bar, alongside a ceiling beam; and a black`globe' sensor was ®tted to the Squirrel itself, on the glass rack above the bar. Afurther black globe sensor was installed in the saloon bar in February, inside apewter tankard hanging from the ceiling beam. This protects the sensor from directradiant-heat from the open ®re, so that its indications were nearer to those for thetrue room-air temperature. It is possible that the black globe sensor on the Squirrelwas a�ected by a downdraught from a cut-out in the ceiling above the adjacent bardownlight, so that its readings may be inaccurate. Also, the sensor outside the (east-facing) front door was a�ected by direct sunlight during the morning, so its readingscorresponding to these hours are not usedÐthey are clearly identi®able by the sud-den leap and subsequent fall in the recorded temperature. Generally the problemhad disappeared by noon (GMT), but, during summer, the onset of this mis-information occurs earlier in the morning. The use of a chrome sensor would havebeen more suitable for this location.

4. Measures to improve energy thrift for the two pubs

4.1. Thermal conditions

Daytime room temperatures are within the comfortable limits of 18 to 25�Cfor much of the year, with both pubs experiencing uncomfortably high extreme


Table 12

The traditional pub: half-hourly electrical consumption data for two extreme days


temperatures in early August. Temperatures above the service bars are higherthan elsewhere due to the proximity of lighting equipment. A curious feature isthat the modern pub experiences higher overnight minima than the traditionalpub, despite the fact that the central-heating at the modern pub does not runovernight, whereas at the traditional pub it will run, unless turned o� manually.The childrens' play-room departs signi®cantly from comfortable conditions, beingeither excessively hot or cold, more regularly and has the greatest daily varianceof any of the public zones; these extremes are due to the high dependence onweather conditions, especially strong sunshine, and the ine�ective space-heatingarrangements.The daily maximum temperature in each zone generally occurs during opening

hours, but the minimum does not. Therefore the lowest temperatures encounteredare not of concern, other than to indicate the amount of heating that will be requiredto re-establish comfort conditions. However, unmonitored zones (such as the pool-table area in the traditional pub, which has an insu�cient number of radiators) maywell encounter discomfort during opening hours.Mean natural-environment outside-temperatures rise from winter to summer as

expected, with high peaks occurring on sunny days. (To eliminate these, data for thelate morning could have been omitted.) The extreme heat occurring during Augustcoincides with the discomfort being experienced inside the pub.

4.2. Results of the energy survey

Table 13 shows the amount of energy used monthly at the modern pub, and itscalculated cost, for the monitored period and the previous year, where data exists.Gas consumption in winter is almost 1300 kWh per day, i.e. more than double thatduring the summer, and this gives an indication of the gas consumed by the heatingsystem. Electricity consumption remains roughly steady throughout the year ataround 840 kWh per day, but displays a peak in summer, which is partly due to theuse of the air-conditioning, and partly because of short-term blips in trade and hencerefrigeration requirements. Electricity usage is generally least on Monday, andhighest on Sunday.The equivalent ®gures for the traditional pub, shown in Table 14, are also available

for 1981. The daily rate of electricity consumption is seen to have risen modestlysince that year, and is more uniform throughout the year than for the modern pub,possibly due to the lack of air-conditioning. The natural-gas consumption hasalmost quadrupled: the variation in rate through the year being large, with summerusage just � one-quarter of the winter rate. It must also be remembered that, since1981, pub opening hours have been extended, so overall energy usage and turnoverare likely to have risen.Table 15 shows the calculation of the energy indices. All available data for fuel usage

and costs are brought together and divided by appropriate ¯oor areas and turn-overs. A point raised in the 1981 thesis [6] is that the ratio of a pub's annual con-sumption of electricity, in kWh, to the total ¯oor area of the premises, in square feet,should lie in the range 18 to 20; this ®gure is revised under present-day conditions.


Table

13

Themodernpub:monthly

energyusagea

Electricity

consumption

Gasconsumptionb,c

Totals

1996

1997

September

1996±August

1997

1997

(kWh)

(kWh/day)

(£)

(kWh)

(kWh/day)

(£incVAT)(100ft3)

(kWh)

(kWh/day)

(£incVAT)

(kWh)

(kWh/day)d

(£)

January

24308

784

2466.68

24308

784

2456.68

1307

40033

1291

380.32

64341

2076

2837.00

February

22486

803

1918.71

22486

803

1918.71

1126

34489

1113

327.65

56976

1916

2246.36

March

22524

727

1325.72

26283

848

1646.03

1037

31763

963

301.75

58046

1810

1947.78

April

25979

866

1483.48

24958

832

1570.07

639

19573

783

185.94

44530

1615

1756.01

May

23460

757

1347.35

27055

873

1696.74

735

22513

750

213.87

49568

1623

1910.61

June

21685

723

1254.64

26655

889

1670.61

674

20645

666

196.12

47300

1554

1866.73

July

24043

776

1370.78

30326

978

1891.71

649

19879

641

188.85

50204

1619

2080.56

August

29306

945

1644.61

32414

1046

2023.08

607

18592

581

176.63

51007

1627

2199.71

September

20308

677

1178.46

20308

677

1178.46

±19200

640

182.40

39508

1317

1360.86

October

23475

757

1049.27

23475

757

1049.27

±20400

658

193.80

43875

1415

1243.07

Novem

ber

23475

757

1988.34

23475

757

1988.34

±23870

796

226.77

47345

1553

2215.11

Decem

ber

25735

830

2681.39

25735

830

2681.39

±36000

1161

342.00

61735

1991

2923.39

Total

286784

±19599.43

307477

±21671.09

6774

306958

±2916.10

614434

1676

24587.19

aThedata

onthisspreadsheetistaken

from

realreadingsandtari�calculations,orfrom

invoices,wherever

possible.Wheretheseare

notavailable,data

havebeenextrapolatedorborrowed

from

theprecedingyear.

bGasconsumption®guresforcertain

monthsare

deducedfrom

published

degreeday®guresÐ

seelatertable.

cCorrectionshavebeenapplied

asfollows:1997gasconsumption:acalori®cvalueof30.63kWh/100ft3isusedto

giveagreem

entbetweenmeter

readings

andinvoicedata;1997gastari�:despitequotedtari�of0.7469p+

VAT/kWh,invoices

suggestactualcost

is0.95p/kWhincl.VAT,so

thisisused.

d1997kWh/daycalculationbasedonintervalbetweenreadings.


Table

14

Thetraditionalpub:monthly

energy-usagea

March1980±February

1981

Novem

ber

1994±October

1995

Novem

ber

1995±October

1996

1997

(kWh)

(kWh/day)

(£incVAT)

(kWh)

(kWh/day)

(£incVAT)

(kWh)

(kWh/day)

(£incVAT)

(100ft3)

(kWh)

(kWh/day)c

(£incVAT)

Electricity

consumption

January

7339

237

318.80

6955

224

588.60

10850

350

819.76

±10850

360

819.76

February

7123

254

325.41

6390

228

410.39

7528

269

499.99

±8498

303

626.28

March

9055

292

253.64

8381

270

473.14

8305

268

485.70

±9219

297

611.06

April

6367

212

196.00

6608

220

404.86

8917

297

535.49

±8931

298

596.25

May

5045

163

156.91

9506

307

540.38

9813

317

585.37

±9596

310

637.35

June

4394

146

138.50

7162

239

418.85

8835

295

532.01

±9195

307

609.34

July

4747

153

146.55

9687

312

551.79

11059

357

653.40

±9677

312

638.15

August

4495

145

143.76

10589

342

599.85

9901

319

574.72

±1008

323

658.34

September

4851

162

152.15

7837

261

457.17

8543

285

506.19

±8543

286

506.19

October

6136

198

192.22

8931

288

515.37

9880

319

426.06

±9880

319

426.06

Novem

ber

7028

234

246.84

8702

281

568.90

8702

281

668.90

±9702

281

568.90

Decem

ber

8692

280

357.37

6618

213

589.07

6618

213

589.07

±6618

219

589.07

Total

75272

±2628.15

97365

±6118.37

108951

±6776.66

±109718

±7286.75

Gasconsumptionb

January

±±

±±

±±

±±

±710

21321

688

187.12

February

18419

213

180.89

±±

±±

±±

635

19099

682

167.61

March

±±

±±

±±

±±

±547

16426

513

144.16

April

±±

±±

±±

±±

±441

13243

530

116.22

May

15107

166

128.71

106241

584

732.14

145002

797

844.54

408

12252

395

107.53

June

±±

±±

±±

±±

±228

6847

221

60.00

July

±±

±±

±±

±±

±199

5976

193

52.45

August

3761

41

41.50

±±

±±

±±

174

5225

163

45.86

September

±±

±±

±±

±±

±±

5880

196

116.22

October

±±

±±

±±

±±

±±

6900

223

144.16

Novem

ber

7978

88

79.05

59053

324

272.39

32600

179

266.20

±13950

465

167.61

Decem

ber

±±

±±

±±

±±

±±

21120

681

187.12

Total

46259

±430.15

165294

±1004.53

177602

487

1110.74

3343

148250

406

1496.15

(continued)


Table

14Ð(continued)

Gasandelectricitytotals

January

32171

1038

1006.88

February

27597

986

793.89

March

25646

811

755.22

April

22174

827

712.47

May

21848

705

744.88

June

16042

527

669.43

July

15653

505

690.60

August

15234

486

704.20

September

14433

481

622.41

October

16780

541

570.22

Novem

ber

22652

746

736.51

Decem

ber

27738

895

776.19

Total

257968

712

8782.90

aThedate

onthisspreadsheetare

taken

from


invoices,wherever


notavailable,data

havebeenextrapolatedorborrowed

from

elsewherein

theyearorprecedingyear.

bGasconsumption®guresforcertain

monthsare

deducedfrom

published

degree-day®guresÐ

seelatertable.

c1997kWh/daycalculationbasedonintervalbetweenreadings.


