地源热泵垂直埋管换热器埋深优化研究

An Optimization Study on Buried Depth of the Vertical U-tube Ground Heat Exchanger for a Ground-coupled Heat Pump System

工程设计中常采用垂直深埋换热器的方式保证地源热泵系统的单井换热量,而实际应用中部分深度埋管换热效果不佳,造成了系统工程经济性下降的问题.首先以现场热响应实验法为基础,研究了垂直埋管换热器的换热性能,发现垂直埋管换热器随埋深变化呈现三个特征不同的换热段,且在近地段内存在热短路与热堆积现象;其次提出了以换热高效段截止深度作为垂直埋管换热器埋深的优化方法;最后结合实际工程案例,论证了系统工程经济性的提升.

Vertically and deeply buried heat exchangers are often used in engineering design to ensure single-well heat exchange of the ground source heat pump systems.In fact,the effect of heat exchange at some depth is not well,which affects the system engineering economy.Based on the field thermal response test,and through the discussion of heat exchange performance of vertical U-tube ground heat exchanger,it can divide into three heat exchange sections with different heat exchange intensities when deeply buried vertical U-tube ground heat exchanger,and there are heat short circuit and accumulation in the nearly section.We propose optimization method to find the cutoff depth of heat exchange efficient section during deeply buried vertical U-tube ground heat exchanger.Combined with the application in actual cases,the better engineering economical with optimizing buried depth is demonstrated.