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Thread: Temperature Gained?
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28-10-2014, 11:19 PM #1
Temperature Gained?
OK guys (gals?),
Please feel free to laugh at me for this one, it is late, my brain is mush and I can't find my trusted rule of thumb book...
What will the temperature rise be in 1m2 of air if 1 watt of heat is added to it for 1 hour?
(Assuming no losses or other heat transfers occur and that we start with dry air at 20ºC)
I will now go and collect my free bus pass, get my slippers on and complain about the youth of today.
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29-10-2014, 08:58 PM #2
Re: Temperature Gained?
Assuming you mean 1m3
Straight forward Viking..
1 Watt = 1j/s
1 hour = 3600 secs
so 1 Watt for 1 hour = 3600joules or 3.6kj
The mass of dry air at 20c is 1.205kg
Specific heat of air is 1.22kj/kg, so
Using the heat transfer formula Q = mass x c x (t1-t2) we can transpose to find the dt
3.6/(1x1.205)/1.22 = dt
dt = 2.4488K
Temperature rise = 2.45 degrees CLast edited by frank; 01-11-2014 at 06:53 AM.
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29-10-2014, 09:08 PM #3
Re: Temperature Gained?
Typo I think frank!
3600joules = 3.6 Kj (not kw)
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29-10-2014, 09:10 PM #4
Re: Temperature Gained?
Thanks Frank,
You are of course right m3 it is.
And thank you for the formula.
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29-10-2014, 09:20 PM #5
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01-11-2014, 06:54 AM #6
Re: Temperature Gained?
Correction made ☺
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02-11-2014, 01:58 AM #7
Re: Temperature Gained?
Cheers Frank,
You are a true gentleman.
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02-11-2014, 08:29 AM #8
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