[TRNSYS-users] Pipe : type 709

[fabien.hachet]

Dear Trnsys users 

I'm trying to simulate a system which allows to recuperate heat of waste water for collective housing. In the simulation, I need to use distribution and evacuation pipes. For that purpose, I use a type 709. However, during the simulation, I noticed that trnsys considered that pipes are always filled with water. Actually, evacuation pipes are not completely filled and the water velocity is higher (1m/s) because the surface is smaller. Consequently, these pipes don't take into account the great coefficient of heat transfert (conduction, convection anr radiation).
So, I would like to know if it is possible to take into account these coefficients and if I can choose the velocity of water (and not the flow rate) without changing the surface of the pipe ?
Moreover, it is a real problem because the duration of waste water evacuation is several hours whereas the duration must be a few seconds.

Thanks

Regards

Fabien

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