Active Closed Loop Solar Water Heating Systems with Preheat Tank


Closed Loop Solar Heating Systems are suitable for single and multiple solar heating application systems, e.g. domestic solar water heating , solar water heating hot tub, solar swimming pool heating or solar space heating systems. The Closed Loop Solar Heating Systems are suitable for areas with questionable water quality and all climate conditions. The Closed Loop Solar Heating Systems are the preferred option for extremely cold areas.


NOTE: The information presented in this page is for guidance only - no part of this may be used for any agreement, whether express or implied, or to form any contract. THERMO TECHNOLOGIES reserves the right to change specifications and prices without prior notice.


Many domestic hot water tanks have the cold feed through a dip tube in the top of the tank. This means that the cold feed is unsuitable for thermosyphoning heat from another tank. On some tanks this can be overcome by using the tank drain and pressure/temperature valve outlet. If the solar tank is situated lower or the electric tank raised until the bottom element is above the solar tank, the system will be more efficient, providing adequate storage and backup at reasonable cost
Advantages: Disadvantages:
  • The existing tank is also used to store the solar energy so the extra tank can be smaller.
  • The existing tank is used to provide backup for the system.
  • When possible solar energy takes care of the standby heat losses in the existing tank.
  • Efficient use of the solar energy.
  • The tanks must be situated close together.
  • The connections between the tanks must be free of air to enable the system to thermosyphon. Air vents may be needed.
  • Stand-by losses are more than twice those of a single tank system.
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