×
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

Estimating cooling load of an AHU, best methods, degree days??

Estimating cooling load of an AHU, best methods, degree days??

Estimating cooling load of an AHU, best methods, degree days??

(OP)
Can anyone advise on the best way to simulate the cooling and heating loads associated with AHU's when you know the airflow, and desired conditions in the room.  

In the past I've used heating and cooling degree days (adjusting the degree day base temperature depending on the room funcitonality but typically allowing for a 2 or 3 degree delta T due to internal heat gain for a room with say 6 Air Changes Per Hour).  

However I am becoming increasingly concerned that the results from these approximations are on the low side.  I know that for instance using cooling degree days will not take into account auxilary loads on chillers (pumps etc.) and heat transfer efficiencies of cooling coils etc. but none the less the values I am getting still seem extremely low.  

Is it necessary to go to more advanced simulation software to get reasonably accurate heating and cooling load estimates?  

Can anyone please advise?

RE: Estimating cooling load of an AHU, best methods, degree days??

To estimate the magnitude of the loads your kind of have to know what the nature of the loads are.

Using degree days, or design temps only gives you a factor to estimate building envelope loads.  They will tell you little or nothing about internal loads that are essentially independant from outdoor temperature, like lighting, office equipment, and people.

An office will be very different from an industrial space will be different from a retail space.

You could SWAG some per square foot numbers for various types of occupancy.

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