×
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!
  • Students Click Here

*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.

Students Click Here

Jobs

Evaporative cooling calculation

Evaporative cooling calculation

Evaporative cooling calculation

(OP)
In a direct evaporative cooler how much water does it take to drop 1 cubic foot of 90 degree F 50% Rh air to 70 degree F?

A simple spreadsheet or software to calculate water consumption in evaporative coolers would be helpful.

Thanks

RE: Evaporative cooling calculation

WorknCrazy!

The rule is you cannot cool air below the wet bulb temperature. With 90 deg.F and 50% RH the WB is 74.5 deg.F

But in practical acheiving wet bulb temperature is also very difficult.So as a general rule evaporative coolers are considered to be operating at 80% efficiency. So now the outlet temperature you acheive is

DBout= DBin- [0.8(DBin-WBin)]
=90 - [0.8(90-74.5)] = 90-12.4 = 77.6 deg.F

Now the process of evaporative cooling is Isoenthalpic. (but the amount of sensible and latent heat capacities change before and after the process)

To check water content, take a psychrometric chart and plot the initial and final conditions. For the second point follow the enthalpy line and see where it cuts the 77.6 deg.F DB line. Now take the moisture content from the right side of the chart. The difference will give you howmuch water is being evaporated in the process.

For your process it is 0.1ml/cu.ft of air.

You can download good psychrometric chart from here.
http://www.heatpipe.com/ProductsServices/forengineers/heat_pipe_psychrometrics.htm

Regards,

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