Ammonia vapour-compression system: The liquid line temperature rise between the condenser outlet and the expansion valve should be kept as low as possible. State whether this is advisable.

Introduction / Context:
In vapour-compression refrigeration, the liquid leaving the condenser should reach the expansion device with minimal heat pickup. Excessive liquid-line temperature rise increases flash gas and reduces evaporator effectiveness.

Given Data / Assumptions:

• Working fluid: ammonia (NH3), but the reasoning holds for most refrigerants.
• Condenser outlet provides subcooled liquid.
• Liquid line transfers refrigerant to the expansion device.

Concept / Approach:
Any heat gained in the liquid line partially cancels condenser subcooling. At the throttling device, higher inlet temperature promotes flash gas formation, reducing the mass of liquid available to evaporate and thus lowering net cooling capacity.

Step-by-Step Solution:
Goal: maximize liquid quality at the expansion device to reduce flash gas.Minimize heat pickup in the liquid line by insulation, short routing, and avoiding hot zones.If liquid subcooling is preserved, the evaporator receives more liquid refrigerant, increasing capacity and stability.

Verification / Alternative check:
Compare two cases: with and without liquid-line heat gain. The case with lower line temperature yields higher mass of liquid after throttling and better evaporator utilization.

Why Other Options Are Wrong:

• “No” and conditional options: Good practice is to keep the liquid line as cool as practical regardless of ambient; it is not limited to capillary-tube systems.

Common Pitfalls:
Confusing beneficial condenser subcooling (inside the condenser) with unwanted liquid-line heat pickup; both affect inlet state to the expansion device but in opposite directions.

Final Answer:
Yes