Boiler

A boiler is an enclosed vessel that provides a means for combustion heat to be transferred into water until it becomes steam.  The steam thus produced which is under pressure is then used for heating in the process or to generate power in the turbine.  Steam is a useful and cheap medium for transferring heat to a process. When water is boiled into steam its volume increases about 1,600 times. This causes the boiler to be extremely dangerous equipment that must be treated with utmost care.

The performance of a boiler, which include thermal efficiency and evaporation ratio (or steam to fuel ratio), deteriorates over time due to poor combustion, fouling of heat transfer area, and inadequacies in operation and maintenance. Other reasons such as inferior fuel quality, water quality etc. can result in poor boiler performance.  

For energy saving tips

https://www.eec-fncci.org/page/saving-tips

Link to e-learning course