Where is refrigerant temperature highest in a mechanical refrigeration system? Identify the line location with the maximum refrigerant temperature.

Introduction / Context:
Locating peak temperatures in a vapour-compression system helps in material selection, oil life assessment, and safety (e.g., avoiding decomposition of certain refrigerants).

Given Data / Assumptions:

• Single-stage compressor without inter-cooling.
• Negligible pressure losses in lines for conceptual answer.
• Condensation occurs downstream at higher pressure.

Concept / Approach:
Compression raises both pressure and temperature. The hottest point occurs at the compressor discharge, before the refrigerant rejects heat in the condenser.

Step-by-Step Solution:
Compressor inlet: low-pressure vapour at low temperature.Compression: temperature rises sharply due to work input.Discharge line: peak temperature exists here before any heat rejection.Condenser: gas cools and condenses, reducing temperature thereafter.

Verification / Alternative check:
T–s or p–h diagrams show the highest temperature at the end of the compression stroke for both ideal and real cycles.

Why Other Options Are Wrong:
(A) Evaporator outlet is cool; (B) liquid before throttling is at saturation or sub-cooled, not the hottest; (D) liquid line is cooler; (E) receiver contains saturated or sub-cooled liquid at condenser pressure, cooler than discharge gas.

Common Pitfalls:
Confusing “highest pressure” with “highest temperature”: while both occur at discharge, the key is the state before heat rejection starts.

Final Answer:
Between the compressor discharge and the condenser inlet (discharge line)