Table

15

EnergyIndices

a

Modernpub

Traditionalpub

1996

1997

1980±1981

1994±1995

1995±1996

1996±1997

Weekly

turnover,presentapproxim

ation

£±

16,500

±±

±6500

Annualturnover,food

£500,089

±±

±103,427

Annualturnover,liquor

£±

257,675

±±

±164,907

Annualturnover,totalto

February

1997

£757,764

757,764

61,000

268,334

268,334

268,334

Treated¯oorarea

m2

712

287

Electricity

usage

kWh

286784

307477

75,272

97,365

108,951

109,718

Electricity

cost

£19,599.43

21,671.09

2628.15

6118.37

6776.66

7286.75

Gasusage

kWh

306,958

306,958

46,259

165,294

177,602

148,250

Gascost

£2916.10

2916.10

430.15

1004.53

1110.74

1496.15

Woodusage

kWh

±±

±?

??

Woodcost

£0

00

450

450

450

Totalfuel

usage

kWh

593,742

614,434

121,531

262,659

286,553

257,968

Totalfuel

cost

£22515.53

24587.19

3058.30

7572.90

8337.40

9232.90

Overallfuel

cost

p/kWh

3.79

4.00

2.52

2.88

2.91

3.40

Energyconsumptionratio

kWh/m

2834

863

423

915

998

899

Energycost

ratio

£/m

231.62

34.53

10.66

26.39

29.05

32.17

Energyconsumptionindex

kWh/m

2/£k

1.10b

1.14

6.94d

3.41c

3.72c

3.35c

Energycost

index

p/m

2/£k

417b

4.56

17.47d

9.83c

10.83c

11.99c

Energyturnover

3.0%

3.2%

5.0%

2.8%

3.1%

3.4%

Electricity

use

per

¯oorarea

kWh/sq.ft.

36.0

d38.5

d23.4

d30.3

d33.9

d34.1

d

aThedata

onthisspreadsheetare

taken

from


invoices,wherever


notavailable,data

havebeenborrowed

from

thefollowingyear(shownin

italic).

b±dRangeclassi®cation:Energyconsumptionindex

(kWh/m

2/k£)bgood<

2.3;cfair

2.3±5.3;dpoor>

5.3.Energycost

index

(p/m

2/k£)bgood<7.5;cfair

<7.5±17;dpoor>17.


Calculations for the modern pub are made for the calendar years 1996 and 1997, withsome assumptions made to cover for periods of missing data. For the purposes ofthe energy index calculations, the treated ¯oor area is taken to exclude the unheatedbottle store, so a ®gure of 712m2 has been used. The total ®nancial turnover forboth calculations is taken as £757,764 per annum, which is the actual ®gure for the12 months to February 1997. The ®gure breaks down into £500,089 (66%) for foodand £257,675 (34%) for liquor, and also suggests �£14,500 total takings per week,compared with the manager's optimistic current estimate of £16,500 per week.Nevertheless, trade is rising, as is likely with a recently-opened pub. The energyindices are found to be:

. Energy-consumption index: 1.10 kWh/m2/k£ turnover (1996), 1.14 kWh/m2/k£turnover (1997)

. Energy-cost index: 4.17p/m2/k£ turnover (1996), 4.56p/m2/k£ turnover (1997)

. Energy/turnover: 3.0% of turnover (1996), 3.2% of turnover (1997)

The two indices both fall well within the ranges de®ned as `good' by BRECSU'sGood Practice Guides [4], despite the signi®cant energy wastages identi®ed for var-ious zones of the pub. The ratio of annual electricity usage to total ¯oor area isfound now to be 38, compared with the previously recommended level of 18 to 20.Calculations for the traditional pub are made for 12-month periods ending in 1981,

1995, 1996 and 1997, with some assumptions made to account for the periods ofmissing data in 1997. Comparisons with 1981 are made possible using data from thestudy undertaken in that year, i.e. before central-heating had been installed, andwhen gas ®res and electric heaters were relied upon for heating. The pub is nowmuch more comfortable as a result of the introduction of the central-heating. Therise in electricity consumption is due to the higher cooking loads that now occur,although electric ®res and electric water-heating previously in use have disappeared.For the purposes of the energy-index calculations, the treated ¯oor area is taken toexclude the unheated bottle store and plant room, so a ®gure of 287m2 is used. Theturnover for the 1995, 1996 and 1997 calculations is taken as £268,334 per annum,which is the ®gure for the 12 months to February 1997. None of the years coincidesexactly with this period. The ®gure breaks down into £103,427 (39%) for food and£164,907 (61%) for liquor, and also suggests £5160 takings per week, compared withthe manager's current optimistic estimate of £6500 per week, which is partly in¯u-enced because trade is rising. The energy indices for the traditional pub are shown inTable 16.The recent values for the energy indices are in the `fair' range, although the ®gures

for 1981 were `poor'; it must also be borne in mind that no attempt has been madeto include the heat contribution from the log ®replaces: although the costs involvedare known, there is no means of telling the volume of wood purchased, its calori®cvalue, or the e�ciencies of the ®replaces. Therefore, the energy-consumption indexshould be slightly higher than indicated. The energy-cost index is a�ected by the unitcost of energy. In approximate terms, the turnover has quadrupled, whilst energy usagehas doubled during the 16-year period considered, thus halving the energy-consumptionindex. The ratio of annual electricity usage to total ¯oor area (in kWh/m2) is found


now to be 34, having been 23.4 in 1981. This indicates that energy intensity hasincreased by 50% since then, due to increases in lighting levels, heating, air con-ditioning and cooking.Attempts are now made to determine the rates of energy consumption for various

items of equipment in the public houses, so that it is possible to compare themagainst published data for a typical public house. This has proved to be an extremelyapproximate exercise, owing to the lack of speci®c monitoring equipment for indi-vidual appliances. However, two energy uses have been closely assessed, namely forheating and lighting. These may then be separated from the total energy usage,leaving an approximate allocation of energy to the remaining items of equipment.Lighting is fully accounted for by counting the number of lamps, their circuit ratingsin Watts, and their hours of operation per day.Space-heating energy usage was also evaluated. In Fig. 4, the results of the outside

temperature monitoring at the traditional pub are translated into degree-day infor-mation, giving the average number of degree-days for a day in each calendar month.As expected, it falls to near zero in summer. The degree-days ®gures obtained aresomewhat lower than those published elsewhere for the East Anglian region [7],especially in winter, and this is attributed to the sensor's unwanted response tomorning sunlight (as discussed earlier). However, their trend is generally reliable,and they give a fair correlation with natural-gas usage to indicate the rate beingburnt for space heating. In Table 17, the gas consumption data obtained for eachpub are plotted against the number of degree-days obtained through measurementand from published records: an approximately linear plots emerge. The almostconstant slope is used for two purposes. Firstly, the number of degree-days for theautumn months of the previous year being known, gas consumption ®gures are®tted to the curve to predict the gas consumption for that portion of the year (i.e.September to December) for which no data were available. Hence these ®gures wereused to compute the energy indices discussed previously. Secondly, a `base' natural-gas consumption for summer is obtained, representing the non-space-heating usage,i.e. for cooking and water heating. It is assumed that this will remain roughlyinvariant throughout the year, thus enabling the extra gas usage in the coldermonths to be deemed to be employed exclusively for space heating.The determination of the rate of energy consumption for the air-conditioning system

is much more di�cult and usually needs to be measured individually. The e�ectivenessof the air-conditioning system is also dependent on the weather, and will vary with

Table 16

The general trends for the traditional pub

Year Energy consumption index

(kWh/m2/k£ turnover)

Energy cost index

(p/m2/k£ turnover)

Energy/turnover

(%)

1981 6.94 17.47 5.0

1995 3.41 9.83 2.8

1996 3.72 10.83 3.1

1997 3.35 11.99 3.4


the rate of solar gain as well as the outside ambient temperature although this is notre¯ected in the number of degree-days. However, it is possible to identify a higheraverage daily electricity usage during summer months, and to attribute this extra loadto air-conditioning and ventilation.For analogous reasons, the e�ective use of refrigeration also poses a challenge.

