The Research and Application of Solar Water Heating System in Zhejiang Province, China

Zhejiang Province is located in east China, right next to Shanghai. It is one of the most developed regions in China. It sits at approximately 30 degrees north latitude with an average annual solar irradiation of 4600MJ/m2.a and duration of sunshine of about 1700~2200hr/a. Due to the high urban population density in this area, multi-storey and high-rise apartment are two main categories of residences. This paper studied the solar radiation characteristics of the local high-rise flats, and proposed systems suitable for providing hot water to multi-storey and high-rise apartments using solar energy. In the paper, advantages and disadvantages of using these systems are discussed, including forms, efficiency, pipeline design, and billing. These systems were also applied to engineering practice, and the results were rather good. Based on the balance between performance and techno-economic indicators of solar water heating systems, it is concluded that the payback period of solar water heating systems varies from 2 years to 8 years under different performance conditions.