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Indirect Solar Water Heating Systems

Indirect (closed loop) solar glycol systems use propylene glycol as the heat transfer fluid in the solar array to overcome issues of freezing (glycol can tolerate – 60F in high concentrations) and eliminate scaling. The glycol is separated from the potable water by means of a heat exchanger that transfers the energy from the array into the storage tank.

Indirect solar water drainback systems are also a indirect design that use a heat exchanger to separate the collector loop from the potable water. Instead of relying on glycol for freeze protection, this system allows all the water in the array to drain back from the array and into a storage vessel in the solar loop when the pump is turned off. Because the array completely drains, water can be used in the solar loop, which avoids the need for double-wall heat exchangers demanded in some localities.

 

Advantages:

  • Impervious to freezing
  • Collectors not affected by scaling in hard water areas

Disadvantages:

Indirect Residential Systems

SunEarth offers the following Indirect Residential Systems:

  • SolaRay AC
  • SolaRay PV
  • SolaRay 2
  • Cascade
  • Cascade 2
SolaRay AC

SolaRay AC

SolaRay is a forced-circulation, indirect system, designed primarily for climates that experience annual and persistent hard-freeze conditions.

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SolaRay PV

SolaRay PV

The SolaRay PV domestic solar water heating system has gone through an extensive design, technical and performance review.

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SolaRay 2

SolaRay 2

SolaRay 2 is a forced-circulation, indirect system, designed primarily for climates that experience annual and persistent hard-freeze conditions

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Cascade Drainback

Cascade Drainback

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.

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Cascade 2 Drainback

Cascade 2 Drainback

The Cascade 2 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.

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