Chapter Questions
Explain the main idea behind pressurized liquid systems, and list their advantages.
The two broad categories of display cases are $\qquad$ and $\qquad$
How are conditions maintained in open display cases when there are high shelves?
What are mullion heaters?
The three temperature ranges for refrigeration systems are $\qquad$$\qquad$ , and $\qquad$
The two methods for rejecting heat from refrigerated cases are $\qquad$ and $\qquad$
When the compressors are located in the equipment room, the piping is routedA. in floor chases or in plastic pipes under the floor.B. in suspended ceilings.C. between the walls.D. in back of the walls.
When one large compressor is used, what desirable feature should it have?A. Discharge mufflerB. Suction mufflerC. Cylinder unloaders or variable-speed driveD. Hot gas bypass
Define a parallel compressor system and list five advantages of these systems.
Three disadvantages of parallel compressor systems are$\qquad$ , $\qquad$ , and $\qquad$
What is the $\overline{\text { difference between an even and an uneven }}$ parallel compressor system?
Exactly matching the refrigeration load with the capacity of refrigeration compressors is referred to asA. capacity control.B. load shedding.C. load paralleling.D. load matching.
What is the function of the pressure transducer in parallel compressor systems?
What is the function of the microprocessor-based controller in parallel systems?
Explain how the oil separator, oil reservoir, pressure differential valve, and oil-level regulators work together to maintain the correct oil level in parallel compressors.
Large or small compressors on parallel compressor racks, which are usually dedicated to the coldest cases, are called A. satellite compressors.B. remote compressors.C. booster compressors.D. both $\mathrm{A}$ and $\mathrm{C}$.
A(n) $\qquad$ varies the frequency of an electronically altered sine wave, which affects the speed of alternating current motors.
Explain the function and advantages of a secondary-fluid system.
Three advantages of unitary, stand-alone refrigeration modules in supermarket refrigeration are $\qquad$$\qquad$ , and $\qquad$
How is defrost accomplished when the equipment room is in the back and the medium-temperature fixtures are in the front?
True or False: The two types of defrosts used with lowtemperature fixtures are hot gas and electric defrost.
What special precautions should be taken with drain lines in walk-in coolers?A. Freeze protectionB. Trapping to prevent air from being pulled inC. Downward slopingD. All of the above
What holds up the structure of a walk-in cooler?
What special valve is used in a refrigerated air drier?A. Four-way valveB. Defrost valveC. Three-way valveD. Hot gas bypass valve
Briefly explain what is meant by a surge-type receiver.
Briefly explain what is meant by a subcritical refrigeration cycle, and list its four processes.
Briefly explain what is meant by a transcritical refrigeration cycle, and list its four processes.
What is meant by carbon dioxide having a critical point?
What is the critical point of carbon dioxide?
What is meant by carbon dioxide having a triple point?
What is the triple point of carbon dioxide?
Define a synthetic refrigerant.
Define a natural refrigerant.