Two stage boiler stack economizer

Two Stage Boiler Stack Economizer

The 2 stage boiler stack economizer is perfect for any NYC building with a heating system of 150HP or larger.

In short, a 2 stage boiler stack economizer is one energy saving device that pre-heats 2 different water applications.

1) The two stage economizer’s first (noncondensing) stage, heats the water from the feed system before entering the boiler.

2) The second stage (usually in a condensing stage) can be used for a variety of applications.  The cold makeup water, heating it before it enters either the vented feedwater tank or the deaerator.  The second stage can be used for heating domestic hot water, pool water, or other hot water applications.

Condensing Info

Two stage stack economizers are usually “condensing economizers” meaning, the hot exhaust is captured and reused, so effectively, that some of the hot exhaust hits it’s “dew point.”   Which means, some of the gases turn to acidic water vapor.   So, this second stage (like all condensing economizers) must be constructed of stainless steel (or better) as these products encounter corrosive water during normal operation.  

Sizing Requirements

Two stage boiler economizers can come either a cylindrical or squared shape design, a great energy reduction plan for any NYC building with a boiler 150HP or larger.

Efficiency Gains

These products create an 3‐5% efficiency gain depending on the cold water temperature and mass flow.  The lower the temperature, and the more the flow means higher efficiency gains approximating another 3‐5%;  additive to the 2‐4% gained in the first or non‐condensing stage.

The rule of thumb to keep in mind is that based on a consistent firing rate, operating pressure and constant ambient temperature, for every 40 degrees the stack temperature is reduced, it’s a full 1% point of fuel savings.

The Bottom Line

A two stage stack economizer can be a very effective way of putting this money back in your pocket.  When working with our professional consultants, the savings are a sure thing, often increasing the boiler’s efficiency by 5‐9% depending on feedwater conditions.

Condensing boiler economizer quotes NYC
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Give us a call to learn more.  800.524.4280