Refrigeration Systems Flashcards

Subcooling in a refrigeration system refers to:

Answer: Cooling liquid refrigerant below its condensing temperature

Subcooling ensures the liquid refrigerant is cooled below its condensing temperature, preventing flash gas before the expansion device.

Which type of expansion device maintains a constant evaporator pressure regardless of load?

Answer: Automatic expansion valve (AXV)

The automatic expansion valve (AXV) maintains a constant evaporator pressure by responding to pressure changes at the valve outlet.

What condition is indicated when a compressor's suction line frosts heavily all the way back to the compressor?

Answer: Overcharge of refrigerant or a flooding TXV

Heavy frosting on the suction line extending to the compressor indicates liquid refrigerant is returning to the compressor, risking liquid slugging.

In a commercial refrigeration system, what is the role of the oil separator?

Answer: Return compressor oil from the discharge line back to the crankcase

The oil separator captures oil discharged with the hot gas and returns it to the compressor crankcase, preventing oil accumulation in the system.

What is the typical evaporator temperature range for a commercial ice cream freezer (hardening cabinet)?

Answer: -40°F to -20°F

Hardening cabinets require very low evaporator temperatures, typically -40°F to -20°F, to rapidly freeze and maintain ice cream at proper hardness.

A technician notices oil pooling in the evaporator of a low-temperature display case. The most appropriate corrective action is:

Answer: Verify oil return lines and compressor crankcase heater operation

Oil pooling in the evaporator indicates poor oil return; checking oil return lines and crankcase heater ensures oil circulates back to the compressor.