SE-14-C046 -- A New Hybrid Model for Borefield Heat Exchangers Performance Evaluation

Ground coupled heat pump systems are gaining importance for heating and cooling of buildings. To assess their performance, detailed simulation models are required with both short-term (to calculate the instantaneous coefficient of performance of the heat pump) and long-term (to calculate the ground temperature evolution) accuracy. A step response is calculated using a combination of a short-term response model which takes into account the transient heat transfer in the heat carrier fluid, the grout and the immediately surrounding ground, and a long-term response model which calculates the boreholes interactions. The state-of-the-art of both models has been chosen from an extensive literature review. Moreover, an aggregation method is implemented to speed up the calculations. Validation shows good results and very high computational efficiency.