Of statistical significance
In the face of spiralling prices and a growing raft of legislation designed to achieve an overall reduction in carbon emissions, all building owners and managers must to do all they can to manage their energy use in the most effective way possible.
An investigation carried out by The Carbon Trust in 2010 analysed large private and public sector organisations and found significant potential for cost effective emissions reductions via energy efficiency measures. It suggested that a decrease of 70-75 per cent could be achieved by 2050 at no net cost using technology that exists today. While the exact figure quoted is something of a moot point, there’s no doubt that the non-domestic buildings sector has much to gain from using energy more wisely.
As the old adage goes, ‘if you can't measure it you can't manage it’, and given that up to 84 per cent of a building’s energy consumption can be under the control of a BEMS, it is without doubt the most effective way to gain a true picture of how and where any potential savings can be made. Using a BEMS allows clear targets and objectives to be set and intelligent technology can assist with on-going analysis of how energy is being consumed by a variety of building services, and suggest remedial action where necessary.
Although a BEMS is at the very heart of a successful data capture programme, it is also vital to establish a set of clearly identified and defined objectives that outline exactly what is to be achieved. Whether it’s a 10 per cent year-on-year reduction or a five per cent lower electricity bill, the principle is the same and setting a realistic goal necessitates a thorough understanding of how energy is currently being managed – or indeed mismanaged – in a building.
At this point it is worth providing a few words of warning. Far too many building owners and managers make the mistake of focusing on quantity rather than quality of data, something that more often than not leads to confusion and error. Meaningful data is imperative in order to make prioritising actions as straightforward as possible. The data should also, where possible, be presented to other stakeholders in a way that they can relate to – for instance, by describing any proposed financial savings in pounds rather than just kWh.
As part of the BEMS set-up process utility tariffs, CO2 ratings and cost and consumption targets should all be configured, while normalisation criteria also needs to be specified to allow comparisons between different areas within a building, or to benchmark consumption against a set of pre-defined profiles. Almost every aspect of a building services infrastructure can be reconfigured to save energy, however, some areas may provide higher gains than others. Therefore, a strategic approach to data analysis will help identify the quick wins.
It is vital to ensure that the BEMS itself is fully optimised as, if not, the data it feeds back will be incorrect. It might be necessary to call in an expert integrator to adjust setpoints and check that items such as boilers, chillers, air conditioning and pumps are working correctly. Furthermore, a full audit might be advisable to ascertain where energy could be saved and to help configure reduction targets.
Configuring a BEMS to account for profiles, rules and exceptions will facilitate a better understanding of how a building works and differentiate correct energy use from what may appear to be an anomaly – saving valuable time and effort. For example, a spike in energy use at 5.00am when a building is empty may appear to be cause for concern, however, if it transpires that this was due to the plant operating to protect the fabric of the building from frost conditions, then it would not require further investigation.
State-of-the-art BEMS use rules to explain why energy related events occur, like in the example above. However, in the event of genuine overuse an alert will be created that as well as being flagged up on the display panel will also be sent to designated individuals via an email or text message.
Acquiring, managing and acting upon BEMS related data should not be considered a ‘one-hit wonder’ – instead it should be thought of as an on-going strategic process. While any changes as a result of data capturing activities will facilitate accurate and effective day-to-day energy management, it will also enable the development of long-term strategies that can drill down into all aspects of a building. Year-on-year profiling will identify where further on-going efficiencies can be made, such as reducing heating and cooling loads and optimising plant operation.
Matt Pickard is duty team leader at Trend Controls
