Question

Consider the following processes; arrange them in the order as performed in a vapor compression refrigeration cycle
(A) Compression
(B) Evaporation
(C) Condensing
(D) Throttling
Choose the correct answer from the options given below:

• A. (A), (D), (C), (B).
• B. (A), (C), (D), (B).
• C. (C), (A), (D), (B).
• D. (C), (B), (D), (A).

Hint:

To remember the sequence, sketch the schematic of a refrigeration system or remember the standard components in order: Compressor \(\rightarrow\) Condenser \(\rightarrow\) Expansion Valve \(\rightarrow\) Evaporator. This corresponds to Compression \(\rightarrow\) Condensing \(\rightarrow\) Throttling \(\rightarrow\) Evaporation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The standard Vapor Compression Refrigeration System (VCRS) operates on a closed thermodynamic loop consisting of four primary components: a compressor, a condenser, an expansion (throttling) valve, and an evaporator.

Step 2: Detailed Explanation:
Let us trace the path of the refrigerant through the complete thermodynamic cycle, starting from the compressor inlet:

1. Compression (A): Low-pressure, low-temperature superheated vapor from the evaporator enters the compressor.
The compressor compresses the vapor, raising its pressure and temperature, and discharges high-pressure, high-temperature superheated vapor.

2. Condensing (C): This high-pressure, hot vapor flows into the condenser, where it rejects heat to the surrounding cooling medium (air or water).
As it rejects heat, it condenses into a high-pressure liquid.

3. Throttling (D): The high-pressure liquid passes through a throttling device (such as an expansion valve or capillary tube).
This is an isenthalpic expansion process where the pressure and temperature of the refrigerant drop significantly, turning it into a low-temperature, low-pressure mixture of liquid and vapor.

4. Evaporation (B): The low-temperature mixture enters the evaporator, where it absorbs heat from the space being cooled.
This heat absorption causes the liquid refrigerant to evaporate, turning back into low-pressure vapor, which then returns to the compressor to repeat the cycle.
Therefore, the sequence of processes is Compression (A) \(\rightarrow\) Condensing (C) \(\rightarrow\) Throttling (D) \(\rightarrow\) Evaporation (B).

Step 3: Final Answer:
The correct order is (A), (C), (D), (B), which corresponds to Option (B).