energy wise hotels...• electricity; and • thermal energy – this is usually natural gas,...

Energy Wise HotelsTOOLKIT DECEMBER 2007

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02 Energy Wise Hotel TOOLKIT

IntroductionThe hotel industry is one of the fastest growing industries in the world due toincreased tourism and market globalisation.

At the same time hotels are providing more facilities and services to customers,leading to increased energy consumption.

As the cost of energy in Australia is increasing, and its use is shown to accelerateclimate change, the hotel industry is becoming more aware of the impact of theirbusiness on the environment. Today most guests are aware of climate change due to the generation and consumption of energy.

The Energy Wise Hotels Toolkit has been developed to assist accommodation serviceproviders to reduce their energy consumption. The toolkit also outlines energyconsumption patterns in hotels and the impact this has on our environment.

This toolkit provides comprehensive recommendations on energy reductionopportunities with technical explanations. Hotel management can use the toolkitto develop the action plans necessary to improve the energy efficiency of the hotel,without sacrificing the comfort of guests. This not only makes the hotel business more profitable but presents a favourable image of hotels that can be marketed.

Who is this Toolkit for?The Energy Wise Hotels Toolkit has been developed for:

• hotel management;

• engineers; and

• staff members responsible for training and work practices.

The toolkit is divided into chapters to enable hotel operators to apply relevantinformation to their own hotel. Each chapter may not be relevant for every hotel,depending on the structure and utilities at each hotel.

The toolkit is based on information obtained from a series of 10 energy auditsundertaken as part of the City of Melbourne’s Savings in the City Green Hotelsprogram. Case studies carried out by Energy Efficiency Opportunities Australia (EEO) are also sourced throughout the toolkit, as well as information collected from general surveys and consultancies in energy conservation.

The Energy Wise Hotels Toolkit

03Energy Wise Hotel TOOLKIT

Using this ToolkitThis toolkit comprises nine sections:

Section 1: Why be energy efficient?

Outlines benefits of conserving energy

Section 2: Energy use and performance indicators

Identifies which areas in hotels are generally the largest energy consumers

Section 3: Energy monitoring and tracking

Deals with the key parameters to be monitored and tracked in order to improveenergy efficiency

Section 4: Taking action

Explains how to start implementing energy saving ideas in your hotel

Section 5: Understanding energy

Basic explanation of energy

Section 6: Energy saving initiatives

Outlines possible energy saving opportunities for hotels

Section 7: Involving staff and guests

Outline of engagement and training techniques for staff and guests

Section 8: Renewable energy

Explains the role and value of sourcing energy from renewable sources suchas wind, power and solar power

Section 9: Technology discussion

Includes three fact sheets with more detailed information and tips to aid energyconservation in your establishment. These include:

• lighting;

• heating, ventilation and air conditioning;

• variable speed drives; and

• environmental management systems.


The Energy Wise Hotels Toolkit

05

AcknowledgementsWe would like to thank the following organisations for their help and information:

• Enman Pty Ltdwww.enman.com.au

• EEO, Department of Industry, Tourism and Resources

www.energyefficiencyopportunities.gov.au

• Crowne Plaza, Melbourne www.crowneplaza.com.au

• Grand Hyatt, Melbournewww.grandhyatt.com.au

• Hotel Ibis, Melbournewww.hotelibis.com.au

• Jasper Hotel www.jasperhotel.com.au

• Saville City Suites, East Melbournewww.savillehotelgroup.com

• Saville on Russell, Melbournewww.savillehotelgroup.com

• Melbourne Marriottwww.marriott.com.au

• Sofitel Grand Hotel, Melbournewww.sofitel.com.au

• Sebel Melbournewww.mirvachotels.com.au

• Hilton on the Park, Melbournewww.hiltonhotels.com.au

This Energy Wise Hotels Toolkit was researched and produced by Enman Pty Ltd.

Energy Wise Hotel TOOLKIT

Why save energy?Energy is fundamental for maintaining comfort standards in a hotel however it is important this energy is used efficiently. Like water and waste efficiencies, the benefits of being energy efficient are:

• reducing your hotel’s environmental impact;

• cost saving on energy bills; and

• enhancing your hotel’s reputation for protecting the environment.

Energy is the largest generator of human-induced greenhouse gas emissions.Greenhouse gases cause global warming which is detrimental to our naturalenvironment systems.

Some of the effects of global warming are:

• a rise in sea level causing coastal damage;

• an increase in the likelihood of extreme weather conditions suchas droughts, floods and cyclones;

• health impacts because of the spread of tropical-borne diseases, the increase of flooding and other such climate changes;

• damage to ecosystems and species diversity;

• damage to agricultural output and food supply; and

• an increase in the earth’s surface temperature causing heat stress and damage.

Reducing the energy consumption in hotels helps reduce greenhouse gas emissions.

Refer to Appendix B for details about the environmental impact due to energygeneration and use.

Why be energy efficient? 1


Energy use and performance indicators 2

09

Before energy use can be reduced in a hotel, motel, servicedapartment or hostel, it is necessary to understand where energy is being consumed. It is also helpful to compare your hotel’s energy consumption to other similar hotels.

2.1 Energy balance An ‘energy balance’ shows where and how much energy is being used in the hotel.

The two most common sources of energy consumed in hotels are:

• electricity; and

• thermal energy – this is usually natural gas, however in remote places LPG and other forms of fuel are used.

Typical energy consumption in hotels is spread relatively evenly to a number of usesincluding kitchens, heating, cooling and lighting. This is shown in Figure 2.1 below.

Figure 2.1: Example of total energy consumed in a hotel

Most of these uses are serviced by electricity (See Figure 2.2), with gas primarily used for hot water and heating (see Figure 2.3).

Figure 2.2: Typical electricity consumption


10% AHU, FCU and ventilation fan

10% Laundry

10% Lighting

3% Refrigeration

13% Space heating

14% Domestic & pool water heating

15% Chiller

1% Miscellaneous

7% Pump

7% Kitchen

10% Electric heating

17.6% AHU, FCU and ventilation fan

17.2% Electric heating

26.6% Chiller

5.6% Refrigeration

12.0% Pump

18.7% Lighting

2.3% Miscellaneous

Figure 2.3: Typical thermal (gas) consumption

2.2 How much energy can you save?It is very important to know how energy efficient your hotel is and where potentialsavings could be made through energy conservation.

Performance indicators and benchmarking

Benchmarking your initial energy use is a convenient way to compare the energyefficiency of hotels. It is important for the benchmark to consider the star quality rating of a hotel so that the comparison is meaningful. Benchmarks are also known as an ‘energy index’ or as ‘performance indicators’.

Energy performance benchmarking is an internal management tool designed to provide ongoing, reliable and verifiable tracking of the hotel’s performance. Realistic targets can then be set for improving efficiency by hotel management.

The most useful performance indicators of hotels are:

• gigajoules (GJ) per square metre of floor area; and

• GJ per guest.

Table 2.1 shows energy benchmarks that are used by hotels in Australia.

Table 2.1: Benchmarks for energy consumption per square metre (GJ/m2.year) for a hotel

Note: Benchmark figures are based on surveys conducted on hotels in various regions,

and buildings of similar nature by Benchmark Hotel, EEO (Energy Efficiency Office)

and IHG Hotels operating results.


16% kitchen

32% domestic & pool water heating

30% Space heating

22% Laundry

Rating Energy use (GJ/m2.year)

Very Good < 0.95

Good 0.95 - 1.09

Satisfactory 1.09 - 1.24

Poor 1.24 - 1.38

Very Poor > 1.38

To achieve energy savings it is important to monitor and track energy consumption, and generate reports on a regular basis. Such a system forms the basis of any ongoing and sustainable energy management program.

