Abstract
This study proposed a heat-transfer model of a Solar Water Heating (SWH) system using a metal reinforced black polyethylene pipe with a diameter of 10mm. The spirally formed pipe plays the role of a solar heat collector and heat injection in a water storage tank. In this study, an outdoor experiment was conducted to evaluate a performance of SWH system in Fukui, 2014. Some experimental results show that heat-carrier fluid temperature in a heat collection pipe was gradually increased at sunrise and reached at 55°C around 14:00 when short wave radiation flux became maximum. At the same time, the water temperature in the tank also reached maximum 53°C due to heat supply from the heat exchange pipe. It was shown that the proposed model could reproduce the spatial and time variations in the fluid temperature along the pipe for the experiment duration. Furthermore, numerical calculations was carried out to evaluate a reduction in the production cost of hot-water supply for bath by using the model and experimental data. It is expected that the SWH system can reduce the cost of hot water supplied from the gas heater system by 27% in Fukui city.
