Effect of glazing number on the performance of a solar thermal collector

In this research paper, an attempt has been made to come across the effect of multiple glazing covers on the efficiency of a solar thermal collector. This experimental investigation was carried out on an active solar energy demonstration system (ET 200), illuminated with a halogen lamp. Three commercial glass panes of 3 mm thickness, having the same dimensions as that of the apparatus glazing, were used. Tests were done with and without the added glass panes, at a fixed water flow rate of 5.8 1/h, taking the whole surface of the collector maintained at an horizontal position. Experiments were performed with two positions of the light meter. In one position, it was placed in the middle of the collector surface. While, in the other, the light meter was placed in the middle of the upper glass added. Double, triple and quadruple glazing, reduce the amount of heat absorbed by water by deceasing water temperature difference between the inlet and outlet of the absorber. Double glazing decreased the efficiency of the solar collector with 15%. This efficiency was decreased by 29,95% for triple glazing, and by 45,96% for quadruple glazing. The addition of glass panes above the collector surface, acts as a resistance to the spread of the energy transmitted by the halogen lamp, this effect reduces the performance of the solar collector instead of improving it, according to a linear equation with a high correlation coefficient.