Numerical Simulation And Test System Design Of Domestic Solar Water Heater Thermal Performance

Thermal performance is an important index to measure the quality of domestic solar water heater, and it is very important to test and analyze the thermal performance to improve the efficiency. Traditional research method on the thermal properties is experimental analysis, however the method not only vulnerable to control environmental conditions, and are unable to get weak links and fluid medium distribution inside the water heater; in addition, with the rapid development of domestic solar water heater, National solar thermal using product quality supervision and inspection center, accept the domestic solar water heaters products commissioned the inspection quantity increasing year by year, but existing domestic solar energy water heater thermal performance test system is single station, which exist low efficiency and automation.Therefore, this thesis is put forward a method which combine with the standard,using computational fluid dynamics software to simulate the domestic solar water heater thermal performance, on the basis of design a domestic solar water heating device testing system.(1)Thermal performance experiment was carried out by Fluent, revealing transfer law of the energy in the water heaters. It is found that the heat storage tank of the water heater will form temperature stratification after the experiment. It provides the basis for the design of thermal performance test system.(2)The effects of experimental conditions on the thermal performance of domestic solar water heater were studied. Compared to 17MJ/m2 provided in the standard, when the irradiation dose was 15MJ/m2, System daily useful energy differs to 1.2%; Experimental simulation of heat loss at different initial temperature, find the heat loss of the water tank will increase with the increase of the initial temperature of the heat storage tank; the heat loss is less affected by the initial temperature of the tank. This can provide a reference for the improvement of the standard.(3)Combined with the simulation results, a thermal performance test system of domestic solar water heater is designed, and the system is able to test the thermal performance of the multi station water heater at the same time. According to the requirement of thermal performance, the reasonable pipeline and control system has been designed.(4)The domestic solar energy water heater thermal performance test system software has been completed. Using LabVIEW to achieve including temperature and flow measurement and control, network communication, test procedures and database functions. Verification shows test system can be meet the requirements of thermal performance test very well.