The temperature of the environment in which a refrigerator operates is in¯uenced bythe outside ambient temperature as well as the rate of heat expelled from the con-denser into the room in which the refrigerator is located. Therefore there will not bea direct correlation with degree-days data. As refrigerators run throughout thenight, their rate of energy consumption at these times may be deduced because most

Fig. 4. Degree days monitored at the traditional pub.

Fig. 3. The traditional pub: daily electricity use.


other appliances are switched o�: however, this rate is lower than the rate of con-sumption during daytime when (i) the room is warmer, (ii) the refrigerator door isbeing opened intermittently and (iii) the contents are replaced with unchilled food.The overnight consumption rate has contributions from all the refrigerators includ-ing the cellar chiller and bar chillers, and also continuously running pumps andkitchen extractor fans, so the catering refrigeration usage will be hidden.The lighting and space-heating ®gures are included in the overall energy usage, as

shown in Table 18. The energy usage of each item is shown as a percentage of the

Table 17

Examination of correlation between degree days and energy used comparing gas usage in kWh with

degree-day ®gures for the same periods


Table

18

Allocationofenergyusage

Themodernpub

Thetraditionalpub

BRECSU

guidelines

total(%

)

kWh/year

Electricity

(%)

Gasa

(%)

Total

(%)

kWh/year

Electricity

(%)

Gas

(%)

Total

(%)

Space

heating

94888

±31

15

88,650

±60

34

25

Gas®res

64080

±21

10

±±

±±

±

Hotwater

61,443b

±20

10

25,797

±17

10

10

Catering(cooking)

61,443

10c

10

10

25,797

12

910

10

Cellar,airchangeloss

18250

6±

312,775

12

±5

±

Cellar,restockingandconductionlosses

431,93

14

±7

13,022

12

±5

10

Refrigeration

61,443

20

±10

25,797

24

±10

10

Ventilationd

23,598

8±

47665

7±

3±

Airconditioningd

7866

3±

1±

±±

±±

Lighting

76,322

25

±12

18,214

17

±7

25

Sta�¯at

30,722

55

512,898

64

55

Appliances

30,722

10

±5

12,898

12

±5

5

Unidenti®ed

±±

13

7±

±10

6±

±100

100

100

±100

100

100

±

Totalelectricity

307,477

±±

±109,718

±±

±±

Totalgas

306,958

±±

±148,250

±±

±±

Totalenerqy

614,434

±±

±257,968

±±

±±

Energyusedto

prepare

ameal

Noofmealsper

week

1800

±±

±585

±±

±±

Noofmealsper

year

93,600

±±

±30,420

±±

±±

Energyusedper

meal,(kWh)

0.06

±±

±0.85

±±

±±

aGas®resatthemodernpubare

taken

tooperate

for12hdailyfor5monthsoftheyear,i.e.

1800h.

bFiguresin

italics

havebeendeducedfrom

theBRECSU

guideline®gure

asapercentageoftheactualtotal.

cWhereadistinctioncannotbemadebetweenelectricityandgasusedbyoneapplication,a50±50splitisassumed.

dAtthemodernpub,itisassumed

thatventilationandairconditioninguse

theremainingelectricityin

theratio3:1.


total electricity or natural-gas usage, as appropriate, and of the overall total con-sumption (see Fig. 5). Other entries in this table have been estimated to improve thereliability of the data. The gas ®res in the modern pub have known rates of con-sumption, and are in daily use during the winter. This is taken to mean 12 h use dailyfor 120 days. The remaining ®gures are calculated `backwards' from the BRECSUguidelines, although this approach is not necessarily appropriate when there isalready disagreement with those guidelines on the proportions of energy used byspace heating and lighting, which amounts are known in this instance. Space heatinguses far more energy, and lighting far less, than the predicted share of 25% each.This result seems more realistic than the prediction.The energy used to prepare a meal may be estimated. It has already been said that

a `cradle-to-grave' approach, including the costs of refrigeration, dishwashing andspace heating for the diner as well as the cooking itself, gives a ®gure of 10 to15 kWh per meal. The approximate number of meals served at each pub is known; ifthis is multiplied by 10 kWh, a ®gure exceeding the pub's total energy usage isreached! The inclusion of environment aspects of the meal is responsible for raisingthe ®gure, so instead the ®gures for cooking and dishwashing (kitchen usage) arecalculated to be 0.66 kWh at the modern pub and 0.85 kWh at the traditional pub,suggesting that the energy used for refrigeration and space heating represents themajor contribution to the energy use associated with catering. In general, cateringconsumes �10% of the pubs' energy-expenditure. The electrical demand hardlyvaries throughout the year. Just 13% of the daily usage occurs during the cheapovernight tari� band, which applies for 30% of the 24 h-day. Also, 17% of the dailyusage during winter weekdays ensues during the afternoon high peak tari� time-band, although this accounts for only 12.5% of the day. It would therefore be®nancially desirable to shift the electricity demand away from the afternoon, intothe night. But, it will be di�cult to do this with most loads, which are determined bycustomer demand, except perhaps those for the washing machine, dishwasher andtumble drier, which could perform one pre-loaded cycle at night with the aid oftimeswitches. Nevertheless it is desirable to restrict the use of electrical appliancesbetween 4 and 7 pm on weekdays during the winter months.Although di�erent tari� patterns lead to di�erent costs, the total amount of

energy used would remain unchanged. By shifting to low-cost tari� periods, bene®tsaccrue to the brewery, although if peak loads were avoided, the electricity suppliercould budget for a lower supply-capacity.Both pubs have access to cheap electricity overnight, at 2.45 p/kWh. During day-

time, the modern pub pays a high unit cost on winter afternoons, but at other timespays 5.48 p/kWh, i.e. less than the traditional pub's 5.99 p/kWh. The traditional pubpays for its winter demand by a one-o� monthly maximum-demand charge,depending on the magnitude of that month's demand peak. It would be desirable totest this approach for the modern pub. Eastern Electricity uses a breakpoint of75 kVA for a quantum leap in the tari�, and, unfortunately, at present the modernpub's consumption lies close to that rate, so the higher tari� would often be incur-red. This is applied to the consumption for 1996±1997 (see Table 19): a cost savingof just 0.22% is made, but the distribution of payments is a�ected, with winter bills


Fig. 5. Proportions of energy usage.


Table 19

Modern pub: comparison of maximum demand and seasonal time of day tari�s. Costs per day, calculated

