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Boiler Stack Economizer

Boiler Stack Economizers Maximize Fuel Usage


Natural gas prices have increased recently and are projected to continue to rise over the coming months. The addition of a boiler stack economizer is one way to reduce fuel usage and cost in your boiler room. Stack economizers recover heat from exhaust gases that would otherwise vent out to the atmosphere and wasted. Reclaiming wasted energy increases the overall efficiency of the boiler system.

What is a Stack Economizer?

A stack economizer is a heat exchanger that transfers heat from flue gases to the boiler feedwater. The boiler feedwater is piped through finned tubes that are placed in the path of the hot flue gases. Economizers are usually located directly above the stack outlet of the boiler.

How Does an Economizer Work?

Steam boilers require a large amount of fuel to raise the temperature of the incoming feedwater to its boiling point. In a conventional steam boiler system, boiler feedwater is pumped directly from the deaerator to the boiler. Routing the water from the deaerator, through an economizer, and then to the boiler allows the feedwater to capture waste heat from the flue gases. Reclaiming the additional heat raises the feedwater temperature and reduces the boiler’s fuel/energy requirements. 


New and Used Boilers– Selecting an economizer when purchasing a new boiler is a great way to maximize savings. The stack design, economizer supports, feedwater piping, and overall boiler room layout can be designed around the selected economizer. A new economizer is also a great addition to an existing boiler system. A retrofit economizer installation is a great way to increase the overall efficiency of an existing boiler by taking advantage of the energy that is currently being wasted. Space is often limited in existing boiler rooms, however, there are many different economizer designs (vertical and horizontal), sizes, and styles to accommodate these limitations.

Single Stage & Two-Stage Economizers-In applications where a high percentage of make-up water is used, a two-stage economizer can be incorporated. The two-stage design incorporates two separate coil sections. The first stage of the two-stage economizer heats the boiler feedwater. The second stage reclaims additional heat that is used to heat the incoming makeup water feeding the deaerator. The two-stage economizer is a condensing model and can only be used in specific applications, but can achieve boiler efficiencies up to 94%.  Both economizer designs can be utilized for boilers up to 2,500 horsepower. 

Economizers Save:

A new economizer is a great way to save money by increasing boiler system efficiency. Economizers can often reduce fuel consumption and typically have a short return on investment (ROI). We represent the entire line of Cleaver-Brooks Boiler Economizers.   Contact Boiler Supply Co. for system analysis and see if an economizer is fit for your boiler room.

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