Question

The ratio of heat extracted in the refrigerator to the work done on the refrigeration known as...............

• A. Coefficient of Performance of refrigeration
• B. Tonne of refrigeration
• C. Refrigeration efficiency
• D. Coefficient performance of a heat pump

Hint:

Do not confuse the COP of a refrigerator with the COP of a heat pump:
- For a Refrigerator: \( COP_{\text{ref}} = \frac{Q_L}{W} \)
- For a Heat Pump: \( COP_{\text{HP}} = \frac{Q_H}{W} = COP_{\text{ref}} + 1 \)
This is a standard thermodymics relationship often tested in exams.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A refrigeration system operates on a thermodymic cycle that transfers heat from a low-temperature region to a high-temperature region.
Unlike heat engines, which produce work output, refrigeration systems require exterl work input to drive this heat transfer against the tural temperature gradient.
Key Formula or Approach:
The performance of a refrigeration system is evaluated using the Coefficient of Performance (\( COP \)), expressed as:
\[ COP_{\text{ref}} = \frac{Q_L}{W_{\text{net}}} \]
where \( Q_L \) is the heat extracted from the refrigerated space and \( W_{\text{net}} \) is the net work input required by the compressor.

Step 2: Detailed Explation:
The efficiency of most thermal devices is defined as the ratio of the desired output to the required input.
For a refrigerator, the desired output is the cooling effect (the amount of heat extracted, \( Q_L \)), and the required input is the electrical or mechanical work (\( W \)) supplied to the compressor.
Because the heat extracted is often greater than the work supplied, this ratio can be greater than 1.
As a result, the term "efficiency" (which is thermodymically capped at 1 or 100%) is not used.
Instead, this performance ratio is defined as the Coefficient of Performance (COP) of refrigeration.
A higher COP indicates a more energy-efficient refrigeration system.
A Tonne of refrigeration is a unit of cooling capacity, not a performance ratio.

Step 3: Fil Answer
The ratio of heat extracted in the refrigerator to the work input is defined as the Coefficient of Performance of refrigeration.