Low-cost Efficient Ground Source Heat Pump with an Innovative Ground Heat Enhancement Technique

This paper summarises the performance monitoring of Solar-Air thermal panels acting as a supplementary source to a Ground Source Heat Pump (GSHP). Given a possibility to use shorter boreholes and higher heat extraction from the ground, solar-air thermal panels could economically be combined with the GSHP; an experimental system has been installed on a full size occupied detached two-storey house in the city of Nottingham, UK. The south-facing solar-air panels collect solar heat on sunny days, bright-sky, and air warmth even during summer nights to warm the glycol/water. The heated glycol/water is sent directly to the borehole then to the GSHP for immediate needs (real-time), and surplus heat is retained the same day (diurnally) during winter and equinox. The solar-air panels continue to work through the summer and are large enough to capture long term warmth to prepare for the following winter season (inter-seasonal). Data were collected in real time. The results show that there are advantages with recharging the ground (soil battery); firstly this increases seasonal performance of the heat pump and the lower soil temperature is maintained at 12°C; this also enables the heat pump to work closer to an expected coefficient of performance (COP) of 4.0, instead of the annual average of 2.65 predicted by the manufacturer.