Question
Explain how Carnot's cycle works with the heat flow diagram. Using the same, explain the working of a refrigerator. Also, give its coefficient of performance.
✓
Answer
Refrigerator absorbs heat from the body at a low temperature and liberates it to a body at a high temperature by doing work. It can be shown by the given diagram.
Q2→ Energy absorbed from sink.
Q1 → Energy liberated to source.
W → Work done on the system.
Coefficient of performance $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}$
Q1 – Q2 refers to the work done on the system/refrigerator.
Coefficient of performance (COP) $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}=\frac{\text{T}_2}{\text{T}_1-\text{T}_2}$
Refrigerator: It works in the reverse Carnot's cycle. Heat is absorbed from sink at low temperature T2 and given to the source at higher temperature T1 with the help of an external agency doing work on the system. (W = Q1 - Q2).
The compressor in the refrigerator uses electrical energy and does work on the system. The coefficient of performance is defined as the heat energy absorbed from low temperature sink Q2 to the amount of work done.
$\text{W}=\text{Q}_1-\text{Q}_2$
$\text{COP}=\frac{\text{Q}_2}{\text{Q}_1-\text{T}_2}=\frac{\text{T}_2}{\text{T}_1-\text{T}_2}$
Q2→ Energy absorbed from sink.
Q1 → Energy liberated to source.
W → Work done on the system.
Coefficient of performance $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}$
Q1 – Q2 refers to the work done on the system/refrigerator.
Coefficient of performance (COP) $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}=\frac{\text{T}_2}{\text{T}_1-\text{T}_2}$
Refrigerator: It works in the reverse Carnot's cycle. Heat is absorbed from sink at low temperature T2 and given to the source at higher temperature T1 with the help of an external agency doing work on the system. (W = Q1 - Q2).
The compressor in the refrigerator uses electrical energy and does work on the system. The coefficient of performance is defined as the heat energy absorbed from low temperature sink Q2 to the amount of work done.
$\text{W}=\text{Q}_1-\text{Q}_2$
$\text{COP}=\frac{\text{Q}_2}{\text{Q}_1-\text{T}_2}=\frac{\text{T}_2}{\text{T}_1-\text{T}_2}$
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