Refrigeration Systems & Components Flashcards
7 cards from real CRST 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 does a high suction superheat combined with normal or low head pressure indicate in a refrigeration system?
Answer: Low refrigerant charge or metering device starving the evaporator
High superheat with normal or low head pressure points to insufficient refrigerant flow through the evaporator, typically from a low charge or restricted metering device.
What is the purpose of a discharge muffler in a reciprocating compressor system?
Answer: Dampen pulsations in the discharge line
A discharge muffler attenuates pressure pulsations caused by the reciprocating action of the compressor pistons, reducing vibration and noise.
When sizing a liquid line, which factor is MOST critical to avoid flash gas formation?
Answer: Ensuring adequate subcooling and minimal pressure drop
Adequate subcooling provides a safety margin against pressure drop-induced flash gas, which would starve the metering device and reduce capacity.
A technician measures compressor amperage at 110% of nameplate rating. What is the most likely cause?
Answer: High head pressure due to condenser fouling or airflow restriction
High head pressure forces the compressor to work harder against greater discharge pressure, drawing excessive amperage.
What is the role of a desuperheater in a refrigeration system?
Answer: Extract heat from hot discharge gas for water heating
A desuperheater is a heat exchanger that recovers heat from superheated discharge gas, commonly used to preheat domestic hot water.
Which type of condenser relies solely on natural convection and radiation for heat rejection?
Answer: Static (natural convection) condenser
A static condenser has no fans or water; it rejects heat through natural air convection and radiation, commonly used in small self-contained units like reach-in coolers.
In a cascade refrigeration system, what is the function of the cascade heat exchanger?
Answer: Act as the condenser for the low-temperature circuit and evaporator for the high-temperature circuit
The cascade heat exchanger links two separate refrigerant circuits, rejecting heat from the low-stage condenser into the high-stage evaporator.