Which side is under evaporator pressure?

The concept of pressure sides in a refrigeration or air conditioning system is fundamental to its operation. In a vapor-compression refrigeration system, the evaporator is the component where the refrigerant absorbs heat and changes from a liquid to a gas. This process occurs at low pressure.

Therefore, the side of the system where the evaporator functions operates under what is termed "evaporator pressure," which corresponds to the low-pressure side of the system. The refrigerant enters the evaporator as a low-pressure gas, gets evaporated while absorbing heat from the surrounding environment, and then leaves the evaporator under low pressure, ready to be compressed by the compressor.

In contrast, the condenser side functions at a higher pressure where the refrigerant releases heat and condenses from gas to liquid, which distinguishes the high side pressure from the low side pressure of the evaporator. The medium side does not specifically refer to a defined pressure in standard refrigeration terminology. Thus, recognizing the role of the evaporator under low pressure solidifies the understanding of refrigerant flow and system pressure dynamics.