[TRNSYS-users] Type 619a - Wrong calculation?

[Martin Thur]

Hello everyone,

 

in my simulation i use type 619a (Open Feedwater Heater - Steam Flow Calculated to Achieve User-Designated Outlet). When I click on the more... button of output 6 (Heat Transfer Rate) it says:

 

"The rate at which energy is added to the de-aerating heater by the high-temperature steam inlet. The heat transfer rate is calculated by multiplying the high-temperature steam flow rate by the enthalpy difference between the high-temperature steam and the entering low-temperature steam (condensate)."

 

In my opinion this difference is wrong. I think the high-temperature steam flow rate should be multiplied by the enthalpy difference between the high-temperature steam and mixed outlet steam, because the high-temperature steam flow can't "cool down" below the mixing enthalpy. One consequence is that output 5 (Required Source Steam Flow Rate) is always too low (according to my test simulation + calculation).

 

I am not 100 % sure about that so any thoughts on that are well appreciated.

 

 

Kind regards

Martin

 

 

 

 

 

 

 

Bei Fragen bitten wir um Ihren Rückruf.


Mit freundlichen Grüßen

BLS Energieplan GmbH
i. A. Martin Thur

Elsenstraße 106
D-12435 Berlin
Tel.: +49 30 53 32 81-0
Fax: +49 30 53 32 81-40
____________________________________________________
BLS Energieplan GmbH
Sitz der Gesellschaft: Berlin
Geschäftsführer: Christoph Lange, Wolfgang Sturm
Registergericht: Amtsgericht Berlin-Charlottenburg, HRB-Nr. 32021 

 

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