Over recent years a number of new pieces of legislation have come into force regulating the amount of energy usage in buildings. These support the government targets on reducing the amount of carbon emissions in the UK by 80% on 1990 levels by 2050. Further important changes to this legislation are on the cards.
Consultation on proposed changes to Part L of the Building Regulations closed in September 2009; and changes to the EU Energy Performance of Buildings Directive are also expected. Each wave of legislation seems to be setting higher targets on reducing carbon emissions caused by energy use in buildings. This creates opportunities for any company that supplies products and solutions that reduce energy use as it drives designers to plan for highly energy efficient buildings, and facilities managers to seek out new ways to drive down energy waste in their businesses.
At Siemens Building Technologies we believe that building controls and building energy management systems (BEMS) have a crucial role to play in the energy efficient design and operation of buildings. We are keen to encourage building managers and facility managers to look to their control systems to find cost-effective and simple strategies. This applies as much to existing buildings as to new properties.
Approximately 70% of building services equipment in existing buildings is controlled by a BEMS. Controls influence every aspect of a building’s operation: heating and hot water, ventilation, cooling and air conditioning, lighting, windows and shading. Too often though a BEMS is installed in a building and then forgotten about. The energy saving potential that the system can provide is overlooked. To overcome this we would encourage a regular review of a building’s current controls and control strategy is carried out.
Maintenance and commissioning, or re-commissioning, are the first steps to effective operation of controls. This should be carried out by competent, trained organisations. Simple steps can achieve immediate savings. For example, ascertaining that sensors are correctly placed – it is easy for a photocopier to be re-positioned under a sensor, sending the false message that cooling is required when it should be switched off. If meters have been installed, they should be connected to the BEMS to ensure that energy use is not simply measured, but can also be monitored over time, and used to identify areas of energy waste. Legislation could encourage building owners to carry out a regular MOT on their system to help achieve these savings.
Metering is another growing area for buildings where Part L of the Building Regulations and Energy Performance of Buildings Directive require their installation. These rules are designed to ensure that building operators know how much energy is being used, and how energy consumption differs across zones in the building. Information gathered from meters is also used for energy certification and benchmarking. While metering can track energy use over time, without added functionality from building controls, meters provide only part of the picture.
Controls not only track energy use, they also help to automatically reduce energy consumption. By linking each meter so that its output can be used as an input to a corresponding control loop, the system can automatically optimise performance and reduce energy. Even simple control systems can work alongside required energy meters to reduce out-of-hours equipment operation, or prevent heating and cooling systems running simultaneously. Advanced BEMS can also help match energy use exactly to occupant requirements, So for example presence detection can ensure that lights are only on when required; or an automatic room booking system can set a meeting room to the required temperature only when a meeting is booked to start.
Metering is needed to keep track of energy use, and identify areas of high energy consumption in a building. But metering on its own cannot achieve energy reductions. Monitoring and management are vital if information is to be used for controlling and minimising energy in the long term.
We would also encourage taking this further and making building occupants aware of their current energy usage. Legislation has already catered for this with the introduction
of energy performance certificates. This can be taken further with dynamic displays of current and credible statistics about a building’s actual energy usage, CO2 reductions and water conservation making the energy profile of a building transparent. The actual values can be displayed alongside target values. This sort of information is ideal to display via a flat-screen in a prominent public area such as a reception or lobby area. This has two benefits; it showcases the environmental commitment of the organisation and it motivates energy saving activities and behaviours among the building occupiers.
Moving forward we would encourage legislators to look more closely at the benefits BEMS can bring in helping to achieve the energy saving targets required for the UK building stock.