Operating Your Buildings
Tom McNeil
Senior Building Performance Engineer
Max Fordham LLP
It may sound like a statement of the obvious, but it is worth remembering that the energy use in a building is a function of the activities that go on inside it. Buildings exist to serve a function, that may be to provide a space for learning, for people to work or highly specialised spaces to deliver theatre or energy intensive facilities such as a swimming pool. A common thread with all these activities is that they require the use of energy.
Without the use of energy these activities cannot take place, it is the responsibility of the designers and the operators of a building to work together so that they make the most of the energy used to deliver their building’s functions effectively and to the benefit of the people that use them.
We have discussed building form, fabric and orientation, the use of daylight and how to heat and ventilate a building but the single biggest consideration and factor in determining energy use is what goes on inside the building. It is a truism that people will generally find a way to get stuff done, it is also true that people generally follow the path of least resistance in getting stuff done. The design and operation of the building must enable them to do that simply and efficiently. To enable that the right questions must be asked and addressed during the design to ascertain how the building will be used. The right questions will vary from building to building but will all involve:
- Who are the building users and how do they use the building?
- When is the building in use?
- How is the building opened up and shut down?
- What systems are in the building?
- How is the building zoned?
- How are we going to monitor energy use?
In answering these questions, procedures, processes and facilities can be put in place and give a better chance of delivering a low energy building in use. Frequently it is the simple measures that have the biggest impact. Simplicity often proves to be more efficient than complexity. Work with the reality of how people use buildings and not how we would like them to. Take lighting controls for example, many buildings install complex controls in the notion that they will deliver exactly what the building users ‘need’ with no input from the occupants. In practice they often prove complex to commission and users make decisions on their own needs and over-ride them. Simple user controls such as switches with timers allow building users to use lights as they need them and often result in lower overall energy use. The first responsibility for any building operator is to understand what energy is used for. As buildings become more efficient the energy used by computers, alarm systems and general ‘stuff’ in the building becomes an increasingly large proportion of the load. The image below shows the make-up of the total energy use in a naturally ventilated office. “Unregulated” energy use (i.e. energy use other than heating, lighting and elements controlled by Building Regulations) makes up over half of the total carbon emissions and just as much thought and control must be applied to these non-regulated loads.
Just as important as where energy is used is knowing when it is used. We have found that the energy use outside of normal opening hours in many building types such as offices and schools is up to 40% of the total energy use. This is all energy use related to but not directly supporting the key functions of the building. Another truism is stuff that is turned off cannot use energy, this is perhaps the single biggest contribution to achieving a net zero carbon building. Combine that simple fact with a simple path of least resistance, in the form of a building off-switch, and energy use will reduce.
If building users are enabled with simple methods to do the right thing they generally will and the chances of delivering a net zero carbon building in use increases.
