Hourly results series - 'Moisture added or removed from air for (de)humidification (lb H2O/ lb dry air)'

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Dear fellow eQuest users,

I am currently solving a system which uses humidistat (coil for
dehumidification and steam loop for humidification).

I have got absurd results in 'hourly reports'. I have chosen a series called
'Moisture added or removed from air for (de)humidification (lb H2O/ lb dry
air)' under 'HVAC system' .

In the results I have got most hours with very large values, as high as 144
lb H2O/lb dry air. The system uses DOE weather data and is recirculation
type with minimum outside air. Is this a bug or am I reading something

Thanks in advance.



Kalpesh Karnik's picture
Joined: 2014-07-18
Reputation: 0


I noticed a similar problem when I was doing a dehumidification study recently. I am convinced the hourly report simply has the units wrong, and it should simply be lbs H20 (not per lb dry air). I don't know much about your building or climate conditions, but 144 lbs (~18 gal) could be a reasonable lbs/hr dehumidification load for a sufficiently large building with high latent loads and/or a humid climate. Not certain, but it's a possibility.

A way to verify this would be to use a combination of other hourly reports to arrive at the humidification load (you have cfm and humidity ratios for the various air streams).


Ari Greenberg, LEED AP BD+C

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100 Cambridge St., Suite 1400
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Greenberg, Ari's picture
Joined: 2014-07-18
Reputation: 0

It is lbs of water, NOT lb(water)/lb(dry air).

I've done the hand calculations using outside air conditions (temp, RH, etc.) from the weather file and coil outlet set point conditions to confirm.

The hourly report number is correct, just not the units associated with it.


Fred Betz PhD., LEED AP (r)BD&C
Senior Sustainable
Systems Analyst

5802 Research Park Blvd. | Madison, WI 53719

P: 608.236.1175 | F: 608.238.2614
fbetz at aeieng.com | www.aeieng.com

Fred Betz's picture
Joined: 2011-09-30
Reputation: 0