How does the efficiency of a boiler change with a rise in feedwater temperature?

The efficiency of a boiler increases with a rise in feedwater temperature because warmer feedwater requires less energy to convert into steam. When the temperature of the feedwater is higher, the heating process in the boiler is more efficient, allowing the heat generated from the combustion process to be used more effectively. This means that the energy input is being utilized more efficiently to produce steam, which translates to better overall boiler efficiency.

In addition, a higher feedwater temperature can help reduce the amount of fuel needed to achieve the same steam output, since less energy is lost in heating cooler feedwater. This results in a lower stack temperature and reduced flue gas losses, further enhancing the efficiency of the boiler. Overall, managing feedwater temperature is an important aspect of optimizing boiler performance and energy consumption.