Analysis of geo-temperature recovery under intermittent operation of ground-source heat pump

In this paper, a three-dimensional model is presented to study the geo-temperature variation with the porous theory. The simulation is validated in comparison with experiment that carried out on the mode of heating. The model was used to predict the geo-temperature distribution in operation and recovery period of ground-source heat pump system. Moreover, the influencing factors including thermal conductivity, porosity, backfill material, air temperature, solar radiation energy and velocity of wind on the soil recovery process were calculated. The results show that the soil temperature recovers more quickly when heat conductivity increases and soil porosity decreases. Under the heating mode, the soil temperature recovers more quickly when the solar radiation and air temperature increase and the wind reduces. Furthermore, the results indicate that the soil properties have great effect on the soil recovery, however the environment factors have little effect.