Design and operation of an improved ground source heat pump system assisted with cooling tower

Abstract A TRNSYS model of ground source heat pump (GSHP) system is constructed and validated according to the measured running data of the studied GSHP system. It has been found that there exists a serious thermal accumulation problem under the ground, and the cooling tower is introduced to the GSHP system for auxiliary heat dissipating. By the simulation of the improved GSHP system in TRNSYS software, the input time of cooling tower, the auxiliary cooling ratio (ACR), and also two control strategies of cooling tower are studied, and the following conclusions are derived: the cooling tower should be put into operation in the third year for the energy saving purpose of the studied GSHP system at the optimal auxiliary cooling ratio of ACR = 30%. For the further study of control strategy, the optimal control parameter is Δ T = 6 °C if the temperature difference control strategy is adopted; while it is T u / T l =30 °C /28 oC if the fixed temperature control strategy is adopted.