FEAT RE MON OR NG FEA ATURE
MONIITORIING & CON
ONTRO L
OL A straight forward approach 5. Verification/certification
The control of energy in buildings is generally poor, despite the availability of a range of tried and tested systems,
The control of energy i bui dings i general y poor, despi e the avai abi ty of a range of tried and tested systems, with guidance perceived to be over com licated, explains A dy Lewryew y, principal consultant at the Building Research Establishment and author of a new briefing note. Here’
th gui ance perceived to be ov over
complicated, explains Andy Lewry, principal consultant at the Building Research Establishment and author of a new
B
uilding controls,whether stand-alone units or full building energy
gymanagement
systems (BEMS), are designed to prov comfortable climate for building occupants while consuming the low of energy
ovide a owest possible amount
gy.Demand-based control is themost
energy-efficient approach,whichmeans turning systems offwhen not needed or, if this cannot be done, then at least dow
own. Energy gy can account for
about 40%of turning them
the running costs of a building ov Anything that can be done to
helpmanage this over its lifetime.
effectively is a benefit to building owners and occupants. Any decision onwhat to specify should be based on lifecycle costs, not short- termthinking about the initial capital cost. Controls can be applied equally successfully to a newor refurbished building. A growing trend is greater integration,which can best be achieved through productswhich use open communication protocols such as BACnet, KNX, LON,Modbus andM-Bus. Remote access is also nowpossible, allowing a facilitiesmanager or service engineer to interrogate the systemremotely and diagnose problems. Itmay even allowfor the plant to be switched on or off for special events without the need to be on site. The author of this article has pre published a guide - Understa
for building controls [1] - that prov explanations of various types
of controls,what ovides simple
they can do, andwhere andwhy they can and should be used - the pros and cons, and how to achieve an effective soluti on in practice . There are ten key issues to address:
1. Specification breaking – procurement routes and ’value engineering’
This is normally a cost-cutting exercisewith the temptation to cut capital costs. Stand- alone controls are cheap, in the order of£250 installed, but severalwill be required. Pre programmed BEMS have an installed price of around£1000. But to fully realise the potential savings fromenergy efficiency, you probably need a programmable BEMSwhich costs in the range of£3,500 and£5,00 0 installed. 2. Occupancy patterns – schedules and density
rc rd re-
Knowledge of howthe building is used improves the estimation of potential savings and, following installation, allows
commissioning of the controls to fully realise the potential energy savings. These range, for
14 14 SU SUMMER 201 ER 2016 | ENERG MANAGEMEN ENERGY MANAGEMENT ew briefing note. Here’s more re
To justify business cases it is increasingly important for the performance of newassets, including control systems, to be verified. A fully integrated systemcan allowcollection and analysis of this data, thus allowing this step to be simple and 6. Commissioning – on-going process [3]
initial set-up and an relatively painless.
It is essential to understand your business and building(s)when producing a Serv and Controls Strategy. The next step is to ensure that the controls are installed and commissioned to achieve this strategy. However, it is an unending process to resolve operating problems, improve comfort, optimise energy use and identify retrofits for existing buildings and
rvicing
Training, like comm
7.Training [3]
issioning, should be a n central plant facilities.
on-going process to ensure that Facilities staff, the FacilitiesManagement (FM) contractor (if you have one) and other users knowhowto optimise the use of the system.
8.Maintenance requirements – planned upgrades [3]
offices, froma potential of 34%for zonal controls to 54%for a fully programmable BEMs
3. Future proofing – flexibility & upgrades
ty
nding the choices reviously
Technology soon becomes dated and to ensure that your systemdoes not become redundant it needs to be programmable. A programmable systemis likely to be flexible enough to take into account changes in usage and can be upgraded to benefit from technological and software advances. 4. Links tomonitoring and targeting ation systems
Energymanage (M&T) – optimis
gement relies on the old
adage ‘if you cannotmeasure it, you canno t manage it’. Thismeans that the control system(i.e. the BEMS) needs to be linked to themetering, so that all themonitoring and targetingM&T functions can be carried out in the same place, thus allow
owing management to be instantaneous. References References
1. Lewry, Andrew J. Understanding the hoices for building
2. BSI. Energy 2. B I. Energy
performance of buildings — Impact of building
performance of buildings — Impact of building
automation, controls and building management. S EN 15232:2012. London, B I, 2012.
3. Lewry, Andrew J. Operating BEMS
3. Lewry, Andrew J. Operating BEMS - A practpractical guide toical guide to buibuilding energylding energy
management systems. E IP 2/14. Bracknell, S B E Press, 2014
management systems. BRE IP 2/14. Bracknell, IHS BRE Press, 2014
automation, controls and building management. BS EN 15232:2012. London, BSI, 2012.
1. Lewry, Andrew J. Understanding the choices for building controls. BRE IP 1/14. Bracknell, I S B
controls. B E IP 1/14. Bracknell, IHS BRE Press,
2014.ress, 2014.
This runs alongside ongoing commissioning, requiring the hardware to bemonitored and upgradedwhere appropriate. This is especially
if they are damaged o true of sensorswhere
r have drifted due to old the systemwill still run
age,ge but not at optimal perf rformance The .
likely result is far higher running costs.
9.Management reporting
For energymanagement to be effective, the data has to be presented in a concise manner and in a formappropriate to the audience.What is required formanagement of the systemwill be farmore detailed than that required for the financial department to reconcile the bills on amonthly basis. Board reports need to be concise and to highligh t any issues .
10. A dditional functionality serv
rvices/alarms
Modern systems can be set up to alert key staff by emailwhen s rvervices fail to switch off when expected, usemore energy than expected orwhen communications go down. Thisminimises risk to the business in terms of uncontrolled usage and possible damage to the asset.
Dr Andy Lewry is the author of a new briefing note, “Energymanage ,
http://www.bre.co.uk/energyguidance. gy BRE
http://www.bre.co.uk/page.jsp?id=1790 T: 01923 66 4359
http://www.bre.co.uk/page.jsp?id=1790 gement and
building controls” onwhich this article i s based. The full publication is available as a free download from:
ty – critical
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ENERGYMANAGEMENT
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