# Question about flow temperature and storage temperature in a cogeneration plant

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.

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

## 1 Answer

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.

• 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?
– Emma
Jan 17 '20 at 12:48
• Can't tell. Can you share more information on the cogernation plant and maybe hte data sheet?
– mart
Jan 18 '20 at 22:16
• 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.
– Emma
Jan 20 '20 at 7:19