Which type of turbine has better thermal efficiency?

Condensing turbines are known for their higher thermal efficiency compared to non-condensing turbines. This is primarily because condensing turbines operate by exhausting steam into a condenser, enabling the system to create a vacuum. The vacuum lowers the pressure in the turbine, allowing for more energy extraction from the steam compared to non-condensing turbines, which exhaust steam at atmospheric pressure.

In a condensing turbine, the steam expands fully through the turbine, converting more of its thermal energy into mechanical energy, which ultimately translates into better electrical generation efficiency. The ability to effectively condense the steam also allows for the reclamation of more thermal energy from the steam cycle, improving the overall efficiency of the cycle.

On the other hand, non-condensing turbines do not use a condenser, which limits their thermal efficiency because they release steam at a higher pressure rather than maximizing energy extraction from the steam. Heat recovery turbines, while important for utilizing waste heat, do not inherently operate at a higher thermal efficiency than condensing turbines in the context of converting steam energy to mechanical energy.

Thus, condensing turbines indeed provide a significant advantage in thermal efficiency.