using maximum demand tari�, £

Decembera January February March April May June July Augusta

Tuesday ± ± ± ± 43.54 ± ± 48.41 ±

Wednesday ± 49.23 ± ± 44.84 ± ± 46.91 ±

Thursday ± 42.82 ± ± 43.44 48.88 ± 46.53 ±

Friday ± 43.28 ± ± 44.77 55.99 ± 49.15 53.78

Saturday ± 45.27 48.75 49.63 47.75 52.65 ± 51.66 51.30

Sunday ± 44.11 48.47 51.02 49.84 56.07 50.42 57.17 55.69

Monday ± 39.93 40.68 42.11 45.37 51.48 43.28 54.99 48.80

Tuesday ± 40.09 40.03 44.68 43.16 41.69 43.87 55.06 49.98

Wednesday ± 40.67 40.64 43.54 44.33 44.51 49.00 55.88 52.45

Thursday ± 41.01 41.02 41.58 45.64 44.59 48.34 50.36 58.45

Friday ± 42.25 40.78 44.92 45.71 46.89 52.20 47.72 62.40

Saturday ± 49.20 45.48 48.99 47.61 50.15 55.01 57.97 65.83

Sunday ± 48.00 45.89 54.59 49.42 50.61 54.72 60.53 63.50

Monday ± 42.21 41.35 42.51 44.32 45.89 47.55 53.41 58.77

Tuesday ± 39.67 41.76 42.73 42.97 42.36 53.74 54.72 60.51

Wednesday 47.31 41.53 42.83 42.05 43.53 44.84 46.62 47.54 55.63

Thursday 48.62 40.88 40.19 43.30 43.43 43.28 48.17 50.76 55.04

Friday 49.77 45.36 45.09 43.81 43.97 46.23 54.31 53.04 62.79

Saturday 50.64 47.95 48.80 49.57 46.94 52.01 51.95 57.79 63.33

Sunday 48.48 49.16 49.03 49.29 48.58 51.63 54.59 56.83 63.48

Monday 45.66 35.47 44.00 42.15 42.57 43.92 43.48 47.60 ±

Tuesday 47.93 41.13 42.00 42.16 42.31 46.61 46.41 54.77 ±

Wednesday 39.63 42.42 46.50 43.92 44.11 44.90 45.30 56.43 ±

Thursday 39.66 42.75 44.93 44.40 44.86 45.28 46.25 57.29 ±

Friday 42.79 43.91 45.43 45.28 45.28 45.35 46.14 56.60 ±

Saturday 45.63 46.63 47.78 48.13 50.26 48.68 50.02 53.94 ±

Sunday 46.03 45.94 47.88 49.12 51.62 52.09 53.66 62.91 ±

Monday 41.97 40.00 41.51 43.93 44.02 53.36 45.05 54.41 ±

Tuesday 46.20 40.36 44.10 43.67 46.82 46.96 45.47 58.32 ±

Wednesday ± 40.45 42.17 45.21 48.96 45.72 43.20 54.81 ±

Thursday ± 41.56 41.39 45.41 ± 44.55 44.50 54.58 ±

Friday ± 42.89 44.05 50.29 ± 49.72 47.31 ± ±

Saturday ± ± ± 49.26 ± 48.87 50.75 ± ±

Sunday ± ± ± 49.38 ± ± 53.38 ± ±

Monday ± ± ± 49.65 ± ± 45.81 ± ±

Monthly total £ 1417.87 1336.16 1232.54 1426.29 1369.98 1485.78 1460.50 1668.10 1790.20

Daily average £ 45.74 43.10 44.02 46.01 45.67 47.93 48.68 53.81 57.751

VAT @ % 17.5

Availability charge per kVA £0.55

Maximum Standing charge £18.85

Demand Availability, (kVA) 110

Low voltage Max demand charge November, February £2.07

>75kVA Max demand charge December, January £6.21 Total

Total bill 2211.63 2137.51 1697.13 1769.13 1702.96 1839.03 1809.33 2053.25 2196.72 £17,416.69

Maximum Standing charge £12.25

Demand Availability, (kVA) 75

Low voltage Max demand charge November, February £2.307

>75kVA Max demand charge December, January £6.90 Total

Total bill 2231.52 2159.84 1684.05 1738.75 1672.59 1808.65 1778.95 2022.88 2166.35 £17,263.58

(continued)


being signi®cantly reduced, at the expense of higher bills in summer. This is becausehigh summer loadings cost more, as the maximum-demand tari� is generally higher,but the punitive winter afternoon tari�s are avoided. If the energy-e�ciency recom-mendations outlined were to result in a reliable reduction in consumption, it wouldbe safe to apply the <75 kVA tari�. This increases the cost reduction to 1.1%. Atpresent, an availability of 110 kVA is being charged for, which could wisely bereduced to 90 kVA, as the peak monitored was 81 kVA, at lunchtime on a particu-larly hot Sunday in August 1997.

4.3. Recommendations for reducing energy waste

Having surveyed the energy consumptions for the two individual pubs, it is nowpossible to suggest several measures for reductions of their energy waste.

4.4. The building fabric

The modern pub is built to high standards of construction and thermal insulation.With concrete block inner-wall construction and wood panelling as the interiordecor, the internal temperature responds swiftly to internal heating within a room.The outer cavity-walls contain a 50mm airgap adjacent to the outer leaf: thus theinsulation batts, attached to the inner leaf, tend to remain dry.The majority of the building is a single-storey structure, beneath a roof void: the

thickness of roof insulant required to meet modern standards had been installed.The pitch of such a roof also in¯uences the rate of heat loss [8]. For a simple pitchedroof with a central ridge, it has been found that employing an optimal pitch of �18�can reduce the rate of heat losses signi®cantly, compared with having a traditionalpitch of 28� as used in this pub. Nevertheless, as a simple retro®t measure, sus-pending a horizontal ba�e shield (e.g. of foamed PVC), from the roof and coveringthe majority of the plan area of the attic, would signi®cantly inhibit heat losses viathe ceilings.Heat from the adjacent occupied rooms enters the cellar. The wall insulation needs

to be improved. The adjacent bottle store could be provided with louvred externaldoors to the ambient environment, so facilitating the natural-ventilation removal ofwaste heat from the line chillers. The doors to the pub's interior require to be insu-lated. An even better solution would be to return to the original concept of anexcavated cellar beneath the pub: the optimal storage temperature for beer (�11�C)

Table 19Ð(continued)

Electricity costs: tari� comparison

December January February March April May June July August Total

STOD 2581.39 2456.68 1918,71 1646.03 1570.07 1696.74 1670.61 1891.71 2023.08 £17,455.02

MD>75kVA 14% 13% 12% ÿ7% ÿ8% ÿ8% ÿ8% ÿ9% ÿ9% 0.22%

MD<75kVA 14% 12% 12% ÿ6% ÿ7% ÿ7% ÿ6% ÿ7% ÿ7% 1.10%

a December and August totals are interpolated from average data over monitored part of month.


is close to the temperatures typically found in underground cellars, thereby reducingthe need for energy expenditure upon cooling. However, the increased constructioncosts are a major ®nancial disincentive, and the arrangement would probably beunpopular with those who have to load the cellar.The original building of the traditional pub is of stone-wall construction and has

no insulation. Only the more recent extensions (to the north of the public bar, andthe family room) are of cavity-wall construction. Hence the building su�ers rela-tively high fabric-transmission losses, whilst its heavy structure dampens tempera-ture ¯uctuations within the pub. Insulation may only be attached to the surface of asolid wall. Adding insulation cladding to the internal faccË ade of external wallsreduces the room space slightly, and every wall ®xing must be sealed if it is not tobecome a thermal short. This process would usually involve closing the pub whilstthe work was carried out, involving signi®cant expense and disruption: so the besttime to do this would be during a major refurbishment. Insulation materialsapplied to the external surface of the outside walls must be covered with a layer ofconcrete rendering, tiles or other sheet materials, which is a costly operation andwould probably not be permitted if it altered the external appearance of this tradi-tional pub.The rates of heat lost, through the building fabric via the roof, walls, windows and

door openings, and ¯oor, are in descending magnitudes. Therefore the roof shouldbe fully insulated. In the case of the roofspace above the saloon bar, this should be asimple matter of laying more insulation on the loft ¯oor. This roof void was onceused as the exit route for exhaust air from the saloon bar below, but the relevant fanis no longer there. A loft access hatch is located between the bar and the toilets. Thisshould be well insulated. For the sta� ¯at, insulation could be ®tted between theroof rafters; but this would involve disruption. The ¯at is known to be thermallycomfortable, whereas previously it was cold; this suggests that the thatched roof,now enclosed, provides adequate insulation. For the ¯at roofs of the family roomand public-bar extensions, `warm-deck' insulation is preferred, in which the struc-ture of the roof remains at the inside temperature, and the insulation is ®tted justbeneath the weatherproof outer cladding. This should have been installed when theroof was covered. For summer comfort, the roof ®nish should be of chippings tore¯ect solar radiation.When next they require renovation, the windows and patio doors should be

replaced by 19mm cavity double-glazed units. The character of the traditional pubmust be maintained, so wooden-framed units with glazing bars, either decorative orfunctional, should be used to replicate the existing windows. The larger bay win-dows in the public bar would be the most expensive to replace, but would make theadjacent seating more comfortable during winter. The payback periods for thesemeasures would each exceed 10 years. Alternatively, as an interim measure, second-ary glazing may be employed in winter, and removed for the summer to allow thewindows to be opened. In the meantime, adding draughtstrip appropriately wouldbe a cheap and cost-e�ective means of draught elimination.Set against the costs of improving the insulation should be the lower capital cost

of the smaller-capacity heating system then needed.


Unfortunately, employing these measures alone does not ensure the energy e�-ciency of the building or the thermal comfort of its occupants: these will dependupon the management of the pub. A further threat to energy e�ciency lies in theopportunities presented by refurbishments to remove energy-e�ciency measures thatdo not appear to work, or are not recognised as worthwhile by the premises' man-agement. Priorities may have changed since the more energy-e�ective equipment, orfeatures, were added. Therefore, once improved, there is little guarantee that a pubwill remain as energy thrifty after it has undergone a change of ownership.

