Simulation Study On Trnsys Based Solar-earth Source Heat Pump System

While the shortage of energy sources and the environmental deterioration have become global problems, people increasingly attach importance to the exploitation and application of renewable energy. Solar heat pump, ground source heat pump and air-source heat pump have been applied to some extent, but they have their own limitations. The solar-earth source heat pump system can overcome the intermittence of solar energy and ease the recovery pressure on soil temperature. This system has a bright future.In this paper, based on the existing solar-earth source heat pump system in Taiyuan City, the math models of the main component in the system were established, and the simulation model of solar-earth source heat pump system was set up in TRNSYS software. Compare the actual operating data in summer, transition seasons and winter with simulation data, and analyze result discrepancy between them to verify correctness of the simulation model.Based on the simulation model which was established previously, this paper changes the control mode of existing solar-earth source heat pump system, carries out the transient numerical simulation, and analyses the operation characteristic of the system under the different control mode. The results show that:In summer or transition season, this system should run during the day, and solar system should be on the dynamic operating condition. In winter, solar system should be on the dynamic operating condition in cooler months (in December, January and February), while it should be on the static operating condition in the rest of the warmer period. In the static operation, to reduce energy loss, we should supply heat as early as possible.Based on the simulation model which was established previously, this paper changes the connection method of existing solar-earth source heat pump system, carries out the transient numerical simulation, and analyses the operation characteristics of the system throughout the year under different connection. The results show that:There are two positions for the solar energy supplement spot to be set, which is to set it between the exits of heat pump system and entrance of buried pipe or to set it between the exits of buried pipe and entrance of heat pump system. The former has a better performance than the later.Based on the field research of solar-earth source heat pump system, the paper analyses its operational control and connection type through the simulation model, which provides a kind of theoretical reference for the future design and application of solar-earth source heat pump system.