# Which is a more effective cooling method?

Assume I have a refrigerator at 0C and I put a can of soda at the center of the refrigerator. The temperature inside the refrigerator will be increased to 5C after I put the soda in, but will go back to 0C after a while

If I consider the speed of cooling, should I keep the pressure inside the refrigerator be atmosphere pressure? OR I should create vacuum inside the refrigerator

If I consider the energy efficiency, should I keep the pressure inside the refrigerator be atmosphere pressure? OR I should create vacuum inside the refrigerator

• Refrigerators work mainly by convective heat transfer, and that is why many of them have a fan inside of them to circulate air. What does that imply regarding an answer to your question? Commented May 29, 2023 at 22:11

• @Marco From the ideal gas equation you can only deduce that if you were to suddenly lower the pressure the temperature would drop (keeping $V$ constant). The soda can isn't part of the ideal gas and the temperature of the can doesn't drop (at least not immediately). If you want to know if it's easier to go to a lower temperature you can have a look at the heat capacity at constant $V$. en.wikipedia.org/wiki/…. The heat capacity only depends on $N$ so for constant density it will stay the same Commented Dec 7, 2021 at 12:28