Fresh air load

[fireandice]

I am trying to work out the heat load of 10 cubic meters per second of fresh air and i am coming up with about 180kw, I don't believe it. Can someone provide me with workings or a program to calculate this. Thanks

[vijay_study]

Hi,

Volume flow rate of fresh air = 10m3/sec (21189 ft3/min)

Step: 01 Get data on Ambient DBT / Ambient WBT. Example: 35°C(95°F) DBT / 28.3°C (83°F) WBT

Step: 02 Calculate enthalpy at ambient conditions. Example: for above ambient conditions enthalpy = 46.9 Btu/lb

Step: 03 Calculate apparatus dew point temperature. Example: Assuming 12°C(54°F)

Step: 04 Calculate enthalpy at dew point condition 22Btu/lb

Step: 05 Based on formula Btu/hr = 4.5 x cfm x Delta H
= 4.5 x 21189 x (46.9 - 22)
= 23,74,227 (695Kw)

Hope its helpful.

Thanks

[nike123]

http://fridgetech.com/software/files/SIahuCalc3.zip

[hendrag]

no problems mate go to this link and use our handy excel

http://www.mylg.co.uk/data%20for%20site/prod%20sht%2093%20Eco-V%20Pre-Heater%20Sizing.xls

hope it helps and its free

regards

Graham

[frank]

Are you looking to heat the air or cool the air?

To input the figures into any formula, you need to specify a start temperature and an end temperature (t1 - t2)

[fireandice]

Wanted to cool the fresh air from approx 28 deg celcius to 20 deg celcius. Once I gave them an estimate of cost they have changed thier mind about the volume of fresh air they require, still waiting to see what they come up with and why it is different just because of price to cool it. Looks like another design coming up that wont work :)