Research Of Heat Accumulation Problem And The Exploitation And Utilization Planning Of GSHP In Chongqing

As the higher request on indoor environmental quality and resources shortage,GSHP(Ground Source Heat Pump)system is developing rapidly with more research about GSHP performance and environmental impact caused by its operation.According to heat accumulation problem scholars put forward the solutions.The usage amount of GSHP increase rapidly in Chongqing.However,there is less targeted research about GSHP and none of shallow geothermal resources planning in Chongqing.As a result,the study of operation characteristics of GSHP and heat accumulation problem caused by it in Chongqing area is necessary.It is indispensable for planning of shallow geothermal resources in Chongqing.First,the office building in Chongqing area is set as the target.Through monitoring the GSHP system,collection and analysis actual data in long-term,the operating characteristics of GSHP system in Chongqing area is studied;Then,a model is established by TRNSYS software to simulate the GSHP system operation condition in three decades under different ratio of cooling and heating load.With four parameters: ground temperature,outlet temperature of buried pipe,COP/EER,energy consumption to evaluate the performance of GSHP,find out the ratio of cooling and heating load which can make the GSHP system stable operation long-term in Chongqing region According to the actual needs of office building of air conditioning design of the running time of the two optimization scheme.According to the actual needs of air-conditioning in office building,two optimization operation time scheme was designed.Then,compared to advantages and disadvantages through simulation.Finally,with the collection information of early stage research,adopting the way of combination AHP(analytic hierarchy process)and fuzzy analysis method,the exploit and utilize of shallow geothermal resources is planned in Chongqing urban area,to lay a foundation for the advance of exploit and utilize to shallow geothermal resources in Chongqing.The main conclusion is as follows:(1)In Chongqing area,there is a large differences between cold and hot load in air conditioning.The load rate of GSHP system is low in heating season.After a long operation,there will be a heat accumulation phenomenon,and it will affect the efficiency of the unit.The imbalance of take and exothermic problems need to be considered in the application of GSHP;(2)In Chongqing,the biggest ratio of cooling and heating load is 0.7(years accumulative total ratio of cooling and heating is 1.14),which can ensure the GSHP system stable operation long-term.When the ratio of cooling and heating load is 0.6(years accumulative total ratio of cooling and heating is 0.975),it has less effect on the temperature of soil;(3)Under the condition of meet the demand of air conditioning,it also can achieve the purpose of relieving heat accumulation by shorting unit operation time.Further the scheme which has more intermittent times is more beneficial to the recovery of soil;(4)In Chongqing urban area,the thermal conductivity of soil is good(the thermal conductivity of soil is 2.62 W/m.K).the average temperature of soil is suitable(18.5 ~ 20.5?).The percentage of best and better suitable area of the shallow geothermal resource planning area in Chongqing urban area is 96.5%.The percentage of the key development and the encourage development of the shallow geothermal energy planning area in Chongqing urban area is 68.33%,which illustrates that most of Chongqing urban area has a huge development potential in shallow geothermal energy development with complete natural and socio-economic conditions;(5)In Chongqing urban area,due to the complexity of underground space structure,it need detailed investigation before the development and application of GSHP system,in order to minimize the impact of the exploit of shallow geothermal resource to soil's temperature.Before exploit shallow geothermal resource,it is very necessary that Investigation and feasibility study on construction conditions,geological conditions,economic efficiency and energy saving effect,etc.