There are standard software packages available to monitor and track energy and greenhouse gas emissions.However, hotels and hotel groups can easily create their own simple database. Some of the key features required for tracking energy efficiency are:

• comparison of energy consumption and key performance indicators;

• bar graphs of energy use and performance index for 12 months over the past few years as shown in Figure 3.1 and Figure 3.2; and

• comparison of actual energy use against target consumption (Figure 3.3). The target can be generated according to seasonally adjusted monthly energy use.

Figure 3.1: Bar graph of electricity consumption over three years

Energy monitoring and tracking 3


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Figure 3.2: Bar graph of natural gas consumption over three years

Figure 3.3: Actual electricity consumption versus target consumption

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Taking Action 4


In order to implement successful energy saving you must have a well structured and realisticplan with management support.

4.1 Following an energy management frameworkAdopting a sustainable energy management framework is the first step of any energy and greenhouse gas emissionreduction program. When developing an energy management plan it is recommended you consider the steps shownin the following flow chart:

Figure 4.1: Energy management plan represented in a flow chart

The following sections outline each stage of the framework in more detail.

4.1.1 Corporate energy policyA corporate energy policy sets the directive and basis on which the energy management plan is developed. This policy must be approved by senior management and endorsed by the CEO. The policy is then circulated to all staff to ensure a common understanding by staff at all levels.

The corporate energy policy should link to other environmental policies, primarily waste and water management.

An example of a corporate energy policy is shown at Appendix A.

Adopt a Corporate energy policy

Develop an energy management plan

Adopt a Energy management coordinator

Identify and train energy champions

Non-capital intensiveEnergy Management Initiative

Capital intensiveEnergy Management Initiative


4.1.2 Developing an energy management planThe ‘energy management plan’ is the plan of action to improve the energy efficiency of a hotel by setting out clearobjectives and targets. To achieve these objectives, management needs to assign responsibilities and allocate resources.

4.1.3 Energy management coordinatorsAn ‘energy management coordinator’ is required for all accommodation establishments; one per hotel or one pergroup of hotels of the same chain. Their responsibility is to manage and coordinate all energy management functionsin the hotel.

The coordinator needs to monitor and report energy consumption and performance as well as drive all of the plannedenergy management initiatives (EMIs) of the hotel. The coordinator must be fully trained and motivated to carry out the required tasks efficiently and effectively.

4.1.4 Energy champions‘Energy champions’ are staff members who can assist with the day-to-day energy management action plan. Hotel service engineers and other supervising staff are the ideal people to be designated as energy champions.

Energy champions should be properly trained along with the energy coordinator to achieve satisfactory outcomes for the hotel. This is a great professional development opportunity for motivated staff.

4.1.5 Introduce energy awareness programIntroducing an energy awareness program consists of several components which are discussed in detail later in this toolkit. These are:

• education program;

• display of corporate commitment in staff member common areas; and

• promotion of energy management through various means including stickers.

Figure 4.2: An example of energy sticker

Understanding energy 5


It is important to understand the basics of energy to monitor and control it.

A guide to understanding energy unitsWhat does the term ‘power’ mean?

The term ‘power’ refers to the rate of change of energy. It is a way of describing the capacity needed to make appliances or equipment operate effectively.

For example:

A lamp of 100 wattage: Power is 100 wattageA heater rated 1 kilowatt (KW): Power is 1 kW (1000 wattage)

What does the term ‘energy’ mean?

The term ‘energy’ links ‘power’ to length of time.

ENERGY = POWER x TIME OF OPERATIONENERGY = WORK DONE BY A SOURCE

Unit of energy = Joule (J) 1 kilowatt hour (kWh) = 1 kilowatt operates for 1 hour 1 kW = 3.6MJ/hr= 10 lamps operate for 1 hour 1 kWh = 3.6 MJ= The heater operates for 1 hour

How do ‘energy’ and ‘power’ link together?

Most common units:• POWER = kW , joules/sec

• ENERGY = kWh , GJ

• 1 kWh = 3.6 MJ

What are the main types of electric power transmission?

1. Three-phase electricity

Many electric motors employ a three-phase load design which runs three alternating currents of the same frequency at different times to give constant power in an efficient, compact and longer-lasting way. Used in pumps, fans, blowers, compressors and some air-conditioning units.

• Power (kW) = Volts (line) x Amps (line) x 3 x Pf

Note: The power factor (Pf) of electric motors is designed at around 0.8 to 0.9. The Pf decreases as motor load decreases.

2. Single-phase electricity

Employs a single circuit of electricity current.

• kW = Volts x Amps x Pf

Example 1:

1 kW motor (full load) operates for 16 hrs/day, 300 days/yearPower = 1 kWEnergy = 1 x 16 hrs/day x 300 days /year

= 4,800 kWh/year

• 1 Btu = 1.05506 kJ or 2519 kcal

• 1 calorie = 4.187 joules


5.1 Greenhouse gas emission factors

Once the amount of power and energy used for operations is understood, it can then be converted into greenhouse gas emissions.

Factors used to calculate the greenhouse gas emissions associated with consumption of different fuels and activities are provided below:

• Electricity greenhouse gas emission factor: 1.325 kg CO2-e/kWh

• Natural gas greenhouse gas emission factor (Small user <100,000 GJ pa): 63.6kg CO2-e/GJ

These emission factors are sourced from the AGO Factors and Methods Workbook and are updated on an annual basis. www.greenhouse.gov.au/workbook/index.html

5.2 Energy pricesThe table below shows the structure of a typical electricity bill. Based on the prices shown in the table, a number of energy charges have been calculated and listed.

Table 5.1 - Breakdown of electricity prices for typical electricity bill structure

5.3 Calculating the cost of electricity.

To calculate the cost savings from the estimated energy savings, you need to know the real cost of energy per kWh you save, cost savings from the bill which is shown as average charges as below.

Example energy charges:

• Peak charges: 8.72 c/kWh

• Off-peak charges: 4.02 c/kWh

• Average charges: 7.31c/kWh(Assuming 70 per cent peak and 30 per cent off-peak energy use)

• Demand cost: $72/kW-month

Typical cost

Energy Peak 6 c/kWh

Off-peak 3 c/kWh

Network Network peak 2.5 c/kWh

Network off-peak 0.8 c/kWh

Network standing charge

Demand $6/ kW-month

Other E&REC – MRET 0.1 c/kWh

NEMCO ancillary charge 0.07 c/kWh

NEMCO pool fees 0.05 c/kWh

Meter provision $900 pa

Retail service fee

Energy saving initiative 6


Energy savings equal financial savings. Hotels can deliver a range of energy saving initiatives grouped as either:

Initiatives that require little or no capital.

These are the energy management initiatives to consider first in your energymanagement plan as they require little or no finance and are simple to do.

Initiatives that require capital investment.

These should be considered based on individual merit.

These opportunities are outlined in more detail in the following sections.

6.1 Energy management initiatives – the first stepsSimple energy management initiatives that require little or no financing include:

• changing operations and practices around the hotel;

• purchasing energy efficient equipment;

• energy efficient maintenance; and

• introducing an energy awareness program for staff and guests.

6.1.1 Change of operational practiceBy simply altering the operations of your accommodation facility you can save a large amount of energy with little cost.

Some of the simplest ways to conserve energy are:

Lights• Turn off lights when not required. Lights in common areas are under staff

control; therefore staff should turn off lights in common areas when not in use. This can be achieved by conducting a staff awareness program.

• Dim reception and foyer lights from late night to early morning when there is minimal activity. This can be achieved whilst still maintaining guest safety and comfort.

• Lights in guest rooms are under guest control. Encourage guests to turn off lightsthrough energy and climate change promotional stickers. Invite guests to join theefforts of the hotel to reduce greenhouse gas emissions and inform them of someof the hotel’s initiatives. This will encourage guests to reduce their own energy use.

Air conditioning• Similar to lighting, the air conditioning can be turned off when its use

is not necessary.

