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. $Q_2 \rightarrow$ Energy absorbed from sink. $Q_1 \rightarrow$ Energy liberated to source. $W \rightarrow$ Work done on the system.
Coefficient of performance $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}$
$Q_1 – Q_2$ 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 $T_2$ and given to the source at higher temperature $T_1$ with the help of an external agency doing work on the system. $(W = Q_1 - Q_2)$.
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 $Q_2$ to the amount of work done. $\text{W}=\text{Q}_1-\text{Q}_2$ $\text{COP}=\frac{\text{Q}_2}{\text{Q}_1-\text{T}_2}=\frac{\text{T}_2}{\text{T}_1-\text{T}_2}$
Coefficient of performance $=\frac{\text{Q}_2}{\text{Q}_1-\text{Q}_2}$
$Q_1 – Q_2$ 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 $T_2$ and given to the source at higher temperature $T_1$ with the help of an external agency doing work on the system. $(W = Q_1 - Q_2)$.
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 $Q_2$ 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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