What is one advantage of having evaporator pressures higher than atmospheric pressure?

Having evaporator pressures higher than atmospheric pressure serves several purposes within a refrigeration system, one of which is to keep air and moisture from entering the system. When the evaporator operates at a pressure above atmospheric levels, it effectively prevents outside air from infiltrating the refrigerant circuit.

This is crucial because air and moisture can introduce contaminants that adversely affect the system's efficiency, potentially leading to issues like corrosion, reduced heat transfer capabilities, and decreased overall performance. By maintaining higher pressures, the system can operate more reliably and maintain optimal performance, as it minimizes the risks associated with air leakage.

The other options, while they may sound beneficial, do not specifically correlate with the primary advantage of maintaining higher evaporator pressures. For instance, increased cooling efficiency and improved heat exchange are important outcomes of proper system design and operation, but are not necessarily direct benefits of simply having higher evaporator pressures relative to atmospheric conditions. Reduced energy consumption is more a function of system design and load management rather than the pressure setpoints of the evaporator itself.