Analysis Of Soil Thermal Balance Of Solar-soil Source Heat Pump System With Cross Seasonal Thermal Storage In Beijing Area

This paper studied the system of solar energy cross season storage and soil source heat pump system through experiment and simulation.The operation status of each part of the system and soil balance rate were studied by experiment.The soil temperature changes in long-term running of the experimental system were simulated.Experimental system was optimized by simulation at last.The main work in this paper is as follows:(1)This paper takes the solar-soil source heat pump experimental system founded at a primary school in Daxing District,Beijing as the experimental object.The study carried out the monitoring and data collection of the experimental system for nearly a whole year.The operating conditions of each part of the experimental system in the heating,refrigeration and heat storage modes of the whole year operation stage was analyzed through the analysis of the experimental data.The experimental results show that the system runs well throughout the year,and the soil imbalance rate is reduced from 29.59%of the single soil source heat pump system to 17.56% of the solar-soil source heat pump system.(2)This paper established a De ST model based on the experimental building,and the disturbances of the model were set up according to the actual operating time of the experimental system.The hourly load of the experimental building was simulated through the established model.In addition,the TRNSYS model was set up according to the experimental system and the mathematical model of the model was introduced in this paper.Then the operations of the experimental system in different condition were simulated by changing the model’ working time of each loop pump,the switching of heat pump and the control strategy of different setting temperature at different seasons in different seasons.Finally,the accuracy of the model was verified by the comparison of the results between experiment and simulation.(3)Facing the problem of heat accumulation in the long run of the model simulation system,this paper optimized the system by simulation.The optimized system results show that the soil temperature changes within a reasonable range after 20-years’ running.There will not be cold or hot accumulation in long term running.In addition,the optimized system has better economic performance in initial investment recovery period and operation cost than the experimental system.This paper studied a solar-soil source heat pump experimental system founded at a primary school in Daxing District,Beijing by experimental and TRNSYS simulation.The experimental system could be optimized and improved according to the optimization scheme.