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Technical

BULLETINJuly 2014Issue 1

Welcome to our very fi rst technical bulletin. This is a new bi-monthly update to provide you with information and topics of interest from across the energy and controls industry.

In each issue we’ll aim to provide you with industry updates on technology, product development and legislation. We hope you fi nd this of interest and of course, if there are topics you’d like to see covered in our forthcoming bulletins just let us know

SAVE ENERGY, MONEY AND CO2 WITH AC DRIVES.

Wasted money. Pumps and fans consume vast

amounts of energy. Often they can be oversized, or

running at full power unnecessarily. Fitting an AC

drive to your fi xed speed pumps and fans allows the

motor to run at a speed that matches requirements

and enables the end user to capitalise on the energy

savings available.

What is an AC drive? Otherwise known as a Variable

Speed Drive (VSD) or inverter, an AC drive is a device

used to control the rotational speed of an AC electric

motor by controlling the frequency of the electrical

power supplied to the motor. Most conventional motors

only run at full speed. However, a motor with a VSD can

be operated at a variable rate. This allows the motor to

drive a pump or fan at a speed appropriate to system

requirements, either stand-alone or automated through

technology such as a Building Management System

(BMS).

INDUSTRY TOPIC 1

Why use an AC drive? The speed of the motor and

energy use are exponentially related. Therefore even a

very small reduction in speed can result in a signifi cant

energy saving for the end user. Fitting an AC drive to

a motor is an attractive cost-saving project for many

businesses, as this can provide quick energy saving

results within a relatively short payback period.

Some interesting facts:

“ VSDs have the potential to make energy savings and increase profi tability in almost every sector of UK business.”

“ Reducing fan speed not only reduces energy consumption but may also reduce noise and vibration.”

“ Most fans and pumps are oversized for the duties they perform.”

“Using a VSD to slow down a fan or pump motor from 100% to 80% can save as much as 50% on energy use.”

You can also download a very useful guide, from the

Carbon Trust, which details how an AC drive works and

the impact of the technology within HVAC applications:

https://www.carbontrust.com/media/13063/ctg070_variable_speed_drives.pdf

How we can help. At ABEC we can offer free AC drive

audits and site surveys incorporating energy saving

calculations, carbon, kWhrs and payback periods

and the full turnkey project delivery to install and

commission your AC drives to achieve these outcomes.

To fi nd out more get in touch 01684 853 780,

enquiries@abec.co.uk

Technical

BULLETIN

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AUTOMATIC NATURAL VENTILATION – COMPLICATED OR SIMPLE?

Energy effi ciency is now commonly at the heart of

good mechanical services design. Many technologies

have entered the race to become the perfect partner

for energy effi ciency within buildings, such as

Combined Heat and Power (CHP), ground and air

source heat pumps. Among these Automatic Natural

Ventilation stands head and shoulders above these

in the technology battle. It offers a simple yet highly

effective solution for free cooling and air quality

control.

Within modern construction natural ventilation is

found in many guises. We see it in actuated windows,

motorised louvres and roof turrets to name a few. All of

these can be coupled together within different modes

of ventilation strategy - such as cross ventilation, stack

ventilation and mixed mode mechanical and natural

ventilation.

To provide some understanding of the differences

between these varied natural ventilation system

designs, we have provided the following summary. It is

defi ned from CIBSE’s Natural Ventilation Guide for non-

domestic buildings, AM10: 2005

SINGLE SIDED DOUBLE OPENING VENTILATION

Where multiple ventilation openings are provided at

different heights within the façade the ventilation rate

can be enhanced with the stack effect. Stack induced

fl ows increase with the vertical separation of the

openings and with the inside to outside temperature

difference. As well as enhancing the ventilation rate

the double opening increases the depth of penetration

of the fresh air into the space, as opposed to single

opening ventilation. As a rule of thumb the limiting

depth for effective ventilation is about 2/5 times the

fl oor to ceiling height of a building.

