The Cascade is SunEarth’s OG-300 certified drainback system. Drainback systems may or may not use a propylene glycol and water mixture as the heat transfer fluid. A drainback system’s primary freeze protection mechanism, however, is gravity itself. The heat exchange fluid in the collector array and solar loop piping drains back by gravity into the system’s storage reservoir whenever the pump stops circulating. This happens during the average solar day whenever the temperature difference between the hottest (collector) and coldest (bottom of the solar tank) points in the system is only a few degrees. Air replaces the heat exchange fluid in the collector array and solar loop piping when the pump is off. No fluid is left exposed in the collector or piping to freeze.
If properly installed and maintained the Cascade drainback system can safely be deployed in areas that experience annual persistent hard freeze conditions. SRCC Rated Freeze Tolernace: -50° F.
The Cascade system incorporates the Empire Series collectors, SunEarth solar storage tanks, and our popular CopperStor drainback storage reservoirs.
The Cascade Drainback System with Side-Arm Heat Exchanger (for Retrofit Installations) is not certified to SRCC Standard OG-300 at this time.
The Solar Rating & Certification Corporation OG-300 systems level rating is an independent assessment of both system reliability and performance. Systems that receive this rating must meet HUD minimum property standards in addition to a rigorous review performed by SRCC staff and design review team. Once the system has passed these quality assurance checks it undergoes a full performance analysis to estimate the actual solar contribution of the system towards an average hot water load. This contribution, as defined by the Solar Energy Factor is listed alongside the different variants of each system type.