Construction and Performance Evaluation of A Low-Cost Flat-Plate Solar Energy Collector

A. Tsiu1, Leboli Z. Thamae1, I. Hapazari2, and B. M. Taele1

1. Department of Physics and Electronics, National University of Lesotho, Lesotho

2. Department of Chemistry and Chemical Technology, National University of Lesotho, Lesotho

Abstract: A low-cost flat plate solar energy collector prototype was designed, constructed and tested for functional performance. The aim of the investigation was to develop functionally-sound and low-cost flat plate solar energy collector suitable for use by low-income groups, including dwellers of remote rural areas, who are generally poor. Hence, apart from functional performance, the device had to be low-cost, simple and easy-to-maintain. Low-cost was achieved through the use of cheap and locally available materials — raw sheep wool, ordinary window pane-glass, and galvanized plate sheet — as substitutes to the more expensive conventional materials. Effectively, it is estimated that the selling price of this system would be at least30% cheaper than what is currently on the market. The parameters measured and used to determine the device performance efficiency were temperature and solar radiation. The collector efficiency during peak sunshine period (that is, 11:00 to 14:00 hours) varied from a maximum of 25% (at 11:00 hours) to a minimum of 20% (at 14:00 hours). Observably the efficiency range is much lower than those of conventional systems, and there is much room for

improvement on the design and/or construction materials. However, ongoing measurements have already shown that the system is capable of sustaining water temperatures above 40°C against ambient temperature of as low as 10°C, which is acceptable for bathing and other household chores.

Key words: solar water heater, solar energy, solar flat plate collector, collector performance