• Increasing the room temperature during cooling provides energy savings of around five to 10 per cent of the cooling load.

• It is recommended the cooling temperature is set to 24°C.


Heating• Decreasing the room temperature during the cooler months can lower the

heating load by five to 10 per cent. It is recommended the heating temperature is set at 18°C.

Kitchen• Turn off the exhaust fans in the kitchen when not required.

• Reduce the speed of fans during times of low kitchen activity by using a ‘variablespeed drive’. Installing a variable speed drive is a wise financial investment, as the reductions in energy bills quickly repay the initial investment.

Hot water• Set hot water temperature to as low as possible. The recommended hot water

temperature is around 60°C.

Office equipment• Turn off office equipment such as computers, computer screens and printers when

not in use, especially after hours. Explain the benefits to staff so they participate inreducing the energy needs from office equipment.

• Always enable energy star features on office equipment to give it the ability topower down or sleep when they are not being used and wake up when they areneeded. For more information refer to the Australian Department of EnvironmentGreen Office Guide 2001.

6.1.2 Buying energy efficient equipmentIncorporate the purchase of energy efficient equipment into the energy management program.

Typically energy efficient equipment is more expensive than the standard option;however the energy savings achieved usually provide adequate paybacks. In addition, equipment needs to be replaced periodically anyway so this is often a perfect opportunity to invest in energy efficient equipment.

Some examples of energy efficient equipment are:

• Office equipment – typically any equipment with a star rating showing is a highlyenergy efficient product.

A flat screen monitor uses less energy than a traditional CRT monitor; and laptopsconsume less energy than desktops.

The hard drive of an average computer uses 49 watts when fully turned on, 29 wattswhen asleep and two watts when switched off.

The average monitor uses 60 watts when in use, 6.5 watts when in sleep mode andone watt when switched off.

Make sure energy saving modes are installed on computers and are operational.

• Use recycled paper which requires 90 per cent less water and 50 per cent less energy to produce and whenever possible print on both sides of the page. Buy other recycled or reused products wherever possible such as furniture. Lease photocopiers where possible.

• Laundry services – buy washing machines and dryers with higher energy starratings that show energy efficiency performance. Be sure to consider waterefficiency when making these purchases.


• Motors and chillers – purchase higher energy efficiency equipment. It is worthpaying more for an energy efficient motor (likely to be an increased cost of around10 to 20 per cent) with an efficiency of between two and four per cent. Over thelikely 20-year life of the equipment, the capital outlay is small compared to the cost of running it as shown in Figure 6.1 below.

Figure 6.1: Life Cycle Costs of a 55 kW Motor

Assumption: 20-year service life with an electricity price of 10¢/kWh.

• Lighting – buy compact fluorescent lamps instead of incandescent, this can achieve energy saving of around 75 per cent.

• Refrigeration – the energy efficiency of refrigerators varies by 50 per cent even if they meet new stringent minimum energy performance standards (MEPS)introduced in 2005. When purchasing a new refrigerator consider high energy star ratings over cheaper, low star refrigerators as these models will offer greater cost savings.

6.1.3 Energy efficient maintenanceThe present trend in the accommodation industry is to cut down maintenance costsallowing just enough to keep everything running smoothly. However, extending themaintenance from preventative or breakdown maintenance to energy efficientmaintenance proves to be cheaper in the long-term.

Energy efficient maintenance reduces energy costs and extends the life of equipment.Some of these maintenance procedures are:

Air handling units

Air handling units condition the air and recirculate it to areas for cooling, heating andventilation. Maintenance procedures include:

• Replacement of filters in air handling units and fan coil units. The filters can becleaned or replaced about twice a year. This improves energy efficiency as well as room air quality.

• Regular calibration check of thermostat control for the air conditioning system.

• Cleaning the motor casings.

• Belt drive – A V-belt is one of the most common types of power transmission to fans in air handling units. If the tension of the belt is too high or low or the beltis worn out, the transmission efficiency of the motor is reduced. Transmissionefficiency is dependent on pulley size, torque, under or over belting and V-beltconstruction. Belt tension is also a very important parameter. Under and overbelting can cause an efficiency drop of as high as five per cent.


1.4% Motor cost

98.6% Energy cost


• Regular checking of the damper control – many of the air handling units found in hotels have an economy cycle. This allows the fresh air and relief air dampers to open or close depending on ambient weather conditions. The economy cyclecan reduce the cooling load by up to 30 per cent. It has been observed previouslyin other hotels that dampers are often faulty or frozen which causes the system to operate inefficiently.

Cooling towers

New types of cooling towers with condensers are emerging. These are mixed wet and dry types which are more water and energy efficient. These condensing coolingtowers operate as air-cooled systems in winter and water-cooled systems in summer.

• Regular checking of cooling tower performance – it is sometimes found that coolingtower capacity reduces due to: unequal water distribution; water not wetting thecooling tower pack; or the spay nozzles not spraying efficiently. As a result, thecooling capacity is reduced along with the energy efficiency of supplied chillers.

Motors• Rewinding motors – motors are used for pumps, fans, chillers and a large amount

of other equipment. As they fail they are normally rewound. Rewinding a motor ischeaper than purchasing a new motor; however each time a motor is rewound itsenergy efficiency is reduced.

The efficiency of rewound motors drops due to the intense heat applied in thestripping of old windings and from using cheaper, thinner gauge wire. Rewinds arenormally priced at between 60 and 80 per cent of the price of a standard new motor.On average, the efficiency of a motor decreases by about one per cent each time the motor is rewound.

• Supply voltage – when the three-phase voltages are not equal, the motor lossesincrease substantially. This is normally due to unequal distribution of the single-phaseloads, such as lighting. A modest phase imbalance of two per cent can increasemotor losses by 25 per cent or overall motor efficiency by around 1.6 per cent.

When operating at less than 95 per cent of design voltage, motors typically loseefficiency by two to four per cent. Supply voltage over and under the rated voltagecan also significantly reduce energy efficiency.

6.2 Energy management initiatives – capital intensiveCapital intensive initiatives are energy saving projects that require small to largefinancing. These projects should be considered based on their individual merits which include:

• payback time – how quickly the works pay for themselves in the form of reduced energy bills and maintenance costs;

• quantity of saving – of financial dollars and greenhouse emissions; and

• other associated benefits such as water, waste, health, noise and amenity improvements.

21


6.2.1 Energy saving in HVAC systemsHeating, ventilation and air conditioning systems (HVAC) are typically a major energyuser in hotels. HVAC can consume as much as 70 per cent of a hotel’s total energyconsumption. However, this is also an area where significant improvements can bemade. Energy efficiency improvement of up to 50 per cent is achievable depending on HVAC configuration control and operation.

The energy saving opportunities in HVAC systems are:

Economy cycle – this is one of the most commonly recommended energy savingfunctions for HVAC systems. The economics of retrofitting an economy cycle dependon the following factors:

• Capacity of the AHU – fan sizes less than 5 kW are less economically viable.

• Fresh air supply duct size – if the fresh air duct which brings the fresh air to theAHU does not require any modification to bring 100 per cent fresh air it is easy and more economically viable to retrofit an economy cycle.

• Control system – if there is a building management system (BMS) the facility shoulduse direct digital control (DDC) and enthalpy-based control to provide more energysavings. The anticipated energy saving is around 25 per cent in Melbourne. If there is an economy cycle fitted, then check the operation as follows:

- Is the controller still functional?

- Is the controller calibrated correctly?

Economiser – an economiser is a heat recovery system. Installing an economiser is a good way to improve the energy efficiency of a HVAC system. An economiser is more economically viable when implemented during the installation of the HVACsystem. You should consider an economiser when the AHU system is on 100 per centfresh air. Economisers are generally more viable in extreme weather conditions such as very cold or very hot. Melbourne’s weather is suitable for the use of economisers.

