[TRNSYS-users] humidity of vetilation air

Marion Hiller Hiller at Transsolar.com
Fri May 18 02:44:44 PDT 2018

Dear Karol,

have set temperature to 20 and humidity to "relative humidity" and "outside". What will be value of ventilation air humidity?

  *   Type 56 does the following:
Example 1:
ambient air conditions: Tamb =  8 °C and RHamb = 80 %;
ventilation: Tvent = 20 °C and RHvent = outside

Result: Type 56 calculates the resulting absolute humidity gain by calling psychometrics kernel routine with that Tvent = 20 °C with RHvent = 80 %

Example 2:

ambient air conditions: Tamb =  8 °C and wamb = 0.003 kg/kg
ventilation: Tvent = 20 °C and wvent = outside

Result: Type 56 uses wvent = wamb = 0.003 kg/kg  as the resulting absolute humidity gain

  *   Thus, if you  want to take into account the condition process which changes the relative humidity you have to

  *   calculate the changed rel. humidity acc. to temperature change by an another component (AHU, Psychometrics) and
  *   give the changed rel. humidity as an input in the ventilation type.

Kind regards,


Dipl.-Ing. Marion Hiller
TRANSSOLAR Energietechnik GmbH
Stuttgart - Munich - New York - Paris
t: +49.711.67976.0<tel:%2B49.711.67976.27>   f: +49.711.67976.11<tel:%2B49.711.67976.11>

KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäuden
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart
Amtsgericht Stuttgart - HRB 23347 / Steuernummer: 99073/00911 / USt-IdNr.: DE 152272639
Geschäftsführer: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle

Von: TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] Im Auftrag von Karol Bandurski via TRNSYS-users
Gesendet: Freitag, 18. Mai 2018 08:55
An: trnsys-users at cae.wisc.edu
Cc: Karol Bandurski <karol.bandurski at put.poznan.pl>; TechSupport at tess-inc.com; hotline <hotline at Transsolar.com>
Betreff: [TRNSYS-users] humidity of vetilation air

Dear Experts,

In Ventilation Type Manager in TRNBuild there is possibility to set temperature of ventilation air to outside and also humidity to outside.

I have set temperature to 20 and humidity to "relative humidity" and "outside". What will be value of ventilation air humidity?

1)      Does TRNBuild calculate that by heating up or cooling down outside air, to setting (20), the relative humidity also change?

2)      If yes: Does TRNBuild take in to account that part of water will condensate if outside relative humidity is high and set ventilation temperature is much lower?

Your respond will be helpful because it is not possible to direct check it by simulation.

Kind regards,

Faculty of Civil and Environemntal Engeneering
Division of Heating, Air Conditioning and Air Protection
Poznan University of Technology
www.put.poznan.pl/~karol. bandurski<http://www.put.poznan.pl/~karol.bandurski>

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