Product Review

The World's Most Efficient Solar Thermal Collector?

The heart of the Ritter XL system is the company’s evacuated tube. While similar to evacuated tubes made by other companies, the tubes used in the XL system are a larger diameter and are made specifically for large-scale use. Ritter increases their performance further by using a unique heat-transfer plate that works in tandem with a parabolic mirror behind the tube to capture sunlight and focus it back onto the collectors at a perpendicular angle—simulating mid-day conditions.

The tubes come preassembled into panels (most evacuated tubes are shipped separately) that put out an impressive Solar Rating and Certification Corporation (SRCC) OG-100-rated 55,000 Btu per day. These panels are modular, so they can be installed in a series of five before going parallel. According to Michael DiPaolo, president of Regasol USA, the company’s real-world collector efficiency should be even higher when compared to other collectors, since SRCC collector testing is done with water and not propylene glycol. Yet in the real world, other large-scale collectors most often use glycol and not water.

Published August 30, 2011

Ehrlich, B. (2011, August 30). The World's Most Efficient Solar Thermal Collector?. Retrieved from