The UK's largest ground source heat pump has been installed in Milton Keynes at the Open University to provide low carbon heat. The installation is at building 12, which is a 2,000 sq metre sustainable new build development at the Walton Hall campus.
The building opened in early 2011 and is hoping to receive a BREEAM outstanding rating. The building does not just utilise heat pumps, in addition it also consists of natural ventilation, solar chimneys, a green roof, night time cooling, automatic lighting controls, solar thermal panels to heat water and photovoltaic solar panels to provide electricity.
The heat pumps were installed by drilling 13 boreholes into the ground to a depth of 100+ metres to install a ground loop system. The ground loop system is connected to four gas absorption heat pumps, which combined have an output capability of 140kW. The heat pumps are being used to heat the building and are estimated to achieve a 45% reduction in carbon dioxide emissions compared to a system heater.
Gas absorption heat pumps are based on the same principle as standard ground source heat pumps except that the solar energy that the earth collects is harnessed by the ground loop and is enhanced by the refrigeration cycle and additionally by the heat generated by combusting gas. This produces very high fuel efficiencies.
Gas absorption heat pumps offer fantastic benefits to the climate as well as cost savings. Along with all the other environmentally friendly technologies building 12 has embraced, the Open University is hoping to reach the outstanding rating by BREEAM. BREEAM is the world's foremost environmental assessment method, so it will be a fantastic achievement for the University if they can reach an outstanding rating.
