A low-carbon renewable energy project retrofitted of HFC-134a ground source heat pumps into 400 flats in eight tower blocks in London. The project was named District Heating Project of The Year at the 25th annual H&V News Awards. This large shared ground loop array heat pump system installed a small HFC-134a ground source heat pump in each of the 400 flats, rather than a few large heat pumps centrally. The heat pumps were connected to ambient temperature shared ground loop arrays having 100 boreholes drilled to depths over 200m, allowing relatively simple sub-divisions into smaller ‘micro-districts’.
The HFC-134a heat pumps used provide space heating and optionally domestic hot water for well insulated buildings with multiple accommodation. By using a communal ground array this avoids the high heat losses associated with running high temperature pipe throughout buildings improving the overall efficiency of the system. Each heat pump has ground side water pump internal to the unit reducing the complexity of installation and the low noise levels allows for installation in places such as an apartment’s kitchen. The heat pump Coefficient of Performance (COP) is around 4 with nominal 3kW or 6kW thermal output.
Note: Hermetic factory assembled heat pumps have essentially zero annual refrigerant leakage, except for failures. There are end of life losses.
Source: Renewable Energy Magazine and manufacturer’s information