CROSS VENTILATION

This occurs where there are ventilation openings on

both sides of the space. Air fl ows in one side of the

building and out the other through, for example, a

window or door. Cross ventilation is usually wind driven

but it can also be driven by density differences in an

attached vertical chimney. As air moves across the

zone there will be an increase in temperature and a

reduction of air quality as the air picks up heat and

pollutants from the occupied space.

A normal approach to achieving cross ventilation is in

opening windows. However other approaches can also

be successful. An older example is the ‘wind scoop’,

built into the main infrastructure of the building. A

roof-mounted ventilator represents a more modern

method of this. It uses the pressure difference across a

INDUSTRY TOPIC 2

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segmented ventilation device to drive air down through

the segment facing the wind and into the space. The

suction this creates through negative pressure draws

air back out of the space. Flow rate can be controlled

using a damper, with air distribution being achieved via

a diffuser module.

STACK VENTILATION

Stack ventilation is driven by density differences. The

approach draws air across the ventilated space and

then exhausts the air through a vertical fl ow path. This

means that occupied zones are cross ventilated, in

that air enters one side of the space and exits at the

opposite site. In order to achieve the required fl ow

distribution without excessively large outlet ventilator

sizes, the stack outlet usually needs to be at least half

of one storey above the ceiling level of the top fl oor.

This can be achieved with a dedicated chimney or

through an atrium. The advantage of atrium ventilation

is that air can be drawn from both sides of the building

towards a central extract point, effectively doubling

the plan width that can be effectively ventilated by

natural means.

AUTOMATIC NATURAL VENTILATION MIXED-MODE VENTILATION

Different strategies may be applied to different parts

of a building, or at different times. This is the so-called

‘mixed mode’ approach. For example, Changeover

Mixed Mode recognises that cooling requirements of

any space varies from season to season. An example of

this would be to use mechanical ventilation in extreme

weather conditions, both hot and cold, but rely on

natural ventilation in milder weather. This reduces the

problem of cold draughts in winter and allows the use

of mechanical night ventilation for precooling in hot

summer periods.

Each different approach to natural ventilation requires

a different level of BMS control, monitoring, interface or

integration to achieve a successful natural ventilation

control system. A key aspect of this is that it empowers

the building occupant to make adjustments to window

openings in order to maintain personal comfort,

without prejudicing the comfort of others. It means

that automatic control strategies need to be carefully

integrated with user behaviour.

Some systems, such as roof turrets, come with optional

stand-alone controls, which are not required when

the technology is being integrated within a site-wide

BMS strategy. Window actuators can also cause

complications where the typical contractual chain

sees these procured as part of the façade package

let directly by the main contractor and not generally

in sight of the BMS specialist subcontractor of the

M&E. So too often by the time the BMS contractor is

engaged on the project the actuator selection has been

agreed. This removes the opportunity to review and

select the best technologies aligned to the overall BMS

design. In an ideal situation the actuator selection will

be withheld until the BMS contractor is appointed and

such detail can be developed through consultation.

For an M&E buyer, clarifying which optional items

are required is all too often a minefi eld, presenting

possible cost overlap, score gap or warranty issues. A

BMS specialist should be able to assist in identifying

the boundary points of all packages, to ensure their

alignment to provide a combined working technical

solution.

If not already stipulated by the design consultants,

an early review and detailed design of the operability,

signals and power requirements between devices (such

as the BMS, window actuators and turrets) across

all suppliers (façade package, M&E procurement,

BMS sub-contractors) is critical to the success of the

overall outcome.

We work closely with our customers to provide this

consultation, ensuring the successful outcome of

BMS automated natural ventilation projects. This has

multiple benefi ts, ensuring the end client’s overall

building control, energy effi ciency and successful

contractual delivery of the project.

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TREND CONTROL SYSTEMS – NEW IQ422 CONTROLLER

Small Footprint, Big Capability. The IQ422 is designed

for use in a variety of applications. It offers Trend’s

smallest footprint for a 12-point universal controller and

boasts multi-browser support. The IQ422 is the second

variant in Trend’s family of IQ4 main plant controllers

and builds on the success of the recently launched

IQ41x series.

