# Coefficient of performance (C.O.P) - Basic Mechanical Engineering

Q.  Which of the following relations is true, for coefficient of performance (C.O.P)?
- Published on 02 Sep 15

a. (C.O.P)heat pump – (C.O.P)refrigerator = 1
b. (C.O.P)heat pump – (C.O.P)refrigerator > 1
c. (C.O.P)heat pump – (C.O.P)refrigerator < 1
d. (C.O.P)heat pump – ( C.O.P)refrigerator = 0

ANSWER: (C.O.P)heat pump – (C.O.P)refrigerator = 1

#### Discussion

• Sravanthi    -Posted on 12 Nov 15
- Coefficient of performance is defined as the ratio of desired effect and energy input.

- According to first law of thermodynamics,

W = Q1 – Q2

here, Q1 = heat received, Q2 = rejected heat

- C.O.P for refrigerator is given as Q2 / W = Q2 / ( Q1 - Q2 )

- C.O.P for heat pump is given as Q1 / W = Q1 / (Q1 - Q2 )

- (C.O.P)heat pump – (C.O.P)refrigerator = 1

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