Refrigeration Systems Quiz

How are conditions maintained in open display cases when there are high shelves?

• Evaporating water from misting systems removes heat.

• A continuous run cycle handles the constant heat load.

• Sinking cold air creates a curtain effect.

• Warm air rises out of the cooler, leaving only cool air.

A mullion heater is used to

• prevent ice formation on the TXV or capillary tubing.

• defrost the evaporator of medium-temperature fixtures.

• prevent the formation of moisture on refrigerated fixtures.

• keep the receiver warm in low-ambient conditions.

The most common temperature ranges for refrigeration systems are

• low- and ambient-temperature.

• high-, medium-, and low-temperature.

• high- and low-temperature.

• ambient- and variable-temperature.

The two common methods for rejecting heat from refrigerated cases are

• inside the store (recirculated-type) or outside the store (ambient-dependent).

• inside the store (ambient-dependent) or outside the store (geothermal).

• inside the store (split-system) or outside the store (package-system).

• inside the store (package-system) or outside the store (split-system).

When the compressors are located in the equipment room, the piping is routed

• in floor chases or in plastic pipes under the floor.

• in suspended ceilings.

• between the walls.

• in back of the walls.

When one large compressor is used, what desirable feature should it have?

• Discharge muffler

• Suction muffler

• Cylinder unloaders or variable-speed drive

• Hot gas bypass

Parallel compressor systems that apply two or more compressors to a common suction header, a common discharge header, and a common receiver are called

• loaded systems.

• rack systems.

• booster systems.

• split systems.

The blank 1 of a gas is the highest temperature that the gas can have and still be condensable by the application of pressure.

(a)  

CO2 (R-744), ammonia (R-717), propane (HC-290), butane (HC-600), and isobutane (HC-600a) are all examples of

• HFCs.

• HFOs.

• secondary fluids.

• natural refrigerants.

The term used to describe the point at which CO2 exists as all three phases (vapor, liquid, and solid) simultaneously in equilibrium is

• critical point.

• triple point.

• transcritical point.

• subcritical point.