Cooling Chimney


In order to cool photovoltaics below 29 degrees Celsius in the summer to maximize performance and maximize durability, we have developed a cooling chimney that can dissipate excess heat.



  • In solar thermal systems, the heat in summer can no longer be absorbed by the heat storage of the heating system
  • Only a few households can feed the heat into a pool or feed it into the ground
  • Before the fluid begins to boil, it is drained into containers via an emergency shutdown.
  • But even without emergency shutdown, the system gets so hot that this is harmful to the system
  • The attic heats up unnecessarily


Problem solving:

  • A cooling system for the thermal fluid of the solar thermal system will be installed on the ridge
  • The cooling system has the form and appearance of a "normal" house chimney
  • The cooling system consists of a heat exchanger similar to the one of a car radiator (hot fluid is cooled by air flowing through)
  • However, this cooler is installed flat i.e. "lying" at the end of the cooling chimney
  • In front of it is a fan driven by an electric motor (as in the car)
  • Between radiator and fan are several spray nozzles for spraying water, which are operated by an electromagnetic valve
  • The water is taken from the water supply system of the house
  • The fan motor and the electromagnetic valve are controlled by a power electronics which in turn is controlled by a temperature sensor and / or by the control of the heating system
  • There is also a so-called "by-pass valve" for the chimney, if no cooling is needed - also controlled



  • The solar thermal system does not overheat and does not have to go into emergency shutdown
  • The solar thermal system is spared
  • The attic remains relatively cool
  • In a solar combination system (solar thermal with photovoltaic) the so-called wafers of the photovoltaic are also cooled. Thus, the performance of the photovoltaic system remains at its highest performance and does not degrade (as otherwise inevitably) with increasing temperature over 29 degrees Celsius)

Such a cooling chimney is particularly advantageous in combination with the solar roof tile developed by paXos, which connects photovoltaic and solar thermal energy. But it could be used even with any conventional solar thermal system or solar combination system.


Sketch: View on the house

Sketch: Construction of the cooling chimney