The Research Of Geological Environment Impact On The Development And Utilization Of Shallow Geothermal Energy In Chongqing

Shallow geothermal energy(SGE)as a new environmentally friendly energy,successfully with remarkable energy saving benefits.With the promotion of environmental protection and energy saving.Chongqing area belongs to the bedrock mountain area,which is dominated by sedimentary rock.The water level is higher,the heat transfer performance is better,but the cooling load in summer is much bigger than that in winter heating load,as a result,the absorption and heat release of the soil is difficult to balance.Meanwhile,system operates for a long term may lead to "Thermal Accumulation",the efficiency of the heat pump system is reduced.Therefore,while development and utilization of SGE resources,the research on the influence of geological environment should also be strengthen.The research of development and utilization for the shallow geothermal energy(SGE)impacts on geological environment belongs to the field of geological environment monitoring.The working areas of traditional geological environment monitoring focus on the city,important economic zone,major projects,the area of mine and geological disaster which threaten more serious,the main objects of monitoring mainly in underground water level,water quality and geological disasters.The development and utilization of SGE to study the influence of geological environment is mainly based on the development and utilization projects,focus monitoring on different depth of geothermal field and chemical field.Dynamic change is obtained by monitoring data,once abnormal phenomenon is appearance,take measures immediately to prevent problems of geological environment.In this paper,the change of geothermal field is mainly studied as a basis for judging the influence of geological environment.In this paper,the projects of development and utilization for the SGE resources in Chongqing are investigated,and the current situation and problems of the development and utilization are analyzed.The dynamic monitoring network of the SGE about development and utilization is established and improved,temperature monitoring data of typical soil monitoring site is collected,and thermal accumulation is analyzed.Heat transfer mathematical models of typical rock and soil storage are established,with the model validation of measured data,according to the change of ground source heat pump project,the environmental effects of SGE development and utilization are studied.The study of the ground source heat pump(GSHP)system is suitable area for the partition of developing and utilizing.The characteristic of rock and soil is representative,the research shows that: in the way of development and utilization of SGE by using GSHP in Chongqing area can obtain little influence on the geological environment because of its good soil thermal properties,result in long-term operation and producing little influence for the geothermal field.It is worth noting that Chongqing is located in thermal partition of hot in summer and cold in winter.In the early stage of system design,the imbalance rate of cooling and heating load should be considered,by using the way of domestic hot water in annual supply,intermittent operation,auxiliary cooling tower and others to reduce cooling-heating load difference,enable to balance the heat release of the rock and soil.