地源热泵地埋管换热器热响应试验方法及影响因素研究

Methods and Influence Factors of Thermal Response Test for Borehole Heat Exchangers of Ground Source Heat Pump System

岩土的综合导热系数是地埋管换热器准确设计的重要参数之一,获得岩土综合导热系数较为广泛的方法是现场岩土热响应测试。阐述了热响应试验的理论基础,介绍了热响应试验的两种方法,并对影响热响应试验结果的因素进行了分析。结果表明,测试时间、岩土初始温度及流体进口温度都会影响热响应测试结果的精度,因此,在进行热响应实验时,首先要保证足够长的测试时间,同时,要测试出准确的岩土初始温度。在测试过程中,要控制热响应测试系统地埋管进口处的温度和进出口温差,使其在热泵机组名义工况范围内。

The rock-soil thermal conductivity is one of important design parameters for borehole heat exchanger of ground source heat pump system. The thermal response test is widely used currently for getting rock-soil thermal conductivity. Basic theories of thermal response test are described in the first place, and then two methods of thermal response test ace introduced, moreover, the influence factors of thermal response test are analyzed. The results show that the duration of thermal response test, rack-soil initial temperature and the inlet temperature of borehole heat exchangers all affect the accuracy of thermal response test results. Therefore, first to ensure a long enough test duration and an accurate rock-soil initial temperature. During the thermal response test, it is necessary to control the inlet temperature and the temperature difference of the inlet and outlet of borehole heat exchangers to make it in the range of the nominal operating conditions of the ground source heat pump.