Theoretical review in optical materials used in Concentrating Dissertation

Theoretical review in optical materials used in Concentrating Photovoltanic (CPV) Technology - Dissertation Example Photovoltaic cells have been widely in use for the production of electricity from solar energy. However, they have high production costs because of which the cost of photovoltaic electricity is high, causing difficulties in their widespread use and market penetration (Swanson, 2000). One approach through which this drawback can be minimized is the use of solar concentrators that can increase solar irradiation per unit area of the solar cells, thereby resulting in increased electricity production per unit area of the receiver (Abdul-Rahman & Wang, 2010). Apart from increasing the electricity efficiency of the photovoltaic solar cells, the use of solar concentrators can also help in decreasing the area required for a given amount of output. Concentrating photovoltaic (CPV) technology uses optical components as solar concentrators. This technology is economically advantageous as it helps in decreasing the cost of solar electricity by using optical material that is less expensive than ph otovoltaic cells, resulting in the need for lesser number of solar cells for the same electrical output. Thus, in simpler words, the goal of CPV technology is to â€Å"reduce the cost of electricity generated by replacing expensive PV converter area with less expensive optical material† (Swanson, 2003, p. 449). ... ectric Fresnel lenses, other types of solar concentrators include dish concentrators, compound parabolic concentrators, and reflectors (Brogren, 2004). As the present study aims at modeling optical parameters for optimum collection of concentrated solar radiation for photovoltaic devices, this theoretical review will focus on the different types of optical materials used in CPV technology. Apart from providing a brief overview of the types of solar concentrators, their optics, and the types of optical materials used, this review will also elaborate the optical and physical properties of optical materials, especially glass and polymeric materials such as poly (methyl methacrylate) (PMMA), which are relevant to the present study. 2.2. Solar Concentrators & Their Types Solar concentrators are of various types depending on the type of optics employed, the concentration ratio, the number of axes for tracking the sun, etc. Fig. 2.2. Schematic representation of solar concentrator, radiation intercepted by the aperture area, A1, falls on the receiver area, A2 (Brogren, 2004, p. 41). The figure 2.2 above shows the diagrammatic representation of a solar concentrator that concentrates solar radiation spread over a wider aperture area, A1, over a smaller receiver area, A2. 2.2.1. Concentration Ratio The geometric concentration ratio of a given concentrating system is the ratio of the concentrator aperture area and area over which the radiation is concentrated. It is given by the following equation: Cg = A1/A2, where, Cg = geometric concentration ratio, A1 = â€Å"aperture area of concentrator†, and A2= â€Å"area onto which the radiation is concentrated† (Brogren, 2004). For solar concentrators, the geometric concentration ratio is defined as â€Å"the area of the primary lens or