Thermosiphonic Tank (Solar Heating)

Thermosiphonic tanks are Solar Storage Tanks which optimize their internal Thermal Stratification by using and encouraging thermal gravity effects. They are not to confuse with Thermosiphon Systems which are replacing pumps in the solar circuit by gravity effects to power the heat transport between Collector and storage tank.

At the center of a thermosiphonic tank, from nearly the bottom to the top, runs a wide thermal conduction pipe, at the base set above or around the solar Heat Exchanger sitting at the bottom of the tank. This pipe works as a convection funnel, in which the water heated by the heat exchanger ascends to the top section of the tank without disturbing thermal stratas in the already heated water surrounding the pipe system. Special designed outlets in the wall of the pipe enable the newly heated water to discharge in the surrounding tank as soon as it has reached a layer (or strata) having nearly the same temperature as itself.

One advantage of these systems is the low thermal inertness: nearly as soon as the sun is heating the collector warm water will ascend to and accumulate in the so-called stand-by section (meaning the top portion of the tank), ready to be used. The second advantage is the optimized stratification with minimized turbulences without the need of an elaborated electronic regulation system, allowing an highly efficient operation of the solar heating system.

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