Efficiency Challenge

18 September 2009

Sourcing, installing and then measuring the performance of energy efficiency technologies can be a complex process. David Bakst outlines the key things to do well in order to reduce energy consumption and CO2 emissions.

THE IN-HOUSE FM DEPARTMENT, or an FM provider, will often be responsible for identifying proven solutions to fast-track their push to reduce CO2 emissions and energy consumption and will also be expected to evaluate potential solutions, manage roll out, validate results and report back to senior management,. All this is not without its
complexities and pitfalls.
As a company that has built its reputation in project managing the installation of its own
patented energy efficiency technology, M2G, we have accumulated considerable knowledge and experience of running nationwide multi-site installation programs and building strong stakeholder relationships. While our methodology and approach is specific to our technology, the underlying philosophy can be adopted for other technology roll out projects.
Base line
Before you get started, you need to understand how much energy you are consuming so start by base-lining your energy consumption. With the Carbon Reduction Commitment coming into force in April 2010, it is vital that organisations who qualify can accurately calculate and report on their CO2 emissions. Now start to identify areas of potential ‘quick win’ energy savings, either behavioural or technical, which are proven to
deliver fast paybacks - usually within two years.
Having identified the areas of focus it is now necessary to identify potential solutions. Attending seminars and energy forums is a good place to meet people who hopefully have addressed the issues you have identified from who you can glean crucial information on your supplier’s reputation and their product claims.
The next step is to understand how each product applies itself to your specific set of
issues and how effectively it has been deployed by other companies. This is where third party client references can prove valuable. Suppliers should provide a forecast on the
level of savings that can be expected, bearing in mind that actual savings will be influenced by other factors such as weather, changes in building occupancy etc. It makes sense to be conservative when estimating projected return on investment; your technology supplier should be able to help you with this by providing client references and proven past results. Ensure that any such works will not impact on comfort conditions in the building(s) as this could lead to complaints from internal customers.
Evaluating the success of any such project depends on the amount of energy reduced and the payback period; measuring this is complex. Automatic Meter Reading (AMR) has been seen by many as a universal panacea, but this is not always the case. AMR measures the total volume of energy being consumed by the building or site, not the individual plant consuming the energy.
Using AMR data in some instances, therefore, is too high-level to gain an accurate assessment of the savings being achieved where energy efficiency technology has been fitted. Installing sub-metering is one solution to verifying gas consumption at plant level, but it is expensive to implement. To overcome this approach, we have developed a ‘toggling’ technique for our specific technology that switches between running the M2G one day and then bypassing it the next, usually over a period of one month. The result is a comparison of ‘with and without’ an energy saving device for each boiler. The general principles can be applied to many different types of projects.
However, there will still be temperature variation from one day to the next, so these
figures need to be adjusted by using degree day analysis. Degree days quantify the daily ambient temperatures for a given region to help account for the effects of weather on energy consumption. Where more precise evaluation is required, degree days for the region can be replaced by a temperature data-logger to gather onsite temperature data.
The changes in energy consumption over longer periods of time (pre, during and post
project) can be established by CUSUM (cumulative sum) analysis, a tool that examines
trends for sequential events over time. Approved for assessing energy projects by the Carbon Trust, CUSUM analysis is effective for viewing overall trends in energy consumption.
In parallel with accurate measurement, it is important to ensure that energy reduction
initiatives are carried out one at a time. If there are two projects running simultaneously for the same energy source, for instance, it will be virtually impossible to determine which is responsible for the results by using CUSUM. It is also important to be aware of other changes in the building that could impact the results. These include changes in the occupancy and occupant behaviour, changes to the building fabric, plant failure, changes to equipment configuration and, surprisingly, disablement of the new energy saving device by others who may not have been privy to the programme in the first place.
It is important to include all stakeholders in the process. They’ll appreciate your consultation, respect you for doing so and it will go a long way to helping you achieve technology adoption throughout your chain of influence.
Aviva installation
In a recently completed estate wide roll-out of M2G at AVIVA, Sabien Technology managed the project from start to finish. The client simply provided us with details of the relevant site contacts and we took it from there, ensuring every stakeholder was briefed on the project and our terms of reference of the same.
When AVIVA set about reducing gas consumption by 5 percent in 2008, it investigated
a number of technologies, including Sabien’s M2G. The pilot was managed by Sabien and during this time gas consumption and associated carbon emissions were reduced by between 14 and 17 percent, with an average of 15 percent across the pilot sites. The average payback was 50 weeks, with annual CO2 savings of 76 tonnes.
On the basis of this success pilot, Aviva commissioned the roll out M2G to a further 33
sites. Given the scale of the Norwich Union estate, Sabien’s ability to manage the project worth £188,000, covering an area from the North of Scotland to the South West of England, was a key criterion. Working closely with the Norwich Union team, a schedule of works was agreed with building managers to ensure there was no disruption to the staff working in the buildings.
Gregory Luxford, AVIVA’s Energy & Utilities Manager said, “In a project of this nature a good working relationship is vital. We found Sabien to be very responsive and very practical in their approach and this was a major contributor to the smooth delivery of the project”.
Once the installation work had been completed, each site was evaluated using a CUSUM analysis to confirm the energy savings across the entire estate. This showed an overall reduction in gas consumption of 12 percent, giving a payback of 1.1 years.
● David Bakst is Operations Director at Sabien Technology www.sabien-tech.co.uk

Dry cycling
When a boiler is standing idle it acts like a giant radiator, losing heat to its surroundings
– even a modern, well insulated boiler will typically lose 1-2 percent of its heat through
radiated/standing losses. In addition, draught within the flue system may draw cooler air
through the boiler, potentially adding a further 2-3 percent to standing losses. This is further exacerbated by the need to purge the combustion chamber each time a pressure jet burner fires (cooling down something you are trying to heat up!) which creates further boiler heat losses.
Inevitably, these standing losses will cause the boiler to fire unnecessarily to overcome
the temperature losses while the boiler is idle. However this firing - dry cycling - does not
contribute to the actual building’s heating demand. It is simply compensating for these
‘standing losses’ and thus wasting energy. It can occur even when BMS or BEMS are in
place.
Dealing effectively with dry cycling in low and medium hot water systems requires another level of control. Sabien’s work in this area shows that ‘intelligent boiler optimisation control’ will deliver typical energy and carbon savings of 10 to 25 percent (depending on site conditions and applications) to give a payback of between six months and two years.