Simulation Study In Feasibility And Operation Characteristic Of Hybrid Ground Source Heat Pump Coupled With Heat Pump Water Heater

ABSTRACT:The world energy crisis has made the development of renewable energy more rapidly, the ground source heat pump is the technology which meets the demands of air conditioning, hot water making, and others in buildings by use of geothermal resources in shallow soil layer. It is an important technical way to apply renewable energy in our major. The application of ground source heat pump is available for the save in the building energy consumption, improvement of energy utilization efficiency and energy construction in our country. A single ground source heat pump will cause soil suction exothermic imbalance due to reasons such as load, the operation process of application which has a negative impact in the long-time running of the system.In this paper, A hybrid ground source heat pump system coupled with heat pump water heater was proposed by integrating heat pump water heater unit and air conditioning unit. It is applied to Changsha area by analyzing the load of air conditioning in the whole year in different places. A Changsha hotel building by the hybrid ground source heat pump system coupled with heat pump heater, and the calculation model was established by transient simulation system software TRNSYS. Run the system by30years, the results of hybrid ground source heat pump system coupled with heat pump water heater and single ground source heat pump was compared, it was found that hybrid ground source heat pump system coupled with heat pump water heater has improved the soil environment, relieved the soil suction exothermic imbalance, improved the operation efficiency of air conditioning unit.Operation characteristics in different control method of hot water temperature were analyzed by system simulation. The result shows that the control method of average temperature in hot water tank is better than the control method of outlet water temperature in hot water supply quality of hot water supplying, thermal improvement in soil, and system efficiency.Operation characteristics in different hot water flow rate were analyzed by system simulation. Result shows that hot water supply quality would decrease when the ratio of hot water is under0.7, the operation efficiency of the system achieves the highest when the ratio of hot water is0.7.Operation characteristics in different length of buried pipes were analyzed by system simulation. Result shows that the length of buried pipes have nothing to do with the supply quality of hot water. The system difference in soil heat suction achieves the best when the number of drillings is150, The increase in the number of drillings has little influence in the soil heat suction. The operation efficiency of the system was improved when the drillings increase during90to150, and the system energy consumption was reduced at the same time.The hybrid ground source heat pump system coupled with heat pump hot water heater in this paper could be applied to the actual engineering easily. The results of system simulation study have a certain reference value to the design of the hybrid ground source heat pump system.