×
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

Temperature of air ventilated from pump room???

Temperature of air ventilated from pump room???

Temperature of air ventilated from pump room???

(OP)
I am trying to figure out the temperature of the air that I am ventilating from a pump room to decide whether it needs to be exhausted to the outdoors.  I have (2)20hp pumps, I have done a rule of thumb to figure out the Btuh that these will be giving off and came up with 15026 Btuh.  (110 Watts per hp> (110*40=4400 Watts > converted to Btuh = 15026).  I am moving 1000 cfm out of the room and intaking the same.  The room is approximately 100 sq. ft.

RE: Temperature of air ventilated from pump room???

13 degrees F warmer than the intake air.

RE: Temperature of air ventilated from pump room???

(OP)
Thanks for the reply.  I am sorry, I really should have clarified that I don't have a good concept of what the intake air temperature is going to be.  This room is in a ventilated garage that is partially buried underground.  I am obviously trying to figure out worst case scenario.  This building is in South Florida.  

RE: Temperature of air ventilated from pump room???


air temp rise = 15026/(1000*1.08)= 13.91 Deg.F

Assuming 95 Deg. Entering air, leaving air = 95 + 13.91 = 108.9 Deg.F

Hope this helps.

RE: Temperature of air ventilated from pump room???

First, I think your heat gain from the motors is low.  ASHRAE has a guideline for this, and a 20hp pump with both motor and pump in the same space releases 58,500 btu/hr.  If both pumps are running, that's 117,000 btu/hr.

The air temperature rise = btu/hr divided by 1.08 x cfm.

If both pumps run continuously, this will be an extremely hot room.

RE: Temperature of air ventilated from pump room???

(OP)
Thanks for the post.  I agree that the 13 degree dT seems very low for (2) 20hp pumps.  Can you tell me where ASHRAE states the guideline for the pump heat gain?  

RE: Temperature of air ventilated from pump room???

108 deg temp rise? (117,000 / (1000cfm x 1.08))

Sounds pretty hot. Is that reasonable?

Ed

RE: Temperature of air ventilated from pump room???

Not all of the motor energy will be converted to heat.  Depending on what the pumps are doing some energy will be transfered to the fluid.

See this thread:

http://www.eng-tips.com/viewthread.cfm?qid=59911

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