Unit 26 Test and Quiz Review

A

A CO2 refrigeration cycle that takes place above the refrigerant's triple point and below the refrigerant's critical point is called a A. subcritical cycle B. transcritical cycle C. natural cycle D. supercritical cycle

C

A mullion heater is used to A. prevent ice formation on the TXV or capillary tubing B. defrost the evaporator of medium-temperature fixtures C. prevent the formation of moisture on refrigerated fixtures D. keep the receiver warm in low-ambient conditions

A

A refrigerant that has both a Global Warming Potential (GWP) and an Ozone Depletion Potential (ODP) of 0 is ________________ A. ammonia (R-717) B. carbon dioxide (R-744) C. HFC-134a D. HFC-404A

D

A secondary fluid or refrigerant is usually A. a methane-based refrigerant B. a type of distilled water solution C. a low-pressure HFC refrigerant D. a low-temperature antifreeze solution

C

A system that operates at the lowest possible head pressure by taking advantage of cool ambient temperatures that are used as the condensing medium, is said to operate with a A. transcritical cycle B. fixed head pressure C. floating head pressure D. subcritical

D

A type of cooler that is made up of interlocking panels that are assembled at the jobsite, which can be disassembled to be located, is called a (n) A. package cooler B. reach-in fixture C. upright chest fixture D. knock-down cooler

B

A type of reach-in system that can be designed with an open top or lids, is normally placed against a wall, and can be either self-contained or split with a remote condenser is a ____________________ A. parallel rack system B. chest type C. knock-down cooler D. walk-in cooler

True

A typical refrigerated air drier can use a hermetic or semi-hermetic compressor and either an air-or water cooled condenser True or False

D

CO2 (R-744), ammonia (R-717), propane (HC-290), butane (HC-600), and isobutane (HC-600a) are all examples of A. HFCs B. HFOs C. secondary fluids D. natural refrigerants

D

CO2, ammonia, propane, butane, and isobutane are all types of ____________________ A. coil cleaning chemicals B. secondary fluids C. synthetic refrigerants D. natural refrigerants

A

Compressors on parallel compressor racks, which can be large or small and are usually dedicated to the coldest cases, are called A. satellite or booster compressors B. remote compressors C. off-site or off-location compressors D. auxiliary compressors

D

Exactly matching the refrigeration load with the capacity of refrigeration compressors is referred to as A. capacity control B. load shedding C. load paralleling D. load matching

C

How are conditions maintained in open display cases when there are high shelves? A. Evaporating water from misting systems removes heat B. A continuous run cycle handles the constant heat load C. Sinking cold air creates a curtain effect D. Warm air rises out of the cooler, leaving only cool air

True

In a series heat reclaim system, the reclaim coil may not be sized to handle 100% of the heat rejected from refrigeration system True or False

B

In low-temperature walk-in systems, the condensate drain line A. must terminate inside of the box B. must be heated to prevent freezing C. must be piped above the evaporator for proper drainage D. should be pitched toward the evaporator

A

On a system with multiple evaporators that are kept at different temperatures, what component is used on the higher temperature evaporators to prevent their pressures from dropping below the desired setting? A. Evaporator pressure regulator B. Hot gas bypass valve C. Pressure transducer D. Crankcase pressure regulator

B

Parallel compressor systems that apply two or more compressor to a common suction header, a common discharge header, and a common receiver are called A. loaded systems B. rack systems C. booster systems D. split systems

A

Reach-in refrigeration fixtures can be either ____________________ A. self-contained or split systems with a remote condenser B. package or unitary systems C. self-contained or package systems D. parallel systems or rack systems

C

Refrigerated air driers typically use a (n) _____________ to place a "false load" on the refrigeration circuit when there is no heat load A. evaporator pressure regulator B. condenser flooding device C. hot gas bypass valve D. condenser air recycler

A

The ________________ of a gas is the highest temperature that the gas can have and still be condensable by the application of pressure A. critical point B. triple point C. dew point D. flash point

D

The mixing of hot gas with subcooled or saturated liquid could cause __________________ A. frost to develop on the fins of the condenser B. acid to develop in the refrigerant oil C. compressor burn out D. liquid hammer

B

The most common temperature ranges for refrigeration systems are A. low-and ambient temperature B. high-, medium-, and low-temperature C. high-and low-temperature D. ambient-and variable-temperature

B

The term used to describe the point at which CO2 exists as all three phases (vapor, liquid, and solid) simultaneously in equilibrium is A. critical point B. triple point C. transcritical point D. subcritical point

A

The two broad categories of display cases are A. open-and closed type B. high-and low-pressure systems C. vertical and horizontal D. indoor and outdoor fixtures

D

The two common methods for rejecting heat from refrigerated cases are A. inside the store (recirculated-type) or outside the store (ambient-dependent) B. inside the store (ambient-dependent) or outside the store (geothermal) C. inside the store (split-system) or outside the store (package-system) D. inside the store (package-system) or outside the store (split-system)

False

The two main processes or cycles of CO2 systems are the transcritical and supercritical cycles True or False

A

To remove condensate, self-contained equipment can _____________ A. evaporate it using heat given off by the compressor B. pump the it back to the evaporator C. store it until it can be evaporated by heat from the defrost cycle D. pump it to an external storage unit

A

Walk-in refrigeration equipment is either ______________ type A. knock-down or permanent B. residential or commercial C. permanent or fixed D. mechanical or electronic

C

When one large compressor is used, what desirable feature should it have? A. Discharge muffler B. Suction muffler C. Cylinder unloaders or variable-speed drive D. Hot gas bypass

A

When the compressors are located in equipment room, the piping is routed A. in floor chases or in plastic pipes under the floor B. is suspended ceilings C. between the walls D. in back of the walls