Which of the following statements about the evaporator bypass dampers in a refrigeration system is true?
a. They decrease the resistance to the passage of air when they close
b. When the face damper is closed, the quantity of air passing over the evaporator coils is at a maximum
c. The quantity of air passing through the duct depends on the damper position
d. Multi-speed blowers cannot be used in combination with face and bypass dampers
e. Actuators are required to provide damper movement
Answer: E
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Power Engineering Chapter 119
- One method of controlling the capacity of reciprocating compressors is to bypass the discharge from one or more cylinders back to the suction side of the compressor. The control is called
- Which of the statements about automatic expansion valves is false?
- A method of controlling the capacity of reciprocating refrigeration compressors, whereby the discharge of high-pressure refrigerant is re-introduced to the suction side of the compressor, is called:
- The most widely used refrigerant metering device, which consists of a pressure-sensitive bellows or diaphragm connected to a temperature sensing bulb, is a/an:
- The simple, small-bore device that restricts the flow of liquid from the condenser to the evaporator and maintains a pressure difference between the two, is called:
- In a refrigeration system controlled by a high-pressure float valve, excessive refrigerant charge will cause
- The type of operation that stops a refrigeration compressor when the temperature setpoint of the cooled substance is reached, then re-starts the compressor when the temperature set-point is exceeded, is called:
- The automatic expansion valve in a refrigeration system operates on the principle of balancing:
- In refrigeration systems, the most common methods used to control the capacity of a reciprocating compressor are:
- What will the effect be if insufficient liquid refrigerant is admitted to the evaporator by a thermostatic expansion valve?
- The device that guides refrigerant vapour into a centrifugal compressor in the same direction as the compressor impeller is turning, is called a
- Sectional evaporators, installed in a refrigeration plant, control their capacity by
- In a refrigeration system controlled by a high pressure float valve, insufficient refrigerant charge will cause
- The thermostatic expansion valve operates on the principle of balancing:
- In a refrigeration system, a weighted valve pin is used in a high-pressure float valve system in order to:
- The control used in a mechanical refrigeration system to maintain a constant level of liquid refrigerant in the accumulator tank of a flooded evaporator is called
- Manual or hand-operated expansion valves are seldom used in modern refrigeration systems except, occasionally:
- Which of the following is NOT a refrigerant metering device?