When developing the CBEX, Cleaver-Brooks engineers focused their efforts on maximizing the overall heat transfer in the tubes and furnace. Utilizing advanced computational fluid dynamics (CFD) and mathematical modeling, the spiral tube design increases the heat transfer by nearly 85 percent compared to a plain tube.
Engineers also redesigned the furnace and pressure vessel of the CBEX to maximize the overall performance of the system. They designed a larger, geometrically optimized furnace with lower heat release to minimize NOx emissions and improve combustion. Better combustion results in high turndown and minimum excess air, which increases energy efficiency.
By optimizing the heat transfer of the tubes and furnace, the CBEX requires less heating surface to achieve the same BTU output, facilitating a more compact design. The CBEX is approximately 15 percent smaller than boilers based on traditional industry standards. Because of its smaller footprint and lower water volume, the CBEX heats up 20 percent quicker than traditional firetube models.
The overall performance of a boiler is based on the ability of the burner, boiler and controls to work together, and the CBEX is an integrated boiler, burner, control and heat recovery system designed and built by a single manufacturer. Controlling the CBEX is the Cleaver-Brooks Hawk, an integrated control system, embodying precise boiler/burner management and safety with logic-based ancillary devices and functions. The system automatically adjusts to changing environmental conditions, maintaining higher energy efficiency compared to a boiler that has to be tuned manually. Available options include a variable speed drive control and NOx trim for controlling the ultra-low NOx burners.
The CBEX is available in sizes ranging from 100 to 2,200 HP. Design pressure is 50 to 250+ on steam and 30 to 125 psig on hot water.