Answer & Solution
Answer: Option B
Solution:
Rankine efficiency is a measure of how well a steam power plant converts heat into electricity.
The efficiency is affected by the temperature of the steam and the temperature of the cooling water that condenses the steam back into water.
In winter, the cooling water (often from a river or lake) is colder.
A colder cooling water temperature leads to a lower condenser pressure.
A lower condenser pressure increases the net work output of the cycle.
This ultimately increases the Rankine efficiency.
In summer, the cooling water is warmer, so the efficiency is lower.
Therefore, the Rankine efficiency is better in winter than in summer.