The newly constructed Luton Sixth Form College is using Dimplex ground source heat pumps in a large-scale 1.5MW installation.
The design consists of 28 ground source heat pumps ranging in size from 11kW to 75kW with a combined output of around 1.5MW to provide space and water heating. Some of the heat pumps are reversible, so in summer, cool liquid can be circulated through the system to draw heat out of the building; the heat pumps give a total of 712kW cooling capacity.
An open loop borehole will extract groundwater directly from the aquifer beneath the site and circulate it around the site on a ring main via a 1MW heat exchanger. Distribution systems specified vary according to the use of the area; a combination of Tarmac Termodeck, underfloor heating and air handling units will be used.
The new college site will incorporate a wide variety of environmentally-friendly features, including a containment area under external recreation space to minimise the risk of flooding in the event of exceptionally heavy rain, a brise soleil mounted on south sides of the buildings to limit solar gain and glare in summer, rainwater harvesting for reuse in the toilets and for irrigation and maximum use of natural light and ventilation.