Performance of Ground Source Heat Pumps in Densely Populated Areas

Abstract

Ground source heat pumps (GSHPs) connected to vertical borehole heat exchangers (BHEs) are a popular technology to provide heat and/or refrigeration in residential and commercial buildings. When such systems only extract/reject heat from/to the ground, the temperature in the ground surrounding the BHEs decreases/increases until it reaches a steady state. How fast the steady state temperature is reached and how different it is from the undisturbed temperature depends on many factors; one factor is the presence of neighbouring GSHPs. As the number of neighbouring systems increases, the steady state condition is reached more slowly and the magnitude of the temperature change in the ground increases. If designed without taking into account the presence of neighbouring installations, the actual temperature change in the ground surrounding the BHE(s) of a GSHP might be significantly higher than the forecasted temperature change in the ground; meaning that the actual performance of the heat pump (HP) would be lower than the expected performance. We had previously suggested a model to evaluate the thermal interference between BHEs of neighbouring GSHPs; in this paper, we couple the previously suggested model with the model of a HP to evaluate how the performance of GSHPs in densely populated areas are affected by the presence of neighbouring installations.