Effect of evaporator temperature on performance: If condenser temperature is held constant, how does the refrigeration cycle COP change as the evaporator temperature increases?

Introduction / Context:
The coefficient of performance (COP) of a vapour-compression system depends strongly on the evaporating and condensing temperatures. Understanding these trends informs set-point selection and defrost strategies.

Given Data / Assumptions:

• Condenser temperature (or pressure) is fixed.
• Evaporator temperature is increased (warmer evaporator).
• Same refrigerant and general cycle configuration.

Concept / Approach:
For idealized cycles, COP_R increases as the temperature lift (T_cond − T_evap) decreases. Raising the evaporator temperature reduces this lift and increases the ratio of cooling effect to compressor work.

Step-by-Step Solution:

Verification / Alternative check:
For a simple ideal cycle, COP_R ≈ T_L / (T_H − T_L) on absolute scale. Increasing T_L while T_H constant increases COP_R.

Why Other Options Are Wrong:

“No/unchanged” contradicts the standard dependence on temperature lift.Non-monotonic or zero COP outcomes do not apply here.

Common Pitfalls:
Comparing COP across different refrigerants or mixing Celsius and absolute temperatures; always use absolute temperatures in theoretical relations.

Final Answer:

Yes