Variable speed drive (VSD) – installing variable speed drives on supply and return air fans is a new trend in energy management. Implementation as a retrofit is verysimple and economically viable. Conventionally VSD were viable only if the system was designed as a VAV (variable air volume) system. However, an advanced controlalgorithm allows you to implement a VSD for any type of air conditioning system. The anticipated energy saving is around 45 per cent of the fan energy depending on the algorithm used for control and the humidity requirement in the space. As hotelair conditioning generally functions to provide comfort conditions, humidity is not a critical parameter.

Infiltration of air – reducing the infiltration of ambient air into air conditioned spacesreduces the air conditioning load. The guest entrance door in the foyer of the hotel is an area where automatic double doors or revolving doors can be considered.

Room temperature setting – room temperature setting is one of most important criteria for energy conservation through change of operational practice. It is recommended room temperatures in winter are set as low as possible; even as low as 18°C and during summer as high as 25°C.



Chiller system – chillers are another large energy consumer in the hotel industry.Chiller efficiency can be improved by measures outlined below.

• Use energy efficient chillers: if chillers are old, replace them with a water-cooledturbo compressor fitted with a VSD. This can improve energy efficiency by up to 400 per cent.

• Use a different size or capacity of chiller: a smaller capacity chiller should be used in low load conditions and a larger chiller for high load conditions. Operating a chiller at part-load conditions reduces the efficiency of a conventional fixed speed chiller.

• Electronic expansion valve (for reciprocating compressors): if the expansion valve is electro–mechanical, replace it with modern electronic valve. This can improveefficiency by around 15 per cent.

• Use a chiller with remote set point control facility.

• It is common practice to design the cooling tower with minimum capacity.Increasing the cooling tower capacity can increase chiller efficiency. Therefore, provide adequate cooling capacity for cooling tower.

• Use a common cooling tower for all chillers with common header and discharge -this not only provides the opportunity to save energy but also provides greaterreliability of the chiller system.

• Use variable speed drives for the following areas:

- secondary chilled water pump;

- primary chilled water pump;

- condenser water pump; and

- cooling tower fans – VSD for a cooling tower fan not only reduces fan energy but also can improve energy efficiency of the chiller compressor.

• Tune control system to avoid simultaneous heating and cooling.

• Insulate ducts and chilled water pipes to prevent heat gain.

Energy efficient comfort condition of HVAC system – the comfort level of air conditioned spaces depends on the following variables:

- gender;

- activity;

- relative humidity and dry bulb temperature; and

- air movement.

Refer to section 9.2.2 for more information on air conditioning comfort

Why cool high?

Adjust your cooling comfort zone to as high as possible. An increase of 1°C in temperature will reduce your energy consumption by five to 10 per cent.

Why heat low?

Adjust your heating comfort zone to as low as possible. A decrease of 1°C in room temperature will reduce your energy consumption by five to 10 per cent.


Glazing and shading – glass windows are one of the major contributors to airconditioning load. Appropriate measures must be taken to ensure hotel windows are efficient. Some energy saving measures that can be implemented are:

• window glazing – a double-glazed window will not only reduce the cooling and heating load of the building but also reduces noise levels in the building;

• use of energy efficient glass that allows less heat to transfer through the glass;

• use of tinted glass to reduce solar absorption – this not only reduces energyconsumption but also improves comfort conditions in the hotel. It is especiallyeffective for windows facing north and west.

Building insulation – building insulation also helps reduce the heating and coolingload of a hotel. The following forms of insulation will be of assistance:

• roof and wall insulation;

• roof paint – use light or white colour, or specialised solar coating to deflect solar radiation;

• building shading – planting of trees around the sunny side of the building to provide shade for lower levels of the building.

6.2.2 Key card room controlHotel key card control is one of the largest potential energy savings of all initiativesidentified during this program. Guest rooms are the largest energy consumers in hotels due to air conditioning and lighting use by guests. Rooms are usuallyunoccupied for a substantial amount of time but the air conditioning and lights arenormally left ‘on’ by guests. Depending upon the policy of the hotel, the cleanerssometimes turn off the air conditioning, lights and television.

Key card room control is a convenient way to turn off air conditioning and lightingwhen the rooms are not occupied. Some 41/2 to 5-star rated hotels are opposed to the concept of key card control as the room temperature is outside the comfort zonewhen guests return to the room (warm in summer and cold in winter). Introducing keycard room control is recommended with either of the following two options:

• option 1 – turn off air conditioning and lighting when room is unoccupied.

• option 2 – turn off lighting only when room is unoccupied, and reset the roomtemperature to an acceptable temperature such as 26°C in warmer months and 18°C in cooler months.

6.2.3 Lighting systemsLighting is one of the major energy consumers in hotels. However, lamp technology is continually evolving, resulting in increased energy efficiency. There are also manysimple lighting control techniques that can be implemented to improve energyefficiency or reduce energy wastage.

Major energy saving opportunities are:

• Use of energy efficient lamps:

Incandescent lamps: change incandescent lamps to compact fluorescent lamps (CFL).This can provide energy savings of up to 80 per cent. The cost of CFL is continuallydropping due to increased demand. The life of CFL is also much longer at around6000 to 15,000 hours, compared to 1000 to 2000 hours for incandescent lamps.


Dichroic lamps: replace dichroic lamps either with compact fluorescent or LEDlamps. A 50W dichroic lamp can be replaced by a 7W compact fluorescent or 2WLED. The same fittings can be used for the new lamps, decreasing the installationcosts. A 2W LED lamp has a little less light output than a 50W dichroic lamp.

Fluorescent lamps: replace 36 W standard fluorescent lamps with 36W energyefficient triphosphor tubes. The triphosphor tube provides around 30 per cent greater light output than the 36W tube. The most efficient fluorescent lamps are T5 lamps. These lamps require new electronic ballasts with a dimming option. They are economically viable when a complete lighting refurbishment is undertaken.

High bay lamps: replace mercury vapour lamps by pulse-type metal halide or sodiumlamps. Low pressure sodium lamps have an orange colour light output and may notbe suitable for some applications.

• Lighting level: over lighting wastes energy. It is important to measure the lux level of areas and minimise these levels where necessary in order to meet AustralianStandards for the activities undertaken. If an area is over lit, de-lamping or dimmingmay be considered to reduce lighting levels. Australian Standards for lighting levelsfor different areas are shown in Table 9.3.

• Lighting control

- Use energy saving voltage control for fluorescent lamps.

- Use timer control for areas which have set occupancy times.

- Use of motion detectors when lighting is not required continuously in areas such as conference rooms.

- Use lux controllers in areas that receive ambient daylight through windows.These controllers can turn lamps off and on, or dim them depending on theambient daylight. This type of control is also called daylight compensation control.

Refer to section 9.1 for more information about how much you can save with energyefficient lighting.

6.2.4 Hot water boilerHot water boilers are generally used in domestic hot water generation and space heating. There are many energy saving opportunities in hot water systems.Some of these are:

• Fuel switching – replace electric heating systems with natural gas systems. This not only has cost benefits but also provides a reduction in associatedgreenhouse gas emissions.

• Separate boilers – keep the space heating hot water boiler separate from the domestic hot water boiler.

• Switch off space heating boiler during warm weather.

• Water temperature – reduce the domestic hot water temperature setting to around 50-60°C.

• Use an energy efficient hot water boiler – some of the new generation boilers are designed with heat recovery from flue gases. This can improve energy efficiencyby around 15 per cent but can only be used in space heating. The cost of such a system makes the conversion economically unattractive.

• Use a VSD in hot water recirculation pumps – this can reduce energy consumptionby around 40 per cent and is economically attractive.


