A growing number of companies, factories, campuses, and healthcare facilities are looking for ways to be more “eco-friendly.” Some are dealing with increased emissions restrictions; others just wish to reduce their carbon footprint. Many companies are now looking at this issue when selecting a boiler system, whether they’re using it for manufacturing, hot water, or their heating systems. How can they get the steam heat they need while still being “green?” What is the most eco-friendly type of boiler available?
This question isn’t as easy to answer as it seems. The reason is that a number of factors go into a company’s needs when selecting a boiler system, and one factor may easily offset another. For example, a steam boiler may be rated for low emissions of greenhouse gases but may still result in high energy bills. One unit might be highly rated for energy efficiency but still runs on fossil fuels like natural gas or propane. When selecting a boiler system based on eco-friendliness, a company needs to balance the desire for environmental responsibility with reasonable expectations for getting the steam and hot water they need to operate properly.
So what constitutes the most eco-friendly boiler system overall? Let’s explore some different types of boiler technologies to see what we can learn.
WHAT IS A GREEN BOILER SYSTEM?
The term “green” loosely means “eco-friendly,” and it is not an “on-off” switch, so to speak. Some systems are “greener” than others. Typically the factors you look at when determining eco-friendliness are:
- Energy efficiency: The ability to produce steam with as little energy waste as possible. Boiler systems typically rank according to an efficiency rating called Annual Fuel Utilization Efficiency (AFUE). The more heat energy goes into the water and the less energy goes up the flue, the better the AFUE rating. An AFUE rating of 100 means no energy is lost between the fuel and the production of steam. (Even the most energy-efficient boilers usually don’t hit that mark.) Energy efficiency also means it requires less fuel use to get full steam because not as much heat is wasted.
- “Clean” energy: This factor refers to how much pollution goes into the air when the fuel is burned to produce steam. Boilers that are rated for low CO2 and NOx emissions are considered greener because they are sending fewer greenhouse gases into the air.
- Fossil Fuels vs. Renewable Energy: Many low-emission boilers still run on “fossil fuels” — fuel sources like oil and natural gas that take millions of years to form and cannot be replenished once they are used. Renewable energy is the energy that effectively can’t run out or is continually renewed (e.g., solar heat, wood). Most boilers still run on fossil fuels because we haven’t yet developed ways for them to run effectively on renewable energy — although some boilers, like condensing boilers, reclaim some waste heat, effectively “renewing” some of the energy they use.
- Carbon Neutrality: This refers not so much to “clean” energy as to whether a boiler sends no more carbon into the air than it takes in. Biomass boilers are considered carbon-neutral because the wood pellets they use have absorbed the same amount of carbon while forming as the amount of carbon being sent back into the air.
HOW DO DIFFERENT BOILER SYSTEMS MEASURE UP?
Now that we understand the concept of green boilers, how do different types of steam boilers fit that idea? Let’s look at a few boiler types:
Conventional Fire Tube Boilers
The most common type of steam boiler, fire tube boilers are considered the least eco-friendly overall. They run on fossil fuels, require lots of water for operation, and typically are not energy efficient because they take so long to heat up and must often stay fired up even when steam is not needed.
Condensing boilers have a very high AFUE rating because they are designed to recycle some of the waste heat back into the water source rather than letting it go out the flue. That said, they aren’t always cost-efficient for companies requiring large amounts of steam.
Electric boilers effectively have no emissions issues and are considered the “cleanest” type of boiler for this reason, with an AFUE rating near 100. However, since electricity is also quite expensive in most places, these boilers are also not very cost-efficient for larger companies.
THE BEST OVERALL ECO-FRIENDLY BOILER TYPE? WATER TUBE BOILERS
For many companies looking for an energy-efficient, eco-friendly boiler, the modular water tube boiler made by zozen is the best option all around. For starters, modular water tube boilers require a lot less water to operate than conventional boilers due to their unique design. Secondly, modular boilers are also more fuel-efficient; even though they run on fossil fuels, they can fire up and power down in minutes, which means they don’t run constantly. The modular design is better at producing steam in a short period of time than larger conventional boilers. And third, water tube boilers are known for producing fewer harmful emissions like NOx and CO2.