Power Engineering Chapter 115
Showing posts with label Power Engineering Chapter 115. Show all posts
Showing posts with label Power Engineering Chapter 115. Show all posts

Refrigerant evaporators

Refrigerant evaporators




a) always have the refrigerant on the shell side
b) are located between the expansion valve and the receiver
c) may have brine pumped past the coils in an indirect system
d) may be of the walk-in type
e) are usually oil cooled







Answer: C

Which of the following statements about a system that circulates warm brine or water back to a chiller tank is true?

Which of the following statements about a system that circulates warm brine or water back to a chiller tank is true?




a) The system is a direct refrigeration system.
b) The evaporator in the system is located in direct contact
with the material being refrigerated.
c) The brine or water is the refrigerant.
d) The evaporator cools the brine or water.
e) All of the above.








Answer: D

Choose the true statement. The economiser of a packaged water chiller, used for air conditioning, does NOT

Choose the true statement. The economiser of a packaged water chiller, used for air conditioning, does NOT



a. Have an intercooling effect on the compressor
b. Reduce the power required for compression of the refrigerant
c. Reduce the flash vapour in the evaporator
d. Increase the refrigerating capacity of a system
e. Eliminate liquid carryover to the compressor







Answer: E

Which of the following is not an advantage of a factory assembled, packaged refrigeration unit?

Which of the following is not an advantage of a factory assembled, packaged refrigeration unit?





a. Components are designed to match each other
b. The final installation must be according to code
c. The unit is equipped with all the required auxiliary equipment
d. Space requirements are minimized
e. The unit is factory tested in operation







Answer: B

The brine pump of a refrigeration system:

The brine pump of a refrigeration system:




a. Circulates the refrigerant through the evaporator
b. Pumps brine through the condenser cooling circuits
c. Circulates the brine through the cooling circuits
d. Maintains the brine level in the cooling circuit
e. Is used to remove heat from the condenser









Answer: C

In the evaporator of a refrigeration system:

In the evaporator of a refrigeration system:




a. The refrigerant rejects heat to the cooling tower
b. The refrigerant absorbs heat from the compressor cooling system
c. The refrigerant absorbs heat from the surrounding medium
d. The surrounding medium evaporates
e. The refrigerant is condensed







Answer: C

In the condenser of a refrigeration system:

In the condenser of a refrigeration system:





a. Latent heat is restored to the refrigerant
b. The surrounding medium must be hotter than the refrigerant
c. The heat in the refrigerant given up in the evaporator must be restored
d. The condensing medium absorbs heat from the refrigerant
e. The high pressure vapour is converted to low pressure liquid.






Answer: D

The temperature in the evaporator:

The temperature in the evaporator:





a. Depends on pressure in the receiver
b. Will decrease when the compressor stops
c. Depends on pressure in the evaporator
d. Depends on the ambient temperature
e. Is controlled by the charging valve






Answer: C

With regard to economizers installed on packaged air-conditioning chillers, which of the following statements is false?

With regard to economizers installed on packaged air-conditioning chillers, which of the following statements is false?





a. Economizers control the flow of liquid refrigerant from the evaporator to the condenser
b. Liquid refrigerant levels in each chamber are controlled by float operated, valves
c. The upper float chamber is connected to the bottom of the condenser
d. The economizer float chamber is connected via the motor to the second stage inlet of the compressor
e. It is composed of two chambers









Answer: A

For a direct expansion compression refrigeration system, which of the following statements is true?

For a direct expansion compression refrigeration system, which of the following statements is true?





a. The evaporator in this system is never in direct contact with the material or space being refrigerated
b. For large systems calcium chloride brine is cooled by the evaporator then pumped to the area being refrigerated
c. Water cooled by the chiller evaporation coils is used to refrigerate below 0°C
d. The evaporator can be located in air circulating ducts communicating with the material or space being refrigerated
e. A direct expansion system is not the same type of system as the direct refrigeration system








Answer: D

In the condenser of a refrigeration system:

In the condenser of a refrigeration system:



a. Latent heat is restored to the refrigerant
b. The surrounding medium must be hotter than the refrigerant
c. The heat in the refrigerant given up in the evaporator must be restored
d. The condensing medium absorbs heat from the refrigerant
e. The high pressure vapour is converted to low pressure liquid.







Answer: D

A purpose of a liquid refrigerant control or regulating valve (expansion valve)is to:

A purpose of a liquid refrigerant control or regulating valve (expansion valve)is to:




a. Drain the receiver
b. Regulate the refrigerant flow to the condenser
c. Maintain a constant level in the receiver
d. Regulate the cooling water to the condenser
e. Meter the flow of refrigerant to the evaporator in response to the evaporator load






Answer: E
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