A project where closed-loop ground-source heat pumps have been used is the Discovery Millennium Centre, Derbyshire, now known as Conkers. The offices and classrooms are naturally cooled and ventilated but the exhibition area and restaurant, which at times are densely occupied, are mechanically cooled and ventilated using a demand-led displacement ventilation system. The building is heated by a ground-source heat pump rated at approximately 25 per cent of the full load capacity (150kW), with the peak loads being met using a conventional boiler.
The heat pump is reversible and can provide some 100kW of cooling for the ventilation system when required. The ground-source heat pump is connected to an array of 39 40m boreholes.