Gloucestershire based Ecovision, was commissioned to design and install a renewable energy solution. After an initial consultation period it was decided that the most efficient system to provide both the heating and cooling to the building, was to install two Ecovision 245kW ground source heat pumps. A motorized valve control strategy enables the non-reversible heat pumps to provide cooling as well as heating. The ground source heat pumps are used to generate the low temperature heating water for the space and air heating systems throughout the winter, with a capacity of approx 450kW. During very cold days a gas boiler system is used to top up the heat pump output on the secondary side of the heat pump buffer vessel.
The heat pumps are also utilized for pre-heating the mains hot water. The initial pre-heat is undertaken by the solar thermal array on the roof and where the performance of the solar thermal array is not sufficient to preheat the incoming cold water, the ground source heat pumps heat the water to the required temperature within the pre-heat vessel.
During the summer the heat pumps will provide chilled water for the mechanical ventilation system. The heat pump system is designed to provide the full cooling load of 510kW, with the heat pumps being connected to the borehole field outside the building under the car park. In total there are 104 boreholes, which are 110 meters deep. The boreholes are headered-up via 4 manifold chambers, which are linked together inside the plant room.
‘Ecovision worked closely with Wilmot Dixon, the principal contractors, to design a system that would supply precisely what the Care Home required. It was a complex and highly technical installation which needed to provide heating and cooling at different times of the year. As a result of the heat pumps the NHS will make significant savings on running costs as well as significantly reduce their carbon emissions.’ Julian Sowerbutts, managing director of Ecovision.