Air Conditioning Repair Refrigeration Cycle Principles Questions and Answers

Question 1

In a standard refrigeration cycle, what is the primary function of the evaporator?

Accepted Answer

To absorb heat from the space to be cooled.

Answer

The evaporator is the component where the cooling effect takes place. As the low-pressure liquid refrigerant flows through the evaporator coils, it absorbs heat from the surrounding space, causing the refrigerant to boil and change into a vapor.

Question 2

A technician measures the refrigerant temperature at the suction line and finds it is significantly higher than the saturation temperature corresponding to the suction pressure. What does this condition indicate?

Accepted Answer

High superheat

Answer

Superheat is the temperature of the refrigerant vapor above its saturation (boiling) point at a given pressure. A high superheat reading indicates that the refrigerant is gaining a large amount of extra heat after it has completely evaporated, which can be a sign of an undercharged system or a starved evaporator.

Question 3

Which of the following describes the state of the refrigerant as it enters the compressor?

Accepted Answer

Low-pressure, low-temperature vapor

Answer

The refrigerant leaves the evaporator as a low-pressure, low-temperature vapor (ideally, superheated) and travels through the suction line to the compressor. The compressor is designed to compress vapor, not liquid.

Question 4

A technician is servicing a residential split system and finds that the liquid line is warm and the system is not cooling effectively. They suspect a component failure. Which component's primary role is to reduce the pressure and temperature of the high-pressure liquid refrigerant before it enters the evaporator?

Accepted Answer

Metering device

Answer

The metering device (such as a TXV or fixed orifice) creates a pressure drop, which rapidly cools the high-pressure liquid refrigerant and regulates its flow into the evaporator. This allows the refrigerant to absorb heat efficiently in the evaporator coil.

Question 5

What is the primary purpose of the condenser in the refrigeration cycle?

Accepted Answer

To reject heat from the refrigerant, causing it to change from a gas to a liquid.

Answer

The condenser receives high-pressure, high-temperature vapor from the compressor and rejects heat to the surrounding environment (usually the outdoor air). This heat rejection causes the refrigerant to condense into a high-pressure liquid.

Air Conditioning Repair Practice Test

Air Conditioning Repair Practice Test

Air Conditioning Repair Refrigeration Cycle Principles Questions and Answers