直膨式土壤源热泵系统的理论与实验研究

Theoretic and experimental study on a direct expansion ground-source heat pump

对直膨式土壤源热泵系统性能系数随影响因素的变化规律进行分析。在热泵系统制热模式下,采用分布参数法建立该系统的稳态数学模型,运用该模型计算热泵系统的性能参数,并在所建直膨式土壤源热泵系统性能试验台上测试该系统的性能。研究结果表明：管壁温度、制热量、性能系数等的计算结果和实验结果较吻合,证明模型基本可靠;随着冷却水流量的增大,热泵系统的制热量和性能系数都会随之增大;随着冷却水入口水温增大,热泵系统的制热量和性能参数都会随之减小;热泵的性能系数在2.8-4.5之间,高于常规的空气源热泵的性能系数。

The changing disciplines of COP（Coefficient of performance） of the direct expansion ground source heat pump system with some factors were analyzed.A distributed parameter method was established for this type of heat pump system,and with this model,the working process of this direct expansion ground source heat pump system was simulated and analyzed.A direct expansion ground source heat pump system test bench was set up and tested.The results of wall temperature,COP,heat-capacity agree well with experimental data,which indicates that the mathematical model is reliable.Heat-capacity and COP of this heat pump system increase when the cooling water flow rate in the tube-in-tube heat exchanger increases;heat-capacity and COP decrease when the temperature of inlet water of the tube-in-tube heat exchanger rises.The COP of the pump system is between 2.8-4.5,and is higher than that of air-source heat pumps.