Study On The Operation Strategy Of Ground Source Heat Pump System In Greenhouse

In recent years,the scale of greenhouse construction has been increasing year by year,and the energy consumption of greenhouse has been widely concerned.From the point of view of energy-saving in greenhouses,the land-source heat pump system for greenhouses is established by utilizing the characteristics of natural light and heat resources collected in the lighting part of greenhouses and the ability of soil to store and extract heat,the excess heat in greenhouse is collected and stored in underground soil in summer,and heat is extracted from underground soil in winter to realize the seasonal balance utilization of heat in greenhouse,reduce energy consumption in greenhouse,and respond to the call for energy conservation and environmental protection.Firstly,through the analysis of the measured data of soil temperature and indoor temperature in one year,it is concluded that the high temperature in greenhouse in summer leads to the thermal imbalance of soil temperature Secondly,a greenhouse model is established to simulate the annual dynamic load characteristics of the greenhouse,and it is found that the annual cumulative cooling / heating load ratio of the greenhouse is 1.56,which has the possibility of heat transfer and utilization,it is found that the soil temperature is relatively stable and the inlet water temperature of the source side of the heat pump can meet the requirements of the code when the cumulative cooling-heating load ratio is 0.9 ~ 1.1,the heat pump can be operated efficiently and with good quality in its lifetime.Finally,the cumulative cooling-heating load ratio and the ground temperature recovery characteristics of the project site are analyzed,and two operation regulation schemes are proposed,both Scheme 1(setting the system to run between 11:00 and 19:00)and scheme 2(setting the system to run between 8:00 and 12:00 and 15:00 to 24:00)can effectively improve the heat accumulation problem in the heat storage season of the system and reduce the thermal imbalance range of the soil,maintain the operation effect of the system in the lifetime,and the operation effect of Scheme 1 is better than that of scheme 2.This subject is to monitor and simulate the performance of a greenhouse-use landsource heat pump system in Beijing,and to study the stability of soil heat and the longterm operation of the system,the simulation method can not only provide a reasonable operation scheme for practical engineering,but also enrich the research work of the existing ground source heat pump system.In addition,the application of ground source heat pump system in agricultural engineering,mainly using geothermal energy,solar energy and a small amount of electric energy,mostly clean energy,can reduce emissions of pollutants,contribute to energy conservation and environmental protection.