Energy saving initiative 6Energy saving initiative 6

Energy Wise Hotel TOOLKIT 25

6.2.5 Swimming poolHotel swimming pools use a substantial amount of energy through keeping the watertemperature warm and circulating water through the filter. There are two forms of heatloss from a swimming pool and pool house: sensible and latent heat losses.

Sensible heat loss is due to temperature difference, such as the temperaturedifference across the building envelope or the difference between make-up ventilationair and exhaust air. Latent heat loss is caused by exhausting moisture evaporatingfrom the pool surface and/or by expending energy to dehumidify the air. Almost all the heat loss from the pool itself is due to surface evaporation.

Hotels can reduce sensible heat loss by adjusting the indoor air temperature,insulating the building and using heat exchangers. To reduce latent heat loss for indoorpools, adjust temperatures and humidity, use a pool cover during unoccupied hoursand install a heat pump dehumidifier. Installing an efficient water heater and adjusting the circulation pump's operating hours can also be effective measures.

A few energy saving ideas for your swimming pool:

• As a no-cost step, investigate adjusting the pool temperature, indoor airtemperature and indoor relative humidity. It is possible to reduce the evaporationfrom a pool surface to a low level or even nil via this strategy.

• Cover the pool consistently during unoccupied hours. A pool cover can result in energy savings of 50 to 70 per cent and also saves water. Liquid insulation is available on the market however its success is questionable.

• Install a solar pool heater; this will significantly reduce swimming pool heating costs.

• Install a heat pump water heater and dehumidifier with heat recovery. A heat pumpwater heater may also include heat pump dehumidification and heat recovery. The dehumidification process recovers latent heat from condensing moisture in the air and uses it to heat pool water. These heat pump dehumidifiers with heatrecovery are commercially available from many companies.

• Reduce the circulation pump's operating hours when the pool is closed for the season, and filtration can be reduced by as much as 50 per cent.

• Use a properly-sized, energy-efficient circulation pump. The pump should not be over-sized.

6.2.6 Lifts and escalatorsLifts and escalators typically use around four to eight per cent of total energy in hotels.Although energy saving in lifts is not going to be as large as other areas of the hotel,there is still scope for improving energy efficiency. Some of these energy savingmeasures are:

• reduction of standby power use by developing sleep mode;

• no lifts on, or doors under power, when the lift is not in use;

• use of efficient drives;

• optimisation of counter weight; and

• use of a variable speed drive with sensors in escalators. This can reduce energyconsumption by 20 per cent. However they are more economically viable whenpurchasing a new escalator.

6.2.7 Energy conservation through controlAutomation, control and optimisation is one of the major energy saving opportunitiesin the hotel industry. Building management systems (BMS) are becoming more popularin medium to larger hotels.

Building management system (BMS)

BMS are conventionally used for:

• Time schedule – allows for switching equipment such as lights, fans and chillers on and off at set times.

• Direct digital control (DDC) of cooling and heating. DDC is the regulatory digitalcontrol algorithm which provides more accurate control than analogue systems and hence opportunities to increase energy efficiency. A DDC control system has the potential to improve energy efficiency by up to 20 per cent from aconventional analogue system.

Energy management system (EMS)

The conventional BMS can be upgraded to EMS providing advance and optimal control for:

• chillers;

• HVAC (heating, ventilation and air conditioning systems);

• pumps;

• cooling towers;

• boilers; and

• electricity demand.

Typically EMS can save energy between 20 to 50 per cent for chillers and HVAC systems.

Refer to section 9.4 for more information.


Involving staff and guests 7


Energy awareness program

This is a program to motivate staff and guests to conserve energy. The focus of theenergy awareness program should be to reduce the impact of climate change ratherthan achieve cost savings.

There are two major types of educational programs:

1. Energy awareness training

This is for key technical and operational personnel who are energy coordinators andenergy champions. The duration of such a program is around four to six hours anddeals with:

• basic understanding of energy;

• energy and our environment;

• how to improve the energy efficiency of hotels in general;

• basic understanding of energy efficient operation for HVAC, boiler and lighting systems; and

• energy efficient technology.

2. Energy awareness seminars

These are seminars designed to educate and motivate all staff. The seminars shouldbe short, imparting a basic understanding of energy consumption and the associatedenvironmental impacts with guidelines on how to improve energy efficiency throughbehavioural and operational practices. The recommended course outline is:

• a discussion about global Issues: energy and the environment;

• benefits to the company and staff;

• presentation about energy misuse based on historical analysis of users;

• brief discussion of recommended energy saving opportunities, mainly throughoperational change;

• personnel participation to develop methods of reducing energy consumption;

• achievements in energy conservation and reduction in greenhouse gas emissions; and

• clear messages that everyone can help reduce energy and greenhouse gas emissions.

3. Guest motivation

Hotel guests can also be motivated to reduce energy use through displays andstickers on energy and climate change and the commitment of the hotel to be ‘green’.

Renewable energy 8


Renewable energy does not produce any greenhouse gas emissions.Renewable energy is energy produced from sources that areconsidered infinite (will not run out) and are essentially non-polluting.The common renewable energy sources are:

• solar power – using technologies that convert sunlight into electricity ormechanical power such as photovoltaic cells or solar hot water systems;

• wind power – converting wind energy into more useful forms, such as electricity,using wind turbines;

• hydro power – using the force or energy of moving water in such systems as hydroelectric schemes, tidal power, and wave power;

• geothermal power – generating energy from the heat stored beneath theEarth's surface; and

• combined heat and power – using an engine to simultaneously generate bothelectricity and useful heat.

The Renewable Energy Act 2001 requires a minimum amount of renewable energy to be sold by each electricity retailer within Australia. There is a government rebateavailable on photovoltaic solar power generation.

8.1 Go carbon neutralMany businesses are finding their corporate image benefits from pledging to becarbon neutral by a set date such as 2020.

Being a carbon neutral business means any greenhouse gases emitted to meetenergy needs are offset by absorbing greenhouse gas elsewhere. This is described in more detail below.

The benefit of your hotel becoming carbon neutral is both in terms of improvedcorporate image as well as being able to service a growing number of business clientsthat have also pledged to become carbon neutral.

8.2 How does a hotel become carbon neutral?Step 1: reducing energy and travel needs

The best way a hotel can reduce its impact on climate change is to save energy. This will make your hotel very efficient in delivering its services and reduce operatingcosts. Travel in cars and aeroplanes needs to be calculated and reduced where possible.

Step 2: sourcing renewable energy instead of traditional coal-fired energy

Businesses are able to source renewable energy for some or all of their energy needs from an accredited electricity supplier.

GreenPowerTM is more expensive than traditional energy and hotels need to manage this expense. This may be managed by using the financials savings fromenergy efficiencies or by phasing in GreenPowerTM gradually over an agreed number of years.

GreenPowerTM is energy produced from renewable sources which is bought by energy suppliers and provided to their customers. The purchase of GreenPowermeans the production of greenhouse gases due to electricity manufacture is non-existent, resulting in a decreased rate of global warming.

Many energy suppliers now provide GreenPower. Most suppliers offer a renewableenergy option, however it is important these are GreenPower approved products.These approved products ensure the supplier meets stringent governmentenvironmental and reporting standards, which ensures that you, the customer, can be confident your money is going directly to helping the environment.

GreenPower is regulated by the GreenPower Auditor. Submission of regular reports ensures confidence in the GreenPower program and provides transparency for customers.

Step 3: Purchasing off-sets to ‘absorb’ any remaining greenhouse gases

If there are remaining greenhouse gas emissions after undertaking the above first two steps these can be ‘off-set’ by accredited programs that ‘absorb’ carbon-dioxidesuch as tree-planting.

For example, there are online systems enabling travel kilometres to be off-set by paying a small fee for trees to be planted locally to off-set the amount of emissions your travel generated.



