Selection Of Collector Area For Solar Collector-ground Source Heat Pump Hybrid System

Nowadays,with the vigorous development of society and economy,people not only require high comfort of living environment,but also attach great importance to building energy-saving,which requires the research of new building energy-saving technologies to continue to progress and develop.Solar collector-ground source heat pump system is a combined solar and geothermal heat pump system.This system uses solar collector to supplement the geotechnical heat loss of ground source heat pump under long-term heating operation,and uses the stability of ground source heat pump system in heating to solve the adverse impact of weather change on solar heating,which is equivalent to an effective comprehensive application of two heating systems.In this paper,the reasonable selection method of solar collector area is studied for the solar collector-ground source heat pump composite system with single heating.Under the climatic conditions of Xi'an city,the dynamic heat transfer model of the composite system was established by TRNSYS software for the 10 000 m2 residential building area.According to whether the solar collector system operates under two conditions in winter,the relative optimal collector area corresponding to different geotechnical thermal conductivity values is obtained,and the relationship between the relative optimal collector area per unit building area and geotechnical thermal conductivity is obtained.Firstly,two kinds of working conditions are designed for the combined heating of solar collector system in winter.During the heating period,a ground source heat pump system is opened in the working condition,without considering the solar energy system as an auxiliary heating system;while in the second working condition,both the ground source heat pump system and the solar energy auxiliary system are opened,and the solar energy collector is used as a supplement to the heating source.During the transitional season(heat storage period),both working conditions open the solar collector system to restore the geotechnical temperature around the buried pipe.Dynamic simulation model of solar collector-ground source heat pump system based on TRNSYS software,and the parameters of the simulation module are set up according to the operation requirements of the first and second working conditions.Among them,building load is calculated by DeST software,buried pipe demand is calculated by GeoStar software,and the results are imported into TRNSYS simulation system model.Thirdly,in the non-heating period,the minimum collector area under two conditions is set to restore the temperature of rock and soil around the buried pipe to the initial temperature,and the relative optimal collector area is selected based on the reasonable operation period of heat storage and the lowest total investment.Finally,the geotechnical thermal conductivity coefficients commonly used in Xi'an urban area are selected to carry out the above experiments,and the relationship between geotechnical thermal conductivity and the relative optimal heat collection area under two working conditions is studied and compared.The purpose of this paper is to determine the optimum area of solar collector for the solar collector-ground source heat pump system,so as to make the system technically reliable and economically reasonable,so as to promote the development of renewable energy technology in the construction industry to a better direction.