The Experimental Study on Forced Circulation Solar Hot Water Supply

Abstract

In recent years, global environmental problems and energy crisis are highly regarded. The research and development of new energy sources and energy saving are two key ways to solve the potential global energy shortage. The solar energy is important for its cleanliness and unexhausting. The solar water heaters are widely used in domestic hot water supply. The former natural cycle system had a lower performance of heat collection, insulation and convenience as well as conflict with architecture. It is necessary to develop a new style solar water heater in north china. This paper presents an forced circulation solar hot water supply system with spiral copper coil as heat exchanger in heat storage tank and plate solar collectors. It has high collection efficiency and it is consistent with the architecture. The system is full of antifreeze to solve the freezing problem in north china. The experimental study was conducted for solar hot water supply system. The experimental results indicate that the forced circulation solar hot water supply system has superior performance of heat collection and heat transfer. The average heat output is respectively 2.82kWh/m2 in spring, 3.13 kWh/m2 in summer and 2.73 kWh/m2 in autumn. The hot water output is respectively75.3L/m2.d in spring, 81.2 L/m2.d in summer and 56.5 L/m2.d in autumn if the temperature difference is 28°C.In addition, by use of the experimental measured data the long-term thermal performance can be forecast.