Trend listened to customer requests for a fl exible

device and has devised a solution that utilises the

popular six input/ six output formation, meaning that

it can be used in small to mid-sized applications such

as primary schools and health centres, as well as larger

installations such as multi-tenanted offi ce complexes.

Featuring IQ4 style DIN compatible casework, to fi t

within electrical enclosures alongside a host of other

IQ4 style capabilities, the IQ422 has the power to

support the most advanced control applications. These

include web supervision using Ethernet and TCP/

IP networking technologies, while XML capability is

offered as standard.

The IQ422 has open system support and integration

features that will benefi t IT personnel. A new style

web interface facilitates the use of all popular internet

browsers including Mozilla, Firefox, Google Chrome,

Apple Safari and Microsoft Internet Explorer. It also

offers a confi gurable web server port for enhanced

IT acceptance. Data can be accessed via mobile

devices such as smartphones and tablets, thanks to

a fi rmware upgrade that detects what type of device

the information is being accessed from, ensuring it is

presented in the correct format.

Graeme Rees, Product Manager at Trend, said: “The

IQ422 represents the next generation of our controller

technology. It is designed to meet the multi-faceted

demands of today’s customers and offers features and

benefi ts that address their requirements for better

space utilisation, fl exibility and cost effectiveness.

KAMSTRUP ENERGY AND WATER METERS NOW SUPPORT THE BACNET® PROTOCOL

The manufacturer of heat energy, cooling and water

meters, Kamstrup, has developed a BACnet module for

its MULTICAL® 601, 602 and 801 heat/ cooling meters

and for the MULTICAL® 62 water meter. The new

communication module makes it possible to integrate

the MULTICAL consumption meters, approved for

legal billing, directly into a BACnet based building

management system.

The new BACnet module adds to the variety of

communication options in the MULTICAL meters, which

also support LON, M-Bus and N2 besides a number of

wireless protocols.

The foresight of Kamstrup to provide communication

options for its products allows ease of equipment

selection when considered for connection into building

management systems or AMR system designs,

eliminating the need for multiple site networks and

gateways, removing unnecessary cost for additional

wiring and gateways for different metering network

protocols.

TECHNOLOGY & PRODUCT UPDATES # 1

TECHNOLOGY & PRODUCT UPDATES # 2

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Acronyms and terminology are used throughout

the HVAC and energy industry, often leading to

misunderstanding. Here we offer some insight to just

a few...

AMR – AUTOMATIC METER READING

This is the term applied to the automatic reading of

consumption data from metering devices such as

water, gas, electricity and heat and the transfer of

that data to a central database for billing analysis and

energy management.

A network of meters is established through

communication networks (TCPIP, MSTP, RS485, RS232)

and protocols (Modbus, M-Bus), to arrive at a central

point of data aggregation. This data can then either be

used in its raw form by energy managers (CSV fi les) or

collected by intelligent metering software applications

like aM&T platforms.

aM&T – AUTOMATIC MONITORING AND TARGETING

This is a software platform and management system

that automatically collects energy consumption data

and analyses this to ensure energy use is in line with

targets set by the user. Energy data can be directly

collected from utility providers’ data collection and

aggregator services, or direct from site installed AMR

systems. aM&T automatically delivers usable energy

management information to the person who can

make changes.

Most aM&T systems allow the user to set targets for

energy use and review current performance against

these targets. Many systems automatically produce

variation reports and notify users of potential problems

by email or text message.

Today many systems are web based and can be

extended to cover consumption of other utilities in

addition to the traditional electricity and gas use eg:

water, fuel, oil, steam. Typically the application of aM&T

can lead to savings of around 5%, although often

even greater savings can be enjoyed on individual

sites. Many users are instantly surprised at the level of

avoidable energy waste that they identify.

We can deliver the turnkey requirements to achieve

these outcomes, at site level and through our technical

support centre services.

JARGON BUSTING

Do you have a current issue?

Is there a particular BMS issue you would like us to research and respond to? Is there an acronym you secretly want explained? Do you want to circulate some industry or product news you feel would benefi t our readers? Why not drop us a line on bulletin@abec.co.uk