What is it?
Steam boilers, often used in industrial processes or for space heating in large facilities, are a major source of gas usage in the United States. Many steam boilers use technology over 100 years old and have efficiencies of 80% or less. New “super boilers” have the ability to reach fuel-to-steam efficiencies of about 94%.
How does it work?
A super boiler system is actually a collection of various energy-saving technologies. It has several stages of economizers to recover heat and water vapor from the boiler stack gas. Water vapor alone can account for 2/3 of the wasted heat in a standard boiler system. Super boilers also have extended-surface fire tubes that efficiently transfer more heat from the burner for steam production. Extended-surface fire tubes have 18-times the heat transfer of standard fire tubes. The boiler burner is also optimized to provide the ideal air-to-fuel mixture for combustion, wasting very little fuel.
What are the most appropriate applications?
The best applications are industrial processes that operate 24/7, where the existing boiler is at the end of its useful life. Industries that typically have high steam usage include paper, chemical, refining, and food. Steam systems used for space heating may also be a good application if there are long operating hours.
What are the savings?
One test installation in an industrial rubber production facility demonstrated a 13% reduction in natural gas usage.
What are the non-energy benefits?
Super boilers have an equipment footprint that is 35-50% smaller than standard boilers due to the superior heat transfer capabilities of the internal fire tubes. They also have extremely low emissions and can comply with stringent environmental standards.
What is the cost and availability?
Reliable cost data is not available as this technology is in the prototype phase and is not yet being mass produced. Some of the individual technologies included in a super boiler system, such as a boiler economizer, are widely available and can provide the same benefits.
What kinds of incentives/programs are available?
This technology would be evaluated in Custom Rebate programs due to the size and likelihood that the boiler system would involve unique industrial processes.