Colorado Clean Energy Systems, LLC
(970) 901-8757


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Drainback Systems
db tank

Drainback tank
The above picture of a heat storage tank, with associated pump and controller, shows the simplicity of a drainback system. When the layout of the house allows for a drainback design to be used, the homeowner can
enjoy these benefits:
  • Higher efficiency; water has a a higher heat transfer/storage capacity than glycol, also, there is usually one less heat exchanger for the heat to pass through.
  • Simpler plumbing design; fewer components, non-pressurized plumbing on solar collection side.
  • No need to "dump excess heat" in summertime in order to protect glycol from overheating.

 shop_panels

Notice downward tilt of drainback pipes
This picture shows the collector panels for the tank on the left. Despite the advantages of drainback, these systems do impose restrictions that cannot be ignored:
  • Panels and supply/return pipes must be tilted adequately.
  • Controls must be designed so as to eliminate the possibility of the drainback circulator coming on when the interior panel temperatures are below freezing.
Drainback systems can operate when outdoor temperatures are well below freezing. I have witnessed the above system come on and collect heat on a sunny morning when it was 3 degrees F!


                     Solar Energy and Radiant Heating Links:
Solar Energy International- Renewables Training
 DOE Energy Savers - Radiant Heating
Recharge Colorado (formerly Governor's Energy Office) - Colorado Rebates
 DSIRE - National Solar Tax Credits and Rebates
Sunward - Solar Domestic Hot Water Systems
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                           Contact Info:
                         (970) 901-8757
                   ccenergy@montrose.net
         62847 Ohlm Rd., Montrose, CO 81403