Commercial photovoltaic module

Figure 4.23 Solar cells are efficiently isolated with a vapour-deposited ORMOSIL layer that ensures long-term durability of commercial photovoltaic modules. (Reproduced from ref. 18, with permission.)...

Photovoltaic devices typically consist of a series of thin semiconductor layers that are designed to convert sunlight to dkect-current electricity (see Semiconductors). As long as the device is exposed to sunlight, a photovoltaic (PV) cell produces an electric current proportional to the amount of light it receives. The photovoltaic effect, first observed in 1839, did not see commercial appHcation until the 1950s when photovoltaic modules were used to power early space sateHites. Many good descriptions of the photovoltaic phenomenon are available (7). 

The photovoltaic power source can be any commercial BSPM (Battery Specific Photovoltaic Module), or can be an ESPM (Electrolyzer Specific Photovoltaic Module). The electrolyzer can either be a PEM (Proton Exchange Membrane) or an alkaline type. 

Conventional solar panels are called BSPMs (Battery Specific Photovoltaic Modules). Most panels sold commercially are of this type and are designed solely to charge battery systems. These panels come in 12 volt, 24 volt and 48 volt configurations. Most have short circuit current ratings of from 2 to 10 amperes. 

The efficiency of the traditional crystalline cells (which are sawed laboriously out of pure silicone ingots) has increased from 4 percent to almost 25 percent for laboratory specimen commercial production modules are about 14 percent efficient. The newer thin-film photovoltaic materials have lower efficiencies so far—17.1 percent for laboratory samples and 10 percent for commercial production modules. However, the thin-film materials... 

Silica aerogel-poly(ethylene-co-vinyl acetate) composite blends were prepared by Allan et al. [117]. Normally, these types of polymers are used for solar coverings including photovoltaic modules and commercial greenhouse films. Here, the silica aerogels were melt-mixed using a mini twin-screw extruder with EVA pellets in order to form S A/EVA composite, which were pressed into thin films with controlled thickness. 

The photovoltaic power system consists of 160 single pedestal concentrator arrays, each containing 256 circular silicon solar cells (64 modules). Each module contains 4 Fresnel lenses, for a sunlight concentration of ca. 33 times over solar cells. These 64 branches are connected in parallel to provide 350 kW of peak power. The electrolysis system is a commercially available HS 2000 electrolyzer with the cell area 0.2 rrfi (No. of cells 144). Electrolyte is 30% KOH solution, system pressure 6 bar, working temperature 100 °C. The plant also contains a grid operated rectifier for initial start-up and special testing. 

Photovoltaic-Thermal (PV/T) Systems - A solar energy system that produces electricity with a PV module, and collects thermal energy from the module for heating. There are no commercially available systems available (as of 11/97). 

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