4.5. Heating and hot water

Condensing boilers should be speci®ed for all new heating-systems, or whenexisting boilers are being replaced. These cost somewhat more, and initially incur extrainstallation requirements, but the short payback period for the extra cost is due to theincrease in e�ciency from�75 to�90%made possible by the reclamation of heat fromthe exhaust products. The highest e�ciency is obtained when the return-water tem-perature falls below the dewpoint of the boiler's exhaust products, typically 54�C (seeFig. 6), which will often be the case when the central-heating is operated from cold orintermittently, where radiators are over-sized for the output required of them, or wherelower-temperature under¯oor heating is used. Even when the return water is hotterthan this, the e�ciency is still higher than achieved with a conventional boiler [9].Thermostats should be resited in open areas away from draughts and distant from

radiators. These will need to be tamper-proof types, to prevent adjustment byunauthorised personnel, although once set, readjustment should not be necessary!Thermostats should be kept clean and dust-free by including them in the main-tenance programme. They should not be used to turn the heating on and o�; easilyaccessible and user-friendly controllers should be installed, perhaps near the mainlight switches, rather than hidden in the plant room behind the boiler. In the tradi-tional pub, which is provided with a heating zone for the sta� ¯at, it would be asimple matter to ®t an extra timeswitch so as to be able to cancel the heating duringthe day, when it is not required; background heat arising from the ground-¯oor barsand kitchen. All timeswitches should then be correctly set, and maintained to theright time. It is easy to overlook timeswitches when re-adjusting clocks to BST or

Fig. 6. Boiler's e�ciencies.


GMT, so resulting in an hour of wasted heating at either end of the day. Manyelectronic clocks now respond to the MSF time-signal from Rugby, and are there-fore self-correcting. Electronic timeswitches and controllers should incorporate thisfeature. Controllers incorporating a compensated start facility should be speci®ed:these are governed by the ambient temperature [10]. This ensures the thermal comfort ofthe building's occupants during occupied hours, irrespective of the ambient temperature.The performance of the enclosed radiators could be improved. The grilles pro-

vided to permit convection should be equally sized above the radiator and below, at¯oor level, and should be at least as wide, and twice as deep, as the radiator theyserve. If this requirement is not met, the radiator's performance is inhibited. Airwaysmust be kept free, and they may be fan-assisted to increase their e�ectiveness. Con-ventionally-mounted radiators should not be obstructed by games machines: soradiators should be placed with consideration as to where such other equipment islikely to be needed in the future. All radiators sited on the inner surface of outerwalls should have additional insulation, or re¯ecting sheets, ®tted behind them, toreduce the rates of heat loss into the wall.The possibility of using under¯oor heating for modern pubs could be investigated.

This is used with lower ¯ow and return temperatures, and therefore is more appro-priate to condensing boilers. It gives a more uniform heating, i.e. without hot or coldspots, is inconspicuous and relatively maintenance free. However, it is cheaper toinstall during the building of the pub (as opposed to retro®tting). Heating pipes arelaid on a frame, well above the water table, above a thick layer of thermal insulantand buried in concrete screed. The pipe spacings may be reduced near windows, togive extra heating to combat cold draughts.Solar-control glass could be ®tted to south-facing windows, to reduce incoming solar

energy and glare during the summer, if these are signi®cant problems. The solution usedin o�ces, of closing blinds to keep sunlight out, is unlikely to be popular in a pub.The winter heating problem in the children's play room at the modern pub could

be reduced by installing ceiling sweeper fans, which would reduce strati®cation bydirecting warm air towards the ¯oor. The thermostats clearly need to be moved fromtheir recess to an open site on the wall. The existing manual switch sites, beneath theheater that they control, could be the ideal place, if tamper-proof thermostats with amanual override switch were used. For summer control, additional opening win-dows should be speci®ed in the design.In fresh-water circuits, such as the water heater, scale may form on the heated

surfaces in the boiler. This will reduce the boiler's heat-transfer capability andincrease the rate of natural-gas consumption, with e�ciency falling by around 25%for a 3mm-thick scale build-up. For the hard-water area of the UK, in which theconsidered pubs are located, ®tting a water softener to the main supply to the waterheater would be cost-e�ective. Many di�erent technologies exist, and traditionalresin-bed water softeners (which require a supply of salt, and renewal of the resinbed) have given way to in-line magnetic, electrolytic and electronic devices whichcause minerals in the water to remain in suspension instead of adhering to metalsurfaces. This latter type of system could replace the water softener ®tted to thedishwasher supply. Furthermore, the washing machine as well as the dishwasher


may then be operated at a lower temperature. Water in pumped heating-circuitsshould be dosed with corrosion inhibitor to prevent scale and sludge build-up withinradiators, which would again reduce their heat-transfer performances.In the traditional pub, fuel combustion in the boilers may need to be improved by

adding extra ventilation grilles in the plant cupboard. A pumped hot-water circulationloop, to keep the water in the pipes hot rather than allowing it to cool whilst standing,would reduce water-heating requirements of the hot-®ll appliances, such as the washingmachine and dishwasher, and of storage tank make-up water due to the prolongedrunning of taps. It would also permit the use of reduced-¯ow spray taps. A return pipewould need to be added, to complete the loop. Alternatively, due to the length of pipeneeded to reach the toilets from the plant room, reversion to the previously-used systemof local electric water-heaters for supplies of water for hand-washing could occur.Heat losses from all hot pipes (i.e. those not at ambient temperatures) could be

reduced by replacing the wrapped lagging insulation with thicker clip-on foam sleeveswith better insulative properties. The exact thickness of insulation to be used, tins,depends on many techno-economic factors, and may be calculated [11] as tins=(reÿri), where

re lnreri

� �� 10

��JNk Tÿ Ta� �

GZ

rin which:

re and ri are the external and internal radii of the insulating sleeve (and thus riis the radius of the pipe to be insulated); e.g. for 25mm diameter pipes,re=0.0255m, ri=0.0125m, and tins=0.013mJ is the cost of a unit of heat; if the heat is provided by burning gas at0.747p+VAT per kWh, via a boiler operating at 75% e�ciency, J=3.25�10ÿ9£/JouleN is the total period in s of operation per year; for a domestic hot-water(DHW) pumped loop in continuous operation, N=31,536,000k is the thermal conductivity of the insulant; for approximate predictions, thismay be taken as k=0.03W/mKT is the temperature of operation of the pipe; for example T may equal 85�Cfor central-heating ¯ow, or T=65�C for return ¯ow or for DHWTa is the ambient temperature, and taken as 20�C for this investigationG is the rate of interest available on the capital if it were not invested in insu-lation, e.g. 8% per yearZ is the cost of the insulant per unit volume; for a 1m length of insulation asdescribed above costing £0.50, Z=322 £/m3

Using these values, the optimal value of re is found to be 55mm, giving an insu-lation thickness of 42mm.At the modern pub, the sta�-¯at's hot-water system could be served by its own

calori®er from the ¯at boiler, so permitting the ground-¯oor hot-water system to beturned o� at night; or perhaps a smaller pumped-circuit could serve the sta� ¯at. At


the traditional pub, where no separate boiler is ®tted in the sta� ¯at, hot water to thebathroom could be provided by an electric local water heater. An electric shower isalready in use.Considerable potential exists for solar water-heating. Solar energy is available all

year round, not just on sunny days, as di�use solar radiation still reaches the groundon cloudy days. This source of free, renewable energy may be used to preheat thewater before it is introduced to a conventional water-heating system. In other words,a second calori®er storage tank is used to preheat the cold feed-water, using solarenergy, before it is passed to the main calori®er for heating to the required tem-perature. Alternatively, a single calori®er with two heating-coils, one powered by theboiler, and one by solar energy, could be used. For a system in which water heaterswith integral storage are used, the extra preheated calori®er is appropriate. In bothcases, the solar energy is collected by solar panels mounted on the roof. The designof the modern pub features a large area of ¯at roof, where panels could be mountedout-of-sight, but the present design features a gentle drainage fall to the north, i.e.opposite to the south-facing slope preferred for solar panels in northern latitudes.In the Midlands and East Anglian regions, typically 1150 kWh is available to be

collected per year for each square metre of roof area. The availability of this solarenergy may not fully coincide with demand, but commercial premises with heavydaytime demands are more likely to bene®t than domestic homes, where the majorrequirements are for evening usage. It is estimated that up to 50% of hot waterenergy requirements can be met in this way. A domestic system may be bought foraround £4000, with a useful lifetime of around 20 years. A system for a pub, withhigh water demand, will cost appropriately more to install; the better match betweenavailability of insolation and energy demand may reduce the payback period, butthis will still be beyond the limits of economic viability under present managementcriteria. Solar water-heating is more likely to become economically worthwhile ifinstalled when the pub is built, possibly with panels displacing traditional roo®ngconstruction-elements; or, it may be wise to include plumbing connections for asolar water-heating system in a new building, allowing for panel installation to occursubsequently, when the unit price of energy rises su�ciently.Another option for the provision of heat is by the use of an air-to-air heat pump.

