Still today everyone seem to prefer a bulky case for their desktop builds, even when modern motherboards (ITX) and power supply can be fitted in much compact place, so my question is, how does an increase in internal void helps in keeping temperature under control, In my view it should be flow of air towards ambient and how much ventilated case that should dictate,
To put it again, after the trapped air inside the large case gets warmer, how can it help in temperature control, unless that air is moved out so it all boils down to air flow not really case size.
3 Answers
Larger cases allow you to use larger, slower and, above all, quieter fans.
Having a restricted airflow to or from a fan can reduce its efficiency because it is having to either fight to push air into a restricted area or to suck it from zones that have already been depleted by other fans.
Fans work best when they have a large area from which to take air in and to push out to.
Smaller fans have to work a lot harder to push the same volume of air as a larger fan. You might be able to focus the air more, but that fan will necessarily work at a higher speed and be noisier than its larger cousin.
Larger cases also allow you to use larger and more effective heatsinks, giving you more surface area to push cool air over and resulting in overall more effective cooling.
Having more effective fans and heatsinks means you can use higher power chips with less worry about overheating.
A bulky case gives you much larger margin of error.
In a super compact case, if you stuff your wires in wrong, you can create hotspots where air does not flow. A large case with multiple fans will prevent this.
1well, its a matter of thermo and fluid dynamics.
So Heat is energy, which means that there is a quantifiable amount of it in an area at any given time, and it doesn't just disappear, it has to go somewhere (Conservation of Energy). When heat moves it must always move into another medium (the air, the case, the heatsink, just about anything) that has less heat than the medium it is currently in (Entrophy). Its like how water flows to the lowest level. Since heat never just disappears, our approach to cooling always focuses on how to evacuate the heat to another place. This also means that you can never use Air to cool a system to a temperature lower than the room temperature. No heat will enter the air in that circumstance.
The CPU and other components are constantly converting electricity into heat as a side effect of their operation, and that heat is bad for them if it reaches a certain point, so we need a way to get the heat away from our critical components, as quickly as possible. If we can't get it away, then it will stay where it is, and eventually damage our hardware.
Our hardware is constantly radiating heat, and our fans are constantly blowing air through our systems, in the hope that we can put enough heat into that air, and blow the air out and new air in to continuously cool the system to a sufficient degree.
Finally, consider a camp fire. if you stand right next to it, it will be hot, and might even burn you, but if you step a few feet away, the volume of the air the heat is filling is enough to make it more comfortable for you. if there was a wall right behind you however, you could not step away. if the wind blew, it might make you more comfortable for an instant, but unless its a very strong wind indeed, it won't be enough to keep you cool indefinitely.
so a large case gives the heat a much larger volume to expand into, and lets air move the heat further away from our delicate components, which is just as effective for our purposes as blowing it out the back of the case and it didn't even cost any fan power. Just like with the camp-fire, if the wall is further back, you aren't roasted by the flames.
