Editing Computer cooling (section)

====Temperature vis-à-vis flow rate====
The equation for required airflow through a chassis is

: <math>\text{CFM} = \frac{P}{Cp \times r \times dT}</math>

where
* <math>\text{CFM}</math> = [[cubic feet per minute|Cubic Feet per Minute]] ({{convert|1|cuft/min|disp=out}})
* <math>P</math> = Heat Transferred ([[kW]])
* <math>Cp</math> = Specific Heat of Air
* <math>r</math> = Density
* <math>dT</math> = Change in Temperature (in °F)

A simple conservative rule of thumb for cooling flow requirements, discounting such effects as heat loss through the chassis walls and laminar versus turbulent flow, and accounting for the constants for specific heat and density at sea level is:

: <math>\text{CFM} = \frac{3.16 \times P}{\text{allowed temperature rise in} ^\circ F}</math>

: <math>\text{CFM} = \frac{1.76 \times P}{\text{allowed temperature rise in} ^\circ C}</math>

For example, a typical chassis with 500 watts of load, {{convert|130|°F|abbr=on}} maximum internal temperature in a {{convert|100|°F|abbr=on}} environment, i.e. a difference of {{convert|30|F-change|abbr=on}}:

: <math>\text{CFM} = \frac{3.16 \times 500\ \text{W}}{(130 - 100)} = 53</math>

This would be actual flow through the chassis and not the free air rating of the fan. It should also be noted that "Q", the heat transferred, is a function of the heat transfer efficiency of a CPU or GPU cooler to the airflow.