Test Method and Compact Facility for Thermal Performance and Energy Efficiency Grades of Compact Solar Water Heaters

Abstract

This paper introduces the overview of China's solar water heater industry. The share of non-pressurized compact SWHs is about 80%. Due to its low pressure-resistant, the thermal performance testing for non-pressurized SWHs is not as easy as the pressurized system. The pressure for the supplied water for the testing must be lower enough to ensure the tested SWH cannot be damaged. So, except the method identified in ISO 9459-2, China national standard introduces another way to test the thermal performance for the non-pressurized SWHs. It uses a pump to mix the water in the non- pressurized water tank, records the temperature at the beginning and the end of the test, and calculates the heat gain under the daily irradiation. This test method is much closer to the real using situation for these SWHs. In 2012, China will issue a new national standard for solar water heaters Minimum allowable values of energy efficiency and energy efficiency grades for domestic solar water heating systems. This standard requires all products sold in China should be labeled with the energy efficiency grade. The energy efficiency grade is calculated with the value obtained by the thermal performance test. A complicated test system like a testing laboratory is not suitable for the factories in China. A compact automatic test facility to assist the factory to determine its products’ energy efficiency grade is needed. This test facility has user-friendly interface developed with LabView, can perform the test and print the test report automatically.