Modelling and Numerical Simulation of Greenhouse Effect in a Solar Collector with a W-Shape Cover

The work presented concerns the modelling of the greenhouse effect in solar thermal collectors with W-shape cover. A mathematical model was used to evaluate the net infrared radiation absorbed, the radiation lost by the absorber and the radiation pathways in the collector. A comparison was made between the three collector configurations: the double-glassed flat collector, semi W-shape collector and W-shape collector. The cover of the W-shape collector has double glass whereby the upper glass is flat, and the lower glass is w-shape. The absorber is also W-shape. The results show that at the maximum of solar radiation, the adsorbed infrared radiation is 678 W.m-2, 620 W.m-2 and 433.2 W.m-2 respectively for the double-glassed flat collector, semi W-shape collector and W-shape collector. The radiation losses are smaller in the W-shape collector (234.3 W.m-2) wherever when the absorber is flat, the radiation lost is greater: 250 W.m-2 and 265 W.m-2 respectively for the double-glazed flat collector, semi W-shape collector. Analysis of the angle factors of the transparent cover and the absorber showed a significant influence on the greenhouse effect in the W-shape collector, when the angle of the W-shape cover increases, the absorbed IR radiation also increases as the radiation losses decrease. This result is validated when the W angle of the absorber is constant. We also saw that, the absorbed IR radiation and the radiation lost at the absorber level grow with the W angle of the absorber.