Articles
THE EFFICIENCY OF THE WATER BAG SOLAR COLLECTOR
The water bag solar collector which is of low cost and affords a high performance has been studied by the computation simulation method.
The present report describes the results of the calculations.
Under optimum conditions of operation, the collector supplied 4 MJ/m2 day in January on an average and 10 MJ/m2 day in August.
Weather data used for most of the calculations were recorded in Tsukuba, Japan, in 1981. The difference in daily heat collection efficiency based on daily solar radiation data and hourly data was 10 % at most.
It is considered that the use of the water bag solar collector in a solar heat collecting system for heating and cooling greenhouses is technically and economically practical, since the water temperature (initial water temperature is 20°C and water depth is 10 cm) can reach 30–60°C and the cost of the apparatus is about 10 dollars/m2. Also it is possible to analyze the collector performance based on daily solar radiation data.