This uses two heat-exchange coils and a compressor, driven by electricity, toupgrade low-temperature heat from the outside environment. The system tends to bemore than twice as energy e�ective as direct electrical heating. (It may also be usedto cool the premises in summer, by using a valve that reverses the functions of thecondenser and evaporator.) Heat pumps can be used to preheat hot water. Theeconomics of such a system depend on the fuel used to power it; a system such as anabsorption heat pump would be cheaper to run if powered by natural-gas, but areverse-cycle absorption heat pump suitable for summer cooling would be a complexdevice su�ering from a relatively poor coe�cient-of-performance.If coils of pipe are buried in the ground, and water is passed through them to a

heat pump, then low-grade heat may be extracted to heat the premises in winter. Therate of purchased energy consumed by the heat pump is, again, far less than that ofthe heat provided.


Small combined-heat-and-power (CHP) plants are becoming available in smallermodels suitable for pubs. Already in use in hospitals and larger o�ce premises, CHPprovides both heating and electricity from a single source of energy, typically nat-ural gas, so considerably reducing wasted energy and electricity transmission-losses.

4.6. Ventilation

The optimum arrangement for fresh-air supply is for a balanced system, in whichair is not only extracted but also supplied by fans (see Fig. 7). This avoids the ingressof draughts around doors and windows, maintains air pressure in the ventilated spaceto prevent unwanted air exchange with other rooms, and may be adjusted to provideextra air supply to meet the requirements of gas-burning appliances.To ensure that (i) air-supply velocities are low, (ii) draughts and noise are avoided,

and (iii) freshly-supplied air is not merely removed almost immediately by theextractors, a system of ceiling mounted di�users, supplied by ducts in the roof void,is recommended. Where air conditioning is to be installed, the two systems may becombined, to avoid duplication of equipment, by passing supply air through thechiller unit. This system would also permit the recirculation of a certain proportionof the extracted room-air through an electrostatic ®lter, thereby cleaning it for re-useand so reducing the loss of heat to the outside environment. The volume of fresh airintroduced is diminished, while ensuring no signi®cant increase in CO2 concentra-tion occurs within the pub.Improvements to automatic controls are desirable, to relieve bar sta� of the task.

The present continuous-extract ventilation may result in a higher airchange rate thanis necessary or desirable. It would be possible to regulate fan speeds to meetrequirements, with consequent reduction of noise and power consumption. Auto-matic control by air-quality sensors would lead to savings, by sensing when fresh airis required or when recirculation is acceptable. Adding passive infra-red (P.I.R.)occupancy sensors to this system would further enhance its energy-saving potential.Owing to its cost, the system described would be applicable only to new buildings,where the opportunity exists to incorporate the equipment from the start.Both considered pubs have the opportunity to increase ventilation in summer by

opening the windows. This would then reduce the need for forced ventilation.At the modern pub, an extra screen, like the one alongside the passageway to the

toilets, would reduce draughts in the dining area.At the time of writing, a campaign is under way to secure legislation for the pro-

vision of smoke-free zones in public buildings. If this contentious issue is imple-mented, then non-smoking zones would require less ventilation, and so su�er lowerrates of heat loss.

4.7. Kitchen and refrigeration

A reasonable range of modular cooking equipment is ®tted in both consideredpubs, thereby avoiding the unnecessary and wasteful use of large ovens for singlemeals during quiet periods. Conventional gas hobs could be replaced by induction


Fig.7.Therecommended

ventilationsystem

.


hobs, which heat the base of each pan by induction and so waste less heat to thesurroundings, and hence achieve improved sta� comfort. But these are powered byelectricity, which would reduce the cost saving, especially if used during winterafternoon high-tari� periods. The cost saving would depend partly on the con-sequential lower hood extraction rates then required.The importance of sta� awareness of the need for a more rational use of energy is

particularly important in the kitchen. Switching on of equipment that will not be usedimmediately, failure to plan properly a cooking schedule, and the use of equipmentinappropriate to the task, all waste energy, yet are commonplace practices. Where foodis cooked to order as and when demanded, planning is made more di�cult [12]. The`early switch-on' guard against forgetfulness could be eliminated by use of time-switches. All kitchen sta� should be trained in the more e�ective use of their equipment.The problem of overheating and hence power cut-out of refrigeration equipment

requires urgent attention. At the modern pub, it is likely that air extraction wouldoperate more e�ectively to cool the room if balanced inlets were provided. At thetraditional pub, forced ventilation of the storage room containing the mainrefrigerators is desirable. Preferably, the evaporators should be relocated well awayfrom the refrigerators and placed outside the pub but under cover. This wouldrequire skilled modi®cation of free-standing equipment.Improvements to the refrigeration system would also reduce the need to ventilate

the kitchens overnight to keep them cool enough for the next day, with considerablesavings on extractor-fan power use, although with the cheap night-time tari�, this isless signi®cant. Whilst refrigeration equipment remains in the kitchen, it is relativelyine�ective because it dumps its waste heat into a relatively high temperature arti®cialenvironment thereby making the refrigerator work even harder. Some waste heatfrom the relocated refrigerators could be ducted to keep the kitchen warm enoughfor comfort during the mornings.Electrical energy powers the motor which drives the refrigerator's compressor.

This motor is loaded fully only when started up. It is possible to reduce the motor'spower to match the load presented by the compressor, using an electronic phase-angle control-circuit similar to a lamp dimmer. This would reduce the motor'soverall consumption by up to 25%, and reduce the unwanted heat-dissipation in themotor. This technique can also be applied to the cellar and bar chillers. For appli-ances that are in continuous use, this saving is considerable, and may permit thecompressor to run at a lower duty cycle (i.e. on±o� ratio). The equipment's lifetimewould then be extended. There is no reason why this circuit should not be ®tted inthe original equipment, and the buyer made aware of the fact; otherwise, purpose-made 13A plugs are available with the circuit incorporated.

4.8. Cellar and bottle store

New cellars should be designed to achieve a low ratio of surface area to volume, soreducing the total rate of heat loss through the building fabric. As discussed earlier,an underground location will tend to reduce the cooling required. If possible itshould be located near to potential users of the recovered waste-heat, although not


directly adjacent to highly-heated rooms such as kitchens. Good thermal insulationof the walls adjoining the heated spaces, and the ®tting of draughtstrips to the door,are obvious measures. Sliding doors reduce the volume of air changed each timethey are opened, and plastic strip curtains tend to `seal' the room thermally, evenwhen the door is left open during restocking. Adjoining areas such as bottle storesshould be kept cool by using ventilated doors. Maintenance of the chiller in goodworking order will be a cost-e�ective measure. Lighting should never be left onwhen the cellar is unattended, as the heat generated adds to the cooling load. Atimed-delay or occupancy-sensing switch should be installed.A controller should be ®tted to prevent heaters, where provided, from operating

simultaneously with the chiller.

4.9. Power-factor correction

All motorised appliances, including those for ventilation, refrigeration andpumping, should be power-factor corrected, to reduce the current, and hence thepower loss in the wiring. Many tari�s add a penalty for achieving only a low power-factor performance. This has not been a problem at the modern pub, which has atypical power factor of 0.9; the traditional pub's tari� does not feature this penalty.

4.10. Lighting

The use of energy-e�cient lighting means the air-conditioning load will be less,but because of the consequential reduction of wild heat, more space-heating will berequired in winter. Nevertheless, heat, when required, is provided cheaper and withgreater control by the gas-®red heating installation than by electric lamps!Light ®ttings with glass or fabric shades could be retro®tted with integral-gear

CFLs without modi®cation. Any dimming circuits would have to be removed. Ifdimming were still required, rewiring would be necessary, because dimmable elec-tronic control gear requires a `constant' as well as a `dimmed' live supply.Building regulations Part L1(e) (118) [13] now require minimum standards of

lighting e�ciency for all new buildings with a ¯oor area exceeding 100m2, and forrefurbishments of existing buildings over that size. Lighting systems are required to`use no more fuel and power than is reasonable', and should have `reasonable pro-vision for control'. There are several routes to compliance with these regulations,either by the selection of appropriate energy-e�cient sources, or by demonstratingthe overall energy e�ciency of the installation, but a general ®gure of not less than50 lm/W is demanded (although CIBSE recommends a lower limit of 65 lm/W).Tungsten lamps produce only 13 lm/W, with halogen types reaching 20 lm/W,whereas CFL sources range from 50 to 70 lm/W, with tinted versions achievingaround 40 lm/W. Standard ¯uorescent lamps, and 70W high-pressure sodium lamps,as in use outside the modern pub, achieve 60 to 70 lm/W. The overall ®gures for themodern pub and the traditional pub are, respectively, just 36 and 28 lm/W (seeTables 4 and 10), owing to the large number of tungsten lamps in use. Clearly, thereis room for improvement.


