The CHOICES project is studying whether the grid impact of ground source heat pumps can be reduced economically by storing air-sourced summer heat in borehole arrays for use in winter (‘active recharge’).
Such an approach improves the overall efficiency of air-sourcing of heat by using direct, on-site PV generated electricity. The improved efficiency of the heat pumps in the winter months (resulting from the higher ground temperatures) reduces the grid impact – higher efficiency means lower grid draw.
The project team constructed a pilot CHOICES Energy Centre in Owen Square Park in Bristol that
comprises an air-source heat capture system and ground source heat pumps rated at 140kW.
Most buildings in the UK burn natural gas in individual boilers for space and water heating. This is supplied by the gas grid which covers around 80% of UK buildings and on a winter day can deliver up to 6TWh – 5 times more energy than the electricity grid can currently deliver. Heat is responsible for around a third of the UK’s greenhouse gas emissions. The replacement of the majority of this gas supply with a low carbon alternative is essential to meeting our carbon emissions reduction targets.