Question
What is a refrigerator? Draw a schematic representation of a refrigerator.
✓
Answer
A refrigerator or a heat pump is a heat engine working in reverse direction.
In the refrigerator, we have 2 bodies, lower temperature (cold) body which is freezer and higher temperature (hot) body which is surroundings. It takes heat from the cold reservoir and then some work is done on the refrigerator and then the amount of heat is transferred to the hot reservoir. Let $Q _2$ be the heat takes from the cold reservoir, W is the work done on the system and then releases $Q _1$ amount of heat to the hot reservoir.
Mathematically, $Q _2+ W = Q _1$
The schematic representation of a refrigerator has been shown in the following Figure. Here the refrigerator extracts heat $Q _2$ from a cold reservoir at temperature $T_2$, work $W$ is done on it and finally, it rejects $Q_1\left(=Q_2+W\right)$ heat to surroundings (hot reservoir) maintained at a higher temperature $T _1$.
The efficiency of the refrigerator can be calculated from the coefficient of performance of the refrigerator, $\alpha=\frac{Q_2}{Q_1-Q_2}$
In the refrigerator, we have 2 bodies, lower temperature (cold) body which is freezer and higher temperature (hot) body which is surroundings. It takes heat from the cold reservoir and then some work is done on the refrigerator and then the amount of heat is transferred to the hot reservoir. Let $Q _2$ be the heat takes from the cold reservoir, W is the work done on the system and then releases $Q _1$ amount of heat to the hot reservoir.
Mathematically, $Q _2+ W = Q _1$
The schematic representation of a refrigerator has been shown in the following Figure. Here the refrigerator extracts heat $Q _2$ from a cold reservoir at temperature $T_2$, work $W$ is done on it and finally, it rejects $Q_1\left(=Q_2+W\right)$ heat to surroundings (hot reservoir) maintained at a higher temperature $T _1$.
The efficiency of the refrigerator can be calculated from the coefficient of performance of the refrigerator, $\alpha=\frac{Q_2}{Q_1-Q_2}$
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