[TRNSYS-users] simulating a humidity controlled ventilation

[David BRADLEY]

Dear Younness,
   I would not worry about switching to the detailed humidity model in 
Type56; the simple one is quite adequate. Make sure that the humidity 
multiplier is set to a value between about 5 and 15. This indicates that 
the zone has between 5 and 15 times the moisture capacitance of the air 
in the zone. If you only consider the moisture capacitance of the air 
(by setting the multiplier to 1) then you are discounting the fact that 
the furnishings and the wall materials in the zone can absorb (and 
desorb) moisture.

   I think also that you are modeling the variation in RH correctly, its 
just that based on your system, there isn't a very good way to dry out 
the space. Look carefully at the RH of the ventilation air that you are 
putting into the space. If its RH is high and if there are any latent 
gains in your space (from occupants or from cooking, for example) then 
the moist air in the residence has no way of drying out. Try changing 
the conditions of the air that you are putting into the space by means 
of a VENTILATION type; set the RH (arbitrarily) to 30% and make sure 
that the RH in the zone drops to something close to that level.
Kind regards,
  David


On 12/29/2011 10:38, youness EL FOUIH wrote:
> Dear TRNSYS users,
> I'm trying to simulate a humidity controlled ventilation system for a 
> flat. As you know in this system the air flow rate is given  as 
> function of the relative humidity. the problem that I'm facing now is 
> that the relative humidity within the kitchen (which has no external 
> walls, only adjacent) does not vary it's almost fix around 98%.
> I cheked the humidity parameter for the considered zone and I changed 
> the model from "Simple Humidity Model" to "Moisture capacitance 
> Moisture" but i really don't know how we could use this model and does 
> every parameter mean.
>
> I would be pleased if anyone who know how can I model the variation of 
> the internal relative humidity show me how to do it.
>
> Thanks for your help in advance.
>
> -- 
> *EL Fouih Younness
> *Ingénieur Process - ENIM - Rabat- Promo 2010
> Master Stratégies Énergétiques - Mines Paristech - Paris
> Tel : +33 6 48 81 01 13 <tel:%2B33%206%2048%2081%2001%2013>
>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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