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Heat Transfer Operations Mcqs

Q:

What is the relation between heat rejection ratio (HRR) and Coefficient of performance (COP)?

A) HRR = 1 + 1/COP B) HRR = 1+ COP
C) HRR = COP/2 D) HRR = 1/COP
 
Answer & Explanation Answer: A) HRR = 1 + 1/COP

Explanation: Not available for this question

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43
Q:

What is the meaning of heat rejection ratio (HRR) of a condenser?

A) Ratio of heat rejected to the heat absorbed B) Ratio of heat absorbed to the heat rejected
C) Ratio of heat required to the heat lost D) Ratio of heat wasted in a cycle to the heat absorbed
 
Answer & Explanation Answer: A) Ratio of heat rejected to the heat absorbed

Explanation: Not available for this question

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61
Q:

Evaporative condensers are used in places where water is _________

A) Scarce B) Plenty
C) Moderately available D) Sufficient
 
Answer & Explanation Answer: A) Scarce

Explanation: Evaporative condensers are used in places where water is scarce or limited. Since water is used in a closed setup, only a small part of the water evaporates while the rest is retained and hence the cooling towers and water-cooled condenser in a single unit are used together to minimise the water loss.

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43
Q:

Evaporative condensers combine the features of a _____________ in a single unit.

A) Cooling tower and water-cooled condenser B) Falling tower and water-cooled condenser
C) Cooling tower and Air condenser D) Rising film tower and water-cooled condenser
 
Answer & Explanation Answer: A) Cooling tower and water-cooled condenser

Explanation: Evaporative condensers are used in places where water is scarce or limited. Since water is used in a closed setup, only a small part of the water evaporates while the rest is retained and hence the cooling towers and water-cooled condenser are used together to minimise the water loss.

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38
Q:

In evaporative condensers, ___________ used to extract heat from the condensing refrigerant.

A) Air is B) Both air and water are
C) Water is D) Either air or water is
 
Answer & Explanation Answer: B) Both air and water are

Explanation: In evaporative condensers, the two mediums undergoing evaporation and heating are water and air, hence the setup should always have water and air both simultaneously.

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36
Q:

In a shell and coil type water cooled condenser, the refrigerant is passed through the ________

A) Coil B) Shell
C) Tube D) Annulus
 
Answer & Explanation Answer: B) Shell

Explanation: The refrigerant having lesser pressure drop is always considered to be kept at the annulus side of the double pipe setup, hence the cooling water in the inner tube as it faces larger pressure drops and in the tube side of as Shell-and-tube type setup.

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62
Q:

In the double pipe setup of the water-type condenser, the cold water flows in the ___________

A) Shell B) Annulus
C) Inner Tube D) Jacket
 
Answer & Explanation Answer: C) Inner Tube

Explanation: The refrigerant having lesser pressure drop is always considered to be kept at the annulus side of the double pipe setup and hence the cooling water in the inner tube as it faces larger pressure drops.

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70
Q:

Double pipe water cooling condensers have a capacity at around ________

A) 10 TR B) 20 TR
C) 30 TR D) 50 TR
 
Answer & Explanation Answer: A) 10 TR

Explanation: Double pipe water cooling condensers owing to its tube-in-tube setup with small area and good pressure drop handling ability, does not have a very large cooling capacity if used in a refrigeration system, hence the minimum of all the options is correct.

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