[TRNSYS-users] Pipe : type 709

[David Bradley]

Fabien,
 I would think that you would definitely need a different model for the 
evacuation pipes; the energy transfer characteristics of a partially 
liquid filled pipe and from a completely filled pipe are quite different 
and I think it would be important to characterize the liquid to soil, 
air to soil, and liquid to air energy transfers separately.
Kind regards,
 David


fabien.hachet wrote:
>
> 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
>
>
>
> Pieddemail <http://www.laposte.net/rallye-des-gazelles>
>
> ------------------------------------------------------------------------
>
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Thermal Energy System Specialists (TESS), LLC 
David BRADLEY                      22 N. Carroll Street - Suite 370 
Partner                            Madison, WI 53703 
                                   USA
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