Study of a concentrating solar collector integrated in the roof

The work conducted in this study is to evaluate the efficiency of two different concentrating solar collector models integrated in the roof and to measure the influence of glass roof tiles on efficiency. The collectors presented here aim to improve the deficiency of conventional flat plate collectors during cold period that fail to deliver a sufficient temperature to fill up the storage tank at a temperature above 60°C for at least 10 minutes per day to limit the growth of bacteria and prevent frequently start and stop of the auxiliary heater. From the M. Touchais collector model we have studied and measured the different efficiency between a longitudinal version and a compact version which have the same input solar radiation area. The result shows that the long model is better than the wide model because it is less sensible to the effect of the solar azimuth and the heat transfer is more efficient with a higher fluid velocity for the same flow rate. The use of glass roof tiles reduces the efficiency of the concentration because it diffuses the incident solar radiation. It also reduces the difference of efficiency between the large model and the long one. A Modelling of this system will help to determine the optimal length.