Paper

TIP SHEET:

January 2013

Tips to Increase Efficiency and Heat Recovery in a Boiler System

As boilers age, they become less efficient. Here are a number of ways a facility can increase boiler efficiency to reduce operating costs: 1. Keep up with annual boiler maintenance – Maintaining a boiler according to manufacturer recommendations is the simplest way to ensure it will continue to run efficiently. Proper water treatment – Check that the boiler system water is treated properly. Particulates clog up internal boiler tubes, and over time the system loses its heat transfer ability. In most applications, a deaerator is a good solution. It can increase the water temperature to 227° F and remove a lot of the particulates from the water. Install a high-turndown burner – Increasing the burner turndown rate will increase energy savings and reduce maintenance. Energy savings increases when on-off cycles are reduced. Each on-off cycle is followed by a purge cycle. During a purge cycle, a large volume of air passes through the boiler, resulting in heat being blown out of the stack. Installing a high-turndown burner enables a boiler to consistently run at its most efficient point. Add VSD controls – Installing variable speed drives (VSDs) on boiler feed or deaerator pumps allows an operator to fine-tune the system to run at optimal conditions, while saving energy. This is because VSDs enable a motor to operate only at the speed needed at a given moment. Incorporate parallel positioning – Adding parallel positioning to a boiler enables it to run at its most capable efficiency point. Parallel positioning uses dedicated actuators for the fuel and air valves. Burners that incorporate parallel positioning are able to maintain excess air levels more precisely. Include O2 trim – Another way to maintain peak efficiency is to add an oxygen sensor/transmitter in the exhaust gas. The sensor/transmitter continuously senses oxygen content and provides a signal to the controller that trims...