Research On Simulation And Optimization Of Solar Coupled Ground Source Heat Pump System

The ground source heat pump system uses soil as the cold and heat source of the building air conditioning system,which is one of the important forms of renewable energy utilization in the construction field.In some areas,due to the different cumulative loads in winter and summer,long-term operation is likely to cause the imbalance of the soil temperature field and reduce the operating efficiency.Based on the characteristics of solar heating system and ground source heat pump system,this paper has developed a set of solar-coupled ground source heat pump systems suitable for buildings in cold regions where the cumulative heat load is greater than the cumulative cooling load to ensure the feasibility,reliability and economical efficiency of the operation of solar-coupled ground source heat pump systems.And it analyzes and optimizes the operating conditions of the solar energy coupled ground source heat pump system through simulation.In terms of the systematic design,this paper states the advantages,working principles,operating modes and corresponding control strategies of the solar energy coupled ground source heat pump system.This paper takes an office building in Qingdao as the research object and build models by using DeST software,so the hourly load of the office building throughout the year is obtained.This paper completes the selection of the key equipment of the solar subsystem and the ground source heat pump subsystem,and analyzes the mathematical model of the main components of the underground heat exchanger,heat pump unit,hot water storage tank and circulating water pump in the solar coupled ground source heat pump system.Based on the TRNSYS simulation software,the simulation model of single ground source heat pump system and solar energy coupled ground source heat pump system is established.The system was simulated for one year.According to the simulation results,the heating season is divided into the early heating period,the middle heating period and the last heating period.And this paper analyzes the operating characteristic of solar energy coupled ground source heat pump system in different working conditions and heating periods.The parameters of the heat pump unit COP,system COP,energy consumption and soil temperature changes were compared and analyzed.The optimization operation of the solar energy coupled ground source heat pump system using variable frequency technology on both the load side and the source side was studied.In this paper,three operating schemes are designed.Scheme One is that the system load side and the source side use fixed frequency pumps at the same time;Scheme Two is that the system load side uses variable frequency pumps and the source side uses fixed frequency pumps;Scheme Three is that the system load side and the source side use variable frequency pumps at the same time.Based on the analysis of the energy consumption of the water pumps of the three schemes,the total power consumption of the water pumps of Scheme Three is the lowest,which is 798139.2k Wh.Compared with Scheme One,the system saves energy consumption by 78981.2kWh and saves 9.0%electricity.