Experimental Study On Small Scale Tri-functional Water-Source (Ground-Source) Heat Pump Central Air-Conditioning Unit

With the development of the people's living standard, household air-conditioner and hot water have become an indispensable part in our daily life. We usually have to buy two units separately, household air-conditioner and water heater. When the two units work they not only waste energy but also cause serious environmental heat pollution, and contradiction exists between them. This system don't meet the requirement of the sustainable development .So this paper designs and studies the small scale GWHP central air-conditioning unit with hot water supply, this unit has three functions-cold supply, heat supply and hot water supply. The unit will bring us both economic benefits and environmental benefits.This paper has made the theoretical analysis and experimental study on the sample unit ,and draws some conclusion as follow:(1) Groundwater-source refrigeration operating mode and Groundwater-source heat operating mode are analysed theoretically by means of enthalpy analysis and exergy analysis, Calculating out the performance coefficient , finishing degree of heating power , exergy efficiency of sample unit and the exergy loss of condenser compressor , evaporator and expander, then offering the basis for improvement and test of the sample unit;(2) Under standard mode, Groundwater-source refrigeration operating mode and Groundwater-source heat operating mode, carrying on performance test to the sample unit respectively, the result shows: The sample unit operates stably, performance are good;(3) Under refrigeration operating and hot water supply mode and heat operating and hot water supply modes, this paper has carried on the experimental study on the influence of condensing heat recovery for hot water, each mode is divided into two kinds of situations to heat hot water , water in inside tank is in static behavior and water in inside tank circulates with water in outside tank .In the course of testing, high-pressure system , low- pressure system and water system have been tested under each kind of situation, and summarizing the change law of every parameter and impact on performance of sample unit in detail, the result shows :Condensing heat recovery for hot water has little impact on sample unit under refrigeration operating mode, but the impact on unit can't be ignored under heat operating mode .In addition, under single hot water supply mode this paper also has carried on the experimental study on the influence of condensing heat recovery for hot water , high-pressure system , low- pressure system of the unit and water system have been tested ,and summarizing the change law of every parameter in detail, the result shows : Each parameter of the air-conditioning unit is in the dynamic change under single hot water supply mode;(4) This paper confirms heat transfer coefficient K of the sleeve pipe type heat exchanger of the inside hot water tank through the test: Interior sleeve pipe K =150.2 â–³T~0.5547, exterior sleeve pipe K =19.1 â–³T~0.7171, this two models can be used to design the condensing heat recovery water tank of other unit types. The warm - keeping test of the inside hot water tank...