Comparative Study of Solar Water Heating Systems - Flat Plate Collector (FPC) with Evacuated Tube Collector

Solar energy is one of the alternatives to replace the use of conventional energy sources to heat water for domestic use. This paper focuses on the design and fabrication of a second generation indigenized FPC with locally available low cost material and compares its performance with existing costlier ETC solar water heating system. Readings of FPC and ETC are taken on different days at different time intervals having varied climatic conditions and humidity levels. Analysis of data showed that the rate of temperature rise in ETC is higher than FPC. The maximum temperature reached by these two solar water heating system varies from 2 degrees C to 4 degrees C. The difference between ETC and the indigenized FPC is the time taken to reach the peak temperature. This is due to a better conversion factor and a comparatively low thermal loss factor of ETC. Considering the energy saving involved, as the difference in temperature between FPC and ETC ranges from 0.10 degrees C to 6.80 degrees C, FPC is better suited to heat water for domestic uses given the climatic conditions prevailing in Coimbatore city, India.