Analysis of intermittent operation on the ground temperature recovery of borehole heat exchanger fields

This paper analyzes the intermittent operation on the ground temperature recovery of borehole heat exchanger (BHE) fields. The outlet fluid temperature is regarded as the field measurement to study the ground temperature recovery. Various factors influencing the ground temperature recovery are studied. The results show that, compared to other influencing factors, the amount of building energy demand has a more significant impact on the ground temperature recovery. While considering the influence of heat pump COP, for the same building energy demand, the performance of continuous operation is better than that of intermittent operation. The rising of the groundwater table is beneficial to the restoration of ground temperature. Ignoring groundwater fluctuations will cause an error of 0.3 degrees C in 20-day operation.