Thermodynamics / Q = mC⌂T equation in air application

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SUMMARY

The discussion centers on calculating the amount of atmospheric air needed to maintain a temperature increase of no more than 15°C in a radio equipment cabin with a heat load of 15kW. The relevant equation used is Q = mC⌂T, where C is the specific heat capacity of air at 1.007 kJ/kg·K and ⌂T is set to -15°C. Participants emphasize the need to convert mass flow rate (m) into a volume of air, utilizing the ideal gas law (pV = nRT) for accurate calculations. The conclusion is that determining the mass of air required per hour is essential for effective thermal management in the cabin.

PREREQUISITES
  • Understanding of the Q = mC⌂T equation
  • Familiarity with the ideal gas law (pV = nRT)
  • Knowledge of specific heat capacity, particularly for air
  • Basic principles of thermodynamics and heat transfer
NEXT STEPS
  • Calculate the mass flow rate of air required using the Q = mC⌂T equation
  • Explore the ideal gas law applications in thermal systems
  • Research methods for effective thermal management in electronic equipment
  • Investigate specific heat capacities of different gases for comparative analysis
USEFUL FOR

Engineers, HVAC professionals, and anyone involved in thermal management of electronic equipment will benefit from this discussion, particularly those working with radio equipment and similar thermal load scenarios.

Phystudent91
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Homework Statement



If you have a radio equipment cabin that has a heat load of 15kW and you wish to stop the temperature becoming more than 15°C hotter than outside, how much 'free air' (outside/atmospheric air) needs to be circulated inside the cabin per hour?


Homework Equations



Q = mC⌂T
C = 1.007
⌂T = -15

The Attempt at a Solution



I don't know how to relate the m (usually a mass, right?) to a volume of air, as I assume that is the equations equivalent.
I hope that makes sense...
 
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There is an ideal gas law saying pV = nRT which is good enough for this kind of thing. You'll have to make a decent assumption for T and p (p is easy, T is more vague).
But: what's against answering soandsomany kilograms per hour if they ask "how much" ?
 
Let m be the amount of air mass that passes through the room in an hour. How much heat does it have to absorb in an hour to remove all the heat generated by the radio equipment?

Chet
 

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