Let's say you have a small metal case that is 3 inches by 3 inches versus 2 inches by 2 inches. Inside at center is a heat generating source (let's say a small processor chip). How efficient is the transfer of heat from the processor to the air... and from air to metal between the 2 different size metal box? How do you compute for this? I know directly gluing the metal to the processor would be more efficient.. but I want to know the thermal transfer if air is in the middle between them where the heat sink is not directly connected to the source but has air medium between them like that occurring in many enclosure housing electronic devices with processor chip inside (like in cctv camera). Thank you.