Fresnel-based Concentrated Photovoltaic (CPV) System
Different designs have been presented to achieve high concentration and uniformity for the concentrated photovoltaic (CPV) system. Most of the designs have issues of low efficiency in terms of irradiance uniformity. To this end, we present a design methodology to increase irradiance uniformity over solar cell. The system consists of an eight-fold Fresnel lens as a primary optical element (POE) and an optical lens, which consists of eight parts, as a secondary optical element (SOE). Sunlight is focused through the POE and then light is spread over cell through the SOE. In the design, maximum sunlight is passed over cell by minimizing losses. Results have shown that the proposed CPV design gives good irradiance uniformity. The concentration module based on this novel design is a promising option for the development of a cost-effective photovoltaic solar energy generation.
Different techniques have been presented in the literature to capture sunlight through solar concentrators. In concentration systems, it is preferred to have a minimum number of modules with an effective output while remaining cost-effective. The idea behind the system is to capture high-intensity sunlight and then focus it over cell. Direct sunlight was focused through the POE. The light went through the SOE and then the light illuminated the cell. Previously, it was difficult to achieve a high concentration of light with high-uniformity. The effect of non-uniformity can be found in all the types of CPV systems. There is a need to design optical elements to achieve high uniformity. To this end, we propose a design to achieve uniform illumination over cell using two optical elements.
In the proposed design, there were two optical elements: the POE and the SOE. The POE was a Fresnel lens, which had eight-folds with different focal points. Layout of the Fresnel lens is shown in Figure. The SOE had eight parts where each part corresponds to each focal point of the POE. Design of the SOE, which was made of spherical and cylindrical parts, is shown in Figure. If we made SOE with single spherical and cylindrical parts, the rays were not uniform. We designed a spherical lens to spread uniform rays from each focal point of the POE over cell. All rays are distributed over cell uniformly. The proposed SOE was designed with eight spherical and single cylindrical parts.External link