Study On Energy-saving Operation Of Ground Source Heat Pump In Solar Greenhouse Based On EnergyPlus

The floor area of solar greenhouse in China,according to statistics,reached 697.4 thousand hm~2,which ranking the first place in the world.With China already committing to peak dioxide emission before 2030 and achieve carbon neutrality before 2060（double carbon goal）,the work to reduce carbon emission of solar greenhouse is significant,because of the huge energy consumption in heating and cooling solar greenhouse.Ground source heat pump（GSHP）utilize geothermal energy,which is efficient and environmental.Heating and cooling the solar greenhouse by GSHP is urgent for the double carbon goal.One of the most important issue in GSHP operation is thermal imbalance of underground soil,which will reduce the efficiency of GSHP system,if paid inadequate attention.GSHP annual operation,the supplement heat energy when GSHP cooling,the supplement heat energy when free cooling（fan coil indoor links directly to underground heat exchanger）,extracting thermal energy from underground soil when GSHP heating,all of these influenced and limited by several factors and environmental parameters.How to determine the difference between extracted and absorbed energy by quantity analysis is a problem puzzled researchers many years.We studied a particular case of underground thermal imbalance,plan to adopt optimized operation mechanism to achieve underground heat balance.This paper studied and simulated annual operation of GSHP system applied in solar greenhouse based on Energy Plus-a numerical simulation software.The main research results of this paper are as follows:（1）A numerical model of solar greenhouse energy consumption has been builtBuilt a numerical model of solar greenhouse construction.Put into Energy Plus,and then built numerical models of shading,movable insulation and natural ventilation.After that,built numerical models of GSHP and free cooling.The establishment and successfully debugging is fundament of energy consumption simulation of solar greenhouse.（2）The optimize and design of solar greenhouse GSHP’s numerical modelDesigned and optimized GSHP underground heat exchanger considering load features of solar greenhouse with plant growth conditions by Energy Plus platform and GLHEpro underground heat exchanger design platform,get an optimized model.（3）The study of underground heat balance of solar greenhouse GSHP annual operationUsing the numerical model of greenhouse operation in summer,aiming at the lowest energy consumption,the collaborative operation of natural ventilation,ground source heat pump and shading was simulated and optimized to obtain underground heat storage in summer.The coordinated operation rule of natural ventilation cooling and free cooling of ground source heat pump in transition season was studied,the starting temperature of natural ventilation and free cooling of ground source heat pump was set,and the running time of free cooling of ground source heat pump was optimized to obtain the best heat storage during the transition season.Study on combined operation law of natural ventilation and Ground source Heat pump heating Simulation in winter.In winter,when the sun is full,the solar greenhouse is naturally ventilated and cooled,and the GSHP heating is controlled according to the set temperature.The study results of shading,natural ventilation cooling and movable insulation for solar greenhouse show:cooling load reduced 84.52%with shading than with no cooling measure in a year,while cooling load reduced 36%with natural ventilation and 87%with shading and natural ventilation.The heating load reduced 65%with movable insulation in winter.All measures effectively save energy.Build the model of free cooling based on GSHP model,free cooling model reduce energy consumption by 38%,while achieved same cooling effect.The optimized operation of the GSHP system annual soil heat acquisition 7.35×10~7 k J,heat storage 7.38×10~7 k J.Under this operation strategy,the total annual power consumption of greenhouse operation is 16.85 MW·h,the average COP of ground source heat pump in heating period is 4.5,and the average EER in summer is 4.53.In this paper,Energy Plus simulation platform is used to simulate the energy consumption of the solar greenhouse ground source heat pump system throughout the year,and the underground heat can be obtained under the single heating operation condition of the solar greenhouse ground source heat pump,which provides reference and theoretical support for practical engineering applications.