Optical and thermal performance predictions for a high concentration point focus photovoltaic system

The optical and thermal behaviour of a high concentration point focus Fresnel lens based photovoltaic concentrator system with the potential for large scale power generation in regions with predominantly direct radiation has been investigated. A ray projection technique was used to evaluate the energy capture of the concentrator when located at Denver (39 degrees 45'N, 105 degrees W), USA, predictions of temperature at different sections of the concentrator using a three-dimensional finite difference model have also been made. The beam radiation normal to the concentrator aperture for the tracking approach used with no self shading was calculated to be 1778 kWh m(-2) year(-1) for the collector located in Denver. For inter trough spacing of 160mm the predicted self shading loss was 14.8%, this reduced to 6.6% when the inter trough spacing was increased to 360mm. For the collector with inter trough spacing of 160mm, when the inter collector spacing of the concentrator increased from 1m to 2m, the predicted annual energy collection for the concentrator increased by 25%, however, further increase of inter-collector spacing had little effect on the energy capture by the collector. Using the three-dimensional finite difference model the temperatures within the collector and at the PV cell have been predicted. The predicted cell temperature reduced from 58.23 degrees C to 48.86 degrees C when the fin thickness increased from 0.2mm to 0.5mm for an illumination of 75 Suns. Increasing fin length from 50mm to 100mm had little effect on the predicted cell temperatures