HVAC Refrigeration 2

Question 1

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

Accepted Answer

Meter refrigerant flow to maintain superheat at the evaporator outlet

Answer

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

Question 2

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

Accepted Answer

Cooling liquid refrigerant below its condensing temperature at a given pressure

Answer

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

Question 3

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

Accepted Answer

Evaporator

Answer

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

Question 4

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

Accepted Answer

R-410A

Answer

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

Question 5

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

Accepted Answer

Remove moisture and contaminants from the refrigerant

Answer

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

HVAC Practice Test

HVAC Practice Test

HVAC Refrigeration 2