Experimental Investigation Of An Opened Water Source Mutil-functional Heat Pump

In daily life, people demands of cooling, heating and domestic hot water. Currently,the way to solve these three demends is using heat pump air conditioning unit and boileror hot water heater, but it can't save energy and protect environment. In addition, someclosed water source multi-functional heat pumps have been used on the market with aset of system to solve these three demends. However, there isn't mature precept of anopened water/air source multi-functional heat pump. In recent years, our research groupputs forward a kind of opened water/air source multi-functional heat pump.In this paper,the experimental investigation was conducted on the opened water sourcemulti-functional heat pump.This paper introduces working principle and four functions of the opened watersource multi-functional heat pump. A testbed of the opened water sourcemulti-functional heat pump has already been designed and built. This testbed cancontrol water temperature entering/leaving the heat exchanger and the watertemperature difference between them simultaneously. During the test, the controlprecision of water temperature entering/leaving the heat exchanger is±0.2?, and thecontrol precision of water temperature diffierence is±0.3?.Using this testbed, heating conditions of the opened water source multi-functionalheat pump have been tested and investigated. This paper gets some important results.The COP of the opened water source multi-functional heat pump is more7.7%than thenational standard about water heat pump whice operates in the heating conditions, whenthe temperature difference between hot water entering and leaving heat exchangers is 5?, and the water temperature entering and leaving heat exchangers in heat source sideis14?/9?respectively, and the temperature of hot water entering and leaveing heatexchangers is40?/45?. In addition, the COP of the opened water sourcemulti-functional heat pump is2.20?4.22, and the exhaust gas temperature is80.3??109.6?, when the water temperature entering/leaving heat exchangers in heat sourceside is10?/5?,12?/7?,14?/9?, and the temperature of hot water leaving heatexchangers is40??55?, and the temperature difference between hot water enteringand leaving heat exchangers is5?. At the same water temperature entering and leavingheat exchangers in heat source side and the same temperature of hot water leaving heatexchangers, the COP of the opened water source multi-functional heat pump is2.60?4.51, and the exhaust gas temperature is78.3??101.3?, when the temperaturedifference between hot water entering and leaving heat exchangers is10?. Throughcontrastive analysis, the COP of heating conditons rises3.1%?18.5%respectively,when the temperature difference between hot water entering and leaving heatexchangers is from5?to10?with the same conditions. These results indicate thatthe opened water source multi-functional heat pump operating in the heating conditionshas better performance when heat pump operates in big temperature difference withsmall water flow rate.