×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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.

Students Click Here

Sensible vs Latent vs Total Capacity

Sensible vs Latent vs Total Capacity

Sensible vs Latent vs Total Capacity

(OP)
Hello, I'm trying to size a dedicated outdoor air unit coil and I get the following values:

Going from 100 degrees db & 63 degrees wb to 55 degrees db/wb
Total Qt = 4.5(CFM)(h2-h1) = 92,907 BTU/h
Sensible Qs = 1.1(CFM)(T2-T1) = 142,358 BTU/h
Latent Ql = 4840(CFM)(W2-W1) = -54,612

This is Utah so the air is pretty dry here which gives me a negative latent value. Which one do I use to size the split condenser unit? My guess is the sensible value but I'm not exactly sure why. Any input is appreciated. Thanks!

RE: Sensible vs Latent vs Total Capacity

Unless you are using direct evaporative cooling to contribute you want to use the sensible value. In this case your total should equal your sensible, your leaving air will be 55, but it won’t be a saturated 55/55 it will keep the dewpoint/humidity ratio of your entering air.

That negative latent number is incorrect the way you have it, a cooling coil only cools and remove moisture as a byproduct of cooling, it doesn’t add moisture in any way. In your case it’s 0 latent.

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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