Explanation:

The working fluid in a vapor compression refrigeration system undergoes several processes as it moves through the various components of the system. One of these processes is the superheating of the refrigerant vapor.

Definition of Superheat:
Superheating refers to the process of raising the temperature of a vapor above its saturation temperature while maintaining its pressure constant. In a refrigeration system, this can be achieved by adding heat to the vapor after it has left the evaporator but before it enters the compressor.

Components of a Vapor Compression Refrigeration System:

A vapor compression refrigeration system typically consists of four main components:

1. Evaporator:
The evaporator is responsible for absorbing heat from the refrigerated space and evaporating the refrigerant. It acts as a heat exchanger where the low-pressure liquid refrigerant absorbs heat from the surroundings and evaporates into a low-temperature vapor.

2. Compressor:
The compressor is the heart of the refrigeration system. It is responsible for increasing the pressure and temperature of the refrigerant vapor. The compressor draws in the low-pressure vapor from the evaporator and compresses it to a high-pressure, high-temperature vapor.

3. Condenser:
The condenser is a heat exchanger that removes heat from the compressed refrigerant vapor and converts it back into a liquid state. It is typically located outside the refrigerated space and transfers the heat absorbed by the refrigerant to the surroundings.

4. Expansion Valve:
The expansion valve is responsible for reducing the pressure and temperature of the liquid refrigerant coming out of the condenser. It controls the flow of the refrigerant into the evaporator, allowing it to expand and absorb heat from the surroundings.

Superheating in the Condenser:

In a vapor compression refrigeration system, the working fluid is superheated vapor at the entrance to the condenser. This superheating occurs because the refrigerant vapor leaves the evaporator at a low temperature and pressure, but it is compressed by the compressor, which increases its temperature and pressure.

Why Option B is the Correct Answer:

The working fluid is superheated vapor at the entrance to the condenser because the compression process in the compressor raises the temperature and pressure of the refrigerant vapor. This superheating is necessary to ensure efficient heat transfer in the condenser and to prevent liquid refrigerant from entering the compressor, which could cause damage to the compressor.

Therefore, the correct answer is option B, the condenser, where the working fluid is superheated vapor at its entrance.