Dedicated Outdoor Air System vs. Recirculating System

[Cjrac]

Im in a debate over indoor humidity levels. I believe a recirculating air system bringing in a percentage of outdoor ventilation air will have higher humidity levels compared to a 100% outdoor air system. The building is a high school in a remote location, very cold dry northern climate. Mechanical humidification is not an option so I believe using a recirculating system will help keep the moisture added from the occupants within the building. Any input is very much appreciated. Thanks.

 

[EnergyProfessional]

Assuming you are concerned about heating, recirculation with minimum OA inflow would be best. Use an ERV since that recovers some of the humidity and you should be fine.

If you think you need humidification (outside a museum or similar application) your building and/or premises are faulty.

 

[317069]

Why Mechanical humidification is not an option, who gave this decision?

 

[MintJulep]

Moisture load of a person in a classroom setting is probably about 20 grams of water per hour. Moisture Control in Buildings
edited by Heinz R. Trechsel - Chapter 8.

With that tidbit of information you can plot your process on a pyschrometric chart and let us know the outcome.