Investigation into geothermal-driven dual-temperature district heating substation and its performance under variable conditions
High-temperature geothermal energy is precious renewable resource for heating.Re-ducing the return temperature of geothermal water is an important way to maximize geothermal heating potential and expand the heating area.Considering that existing buildings generally use high-temperature radiators and other heating terminals,while newly constructed buildings mostly use low-temperature floor heating terminals,the required supply water temperatures for these two types differ.In response to this,a geothermal energy-driven dual-temperature district heating substation system with a single absorption heat pump and two heat exchangers is proposed.This system aims to produce dual-temperature hot water for both high-and low-temperature heating terminals and reduce the return temperature of geothermal water.Simulation results show that when the geothermal outlet water is 100 ℃,and the secondary network's high-and low-tempera-ture terminal supply water temperatures are 50 ℃ and 35 ℃ respectively,the return temperature of geothermal water in the dual-temperature district heating substation one can be reduced to 20.1 ℃.Compared to a substation using two serial heat exchangers,the proposed one can lower the geothermal water return temperature by 14.9 ℃,reduce the geothermal water flow rate by 18.6％,and improve COP by 11％,demonstrating significant energy-saving advantages.Variable working condition analysis indicates that promoting the use of low-temperature heating terminals helps further reduce the return temperature of geothermal water,increase the heat supply to us-ers,and improve the COP of the dual-temperature district heating substation.
geothermal energydual-temperature district heating substationabsorption heat pumpvariable conditionscentral heating
万方数据
维普
