Herein, a SunTrack Carousel tracker is described for mounting on residential or commercial building flat rooftops in order to produce more k\Vh per kW relative to fixed PV modules. The JX Crystals (JXC) fixed-tilt / azimuth carousel is a low profile tracker designed to distribute weight evenly over a large area and for low wind resistance on the roof. Multiple JXC SunTrack Carousels have now been in operation for up to 2 years at various locations in the USA. This paper describes the performance of JXC SunTrack Carousels at three different locations. Data presented herein shows that Carousel performance is consistent with RETScreen model predictions for these three sites. The RETScreen Solar model predicts that a single axis azimuth tracker will produce between 20% and 40% more kWh per solar module peak kW when compared with solar modules mounted in a fixed position without tracking.
It is now clear that solar PV trackers are preferred for large remote solar PV utility fields producing peak power. However, electricity still needs to be transmitted to customer sites. Of the potential markets for PV, residential and commercial customers also represent an excellent opportunity. Residential and commercial customers presently pay retail prices for electricity rather than wholesale prices and they need electricity during the day when the sun is shining. There is an opportunity to reduce the cost of solar electricity for residential and commercial systems when trackers are mounting on building flat rooftops near the point of use.
However, for building flat rooftops, the design constraints are different. Solar trackers are needed that are sized to fit on the roof with no roof penetration and with low profiles for low wind resistance. The JX Crystals (JXC) fixed-tilt / azimuth carousel is a low profile tracker designed to distribute weight evenly over a large area and for low wind resistance on the roof . As shown in figure 1, it is designed as a compact pre fabricated unit where the module-support arms fold down for easy shipping. When these arms are folded down, the carousel is only 8' tall. Without mounted modules, it is slightly less than 8 ft wide and slightly less than 10 ft long so that multiple carousels can be stacked and easily shipped on a flat bed truck. A shipping and installation sequence is shown in figure 2.
Solar PV Carousel Trackers for Building Flat Rooftops