Refrigeration Fundamentals & System Components Flashcards

What condition is indicated when the suction pressure is lower than normal and the discharge pressure is also lower than normal?

Answer: Refrigerant undercharge or low suction load

Low suction and low discharge pressures together typically indicate a refrigerant undercharge or insufficient heat load on the evaporator.

In a hermetic compressor, the motor and compressor are:

Answer: Enclosed in the same sealed housing sharing refrigerant

A hermetic compressor seals both motor and compressor in one welded shell, with suction gas cooling the motor windings.

The coefficient of performance (COP) of a refrigeration system is calculated as:

Answer: Refrigerating effect divided by work input to the compressor

COP = Q_evaporator / W_compressor, expressing how many units of heat are moved per unit of energy consumed.

Which refrigerant is classified as an HFC (hydrofluorocarbon) with zero ozone depletion potential?

Answer: R-134a

R-134a is an HFC containing no chlorine, giving it zero ozone depletion potential (ODP), unlike older CFC and HCFC refrigerants.

An oil separator in a refrigeration system is located:

Answer: Between the compressor and condenser

Oil separators are installed in the discharge line to capture oil carried over from the compressor before it reaches the condenser and evaporator.

What is the purpose of a sight glass installed in the liquid line?

Answer: Indicate refrigerant charge level and moisture presence

A sight glass allows technicians to observe bubbles (indicating low charge or flash gas) and a moisture indicator changes color if moisture is present.

Sensible heat transfer in a refrigeration system occurs when:

Answer: Temperature of a substance changes without a phase change

Sensible heat transfer changes the temperature of a substance without a phase change, unlike latent heat which involves phase changes at constant temperature.