Refrigeration Flashcards

What is the purpose of a thermostatic expansion valve (TXV) in a refrigeration system?

Answer: Meter refrigerant flow to maintain superheat at the evaporator outlet

A TXV meters refrigerant flow into the evaporator to maintain a set superheat, ensuring only vapor enters the compressor.

What does 'subcooling' refer to in a refrigeration system?

Answer: Cooling liquid refrigerant below its condensing temperature at a given pressure

Subcooling is the process of cooling liquid refrigerant below its saturation temperature at the condenser pressure, preventing flash gas in the liquid line.

In a refrigeration cycle, where does the refrigerant absorb heat from the space being cooled?

Answer: Evaporator

The evaporator absorbs heat from the refrigerated space as liquid refrigerant evaporates into vapor.

What refrigerant replaced R-22 as the most common choice for residential air conditioning in the US?

Answer: R-410A

R-410A replaced R-22 in residential AC systems because it has zero ozone depletion potential and higher efficiency.

What is the function of a liquid line filter-drier in a refrigeration system?

Answer: Remove moisture and contaminants from the refrigerant

A filter-drier removes moisture and solid contaminants from the liquid refrigerant to prevent system damage and acid formation.

What is 'flash gas' in a refrigeration system?

Answer: Refrigerant vapor that forms in the liquid line due to pressure drop or heat gain

Flash gas is unwanted refrigerant vapor that forms in the liquid line before the expansion device, reducing system efficiency.

Which type of compressor uses rotating scrolls to compress refrigerant and is commonly found in modern residential heat pumps?

Answer: Scroll compressor

Scroll compressors use two interlocking spiral-shaped scrolls to compress refrigerant and are valued for their efficiency, quiet operation, and reliability in residential systems.