Table 20 demonstrates a calculation of the payback period for a CFL retro®t,using lamps with integral ballasts for direct replacement of tungsten lamps. Existingtari�s at both premises are used as the basis for the value of the electricity saved,and comparisons are made for various lamp ratings, across a range of CFL lampcosts. The longest payback period obtained is 1.25 years, at the traditional pub; theshortest, just 10weeks, at the modern pub. It should be pointed out that the calcu-lations for the traditional pub make no attempt to account for the reduced max-imum-demand payments achieved during winter with CFLs ®tted, so the paybackperiod would be reduced to around the same level as that of the modern pub. Apayback period of less than 1 year represents a very approximate value, naturallydepending on the time of the `tari� year' when the retro®t was undertaken.When a pub is built or refurbished, decorative light ®ttings with built-in electronic

control gear for CFL sources, with a dimming option if required, should be used.Normal or tinted lamps may then be employed as desired.Further economies may be made by improving the controllability of the lighting.

Whilst it may be necessary to light the bar during the day, to emphasise that the pubis open for business, certain areas near windows need not be lit. Lighting here shouldtherefore have separate switching. Outside lighting should ideally be controlled by aphotocell and a timeswitch, as it will normally be required from dusk until shortlyafter closing time. A timeswitch alone is inadequate unless regularly readjusted, andeven this method will fail when bad weather brings an early dusk. CFLs used outsideshould be enclosed, as they are highly temperature-sensitive and give less light whencold; the `cluster' of narrow tubes tends to attract dirt, so further reducing output;and where they are within easy reach, they are liable to go missing. Occupancy-controlled lighting, whilst popular in o�ce premises, is not suitable for pubs, wherelighting is used to make the premises appear attractive even when empty.In working areas such as the kitchen, increased use should be made of natural

daylight. The traditional pub's kitchen window opens onto the covered yard; if theyard roof were replaced with transparent roo®ng, and the opaque dome of thekitchen roof light were renewed, it would be possible for the arti®cial lighting to beswitched o� for considerable periods during the day. Also lights in the refrigerationroom are unnecessary during the day, and contribute to the room's excessive tem-perature, so reducing the e�ciencies of the refrigerators. At the modern pub, thekitchen has no windows but is beneath a roof void, so permitting the use of lightducts. These bring daylight from a polished dome collector on the roof, via a mir-rored duct, to di�users in the ceiling of the room, thereby allowing the arti®ciallighting to be switched o� during the day. A calculation is shown in Table 21 thatassumes an ability of each light pipe to replace two 70W ¯uorescent lamps duringthe day, giving a payback period of around 3 years for the purchase cost of theequipment. No allowance has been made for installation costs: it is hoped that ifthese units are incorporated into new buildings, these will be largely absorbed byoverall construction costs.One ®nal, and easily overlooked, lighting ®xture is found in pumped beer-taps on

the bar. These often contain a tungsten lamp to illuminate the display from within,although CFL versions are available. The 80% reduction in heat generated by a 5W


Table 20

Calculation of payback periods for compact ¯uorescent lamp retro®ts

Electricity savings achieved over 15 h daily use, 9 a.m.±12midnight

Modern pub Traditional pub

Tari� STOD MD

Period December±

January

November±

February

March±

October

All year

From Until Days 62 58 245 365

09:00 16:00 Tari� 7.22 7.18 5.48 5.99

16:00 19:00 p 26.20 16.50 5.48 5.99

19:00 20:00 excl. 7.22 7.18 5.48 5.99

20:00 00:00 VAT 5.48 5.48 5.48 5.99

GLS lamp (W)a 40 CFL retro®t (W) 9

Electricity savingb Day 0.06 0.05 0.03 0.03

£ Period 3.57 2.72 7.34 11.95

Year ± ± 13.63 11.95

Payback period CFL cost 5 ± ± 4.0 4.5

Months £ 10 ± ± 8.4 9.5

15 ± ± 12.8 14.6

GLS lamp W: 40 CFL retro®t (W) 11 (tinted)

Electricity saving Day 0.05 0.04 0.03 0.03

£ Period 3.34 2.55 6.86 11.17

Year ± ± 12.75 11.17


Months £ 10 ± ± 8.9 10.2

15 ± ± 13.6 15.6

GLS lamp (W) 60 CFL retro®t (W) 11


£ Period 5.65 4.30 11.60 18.88

Year ± ± 21.55 18.88


Months £ 10 ± ± 5.3 6.0

15 ± ± 8.1 9.2

GLS lamp (W) 60 CFL retro®t (W) 15 (tinted)


£ Period 5.19 3.95 10.65 17.34

Year ± ± 19.79 17.34


Months £ 10 ± ± 5.8 6.6

15 ± ± 8.8 10.0

a Assume GLS lamp cost: £0.50.b Electricity savings include VAT at 17.5%. Costs of maintenance, and of further replacement GLS

lamps, are ignored.


CFL, compared to a 25W bulb, can only be bene®cial for chilled beer held nearby innarrow pipes!

4.11. Heat recovery

Waste-heat availability from the cellar chiller may be poor during winter months:the cellar may even require heating. It is far more feasible to recover waste heat fromthe cellar when combined with recovery of waste heat from food refrigeration. Thisis available all year round, especially in pubs with high rates of food turnover. It isclear that, at present, trapped waste heat during summer causes operating problemsand needs to be carried away.A heat-exchange mechanism between refrigeration condensers and the cold water-

main feeding the water heater would cool the refrigeration condensers, and reducethe heating load on the boiler. This could also be achieved using a pumped loop tobring waste heat from the heat source to a second calori®er storage cylinder for pre-heating the cold feed to the main calori®er. In this way, a moderate distance wouldbe permissible between the heat source and sink. At the modern pub, the refrig-erators are close to the plant room. In the standard modern pub layout, the hot-water plant room is located on the ®rst ¯oor adjacent to the sta� ¯at, i.e. furtherfrom the refrigeration area, and so attempts should be made to keep pipe lengths toa minimum. Naturally, all heat-bearing pipes should be thermally insulated. At thetraditional pub, the refrigeration systems (i.e. heat sources) and water heater (theheat sink) are on opposite sides of the building, some 13m apart.

Table 21

Calculation of payback period for light pipe

Electricity savings achieved over 9 h daily average, from 9 a.m. to 3 p.m. (winter) or 9 p.m. (summer),

and assuming that each light pipe allows two 70W ¯uorescent lamps to be switched o�, thereby saving

170Wa

Tari� Period December±

January

November±

February

March±

October

From Until Days 62 58 245

09:00 16:00 Tari� 7.22 7.18 5.48

16:00 19:00 p ± ± 5.48

19:00 20:00 excl. ± ± 5.48

20:00 00:00 VAT ± ± 5.48

170W electricity cost saved (£) Day 0.09 0.10 0.11

Period 5.36 5.82 27.49

Year ± ± 38.68

Payback period (years) 100 ± ± 2.6

125 ± ± 3.2

150 ± ± 3.9

a A 70W ¯uorescent lamp circuit consumes 85W.


A heat-pump based system would also be able to harness waste heat from othersources, such as the ice-maker and cellar equipment. To become economically feasible,there must be a sink su�cient for the heat recovered, in this case domestic hot-water.The quantity of hot water used each day, and the cost of heating it by natural-gascombustion, will determine the payback period for the system.Further heat-recovery possibilities, such as harnessing heat from the waste washing-

water, are fraught with technical di�culties, must deal with the problem of satisfyinghealth and safety regulations (as a heat exchanger would bring fresh and waste waterinto close proximity), and would usually have relatively long payback periods.Although the power demands of tumble dryers form only a small proportion of

the energy load incurred in a pub, heat recovery from exhaust-air is possible and hasbeen investigated . Dryers are available with heat-recovery between the inlet andoutlet air¯ows, or with latent heat recovery from the moist exhaust air, so requiringa condensate drain or drip tray [14]. Condensation occurs when the hot, moist air ispassed through a heat exchanger cooled either by air or water; the latter removingthe need for an air vent to the outside. These models would incur a lower electricaldemand, which would permit considerable savings, especially when used duringpeak-tari� hours, or during high-demand periods. Alternatively, gas-fuelled modelsmay be used, which when combined with heat recovery would give a far lower runningcost. Tumble dryers may also save energy by switching o� the heat source for the ®nal10min of the drying cycle, thereby relying on residual heat to complete the process, anddelivering a cooler load at the end. Air humidity-sensing could automate this feature, soavoiding the unnecessary running of the dryer once the load has been dried.

