Let's assume I have a cogeneration plant that produces heat with a nominal output. The heat is given into a heat storage tank, which is filled from above. The maximum flow temperature of the cogeneration plant is 85 °C, if this occurs an emergency shutdown takes place. The maximum water temperature in the heat storage tank is 95 °C.

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Is it theoretically possible in this case to reach a water temperature of over 85 °C only with the cogeneration plant?


1 Answer 1


when the cogeneration plant switches of upon reaching 85°C flow and without another heat source, there's no way to reach 95°C.

Are you sure the switch-off happens at 85°C flow, and not at 75°C return to the cogernetion plant(this is a typical value for Otto-cycle cogeneration plants for the emergency cooler to kick in)?

If you have other heat sources and want to achieve a higher flow temp. you can use a setup with flow like this: cold site of storage -> cogeneration plant -> boiler -> hot side of storage.

  • $\begingroup$ Thank you very much for your answer. Unfortunately, I am not sure if the cogeneration plant makes an emergency shutdown at 85 °C. But the data-sheet specifies a maximum flow temperature of 85 °C. Do you think that this is simply the maximum flow temperature that is reached when the cogeneration plant runs for several hours? $\endgroup$
    – Emma
    Commented Jan 17, 2020 at 12:48
  • 1
    $\begingroup$ Can't tell. Can you share more information on the cogernation plant and maybe hte data sheet? $\endgroup$
    – mart
    Commented Jan 18, 2020 at 22:16
  • $\begingroup$ Thank you, I got it cleared up. A thermostat regulates the heat output in such a way that the flow of the cogeneration plant has a maximum temperature of 85 °C. $\endgroup$
    – Emma
    Commented Jan 20, 2020 at 7:19

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