Rheem RS47-21BP 47 Gallon Passive Solar Water Heater with 21.35 Square Feet Total Collector Area Residential

- Item #: BCI2143133

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Solaraide Collection Residential Passive Solar Water Heater with 21.35 square feet total collector area and 47 Gallon Tank

Rheem's closed loop passive solar water heating system.

Closed Loop vs. Open Loop

In a closed loop system another fluid (usually a glycol-water antifreeze mixture) is heated up by the solar collector. The storage tank has a heat exchanger that transfers the heat from the other fluid to the water for household use. In an open loop system the water would travel through the solar collector to be heated. The disadvantage of an open loop system is that if the weather drops below freezing then the pipes can burst from the water freezing.

Active Solar vs. Passive Solar

Active solar systems rely on external electrical or mechanical equipment (such as a pump) to assist in converting the solar energy for use. A passive solar system does not use external energy sources, it relies on the solar properties of the system to operate.

The System

With the passive solar design no pumps or controllers are required. The complete system includes tank, collector, installation kit, and heat transfer fluid.

The Tank

The single wall external heat exchanger completely surrounds the storage tank. The tank is rugged steel with a vitreous enamel tank lining. Included is an immersion, copper sheath backup element.

The Collector

The collector is a flat plate design and features 35 multi-flow risers for faster heat transfer. The collector absorber coating is black polyester powder coat.


  • System: 97-1/2" L x 58-1/2" W
  • Tank: 58.5" x 20.1" x 20.1"
  • Collector: 76.3" x40.3" x 3.04"


  • Tank Capacity: 47 Gallons
  • Solar Energy Factor: 1.3
  • Number of Collector Panels: 1
  • Working Pressure (Tank): 145 PSI
  • Delivered Capacity (Solar): 42.3 Gallon
  • Backup Element: 2.4kW, 240V
  • Warranty: 5 Year Limited

Rheem has been manufacturing water heaters since the 1930's, with coast to coast distribution by 1936. Their product offerings cover commercial and residential heating, cooling, solar water heating systems, conventional storage-style water heaters, tankless water heaters, replacement parts and accessories. Rheem's manufacturing facilities are ISO 9001 certified, with four facilities in the United States. Choose an industry leader that is respected for reliability. Choose Rheem.

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Our SKU: Rheem RS47-21BP

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  • Rheem RS47-21BP

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