The case wouldn't heat up due to conduction.
Conduction is Heat Transfer from DIRECT CONTACT from one surface to another. On a Molecular/Atomic level...
CPU IHS - Thermal Material - Heatsink - That's conduction.
Cases aren't made of aluminium because of it's cooling properties.
Aluminium isn't that great for cooling. (COPPER, GOLD, SILVER or DIAMOND) would be used if that was true. Aluminium is used because it's light and fairly durable. Not to mention, much cheaper the the mentioned above.
If your aluminium case gets hot enough to the touch, were you can tell the difference... You've got one SERIOUS problem with your other components. Your enclosure might as well be a convection oven.
Difference between steel and aluminum is that the aluminum doesn't hold thermal energy nearly as long as steel. It would help in cooling. Why do you think some drag cars use aluminum radiators? The airflow through the radiator will cool the coolant faster because the aluminum transfers heat faster.
Difference between steel and aluminum is that the aluminum doesn't hold thermal energy nearly as long as steel. It would help in cooling. Why do you think some drag cars use aluminum radiators? The airflow through the radiator will cool the coolant faster because the aluminum transfers heat faster.
He said, "Aluminium of the case is a good heat conducter". In that statement he was saying that the heat transfer is CONDUCTION.
This is false. It's convection. Which your example is also convection, not conduction. Covection is heat transfer due to fluid movement.
(AIR - Case Fans) (COOLANT - Radiator)
The aluminium of a PC case may get warmer then room temp, but that is due to CONVECTION... not CONDUCTION.
Conduction heat transfer would be if you attached a heatsink directly to the CPU IHS, then had a heatpipe, attached to the aluminium of the case. (PASSIVE COOLING) that would be conduction.