Design Method Of Solar Collector Area Based On Soil Temperature Restoration

The main function of the collector in solar ground source heat pump system is to balance heat during the long-term operation.There are two ways to design the collector area,Solar fraction method and heat balance method.However,the Solar fraction is difficult to obtain,while the thermal balance method does not take into account the influence of the natural temperature restoration.Therefore,this paper presents a design method of the collector area considering the soil temperature recovery rate.Soil temperature recovery is a complex physical process,and there is no complete theory to describe it.According to the sources of heat,the soil temperature recovery is divided into two parts:soil heat recovery and soil natural restoration.How to set up the relationship between soil temperature recovery and collector area,and combining collector area design with soil temperature restoration are the key problems.This paper starts with the relationship between soil temperature recovery and related factors,found that the number of drilling and the cumulative heat/cooling load ratio are the main factors.With the number of drilling and cumulative heat/cold load increased soil temperature recovery rate decreased.Then,the relationship between drilling depth,groundwater seepage and soil temperature recovery rate was further studied.It is found that the smaller the total drilling length,the greater the cumulative heat/cold load ratio,and the greater the effect of drilling depth on the soil temperature recovery rate.With the increase of drilling length,the influence of drilling depth is becoming smaller and smaller.Groundwater seepage has a significant influence on soil temperature recovery rate,and is beneficial to soil temperature recovery.In the study area of groundwater seepage intensity,the stronger the seepage action,the better the soil temperature recovery.This paper quantifies the relationship between soil temperature recovery rate and various influencing factors.Taking FuXin region as an example,the relationship between soil temperature recovery rate and various influencing factors was regressed,(?)To establish the relationship between soil temperature recovery and collector area,and using the recovery rate of soil temperature,the calculation formula of collector area is given,(?).Taking Fuxin auto parts city system as an example,the calculation results of thermal balance method and soil temperature recovery rate method and long-term operation of the system are compared.It is found that the calculation result of soil temperature recovery rate is 12.9%greater than that calculated by the method of specific heat balance,After 8 years simulation,it is found that the average soil temperature is 8%higher and the average soil temperature recovery rate is 7%higher than that calculated by the existing thermal balance method.