Answer to Question #87610 in Molecular Physics | Thermodynamics for Chirag dash

Question

Carnot refrigeration cycle absorbs heat at 280k and rejects heat at 310k.
a: Calculate the coefficient of performance of this refrigeration cycle.
b: If the cycle is absorbing 1120KJ/min at 280k, how many KJ work is required per second .
C: If the carnot heat pump operates between the same temperature as the above refrigerator, what is the coefficient of performance ?
d: How many KJ/min will the heat pump deliver at 310k if it absorb 1120 KJ/min at 280k.

Answer 1

a: Calculate the coefficient of performance of this refrigeration cycle.

Solution:

For Carnot refrigerator cycle:

$$COP_R = \frac {T_L}{{T_H - T_L}} (1)$$

Using (1) we got: COP_R=9.34

Answer:

COP_R=9.34

b: If the cycle is absorbing 1120KJ/min at 280k, how many KJ work is required per second

Solution:

The COP of a refrigerator is given by the following equation:

$$COP_R=\frac {Q_L}{W_i} (2)$$

Using (2) we got:

$$W_i=\frac {Q_L}{COP_R} (3)$$

$$W_i=\frac {1120}{60\times 9.34}=2KJ$$

Answer:

2KJ

C: If the carnot heat pump operates between the same temperature as the above refrigerator, what is the coefficient of performance ?

$$COP_P=\frac {T_H}{T_H - T_L} (4)$$

Using (4) we got: COP_P=10.33

Answer:

10.33

d: How many KJ/min will the heat pump deliver at 310k if it absorb 1120 KJ/min at 280k.

$$COP_P=\frac {Q_H}{W_i} (5)$$

Using (5) we got:

$$Q_H = COP_P \times W_i (6)$$

Q_H= 11570 KJ/min

Answer:

11570 KJ/min