The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by (T₁ - T₂)/T₁. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)_R and the co-efficient of performance as a heat pump (COP)_HP are

A

(COP)_R = (COP)_HP = 0.6

B

(COP)_R = 2.5; (COP)_HP = 1.5

C

(COP)_R = 1.5; (COP)_HP = 2.5

D

(COP)_R = (COP)_HP = 2.5

The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by (T₁ - T₂)/T₁. The co-efficient of performance (CO.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

A

T₁/(T₁-T₂)

B

T₂/(T₁-T₂)

C

T₁/T₂

D

T₂/T₁

The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by $$\frac{{{{\text{T}}_1} - {{\text{T}}_2}}}{{{{\text{T}}_1}}}.$$ The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

A

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_1} - {{\text{T}}_2}}}$$

B

$$\frac{{{{\text{T}}_2}}}{{{{\text{T}}_1} - {{\text{T}}_2}}}$$

C

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}}$$

D

$$\frac{{{{\text{T}}_2}}}{{{{\text{T}}_1}}}$$

The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by $$\frac{{{{\text{T}}_1} - {{\text{T}}_2}}}{{{{\text{T}}_1}}}.$$ The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

A

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_1} - {{\text{T}}_2}}}$$

B

$$\frac{{{{\text{T}}_2}}}{{{{\text{T}}_1} - {{\text{T}}_2}}}$$

C

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}}$$

D

$$\frac{{{{\text{T}}_2}}}{{{{\text{T}}_1}}}$$

A Carnot heat engine receives heat at 750 K and rejects the waste heat to the environment at 300 K. The net work output of the heat engine is used to drive a Carnot refrigerator, whose COP is 6.14. If the heat removal rate from the refrigerated space is 6.6 kW, determine the rate of heat supply to the heat engine?

A

2.79 kW

B

1.79 kW

C

4.79 kW

D

7.79 kW

Consider the following statements: 1. The entropy of a pure crystalline substance at absolute zero temperature is zero. 2. the efficiency of a reversible heat engine is independent of the nature of the working substance and depends only on the temperature of the reservoirs between which it operates. 3. Carnot’s theorem states that of all heat engines operating between a given constant temperature source and a given constant temperature sink, none has a higher efficiency than a reversible engine Which of the above statements are correct?

A

1 and 2 only

B

1 and 3 only

C

2 and 3 only

D

1, 2 and 3

A heat pump is used to meet the heating requirements of a house and maintain it at 20°C. On a day when the outdoor air temperature drops to 2°C, the house is estimated to lose heat at a rate of 80,000 kJ/h. If the heat pump under these conditions has a COP of 2.5, determine the power consumed by the heat pump.

A

32000 kJ/h

B

33000 kJ/h

C

34000 kJ/h

D

35000 kJ/h

For absolute chamber gas temperature Tg, absolute liquid temperature Tl, absolute wall temperature on the gas side of the wall Twg, overall film coefficient h, gas film coefficient hg and liquid film coefficient hl, determine the expression for heat transferred per unit area q.

A

q = hl (To – Twg)

B

q = h (To – Twg)

C

q = hg (To – Twg)

D

q = hg/h (Twg – To)

A reversed Carnot cycle is operating between temperature limits of (-) 33°C and (+) 27°C. If it acts as a heat engine gives an efficiency of 20%. What is the value of C.O.P. of a heat pump operating under the same conditions?

A

6.5

B

8

C

5

D

2.5

The following heat engine produces power of 100000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is

A

100, 000 kW

B

160, 000 kW

C

200, 000 kW

D

320, 000 kW

The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by (T₁ - T₂)/T₁. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T₁ and T₂ is given by

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