Refrigeration Systems & Components Flashcards
7 cards from real ATP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Refrigeration Systems & Components flashcards as text
What is the primary purpose of a receiver in a refrigeration system?
Answer: To store liquid refrigerant and ensure a steady supply to the expansion device
A receiver acts as a reservoir that stores excess liquid refrigerant and ensures a continuous, bubble-free supply to the expansion device under varying load conditions.
Which refrigerant characteristic is described as the temperature difference between the saturation temperature at the evaporator outlet pressure and the actual vapor temperature leaving the evaporator?
Answer: Superheat
Superheat is the temperature of refrigerant vapor above its saturation (boiling) point at a given pressure, measured at the evaporator outlet to confirm all liquid has evaporated.
In a refrigeration system, subcooling of the liquid refrigerant leaving the condenser primarily helps to:
Answer: Prevent flash gas formation in the liquid line
Subcooling ensures liquid refrigerant reaches the expansion device without flashing, preventing flash gas that would reduce system capacity and efficiency.
A refrigeration technician measures 20°F of superheat at the outlet of a direct expansion evaporator coil. This reading indicates:
Answer: The refrigerant has absorbed heat and is fully vaporized with 20°F above saturation
20°F of superheat means the suction vapor is 20°F warmer than its saturation temperature, confirming complete evaporation and providing a safety margin for the compressor.
Which component in a refrigeration system is responsible for metering the correct amount of refrigerant into the evaporator to maintain the desired superheat?
Answer: Thermostatic expansion valve (TXV)
The TXV senses evaporator outlet superheat via a sensing bulb and modulates refrigerant flow to maintain a set superheat, optimizing evaporator efficiency.
What happens to the compression ratio of a refrigeration system when the evaporator temperature is lowered while the condensing temperature remains constant?
Answer: Compression ratio increases, reducing volumetric efficiency
Lowering evaporator temperature reduces suction pressure, increasing the pressure differential the compressor must overcome and raising the compression ratio, which decreases volumetric efficiency.
A suction accumulator is installed in a refrigeration system primarily to:
Answer: Trap liquid refrigerant before it enters the compressor during a flooded start
A suction accumulator prevents liquid refrigerant slugging into the compressor by temporarily storing liquid and allowing only vapor to pass, protecting the compressor during flooded starts or load swings.