There are four primary energy technologies that hotels need tounderstand and manage efficiently. These are discussed in more detail in this section:

1. lighting;

2. heating, ventilation and air-conditioning systems;

3. variable speed drives; and

4. energy management systems (EMS).

9.1 Lighting systemsLights are a major energy consumer in hotels and accommodation services.

The energy efficiency of lamps has significantly improved over the last few years and it is worth replacing older, inefficient lights with these better performing alternatives.Not only will this save on energy bills but it will also save on maintenance time inreplacing bulbs.

The main types of lamps being used in hotels are:

• dichroic lights;

• incandescent lamps;

• LED lamps;

• compact fluorescent lamps; and

• fluorescent tubes, mostly 36W.

Technology discussion 9


9.1.1 Dichroic lampsDichroic lamps are extensively used as downlights in receptions, foyers and corridors.

These are known as ’cool beam’ lights. They are high brightness lamps suitable fordisplay and special effect lighting.

Advantages:• excellent colour rendering;

• instant start;

• lamp life 2000 to 5000 hours;

• higher lumens than incandescent type;

• excellent lumens maintenance; and

• can be dimmed.

Disadvantages:• power loss in transformers create heat loss (50W lamps require transformer

of 12W loss). The 12W power used by transformers only transforms electricity to heat in the space;

• ultraviolet content of light can fade some surfaces;

• voltage fluctuation can reduce lamp life. A slight increase in main voltage supply can reduce lamp life by 50 per cent;

• lamp cost is greater than incandescent; and

• touching of the quartz lamp may lead to premature lamp failure.

9.1.2 Incandescent lampsThese are the original filament type lamp. They consist of a glass enclosure with inertgas. Here most of the power consumed dissipates as heat and does not transform to light.

Advantages:• they are cheapest of all lamps; and

• dimmable.

Disadvantages:• they are the most inefficient lamps; and

• the life of the lamps is very short – between 1000 to 2000 hours.

The efficiency of these lamps varies from eight to 17 lm/W compared to 85 lm/W for fluorescent lamps with a lifespan of 10,000 hours.

Due to its inefficiency these lamps are in the process of being phased out of themarket by government regulation. It is worthwhile reorganising your lighting to provide for this inevitable regulatory requirement.



9.1.3 LED lampsLED (light emitting diode) lamps are a new technology which fit all twist and lockfittings and can replace the 50W halogen twist and lock lamp.

Advantages:• the anticipated life is 30,000 to 50,000 hours; and

• a 2W LED lamp can be considered to replace 50W dichroic lamps without change of light fittings.

Disadvantages:• energy efficient LEDs are expensive; and

• require constant voltage transformer.

This technology is expected to increase in popularity and usage in the near future.

9.1.4: Compact fluorescent lampsA compact fluorescent lamp (CFL), also known as a compact fluorescent light bulb or an energy saving light bulb, is a type of lamp designed to fit into roughly the samespace as an incandescent lamp, but with the advantages of a fluorescent lamp. Many CFLs can directly replace an existing incandescent lamp.

Compared to incandescent lamps of the same luminous flux, CFLs have a longer-rated life and use less energy. The initial purchase price of a CFL is higher than an incandescent lamp of the same output, although this cost may be quicklyrecouped in energy savings assuming average bulb use.

Although CFLs do radiate a different spectrum of light than incandescent lamps, recent technological advances have reduced that difference dramatically. The light emitted by the best soft white CFLs available today is similar in quality to standard bulbs.

The life of CFL is around 6000 to 15,000 hours compared to the 1000 to 2000 hours of an incandescent lamp.

An 11W CFL provides almost the same lumens (light) as a 60W incandescent lamp.Normally they are 75 to 80 per cent more energy efficient than incandescent lamps.However they are around six to 10 times more expensive than incandescent lamps.

Recently CFL technology has improved and the lamps are now available as dimmable.Dimmable CFL are much more expensive than non-dimmable.

CFL are also available as a down-light to replace dichroic lamps which are being usedextensively in hotel foyers and corridors. A 9W CFL can replace a 50W dichroic lampusing the same fittings.

9.1.5 Standard fluorescent lampsThis is a glass tube lamp that is conventionally used in offices. The length of tubevaries with power. More information about standard fluorescent lamps is set out in Appendix D.

9.1.6 Maintaining lampsMaintaining lamps is very important for energy efficiency. The light output decreaseswith the operation hours of the lamp and dirt builds up in the shield

• Light depreciation with lamp life. As the lamp gets older it reduces output.Therefore it is important to replace lamps as they get older.

• Loss of light resulting from build up of dirt. Lamps should be maintained and cleaned regularly. Figure 9.1 shows light reduction against clean lamp.

Figure 9.1 - Loss of light from dirt built up

9.1.7 Lighting level standard

In all spaces including hotels, actual lighting requirements depend on the activity of an area. The Australian Standard AS 1680-2006 is as follows for various activities.

Table 9.1 - Recommended lighting level


Area Light level (Lux)

Office work 320

Store rooms and stock rooms 320

Kitchen 240

Entrance areas and waiting rooms 160

Corridors 40

Toilets 80

50

60

70

80

90

100

55

65

75

85

95

11109876543210

Expected loss of light resulting from dirt build-up

Time between cleaning (years)

% M

aint

aine

d Li

ght



9.2 Heating, ventilation and air conditioning systemsAs the heating, ventilation and air conditioning (HVAC) system is the major energy user in a hotel, it is important to understand. The HVAC system delivers:

• heating;

• cooling; and

• air circulation.

9.2.1 HeatingHeating can be provided by three different means:

• Hot water (or steam) system – the lowest energy cost system if natural gas is available and the most common heating system in older hotels.

• Electric heating elements – the most energy inefficient and high energy costsystem. Many hotels use electric heating systems which were historically installedas a convenient low capital cost system.

• Heat pumps – relatively new technology that is energy efficient. The energy cost is similar to or slightly higher than gas-heated hot water systems. Consideringmaintenance and auxiliary equipment, heat pumps are one of the most overall cost-effective systems.

9.2.2 CoolingThere are different types of air conditioning systems. Each type of system has its own advantages and disadvantages. Therefore they are selected based on theirapplication, capital cost and energy performance. However, in the past very littleconsideration was given to energy efficiency. Capital cost is normally the dominantfactor in selecting and designing air conditioning systems. The most common types of air conditioning systems are:

• single zone systems;

• reheat systems;

• multi-zone systems;

• dual duct systems;

• induction systems;

• variable air volume systems;

• water source heat pump systems; and

• air cooled heat pumps.

The cooling can be provided by:

• Refrigeration system: this is the cooling media and requires a compressor formechanical compression or an absorber for an absorption-type cooling system.Electrical energy is being used for a compression-type system and thermal energy as heat is required for an absorption system.

• Evaporative cooling: this is a low energy intensive cooling system ideally suitable in dry weather condition. It cools air by humidifying air and does not need any refrigerant. Although it is around 80 per cent more energy efficient than a refrigerated cooling system, it does not provide comfort levels as easily as a refrigeration system and can be noisy and inconvenient.

Some HVAC systems do not have cooling towers. The condenser cooling is done by blowing air over the condenser tubes. These are called air-cooled systems.

Basics of an air conditioning systemFigure 9.2 - The schematic of a basic air conditioning system

Figure 9.2 is a typical guest room air conditioning system. This is a four pipe system,with two pipes for chilled water and two pipes for hot water (the hot water piping isnot shown).

Chilled water is circulated by chilled water pumps and hot water is circulated by hotwater pumps.

In some hotels the guests’ rooms are heated by electric heating elements replacingthe hot water coils in the fan cool unit.

Economy cycle

Economy cycle reduces energy costs. The energy saving can be in the order of 25 to30 per cent in Melbourne’s climate. Since an economy cycle brings in more fresh air,the system may require slightly more cleaning of air filters.

