The term “boiler efficiency” is often substituted for thermal efficiency or fuel-to-steam efficiency. When the term “boiler efficiency” is used, it is important to know which type of efficiency is being represented. Why? Because thermal efficiency, which does not account for radiation and convection losses, is not an indication of the true boiler efficiency. Fuelto-steam efficiency, which does account for radiation and convection losses, is a true indication of overall boiler efficiency. The term “boiler efficiency” should be defined by the boiler manufacturer before it is used in any economic evaluation.
System load is measured in either BTUs or tons of steam (at a specific pressure and temperature). It would be nearly impossible to size and select a boiler(s) without knowing the system load requirements. Knowing the requirements leads to the following information:
The boiler(s) capacity, taken from the maximum system load requirement.
The boiler(s) turndown, taken from the minimum system load requirement.
Conditions for maximum efficiency, taken from the average system load requirement.
Determining the total system load requires an understanding of the type(s) of load in the system. There are three types of loads: heating, process, and combination.
Condensing boilers can achieve up to 98% thermal efficiency, compared to 70%-80% with conventional designs (based on the higher heating value of fuels). Typical models offer efficiencies over 90% when the return water temperature is at 110 ºF or less; the lower the return water temperature, the higher the efficiency gain.
There are so many options to weigh when looking for high efficiency boilers: hot water or steam, wetback or dryback, type of fuel, and more. However, there are a few key considerations to make when evaluating a new boiler for efficiency that will help you no matter what your other considerations may be. Look for a fan that can deliver a stable air supply, a burner and boiler unit that can produce low emissions, a design that maximizes flue gas velocity, smart pressure vessel design, and an efficient heating power to boiler surface ratio are just a few considerations to keep in mind. These simple but powerful design elements are hallmarks of solid construction and will add up to significant performance enhancements. Our team members are always available for consultation and can make specific recommendations when it comes to models once we know more about your needs.
The boiler gas consumption calculation need the following parameters: gas calorific value and boiler thermal efficiency.
Theoretically, the gas consumption of boiler = boiler thermal capacity ÷ (calorific value of gas x boiler thermal efficiency )
Take the 1 tph steam boiler as an example:
= 600,000 cal / (8500Kcal * 0.98) =72m3/h, the 1 tph boiler's gas consumption per hour is about 72 cubic meters.
In a water tube steam boiler, unlike a fire tube, water circulates inside the tubes. The heat that is generated and the combustion gases that surround the tubes heat the water that circulates inside them. Many water-tube boilers operate according to the principle of natural water circulation.
The capacity of this type of boiler can be enhanced by increasing the number of tubes in the boiler.
The action of starting up a fire tube boiler for the first time is already a cold start. As a result, the mechanical load in this type of boiler is much greater, as the main characteristic of cold starts is the absence of boiling water and greater stress on the connection and anchorage elements of the boiler.
To make this start a bit easier for the boiler, the boiler operator should reduce the burner load to a boiling point.
In superheated industrial water boilers, the water is pressurized and boiled to 100°C producing steam. These boilers are pyrotubular, with a high volume of water and a large temperature exchange zone. The designs can adapt to temperatures and pressures according to needs.
