Is a Freezer Different From an Air Conditioner?

Heat

• Heat always flows from hot objects to cold ones, just as balls don't spontaneously roll uphill. To make it flow the other way, you have to input energy. Both freezers and air conditioners do so by compressing a refrigerant to liquefy it and force it through a condenser, where it releases heat. Next, the refrigerant squeezes its way through a narrow valve, evaporating in the low-pressure evaporator on the other side and absorbing heat as it does so.

Effects

• The net effect in both a refrigerator and a freezer is to take heat from a low-temperature environment and transfer it to a high-temperature area, and they do this in the same basic way. With that in mind, however, there are also many differences in the way the two systems are designed. An air conditioner is larger and must remove heat from a whole house rather than a small compartment.

Differences

• Air conditioners generally have fans to blow air across the evaporator and condenser coils while freezers do not. Freezers and air conditioners may also make use of different chemical refrigerants although in many cases the same compound can be used interchangeably. HCFC-22 is the most common refrigerant for air conditioners and is common in freezers as well. Air conditioners must also deal with moisture because water tends to condense on the evaporator, so the air that returns to the room is relatively dry. In the freezer, by contrast, moisture in the air will freeze onto the evaporator instead.

Considerations

• The most obvious difference between the two systems, of course, is their operating temperature: freezers run at much lower temperatures than air conditioning systems. The specific parts and components in the two systems may also be designed very differently; air conditioners, for example, typically have air filters to remove particulate matter from intake air, whereas freezers do not. Overall, however, both systems are just different types of heat pumps, and the way they transport heat is essentially the same.