The cost of an economy cycle can be as low as $3000 plus additional costs for ductmodification, if required.

For more information about an economy cycle refer to Appendix E.


COOLING

TOWER

CONDENSER

CHIL LER

CONDI TONED SPACE

COOLING

WATER

PIPING

COMPR ESSOR

CHIL LED

WATER

PIPING

AIR F ILTERS

INSUL ATED

RE TURN A IR

DUC TING

COULD B E AIR

COOLED

COOLING

WATER PUMP

CHIL LED

WATER PUMP

AIR

HANDLING

UNI T

INSUL ATED

SUPP LY AI R

DUC TING

AIR OUTLETS

SUPP LY

AIR FAN CHIL LED W ATER

COOLING CO IL



Economiser

It is possible to cool the fresh air by exhaust air with an air-to-air heat exchanger.Types of heat exchangers are:

• rotary heat exchange wheel;

• plate heat exchanger; and

• heat pipe system.

Expected energy savings from this system are between three and 15 per cent.

The higher the amount of fresh air used in the HVAC system, and the more extremethe weather conditions, the higher the energy savings will be.

Figure 9.3 - Typical economiser

9.2.3 Heat pump technologyHeat flows naturally from higher to lower temperature. However heat pumps useexternal energy to force heat flow in the opposite direction. All heat pumps require a vapour compression cycle which is a mechanical refrigeration system.

There are two types of heat pumps, described below.

COP is the ‘coefficient of performance’ which is the ratio of energy output/energy input.

1. Conventional air-cooled heat pump

A conventional heat pump is commonly known as a reverse air conditioner which can cool and heat. The COP of conventional air-cooled heat pumps for space heating is shown in the table below.

Table 9.2 - COP of conventional air condenser heat pumps

COP is the ratio of power output to input and is the efficiency of the refrigeration cycle. Higher the COP more energy efficient it is.

Return Air 22 C

Spill Air 27 C

Fresh Air 25 C

Fresh Air 30 C

Size (kWr) COP heating COP cooling

7 3.28 2.78

26 3.63 2.94

32 3.67 2.95

2. Water source heat pump

This is a very energy efficient way to heat and cool hotel rooms. There is no centralcompressor and instead there are central water heaters and a heat rejection (coolingtower) system. Each room has a fan coil unit refrigerant compressor. During theheating cycle the hot gas is used to heat the room (utilising condensing heat). The hot water from the boiler is used to cool water from the evaporator.

Heat recovery: it is possible to recover some heat during cooling time to produce hot water that can be used as domestic hot water.

Energy efficient comfort condition of HVAC system

The comfort level of an air conditioned space varies with the following variables:

• gender of occupants as females generally feel colder than males;

• activity within the building;

• relative humidity and dry bulb temperature; and

• air movement.

The comfort condition is not a single temperature level but a zone, which is shown in the shaded area of Figure 9.4 below. It is recommended that HVAC systems should be operated at a higher temperature in this zone when cooling and a lowertemperature in this zone when heating.

During the cooling cycle, every 1oC temperature rise will reduce energy consumptionby five to 10 per cent.

Similarly during the heating cycle, every 1oC temperature decrease will reduce energyconsumption by five to 10 per cent.

Figure 9.4 - Psychrometric chart of comfort zone


0.002

0.006

0.004

0.010

0.008

0.012

0.014

0.016

0.018

10 13 16 18 21 24 27 29 32 35 38Operative Temperature,˚C

Hum

idity

Rat

io

-5-10

5

0

10

15

20

Dew

Point Tem

perature,˚C

908070605040302010% RH

Data based on ISO 7730 and ASHRAE STD 55

Upper Recommended Humidity Limit, 0.012 humidity ratio

0.5 PMV Limits

1.0 Clo 0.5 Clo

0

1

2

3

4

5

6

7

20253035404550

Speed (Hz)

Power Factor

Power

Pow

er (k

w)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

8 0.8

15

Pow

er F

acto

r

9.3 Variable speed driveAir conditioning motors run at a fixed speed although the demand for air flow or waterreduces in lesser cooling load conditions. As the air or water flow demand reduces the damper or valve throttles to restrict flow. Throttling is an irreversible process (that is, wastes energy which can never be recovered).

It is possible to vary the speed of the motors through change of frequency ofelectricity supply. To deal with the problem of throttling, a variable speed drive (VSD)can be installed. This allows the controller to change the speed of the drive instead of throttling and avoids the loss of energy.

Figure 9.5 - Power requirement for throttling with fixed speed and VSD drive with no throttling

Variable speed drives are one of the biggest and most economically viable energysaving opportunities in HVAC systems for supply and return air fans, chilled andcondenser water pumps and chiller compressors.

Figure 9.6 - Power VS fan speed of a typical AHU fan



0

20

40

60

80

100

120

120100806040200

Volume flow rate %

Damper control

Speed control

Comparative power requirements. Speed and Damper control of fan duty

Fan

Pow

er %

Figure 9.7 - Power VS fan speed of a typical cooling tower fan

Figure 9.8 - Power VS pump speed of a typical water circulation pump


0

02

04

06

08

10

12

14

20253035404550

Speed (Hz)

Pow

er (k

w)

0

10

20

30

40

50

60

70

20253035404550

Speed (Hz)

Pow

er (k

w)

9.4 Energy management system (EMS)An energy management system (EMS) is a computer-based energy monitoring and optimal control system for building services. Normally the system is based onconventional BMS (building management systems). The functionality of a building EMS is as follows:

• Economy cycle control. An economy cycle is illustrated in Section 9. Althoughthere are stand alone economy cycle controllers available, they do not operate tooptimal efficiency. An energy management control system provides superior controlsuch as enthalpy-based control, which provides additional energy and cost savings.Refer to Appendix E for more information.

• Optimal start of HVAC. Space heating and cooling always requires time topreheat or cool the space before it reaches comfort conditions. Normally such pre-cooling or heating time is preset however this can be changed to be a functionof ambient temperature. On a hot day, the hotel requires more pre-cooling timethan on a more temperate day. Optimum start time resets pre-cooling time to avoid keeping the space cooled longer than required and hence reducing waste of energy.

• Night purge. This involves pre-cooling a building at night especially during hottermonths when the outside air temperature is low, thus reducing the energy requiredfor building pre-cooling.

• Feed forward variable speed drive control is intelligent speed control of supplyand return air fans. The conventional speed control of a fan is based on a presetsupply pressure. When the HVAC system is not designed as a variable air volume(VAV) system, the conventional feedback control is not viable. The speed set pointis determined by a function of area cooling load.

• Chiller and cooling tower optimal control. The chiller is used to provide buildingcooling and is one of the major energy consumers in a hotel. Larger to medium sizehotels typically have a centralised chiller system to provide chilled water for cooling.The chiller plant may consist of multiple chillers, which depend on the intelligence ofthe supervisory control for energy efficiency. The energy efficient functions of thesecontrollers are as follows:

- chiller optimal selection selects the combination of chillers to run at any giventime to meet the cooling load with minimum energy consumption. At low loadcondition it also cycles the operation of chillers;

- chiller loading and control ensures the optimum loading of each chiller to reduceenergy consumption;

- chilled water temperature reset. Conventionally the chilled water temperature is set to a low temperature of 6°C to 7°C. When the cooling load is low, the setpoint of the chilled water system can be increased. Every 1°C increase in chilledwater temperature reduces energy consumption by around 2.5 per cent.

- cooling/condenser water temperature reset. Similar to chilled water temperaturereset, the condenser water temperature increases the energy efficiency of boththe chiller and cooling tower. The decrease of condenser water temperaturereduces energy consumption by around 2.5 per cent per degree watertemperature reduction.



