Lower cost 3-sun mirror module designs for rooftop sun tracking carousels

It is now well known that solar trackers pay for themselves with PV systems in field installations relative to fixed mounted systems by generating up to 1.4 times more kWh per kW installed. Solar trackers such as the JX Crystals´ carousel tracker can also be profitably installed on commercial building flat rooftops. A commercially available JXC carousel tracker is equipped with six 200 W Sanyo planar PV modules generating 1.2 kW of electricity. The modules are mounted in two rows of 3 modules with each module mounted in landscape mode for low wind resistance. While the carousel tracker is desirable because it reduces the cost of solar electricity by producing more kWh, it is also desirable to reduce the cost of solar electricity still further by reducing the cost of the modules. Since mirrors are much cheaper than single crystal silicon solar cells, this cost reduction can be achieved by using 3-sun mirror modules. The module cost can potentially be cut in half. Various 3-sun module designs with similar sizes to the Sanyo planar modules are possible using 23% Sanyo cells or SunPower cells. More conventional 18% efficient Si cells can also be used.