Study On Heat Recovery Characteristics Of The Soil Around Ground Heat Exchanger

In recent years, groundcoupled heat pump gets more and more widely usedbecause of its advantages of energy-saving, environmental protection, high efficiency.As the continuation of groundcoupled heat pump running, though, by the cold and hotload imbalance and the heat accumulation caused by soil temperature not recover intime for the influence of the heat pump system is more and more significant, and evenlead to losing the ability to run part of the heat pump system. So in this paper that thefeatures of recovery of soil heat are studied, the main works are as follows:1.Respectively for the summer and transition seasons (fall) analysis throughestablishing the finite element heat transfer model of single well and well group, andcombining the already measured experimental data, comparison between the changes ofsoil temperature between measured and simulated values found in the summermaximum relative error is11%, the average relative error is3%; Transition season(autumn) maximum relative error is0.12%, validate the correctness of the model.2.For three consecutive years of experiments are carried out using test bench test.The study found that the experimental condition of input soil accumulated hot and coldload unbalance rate of73%, and the soil temperature only decreased0.6℃after twoyears of running, the main period of soil heat of the wall recovery for the spring andautumn period and the transition season. In the third year of one year after the downtimebasic return to the initial temperature of soil temperature.3.Respectively using the heat transfer model is established, and analyzed the soilcoefficient of thermal conductivity, density, specific heat, and intermittent operationtemperature conductivity and linear meter in heat impact on soil thermal recoveryfeatures, found that the key factor affecting soil thermal recovery features is theconductivity of the soil temperature coefficient and the coefficient of thermalconductivity, soil density, specific heat, intermittent operation condition and linearmeter in heat is the heat recovery has certain influence to the soil.4.Using well group model continuous operation and intermittent operation areanalyzed when the working condition of sandstone soil thermal recovery features ofwell group, got in two kinds of sandstone under the condition of soil temperature can restore range.This article research is useful to solve the problem of soil thermal recovery andprovide the soil temperature under different operating mode can restore range,referencing for the design of ground-source heat pump system.