[TRNSYS-users] Relative humidity of Kitchen is illogical (with attached files)

[David BRADLEY via TRNSYS-users]

Ismail,

   Type56 assumes that zones have neutral pressure. If you add air to a 
zone, it is assumed that the same mass of air leaves the zone by some 
means. The same would be true if you were to actively extract air from 
the zone; more air would come in to replace the air that you extracted. 
The issue, I think, is where the air that comes into the zone comes 
from. If it comes from a humid source then the zone humidity is going to 
go up. If the air comes from a dry source then the zone humidity will go 
down. One of the challenges with natural ventilation is that if the 
building is cooler than the ambient when natural ventilation is 
activated then humid air comes into a cool space from outside and the RH 
in the space goes way up (cool air can hold less moisture than warm air).

kind regards,

  David



On 07/10/2017 08:43, Issmail OUHALLOU via TRNSYS-users wrote:
> Dear colleagues,
>
> I am trying to simulate the impact of natural ventilation by 
> calculating the mean air velocity entering through the window (in m/s) 
> according to the equation below:
>
> ​I got the results as shown in attached files before and after natural 
> ventilation. The humidity has increased enormously !
>
> I figure out that in TRNBuild the air cannot be extracted from the 
> zone ! How can I extract the air from a zone after activating natural 
> or mechanical ventilation ?
>
> Does anyone have experience to deal with such a problem ?
>
> Thanks in advance,
> Best
> Ismail
>
>
> -- 
> /************************************************/
> /Ismail OUHALLOU/
> Green building & Sustainability consultant
>
> *Morocco*
> P:+212**620**548**116
> F:+212**522**326**440
> i.ouhallou at trusted-energy.com <mailto:i.ouhallou at trusted-energy.com>
> issmail.ouhallou at gmail.com <mailto:issmail.ouhallou at gmail.com>
>
>
>
>
>
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-- 
***************************
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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