No matter what your fuel source, every boiler runs on heat. That’s what converts the water to steam, and the steam to warmth and work. The more efficiently you can use that heat, the less you’ll end up paying for fuel. Another way to look at it is, the hotter your exhaust stack, the more energy you’re wasting every day your boiler runs. Because if that heat is just venting out into the atmosphere, it isn’t doing you any good. That’s where an economizer comes in.
Take Another Pass At It
An economizer captures unused heat before it can escape into the atmosphere, then puts it back to work for you. It does this by routing your exhaust through a heat exchanger that, in turn, transfers the heat to the boiler’s feedwater supply. Since the heat pre-warms the feedwater, the burner will have less work to do converting it to steam. In the end, you’ll have more usable steam in less time, with less fuel required.
At some point after installation, an economizer will have saved enough in fuel costs to pay for itself. Every minute your boiler runs after that is just pure savings. When that payback point occurs depends on the size and model of your boiler system, but nearly every system out there that operates at 50 psi or higher can benefit from an economizer.
Shock To The System
Another important function that an economizer serves is to reduce thermal shock. Thermal shock occurs when fresh feedwater is introduced into the boiler. Conventional boiler preheat tanks usually preheat the feedwater to around 185⁰ F. In a deaerator system, that incoming feedwater temperature can be as high as 225⁰ F. But neither is close to the typical operating temperature inside a boiler, which can average 350⁰ F or higher. Since the incoming water is invariably cooler than the water already present in the boiler, that incoming water cools the boiler down, causing a drop in steam quantity and pressure.
Thermal shock is also harmful to a boiler, causing stress in the components and shortening the life of the system. By scavenging as much heat as it can from your exhaust, an economizer can make the feedwater just that much hotter. When it comes to thermal shock reduction, every bit helps.
There’s another important benefit that an economizer brings to a boiler system, one that goes beyond your bottom line and your equipment life. Economizers can also potentially lower your carbon footprint, as well. And that’s something that helps everyone.
If you’d like to have an economizer installed, or if you’d like to have yours inspected and serviced, our trained technicians are standing by. We can also help you calculate the savings you’ll get from having an economizer installed in your system. Please contact us today.