Refrigeration Flashcards

What does a high-pressure cutout switch do in a refrigeration system?

Answer: Stops the compressor when discharge pressure exceeds a safe limit

A high-pressure cutout switch shuts off the compressor when discharge pressure exceeds a preset limit to prevent equipment damage.

What is the primary purpose of an accumulator in a refrigeration system?

Answer: Prevent liquid refrigerant from entering the compressor

An accumulator is installed in the suction line to catch any liquid refrigerant before it reaches the compressor, preventing compressor damage from liquid slugging.

What is the Global Warming Potential (GWP) used to measure?

Answer: The heat-trapping ability of a refrigerant relative to CO2 over 100 years

GWP measures how much heat a greenhouse gas traps compared to CO2 over a 100-year period, with CO2 having a GWP of 1.

In a refrigeration system, 'head pressure' refers to which pressure?

Answer: Discharge pressure at the compressor outlet

Head pressure is the high-side discharge pressure measured at the compressor outlet, representing the condensing pressure of the refrigerant.

What refrigerant safety classification is assigned to ammonia (R-717)?

Answer: B2L (toxic, low flammability)

Ammonia is classified B2L — toxic (B) and mildly flammable (2L) — making it effective for industrial refrigeration but requiring special safety precautions.

What is the effect of non-condensable gases (such as air or nitrogen) in a refrigeration system?

Answer: They raise the condensing pressure and reduce system efficiency

Non-condensable gases accumulate in the condenser, raising condensing pressure and head pressure, which reduces efficiency and can cause high-pressure cutouts.

What does the term 'ton of refrigeration' represent?

Answer: 12,000 BTU/hr of heat removal capacity

One ton of refrigeration equals 12,000 BTU/hr, originally based on the heat required to melt one ton of ice in 24 hours.