INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

How much condensate when 90F 80%RH air dropped to 40F?

How much condensate when 90F 80%RH air dropped to 40F?

(OP)
Per cubic foot of hot 90F humid 80%RH air, how much water is released when that air temp is dropped to 40F?

Thank you for any comments.

RE: How much condensate when 90F 80%RH air dropped to 40F?

I think you need one more parameter on the outlet. Then use a psychrometric chart.

RE: How much condensate when 90F 80%RH air dropped to 40F?

(OP)
I've been looking at one, think I need to figure out water content of 90F 80%RH air - 40F 100%RH air, and that would give me answer, working on that now.

RE: How much condensate when 90F 80%RH air dropped to 40F?

A psychometric chart makes short work of this problem. About 0.0246 - 0.0052 = 0.0194 Grains/lb of dry air. The 90F/80%RH air is 14.4 ft^3/lb of dry air. So, 0.00135 Grains/ft^3 of dry air. 1 lb = 7000 Grains. So, 1.92x10^-7 lbs of H2O/ft^3 of dry air.

Psychometric Chart

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

RE: How much condensate when 90F 80%RH air dropped to 40F?

Can you follow my previous post, or should I explain in detail?

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

RE: How much condensate when 90F 80%RH air dropped to 40F?

(OP)
I just now came up with 0.02192 ounces of condensate water per cubic foot by using this chart...
http://www.process-heating.com/ext/resources/PH/20...
where I took the water content of 90F 80%RH air and subtracted water content of 40F 100%RH air.
Not sure if correct, yet, double checking it...

RE: How much condensate when 90F 80%RH air dropped to 40F?

Your 0.02192 oz/ft3 looks right to me.

The chart I gave a link to has an error in their moisture content numbers. It should be lb/lb dry air for the numbers I used, not Grains/lb of dry air. My redo is:

About 0.0246 - 0.0052 = 0.0194 lbs H2O/lbs dry air. The 90F/80%RH air is 14.4 ft3/lb of dry air. So, 0.00135 lbs H2O/ft3 of dry air, and 0.0216 oz H2O/ft3 of dry air.

Both our numbers round to 0.022 oz/ft3 of dry air.

You are good to go!

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

RE: How much condensate when 90F 80%RH air dropped to 40F?

(OP)
Latexman, many thanks, having our numbers jive is very reassuring here.

RE: How much condensate when 90F 80%RH air dropped to 40F?

(OP)
Thanks, Caloooomi, that's a keeper.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close