Achieving five star energy performance
September 1st 2006 The application of a few well-proven techniques can save energy, reduce carbon emissions and cut energy bills, as Alan Aldridge, executive director of the Energy Systems Trade Association (ESTA) explains.
For many industries, energy is a vital and expensive production component, one that like all other production elements is strictly controlled.
However, all too often the energy that is used to heat, light and air condition the buildings in which those processes take place is not so well managed. This leads to energy wastage, increased overheads and lower profit. Because this 'other' energy load is not analysed and controlled in the same way as production energy, unnecessary expenditure is incurred.
Yet careful attention to building energy use can bring significant reductions in costs and consumption in this area as well. The importance of reducing emissions and cutting energy use in buildings is an increasing priority for the Government. Buildings account for nearly 50% of the nation's carbon dioxide emissions, and that comes from fossil fuel use. Both Government and EU estimates show that about 20% of our energy could be saved through cost-effective measures i.e. it is currently being wasted. To address this, a new set of requirements for energy performance were introduced in April which mean that new buildings must use between 23-28% less energy than a comparable structure built just last year.
But these regulations do not just apply to new building projects: any refurbishment work must now comply with them as well. With the building stock being replaced at a very slow rate of about 1% a year, tackling the energy performance of existing structures is key to any climate change programme.
Some business organisations fought the uprating of the regulations on the grounds of potential added costs for building owners and operators. Yet calculations by ESTA, using the Government's own energy software (the Simplified Building Energy Model, or 'SBEM' for short), shows that the use of just five, well-established and extremely cost-effective energy technologies can help meet these new requirements as well as producing yearon- year cost savings. ESTA estimates that these techniques can deliver 50% of the carbon dioxide emissions cuts required by the regulations for new buildings and 20% of energy consumption when applied to existing ones.
The five technologies are: automatic Monitoring & Targeting (aM&T)
Some of these technologies will be installed in new buildings anyway, due to the changes in the regulations variable speed drives in air conditioning systems for example. In existing buildings, though, they remain options but highly costeffective choices. Most will be already be known to industrial organisations but the latest applications to building energy management may be less familiar.
Choosing the right combination and format in these areas will result in real savings.
Zone and boiler controls It is recognised that a single temperature setting in the operations manager's office will not provide a comfortable working environment across a whole site. So the new regulations require that: "The [building services] systems should be subdivided into separate control zones to correspond to each area of the building that has a significantly different solar exposure, or pattern, or type of use." In other words, south-facing meeting rooms need a different control strategy from storage areas in the north of a building.
Heating and hot water systems must also have effective control systems.
While the regulations are clear on what the end result must be, they do not mandate specific solutions. That is up to the designer/owner. There is a range of strategies and products that can be employed from standalone controls right up to full Building Energy Management Systems (BEMS) and the correct choice will depend on individual circumstances.
ESTA will be happy to advise on this. It should also be noted that, in the case of new-build, the regulations give an allowance of up to 4% on the carbon emissions target for installing appropriate boiler controls.
Lighting controls In modern buildings, the high standards of insulation mean that cooling may require more energy than heating in all but the coldest months. But conventional lighting can contribute to heat gain and so increase the cooling load (a conventional tungsten filament lamp converts 90% of energy consumed into heat). While the use of low energy lighting will reduce this wastage, unnecessary losses will still occur if the lighting is used when it is not needed. To avoid this, proper controls are needed. Available systems range from simple timeswitches to ensure that lighting is not left on all night or during shutdown periods, through to daylight sensors which maintain a set level of illumination whatever the external light conditions.
ESTA's calculations using the SBEM model show that lighting controls can account for up to 15% savings on total building energy use.
automatic Monitoring & Targeting All energy managers are familiar with Monitoring & Targeting (M&T) techniques they form the backbone of all effective energy management. Without accurate metering and analysis, consumption cannot be kept under control. At large sites, the building regulations already require sub-metering and, indeed, automatic meter reading must be installed in all non-domestic buildings (new build or those undergoing refurbishment) of more than 1000m2.
The development of automatic Monitoring & Targeting (aM&T) systems has taken much of the repetitive and tedious elements out of this technique.
These systems include the metering, automatic reading, data collection and waste analysis, as well as incorporating alarms to alert users to 'out of range' performance. They can be applied to all energy and water utilities.
The effectiveness of aM&T is now officially recognised. They qualify for a 5% carbon allowance when installed in new buildings. ESTA's calculations again using the Government's official software show that they can in fact deliver about 20% of the carbon savings required, as well as reducing energy consumption by that amount. Since in many industrial cases automatic metering and submetering will already be required, the step up to a full aM&T system which will produce much higher energy savings is a relatively low cost investment.
Power factor correction Energy managers in industrial organisations know the importance of good power factor in process applications.
Yet it is important for building energy supplies as well and some energy suppliers charge for poor power factor in order to recover some of the losses from reactive power. The Building Regulations provide a further 2.5% allowance against the carbon emissions target if a new building has correction equipment installed that ensures a power factor in excess of 0.95.
Variable speed drives Variable speed drives (VSDs) are becoming standard on most motorised industrial equipment today. They allow equipment to operate efficiently at partload.
Their use in building services is also increasing and, in fact, the latest building regulations require that variable air volume (VAV) systems achieve the same specific fan power at 25% flow as at 100% (for motors consuming more than 1.1 kW).
Only systems employing VSDs will satisfy the new standards. It has been estimated that this type of drive will save at least 40% of the power previously required to run the fans at varying loads.
Five star performance Using these five technologies alone will achieve 50% of the carbon reductions required in new buildings by the new regulations. Just as importantly, it is estimated that they will reduce energy consumption in existing buildings by up to 20%. When process energy is routinely controlled in order to keep costs down, it surely makes sense to do the same with building energy consumption. The savings are there to be made!
ESTA has organised a series of free, one-day conferences taking place around the country in November. These will address the issue of how to achieve 'fivestar' energy performance. For details of dates and venues and to register for one of the events please use the enquiry bar below: More articles from ESTA: | 