• Optimal pump control. Optimal pump control is useful when multiple pumps areused for chilled water, hot water or domestic water supply to the hotel. It involvesinstalling a VSD on one of the pumps and selecting the number of pumps tooperate, therefore controlling the supply pressure. Energy savings of 20 to 40 per cent are achievable through this technique.

• Hot water boiler

- optimal start/stop of boiler.

• Demand management system

- demand and energy monitoring;

- demand control; and

- energy sub-metering.

How much can you save with an EMS?

Chiller system:

• reduce energy consumption by 20 to 40 per cent; and

• reduce run hours by up to 30 per cent.

HVAC:

• reduce fan energy cost by 40 to 50 per cent.

DDC control:

• reduce cooling and heating load by up to 20 per cent.

House-keeping:

This is to monitor and track energy use and key performance indicators as well as various energy efficiency parameters. As a rule of thumb, the saving is expected to be around one to five per cent of the overall energy consumption.



A corporate policy should be set to meet corporate goals andstandards. An example of a corporate policy is set out below.

Energy is one of our organisation’s major ongoing costs. Its impact on climate change is a great concern to us. As a good corporate citizen we as a company set the following policies:

1. Reduce energy consumption of each hotel by 10 per cent per year for the next three years.

2. Energy efficiency should be considered in purchasing and maintaining all equipment.

It is the responsibility of each individual employee to use energy wisely and efficiently.

Appendix A: Example of corporate policy A


1. Energy and our environment

Greenhouse gas emissions cause global warming which is detrimental to our environment.

The earth is covered by a blanket of gases in the atmosphere which allows lightenergy from the sun to reach the earth’s surface. This light energy is converted to heat energy. These gases are called greenhouse gases.

Most of the heat is re-radiated towards space but some is trapped by greenhousegases in the atmosphere. This is a natural effect, which keeps the earth’s temperatureat levels necessary to support life.

The problem we face is that human actions – particularly burning fossil fuels and landclearing – are generating more greenhouse gases. These additional gases trap moreheat and raise the earth’s surface temperature.

This is known as the enhanced greenhouse effect – it causes global warming and is changing our environment.

Reducing the use of energy reduces the power generation where the majority of greenhouse gases are generated.

Figure B.1: Heat balance

Appendix B: Energy and our environment B

Atmosphere emits longwave radiation (60%)

Transfer of heat betweenEarths surface andAtmosphere (zet zero)

Earths surface emits longwave radiation (9%)

The increase in greenhouse gases within the atmosphere traps more heat, and raises the Earths surface temperature.

Incoming solar radiation (100%)

Increased used of fossil fuels

Earth’s surface reflectssolar radiation (6%)

Convection to atmosphere (31%)

2. Global warming

Some of the effects of global warming are:

• a rise in sea level causing coastal damage;

• an increase in the likelihood of extreme weather conditions such as droughts,floods and cyclones;

• health impacts because of the spread of tropical-borne diseases, the increase of flooding and other such climate changes;

• damage to ecosystems and species diversity; and

• damage to agricultural output and food supply, and an increase in the earth’ssurface temperature causing heat stress and other damage.

3. Saving our environment

It is essential that all efforts are made to reduce greenhouse gas emissions. Hotels can help by:

• reducing energy use; and

• using environmentally friendly refrigerants. The two most common environmentally friendly refrigerants are:

- CFC – 123: Environmentally friendly but not accepted by energy andatmospheric credit #4, which is regarded as the current standard forenvironmentally friendly refrigerant. This gas has low global warming potential and high energy efficiency.

- HFC – 134A: Environmentally friendly.

4. Measurement of greenhouse gas

Greenhouse gas is measured in carbon dioxide equivalent (CO2 – e) which takes into account the global warming potential of each of the greenhouse gases.

• Energy related:

- Stationary: this is the source of greenhouse gas emission from energy used by stationary equipment such as a boiler, generator or power station.

- Transport: greenhouse gas emission from cars, trucks and other vehicles, which Is used for the transport industry.

• Non-energy related:

- Waste: this is the source of greenhouse gas emission from all types of wastes,such as paper, textile, wood and other sources.


Figure B.2: Greehouse gas emissions for stationary energy

Figure B.3: Greenhouse gas emissions for transport energy

Figure B.4: Municipal solid waste

Appendix B: Energy and our environment B


0

100

200

300

400

Coke Briquettes(brown)

Coal(brown)

Coal(black)

Fuel Oil Diesel LPG Natural Gas

Electricity

kg C

O2 -e

/GJ

0

20

40

60

80

100

Petrol Diesel Fuel Oil LPG

kg C

O2 -e

/GJ

0

0.5

1.0

1.5

2.0

2.5

3.0

Paper Textiles Wood GardenFood

kg C

O2 -e

/GJ

For more information about the measurement of greenhouse gases refer to the AGO Factors and Methods Workbook.


Global warming potential (GWP)

1. Carbon dioxide CO2 GWP = 1

2. Methane CH4 GWP = 21

3. Nitrous oxide N2O GWP = 310

4. Hydro fluorocarbons (HFC’s) GWP = 140 - 11,700

5. Per fluorocarbons (PFC’s) GWP = 65,000 – 9,200

6. Sulphur hexafluoride GWP = 23,900

What is power factor?

The power factor is the ratio of true or active power (kW) over the apparent power (kVA).

Figure C.1- Diagrammatic representation of power factor

The causes of reactive power are inductive devices such as AC motors, inductionfurnaces, arc welders, fluorescent and mercury vapour lighting. These cause a timelag between current and voltage cycles which causes large reactive currents.

How to correct power factor• Use of synchronous motor; or

• Use of capacitor bank.

The required sizing of a power factor controller is calculated as follows:

CosØ1 = Current power factor

CosØ2 = Desired power factor

kVAR required = kW x (tanØ-11 - tanØ-12)

Appendix C: Power factor correction equipment C


kVAR 1

kVAR 2

kVA 1

kW

kVA 2

Ø 1

Ø 2

A typical luminaries or fixture for fluorescent lamps is shown in thefigure below. This consists of:

• housing;

• reflector;

• lamps;

• ballast; and

• shielding.

Figure D.1 - Typical luminare of a fluorescent lamp

The type of reflector, lamps and shielding can all contribute to light efficiency.

In a fluorescent lamp there is no filament as in incandescent lamps. Instead, cathodes at each end send currents through mercury vapour sealed in the tube.Ultraviolet radiation is produced as electrons from the cathodes knock mercuryelectrons. The tubes are lined with phosphor to turn the radiation to visible light. This requires ballasts which are in every fixture and regulate the voltage during start up.

The light output of these lamps varies from 69 to 104 Lumens/W. TL5 is the latestfluorescent lamp technology and with electronic ballasts produces 3300 lumens with 33W.

There are two types of ballasts:

• electromechanical – the standard ballast loss is around 10W; and

• electronic – which can be fixed or dimmable ballasts. The electronic ballasts losses are generally less than 2W.

Appendix D: Detail of a fluorescent lamp D


When the ambient air enthalpy is less than that for return air it iseconomical to introduce as much fresh air as possible to cool thebuilding. However, this is restricted by the return air duct filter.

Therefore a motorised damper is required to regulate the fresh air make-up. An increased supply of fresh air is more hygienic and comfortable. The economy cycle of an air conditioner reduces energy costs. The energy saving can be in theorder of 25 to 30 per cent in the Melbourne climate. Since the economy cycle brings in more fresh air, the system may require slightly more cleaning of air filters.

The cost of an economy cycle can be as low as $3000 plus additional costs for ductmodification, if required.

Figure E.1: Economy cycle

There are two types of economy cycle which are:

• temperature-based; and

• enthalpy-based.

The enthalpy-based economy cycle provides better control with higher precision and provide more energy saving. This requires an energy management system.

Appendix E: Air conditioning economy cycle E


energy wise hotels...• electricity; and • thermal energy – this is usually natural gas,...

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