无渗流条件下U形地埋管换热器能效特性研究
Energy efficiency characteristics of U-tube ground heat exchangers under non-influent conditions
摘要：
选取无穷远边界值，利用三维数值模型对无渗流条件下地埋管换热器传热过程进行动态模拟，研究了地埋管换热器能效系数的主要影响因素。结果表明，增大岩土体导热能力和埋设深度及适当减小管内流速能够提高地埋管换热器的能效系数，而加大支管间距仅能在较短换热时间内提升地埋管的换热能效；采用间歇运行模式，特别是小周期循环和较长时间温度恢复期，有利于提高地埋管换热器的能效系数；岩土体初始温度和地埋管进口温度的变化并不影响地埋管换热器的能效系数。
Abstract：
Selecting infinite distance boundary, simulates the heat transfer process of the ground heat exchangers(GHE) under non-influent conditions by using three-dimensional numerical model. Investigates the major impacting factors of energy efficiency coefficient of GHE. The results show that increasing soil-rock heat transfer capability and buried depth and properly decreasing flow rate inside the GHE can improve the energy efficiency coefficient, but enlarging the distance between two legs can take effect on the energy efficiency of heat transfer in a short run time, that adopting intermittent operation mode with shorter periodic cycles and longer temperature recovery time is helpful for increasing the energy efficiency coefficient of GHE, and that the initial temperature of soil-rock body and inlet temperature of GHE have no effect on the energy efficiency coefficient.
Keywords:non-influent, U-tube ground heat exchanger, energy efficiency coefficient, operation mode