4.12. Other possible improvements to any modern pub's written speci®cation

The orientation of the considered modern pub is well chosen, with the barwindows facing south for solar gain by the occupied areas, whereas the cellar wallsbeing on the north-east corner experience far less insolation intensity. It is notknown whether this fortuitous orientation was intentional, or due to other factorssuch as site layout, road access and view.

5. Conclusions

The overriding priority for a brewery, as for any commercial enterprise, is to makea ®nancial pro®t. Leaving aside the other areas of the business, the managed pubsmust generate their share of the pro®t, and the planned rate of expansion of sitesdemonstrates that they do so. Where investment in new methods can result in arunning-cost saving, the payback period required is usually less than one year if themeasure is to be examined seriously. The urgency with which new pubs, once plan-ned, are built and opened, emphasises the immediacy with which returns arerequired. This rules out many of the worthwhile energy-related improvements dis-cussed here, if intended to be applied as retro®t measures; nevertheless they mayappear more attractive while the pub is being built or during a major refurbishment.


A further factor that may have been overlooked is the possibility that trade will riseif the thermal comfort improves after a refurbishment, and that this should be con-sidered in the payback calculations for any measures incorporated. The emergenceof competition within the energy-supply market has led to falling, not rising, unitenergy prices. At present, the pubs' turnovers are around 30 times their energy costs.How can energy savings through energy e�ciency of, say, 25% seem signi®cant inthis context? One argument is the `look after the pennies' approach, whereby takingcare of environmental conditions within a building will increase the productivity ofthose who work there, giving a better return for the labour costs which form thelargest portion of the expenditure. This is unlikely to apply to a pub, where customerschoose to spend their leisure time, although it may be relevant to uncomfortableworking conditions in an overheated kitchen.Division of the company, whilst essential in such a large organisation as a leisure

business with so many di�erent functions, results in further obstacles. For example,the possibility of recovering waste heat from the cellar chiller to preheat hot water isunderstood, but has not been implemented for political as well as technical reasons.Separate administrative control of the various functions of building design andconstruction, pub operation, cellar maintenance and bill payment, dampens theincentive to cut running costsÐinvestment by one arm of the organisation wouldresult in less clearly identi®able savings for another. This problem is clearly illu-strated by the reluctance of managers to ®t CFLs, as whilst they are encouraged todo so, the cost of the lamps would be met by the pub's budget, but the bene®ts interms of reduced bills would be enjoyed by the brewery which pays the energy bills.Thus there is no incentive for the managers to ®t CFLs, and this would presumablyapply to other energy-saving equipment.The speci®ers of equipment and furnishings are more likely to be quali®ed in the

®eld of interior design rather than possess a scienti®c background. In this event,energy e�ciency is unlikely to feature in the choice of equipment. It has been seen howinterior designers forbid the use of CFLs, and yet other parts of the organisationrequire pub managers to install them. Thus there are often con¯icts of interest.Recent advances in environmental legislation, however, may provide the necessary

encouragement. Through a `stick and carrot' incentive approach, legislation givescompanies who achieve accreditation the opportunity to use the fact as a marketingtool. This may place companies who have not sought accreditation at a commercialdisadvantage. Compliance with such legislation applies not only to breweries, butalso to the contractors hired to build, equip and maintain pub premises, to themanufacturers of the equipment, and to energy-supply companies. As competitionbecomes established and the new supply companies turn their attention to com-pliance with the power-generating plant emissions legislation, unit energy prices willbegin to rise again. Carbon or toxic-and-noxious pollution taxes have yet to beintroduced, but there is a consensus that these are inevitable and only await thepolitical will to be implemented.The appointment of an energy manager to serve the entire estate of the brewery

would permit more detailed studies to be carried out, ®nding common problems andapplying the remedy to each in a single programme, thereby reducing costs. Best


practice could thus be propagated throughout the estate. More appropriate tari�sfor energy supply could be determined for each pub, given its load pattern and thetari�s available locally. Such an energy manager should be able to cover his ownsalary costs by the energy-cost savings realised.Regional energy e�ciency o�cers can provide specialist advice and support con-

cerning the achievement of energy e�ciency within an organisation. They are basedat the appropriate local regional Government O�ce.Reducing energy consumption in a pub could feature as part of a `greener' image

for the brewer: it could be used as a marketing tool. The building industry at largeseems reluctant to take rapid steps towards achieving signi®cant improvements inenergy e�ciency, but once a lead is taken, others would surely follow. Majoreconomies-of-scale for new components (such as solar panels) are yet to materialiseto strengthen the ®nancial argument for installing such equipment.

6. Further improvements that should be achieved in subsequent surveys

Closer attention can be paid to certain factors to improve the accuracy of theresults, and these are listed here.If the volume turnover of beer through the cellar, and the temperature di�erence

between the time of delivery to the premises and the point of dispensing to the cus-tomer are known, the energy required for cooling the beer may be calculated.The energy loss via ventilation requires a knowledge of the volumetric throughput

of the ventilation fans, the temperatures and moisture contents of exhaust air andincoming fresh air, and the fans' motor power-rating.An average value for the energy loss through cellar walls could be calculated by

combining daily weather data with known pertinent wall areas, U-values and sur-face coe�cients (which depend on surface type and wind exposure).If the volumetric hot-water usage is known, an accurate value for the corre-

sponding natural-gas usage in water heating can be deduced.The warmest air expelled is that from the kitchen extractor hood and the tumble

dryers; hot water from dishwashing and laundry operations is also lost. These arethe most likely sources for achieving economic waste-heat recovery.

7. Footnote: The UK's ®rst solar pub

A visit was made to `The Jolly Gardeners' public house in Wandsworth, SouthLondon, where plans for `the UK's ®rst Solar Pub' were then shortly to be put intopractice. In partnership with RENUE (Renewable ENergy in the Urban Environ-ment) and with Millennium Commission funding, the manager of this traditionaltown pub planned to install solar panels, a heat-pump system for cellar cooling withheat recovery, and numerous other energy-saving measures, some of which aredescribed in this study, with the aim of reducing the amount of electricity boughtfrom the grid supply. The Jolly Gardeners was built around 1880, and the present


project demonstrates that energy `modernisation' is feasible within old buildings, tocounter the impression that low-energy building projects tend to relate only tonewly-built premises. As the pub is a focal point for the local community, the projectalso raises energy awareness amongst its customers, who come from all walks of lifeand were suspicious about the project, even ridiculing it when it was ®rst announced.However they have been converted into enthusiastic supporters, and it is hoped thatif the project is a success, it will motivate customers to reduce their own domesticenergy usage. The scheme also features on the Internet.The project had been fully costed, and the total expenditure was put at £106,000.

It was also estimated that, at prevailing energy costs, the payback period may be aslong as 30 years, which may be longer than the lifetime of some of the equipment. Ifenergy costs rise as forecast, however, this payback period would shorten, and theeducational value of this pilot project, both for its owners and for observers, mustnot be overlooked. The Jolly Gardeners is smaller than those featured in this report,and has less extensive catering, so its rate of energy consumption is lower, and it ismore of a challenge to make an economic case for energy saving there. The addi-tional measures planned were the insulation of the underground cellar (for which theeconomic thickness of insulation had been calculated to be 80mm), installation of awater softener to reduce scale build-up, a circulating hot-water ring main to elim-inate standing losses, low-energy lighting, light pipes to bring daylight to thekitchen, and low-emissivity glazing. As it was estimated that the rate of energydemand would always exceed the supply of solar energy, no storage was planned,but the photovoltaic solar panels would directly feed an inverter to supplement themains electricity-supply.This project would win enhanced status and attention for The Jolly Gardeners, for

its application of new technology, whilst permitting it to continue its normal life as apub. This special status of `UK's First Solar Pub' can only be won once, but thetechnology can most certainly be applied to other pubs if economic factors and thepolitical will are favourable.

Acknowledgements

The two public houses, chosen for detailed assessments of their energy perfor-mances, are representatives of the ancient and modern categories. Their exact iden-tities have been concealed deliberately so that full co-operation with their sta�s andthe brewery could be obtained without embarrassment. We are very grateful for thiscollaboration.

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UK, 1981.

[7] The resource, July/August 1997. Cambridge: Eclipse Group.

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energy thrift and thermal comfort in public houses

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