# Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

Discussion Forum : Heat Transfer, Refrigeration and Air Conditioning - Section 6 (Q.No. 1)

1.

A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be

Discussion:

25 comments Page 1 of 3.
Kajal Patil said:
4 years ago

3 is the correct Answer.

(2)

Swagat said:
5 years ago

COP = (120-30)/30.

= 3.

= 3.

(2)

Pratheesh said:
4 years ago

The Answer should be 3.

(1)

Vinay BEL said:
4 years ago

120 - 30 = 90.

Cop=90/30=3 => answer.

Cop=90/30=3 => answer.

(1)

Swapnil Shelke said:
5 years ago

I also agree with the answer 3 as here COP of the refrigeration system is asked clearly here REFRIGERATING EFFECT is 90 and work input 30.

(1)

S Kamran said:
5 years ago

Answer will be 3..

120kw is heat rejected(not R.E)by the condenser that heat is the sum of Refrigeration effect(R.E)& The heat added by compressor work.. & COP= R.E/Work Input. So the final answer will be COP=(120-30)/30=3.

120kw is heat rejected(not R.E)by the condenser that heat is the sum of Refrigeration effect(R.E)& The heat added by compressor work.. & COP= R.E/Work Input. So the final answer will be COP=(120-30)/30=3.

(1)

Prabhat swain said:
7 years ago

@Rakesh Thakur.

Output/input not COP.

This is efficiency.

COP is the reciprocal of efficiency.

Output/input not COP.

This is efficiency.

COP is the reciprocal of efficiency.

Amaan Sayyed said:
4 years ago

120/30=4 this is the right answer.

Zeeshan said:
6 years ago

Point to ponder is whether the COP of the heat pump is asked or COP of the Refrigeration system. The question doesn't define the fact categorically. Assuming heat pump answer is 4, of we assume COP of refrigeration system then given answer is wrong and it must be 3.

Vishnu said:
6 years ago

The answer is 3.

Here 120 is the heat rejected to the atmosphere, not the heat absorbed from the refrigerated space.

120 - 30 is the heat absorbed from the refigerated space.

The Work input is 30.

Here 120 is the heat rejected to the atmosphere, not the heat absorbed from the refrigerated space.

120 - 30 is the heat absorbed from the refigerated space.

The Work input is 30.

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