The world of commercial water boilers can be a little bit confusing and overwhelming. One of the reasons is the technology has evolved immensely in a short period of time, and if you didn’t keep up with the pace, you might be behind. Luckily, we’ve compiled a list of 5 facts to bring you up to speed.
1. There are three different types of commercial water boilers
Choosing the right one for your application is essential to ensure the efficiency of your system. Each boiler has its pros and cons, and the wrong choice can significantly impact the lifespan of your unit and compromise energy savings. We advise that you always count on the expertise of an engineer to help you determine what piece of equipment best fits your design.
- A fire-tube boiler has tubes running through a sealed heat exchanger filled with water. Hot gases pass through the tubes, and the heat generated is transferred to the water through the walls of the tubes by thermal conduction.
- A water-tube boiler also has tubes, but they are filled with water instead of gas. The tubes are externally heated. Inside the combustion area, fuel is heated by fire, generating hot gas that heats the water.
- Electric boilers are simpler because there is no gas combustion involved in the heating process. As the name says, electric boilers use electricity to heat water. Cold water is brought to a sealed tube that contains electric heating elements and these elements heat the water. This type of boiler is a good solution for low NOx emissions regulations or for areas where electricity is not expensive. Nevertheless, this type of boiler is the least popular one as it usually costs the most to operate.
2. Gas-fired commercial water boilers can be condensing or non-condensing
Condensing boilers run at low temperatures, less than 130 degrees. Flue gas condensation occurs because the flue/exhaust gas cools to the point where it can no longer maintain saturation. A good application for condensing boilers would be a water-source heat pump loop.
A condensing boiler usually needs an AL294C stainless steel exhaust flue. In some instances, CPVC, PVC or polypropylene can be used. Fire-tube boilers can either be piped primary-secondary or variable primary. Water-tube boilers must be piped primary-secondary with the use of a dedicated circulating pump.
One of the things to remember is that if your application will generate condensation, your best option of heat exchanger material is stainless steel, due to its highest level of corrosion resistance. Due to condensation being very acidic, other materials such as copper would fail quickly. A big advantage of condensing boilers is that they can reach up to 99% efficiency at low return water temperature and low firing rate.
Non-condensing boilers run at above 130 degrees, and even though they will most likely present a low upfront cost to be acquired, operating costs can impact savings. Some additional advantages of non-condensing boilers are:
- They can oftentimes be vented with a B-vent exhaust flue instead of stainless steel
- The airside coils can oftentimes be smaller/less expensive
- They offer easier controls integration with building controls systems
3. There is a big difference between high-efficiency boilers and standard boilers
Efficiency in boilers has nothing to do with how quickly the boiler heats the space, or with the temperature the boiler can reach. A commercial water boiler is more or less efficient depending on how much of the heat energy from gas is used to heat the space and much is wasted in the flue gases.
High-efficiency boilers have the capability to recover the extra heat, also called latent heat. This makes these boilers more efficient to run. In addition, standard efficiency boilers lose about 20% of the heat produced from the fuel gas via the flue, while high-efficiency boilers lose only about 10%. Even though high-efficiency boilers still lose heat, the 50% reduction loss makes a big difference over time.
4. Proper maintenance is not only a financial benefit, but it’s also a safety requirement
When it comes to boilers, lack of maintenance can be dangerous. If a gas boiler is leaking in your facility, DO NOT try to fix it yourself. Gas Safe Registered engineers are qualified to do the job. Believe it or not, a leaking boiler is quite serious, and it is a sign that a component is not working as it should.
This means that repairing requires looking for the source of the problem instead of just an easy fix. A seal or a valve could be broken, affecting the entire system pressure and creating a very serious safety issue.
5. Commercial water boilers cannot be retrofitted
If your boiler is more than 15 years old, you should seriously consider buying a new one. Not only will the new piece of equipment save you money in the long run, but it will also ensure the safety of your facility and the people in it. Trying to retrofit a boiler is expensive and inefficient. The problem boils down to one thing: it is not worth the risk.