Abstract
Concentrating solar power technology is one of the most promising alternative energy technologies. In recent past, Linear Fresnel Reflector systems have received great attention and novel designs have been proposed keeping in view the objective to enhance its functionality and performance. For achieving the same objective, this study presents a novel concept where a conventional LFR is enclosed in a greenhouse called greenhouse-LFR. It was expected that such an enclosure can: (1) increase the incoming solar radiation, (2) further improve the overall efficiency due to simplified cleaning process and (3) reduce the capital cost for the construction of LFR support system. A complete thermal and optical analysis was presented for modeling and performance evaluation of the solar field of both conventional-LFR and novel greenhouse-LFR. Sets of non-linear equations for each system were solved using Newton-Raphson method. More detailed optical analysis was further performed for conventional-LFR considering the seasonal variations. The results concluded that the greenhouse-LFR is better than the conventional-LFR as it had higher efficiency and useful heat with lesser heat losses. For greenhouse-LFR, the maximum thermal efficiency was 73.2% whereas for conventional-LFR it was 37.2%. Also, there was an average increase of useful heat by 3 times in the month of February and 4.7 times in the month of September. SolTrace (TM) analysis indicated significant spillage loss when a conventional-LFR was used without a secondary reflector or slight curvature of the mirrors.