Re: [TRNSYS-users] Issues with Relative Humidity of a lecture hall model

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

Teo,
  I would look at the conditions of the air that you are supplying to the building; my guess is that the air going in is VERY dry and probably quite cold as well. The RH in the room would drop because of the dry air being added to the zone (and the quantity of mixed air being drawn out of the zone and returned to the cooling coil.

1) does the gain from human actually contribute moisture? Or it only contributes only the latent heat in terms of energy but not in term of moisture?

yes, it does. If you look in the *.inf file, you'll see the following lines:

GAIN PERS_ISO02
 CONVECTIVE=156 : RADIATIVE=78 : HUMIDITY=0.081

there is 0.081 kg/h of water added to the airnode per person (and according to your schedule)

2) Does the humidity model actually affects the amount of moisture the space is able to hold?

yes. There are two humidity models. The simpler of the two is the effective moisture capacitance model. Type56 computes the quantity of moisture that the air can absorb (based on its current conditions of temperature, pressure, and humidity ratio), then multiplies that quantity by the user-specified multiplier to determine the zone's actual ability to absorb moisture.

3) Where the moisture actually goes to in my model as i have a schedule running.

I am not sure I understand your question; humidity gains go into the zone's air node.

3) I would also like to have a positive pressure inside the space, how may i go about doing this?

Type56 assumes that the air in the building is at 1atm; there is no way to change that assumption as far as I am aware.

Best,
 David

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

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d.bradley@tess-inc.com

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