Three foundations for building-control success
From long experience with an energy-services company, Simon Redvers of Honeywell Building Solutions focuses on how improvements in control have a key role to play in improving energy efficiency.
The pressure to drive down energy usage and associated costs can be hampered by the lack of in-house resource needed to identify efficiency improvements or by lack of the capital required to realise them. That’s where an energy services company (ESCo) partner can help.
ESCos design, install and maintain projects that improve the energy efficiency and maintenance costs of facilities, increase equipment lifespan and deliver measurable saving opportunities. These improvements can be funded through the provision of an energy performance contract (EPC), with the ESCo guaranteeing future energy savings that repay the finance required for the work.
Projects are based on detailed investment-grade audits that often combine retrofits with short and long return on investment that together make an attractive package and can incorporate a wide range of measures. An EPC for an NHS Trust in Wales involves 17 energy and utility saving initiatives — including boiler replacements, converting lighting ballasts to high-frequency units, new chiller plant and the installation of a modern building-management system to realise guaranteed savings of £380 000 a year.
But not all energy saving measures have to involve equipment investment; control improvements also have an important role to play.
No matter how efficient a building’s infrastructure, waste still occurs if energy is used when it isn’t actually needed. Incorporating measurement, control and behaviour, the three foundations for building-control success, into an energy strategy can reduce the element of waste significantly.
Measurement is required for ongoing analysis that identifies trends and events that could cause concern. Issues may include, for example, plant running at unexpected times, excessive demand peaks, and events that trigger load shedding or energy-resource conversion changes.
Installing sub-metering to create granular data to benchmark and understand a building’s characteristics is essential to identify initial saving opportunities and deliver long-term, sustained benefits.
In one multi-occupancy London office building, 50 sub-meters were used to identify scheduling, base load and plant issues as well as using the data to engage with building occupiers to achieve behavioural change. The landlord attributed a 10% energy reduction to this system, with a payback on the investment in metering of 18 to 24 months.
The value of a good building control system depends on a comprehensive understanding of a building’s characteristics, its systems and how the building is actually used. In one example, a school hall felt cold at morning assembly, so a teacher regularly turned up the local thermostat two or three degrees and left it there. An investigation revealed the hall was slow to heat up and was under-temperature during assembly. Programming the heating to come on slightly earlier resulted in an acceptable temperature during the assembly and avoided unnecessary energy usage during the rest of the day.
Turning the temperature down one degree is a cheap and quick way of saving cash and carbon. However if control can only be achieved by, say, ±3 degrees, the mean temperature has to be 3 degrees above the required minimum. If the range can be reduced to ±1 degree, the thermostat can be kept 2 degrees lower on average, with the potential for significant savings, as buildings can be run at a lower temperature (or higher if cooling).
A 2009 report on over 600 relatively new buildings in the USA showed that ‘energy drift’ in commercial buildings happens surprisingly fast —10 to 30% in the first two years alone. Using an ESCo to watch over the operation helps prevent this expensive and environmentally damaging drift in building energy use.
People are more likely to modify their behaviour voluntarily if they can understand and appreciate the reasons for doing so. Facts and data are key in this regard, and can be obtained through accurate metering and the presentation of relevant information in an easily understandable format, such as lobby signage or intranet pages.
However, achieving behavioural change requires more than just awareness. The challenge is to create new social norms and to enable people to act easily in the desired way. Highlighting that others are reducing energy by utilising a building-management system to collate and present relevant data automatically on a frequent or ongoing basis helps in this regard.
Optimising the solution to achieve the most cost-effective energy-management solution involves bundling controls and reporting tools with behaviour changes — providing a high return and a low upfront capital investment. Rather than simply collate and report data, the solution should align with the existing systems and collect data from them in order to recognise trends, highlight issues, analyse faults, recommend actions and, where appropriate, implement corrective actions in real time.
Working with a company that can put in the systems, carry out the analysis, advise and assess corrective actions and then implement the control and behavioural changes, as well as any required capital plant upgrades, is the best route to success.
Simon Redvers directs marketing and strategy activities for Honeywell Building Solutions’ UK operations.
