Author Topic: Heat calculation  (Read 1964 times)

Offline preetnep

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Heat calculation
« on: October 19, 2015, 08:28:21 PM »
Can someone  help.
I have a room of 30ft x 30ft. R values of material are 20,10,5. Outdoor temp is 80 f and indoor is 100' . How much heat has to be removed from room.

As per my understanding
Q=a.u.delta t
= 90 × .03 × 20
=54.
Is it btu h ?

Offline walker

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Re: Heat calculation
« Reply #1 on: October 19, 2015, 10:43:14 PM »
whats the height of the wall?

Offline preetnep

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Re: Heat calculation
« Reply #2 on: October 19, 2015, 10:54:26 PM »
It doesn't say height of wall . It's one of practice questions for 313D exam

Offline walker

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Re: Heat calculation
« Reply #3 on: October 19, 2015, 11:16:30 PM »
well first off a= L x W, in your case would be 30 x 30 = 900 not 90 as you've put in your equation.

Offline preetnep

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Re: Heat calculation
« Reply #4 on: October 19, 2015, 11:20:33 PM »
Yes . It should be 900.
I don't have answer so I want to know if it's the right way to calculate btuh or I m missing some thing.

U is 1/R
Where R = r1+r2+r3

Offline walker

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Re: Heat calculation
« Reply #5 on: October 19, 2015, 11:45:55 PM »
then you're looking at removing 540btu