Re: [TRNSYS-users] cooling flower

[David BRADLEY <d.bradley@tess-inc.com>]

Bastien,
  When you segment an active layer, the segments are in series, not in parallel so I would think that the first segment would have the highest effective cooling power (biggest difference between water and air temperature) and that the cooling powers should drop off asymptotically (a lot at first, then less and less with each additional segment).

  As for whether QCOMI is the correct ntype to watch, I am less sure. My understanding is the QCOMI is the energy that crosses the inside surface boundary. As a result, it is going to have other effects besides the cooling floor. For example convection on the inside surface, radiation exchange on the inside surface, energy that was already stored in the floor (not so important in your case since you are looking at steady-state operation), interactions with whatever you have beyond the active layer such as a BOUNDARY temperature or another zone. Still, if you want to see the cooling effect of the floor on the room (taking into account all those other factors), QCOMI is probably a good place to start.
Best,
 David


On 11/14/2011 09:40, Bastien GARBAY wrote:

Dear TrnSys users,

I'm trying to model a cooling floor under TrnBuild. I use an active layer with a constant input temperature (17°C). I would like to model the effect of a constant fluid flow on the building temperature and on the effective cooling power of the floor. In order to allow for my constant flow (3.8 kg/h.m²), I use the automatic segmentation of the active layer. My model runs all right.

In order to assess the cooling power of the floor, I use the surface output n°19 "QCOMI". This output is calculated for each segment. My problem is that when I compare the QCOMI for each segment, they are really diffrenet. I would have expected similar results.

- Is my model allright to model a cooling floor ?

- Is QCOMI the correct output to assess the effective cooling power of the floor ?

- If both previous answers are yes, would have any idea of why such a difference between the QCOMI of each segment ?

Thank you for your help !

 

Bastien GARBAY

Cabinet SIDLER / ENERTECH
Quartier Bourgounion
F-26160 FELINES SUR RIMANDOULE
tel-fax : +33 (0)4 75 90 18 54
Courriel : garbay@enertech.fr
Site : www.enertech.fr

 

 

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