Construction, fabrication and performance analysis of an indigenously built serpentine type thermosyphon solar water heater

A serpentine type thermosyphon flat-plate solar water heater has been constructed and fabricated with locally available material. The hourly system performance of the solar water heater has been experimentally investigated for several days in Dhaka city (lat 23.7° N, long 90.38° E) of Bangladesh. The single glazed collector was made from copper sheet and tubes. The collector was tilted at an angle of 27 degree facing south on a supporting structure. The working fluid of the closed thermosyphon heated at the serpentine type flat-plate collector enters the water tank due to density gradient caused by temperature differences. Such collectors are adequate for water heating and this at present is an economical way to use solar energy for water heating. In performance evaluation of the serpentine type solar water heater, inlet and outlet water temperature of collector and tank water temperature was recorded for consecutive hours. Maximum collector outlet water temperature obtained was 67°C and maximum tank water temperature obtained was 61°C during June-July period. From the collected data, various temperature graphs are plotted and analyzed for different solar time, various amount solar insolation and different weather condition. A pH test was also carried out to study the pH value of water within the aluminium built water tank. Some recommendations are made after evaluating the performance of thermosyphon, thermal insulation of water tank, collector radiation absorption, effects of glazing and losses of the collector. This is a field level experiment to improve the device performance and cost reduction for the construction. Conclusion can be drawn after evaluating the performance over a certain period of time for different designs and modifications.