Too less energy from CHP

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Posts: 12
Joined: Tue Oct 24, 2017 12:33 pm

Tue Dec 19, 2017 1:47 pm

Hallo Polysun Community,

I have been trying to simulate a CHP system with PV and peak load boilers.
Unfotunately the energy produced by the CHPs in polysun simulation is almost half of that in another simulation software (2000 fully used hours as compared to 4000 hours in another software for one year. We are in testing phase, and want to compare results).
I am aware that this can depend on lot of factors, I would like to ask if someone else is facing the same problem or whether there is some error in the given control strategy.
The CHPs has 9 kW electric and 20 kW thermal power capacity.
Total produced energy in simulation is 20.78 MWh electrical energy, and 51.43 MWh thermal energy.

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Lars Kunath
Posts: 87
Joined: Thu Mar 02, 2017 2:35 pm

Wed Dec 20, 2017 2:27 pm

Hi Zaideus,

to d a comparison with different software is always tricky. Anyway I think I can give you a valuable hint.

First of all I think your system and your control strategy are alright.

You write that you have an amount of thermal energy to the system of 51.430 kWh divided by 20 kW it equals roughly 2500 h (running time).

In the other software you have a running time of 4000 h so thermal energy to the system must be 80.000 kWh.

-> check the defined energy demand (building and hot water) and compare it between both software solutions, also losses in the system (is input equal output)
-> have both co generation units the same efficiency?
-> how much energy delivers the back up burner in Polysun and in the other software?

I hope this helps you!

BR Lars

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