跨季节蓄热型地源热泵热传递规律研究

基于有限元分析法，建立了准三维非稳态传热模型。在试验验证的基础上，分析了跨季节蓄热型地源热泵蓄热过程中土壤温度、单位井深换热量、热作用半径随热泵运行时间的变化规律，讨论了土壤结构、入口水温、入口质量流量、热泵运行模式等对土壤传热规律的影响，并研究了土壤热平衡问题。结果表明:同一半径不同深度处，土壤温度增长幅度随土壤热扩散率的增加而增大；土壤热作用半径随热泵运行时间及入口水温的升高而增加，并逐渐趋于稳定；间歇运行模式下，地埋管附近土壤温度及换热量均呈波动式变化，且当径向距离大于0.3 m时，与连续模式一致；在满足换热量的情况下，流体质量流量不宜过大；系统运行一个周期（360 d）后土壤温度基本可以恢复，且流体入口温度不宜低于40 ℃。

A study of the heat transfer law of ground source heat pump with seasonal heat storage

Based on the method of finite element analyses a quasi 3-D unsteady-state heat transfer model was developed. Changes in soil temperature, transfer rate per unit borehole depth and thermal influencing radius for ground source heat pump with seasonal heat storage with the heat pumps operation time were analyzed by comparison with the experimental results. The effects of soil structure, inlet water temperature, inlet mass flux and operation models on heat transfer of soil and the issue of ground heat balance were investigated. The results indicate that soil temperature at the same radius of different depths increases with the soil thermal diffusivity, the thermal influencing radius increases with the operation time, and the inlet water temperature gradually tends to be steady. The fluctuation changes in the soil temperature and heat transfer rate under the intermittent operation model and the soil temperature of radial distance more than 0.3 m were fitted with two models, indicating that the mass flow rate of the inlet fluid was not too big under the requirement of the heat transfer rate of the system, the soil temperature is recovered after one cycle of operation (360 d) of the ground source heat pump system with seasonal heat storage, and the fluid inlet temperature should be more than 40 ℃.