In a refrigeration cycle, which stage involves absorbing heat from the surroundings?

In a refrigeration cycle, which stage involves absorbing heat from the surroundings?

• A. Condensation
• B. Evaporation
• C. Expansion
• D. Compression

Answer: (B)

The key idea is that cooling in a refrigeration cycle comes from the refrigerant absorbing heat as it changes phase in the evaporator. In this stage, the refrigerant is at low pressure and low temperature. As it passes through the evaporator, it takes in heat from the surroundings (the space you’re cooling). That heat is used as latent heat of vaporization to turn the liquid refrigerant into a vapor. Because heat is drawn from the surroundings, the area being cooled gets colder. After this, the vapor is compressed to raise its pressure and temperature, then released to the condenser, where it gives off heat to the surroundings as it condenses back to a liquid. The throttling in the expansion stage lowers the refrigerant’s pressure and temperature, setting up the next cycle, but does not primarily involve absorbing heat from the surroundings. So, the stage that absorbs heat from the surroundings is the evaporator.

The key idea is that cooling in a refrigeration cycle comes from the refrigerant absorbing heat as it changes phase in the evaporator. In this stage, the refrigerant is at low pressure and low temperature. As it passes through the evaporator, it takes in heat from the surroundings (the space you’re cooling). That heat is used as latent heat of vaporization to turn the liquid refrigerant into a vapor. Because heat is drawn from the surroundings, the area being cooled gets colder.

After this, the vapor is compressed to raise its pressure and temperature, then released to the condenser, where it gives off heat to the surroundings as it condenses back to a liquid. The throttling in the expansion stage lowers the refrigerant’s pressure and temperature, setting up the next cycle, but does not primarily involve absorbing heat from the surroundings.

So, the stage that absorbs heat from the surroundings is the evaporator.