Higher efficiency during the regeneration process in ‘Rankine cycle’ is because of: 

Explanation:

Concept of Regeneration in the Rankine cycle:

• Regeneration means to take some part of the heat from the expanding steam in the turbine to decrease the overall heat supplied in the process.
• The thermal efficiency of the Rankine cycle can be increased by the use of a regenerative heat exchanger.
• In the regenerative cycle, a portion of the partially expanded steam is drawn off between the high and low-pressure turbines.
• The steam is used to preheat the condensed liquid before it returned to the boiler.
• In this way, the amount of heat added at the low temperatures is reduced and the mean effective temperature of heat addition is increased, thus cycle efficiency is increased.
• At point 2 some amount of steam is taken out for the heating purpose of water.

Effect of Regeneration:

• Decrease in turbine work due to a decrease in the mass flow rate of steam.
• Decrease in heat rejection in condenser due to a reduction in mass flow rate.
• Increased of efficiency and mean temperature of heat addition (T_m).