# Thread: HVAC formula question

#### Hybrid View

1. Regular Guest
Join Date
Sep 2005
Posts
1
Post Likes
I'm currently enrolled in an HVAC apprentice program and as a bonus assignment, the instructor gave us a formula and asked us to find its meaning and application.
Try as I might though, I couldn't find anything in my books or on the internet on this formula.
Does anyone here have even a general idea what this formula is and what it's used for?

Q =
q
--------------------
(Tr-To)(60P Cp)

Q = Ventilation Rate - CFM
q = Room Heat - Btu/hr
Tr = Allowed Room Temp - Farenheit
To = Outside Air Temp
P = Air Density - Lb M/Feet cubed
Cp = Specific Heat of Air = 0.24 Btu/lb M Farenheit

2. That's the formula you'd use to find how much ventiliation [exhaust] you need in something like a generator room. The air quantity is based on how hot you can let the room get.

3. Banned
Join Date
Apr 2004
Location
where you at?
Posts
3,359
Post Likes
try the ASHRAE handbook(s)...it's ALL in there.

4. ct2
Regular Guest
Join Date
Sep 2004
Posts
3,157
Post Likes
ralphtheplumber

Buy a guy a fish and you feed him for a day

teach him how to fish and you feed him forever

what I am asking you is this : Make us work for the answer a bit. If all we have to do is post a class assigned question and get an answer , just like that , we are going to need you to take our tests for us also

5. Sell a man a fish and you feed him for a day.

Teach a man to fish and you ruin your market share.

(you'll also learn that latter on in life.)

6. Originally posted by ct2
what I am asking you is this : Make us work for the answer a bit. If all we have to do is post a class assigned question and get an answer , just like that , we are going to need you to take our tests for us also
You must have missed the part where he said:

Originally posted by jgman
Try as I might though, I couldn't find anything in my books or on the internet on this formula.
Please note that he's not asking for diy advice, or anything else that's likely to get him into trouble. Now that he knows what the formula is for, he can go figure out what it means and finish his assignment.

7. ct2
Regular Guest
Join Date
Sep 2004
Posts
3,157
Post Likes
No i didnt miss that part , and I appricate the answer that you gave him ...as a matter of fact I got my book out after reading your answer to look it up myself

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•

## Related Forums

The place where Electrical professionals meet.