Custom-Designed Boiler Solution for Ivy League School Achieves <9 ppm NOx

Case Study

  • Company: Ivy League University
  • Industry: Education
  • Location: Connecticut
  • Profile: The university has more than 300 buildings and owns and operates two utility plants on campus.
  • Challenge: The university’s goal is to reduce its greenhouse gas emissions 43% by 2020 compared to 2005 levels.
  • Solution: A pair of 100,000 lb/hr O-type industrial watertube boilers with ultra-low NOx burners.
  • Results: Immediate achievement of <9 ppm NOx.

One Ivy League university is committed to environmental citizenship and embraces responsible growth as a critical part of its mission. At the center of its efforts is a sustainability task force, charged with advancing a culture of environmental accountability both on campus and throughout the world. One of the university’s goals is to reduce its greenhouse gas emissions 43% by 2020 compared to 2005 levels. With more than 300 buildings on campus to heat, cool and power, the manner in which each building is designed, constructed and managed has a significant impact on the university’s carbon footprint.

The university owns and operates two utility plants on campus. Its central power plant produces steam to meet the heating requirements of the campus and also contains a set of steam-driven chillers coupled with a set of evaporative cooling towers to satisfy campus-cooling loads. The plant is a co-generation facility as well, providing electricity using combustion turbines. The plant can operate on either natural gas or fuel oil, depending upon fuel cost and need. From a risk management perspective, the university did not want to rely exclusively on the existing HRSGs that produce steam for the campus. They desired a new auxiliary system to pick up the campus load, should the gas turbine units fail unexpectedly. 

In early 2008, the university’s engineering team reached out to several boiler and burner manufacturers, including Cleaver-Brooks, to provide design input for an auxiliary system to supply redundant steam capacity for its power plant. One of the major directives required that the boiler system meet ultra-low NOx emission regulations to help further the university’s sustainability goals.

The job presented a number of design challenges. First, the power plant is housed in a neo-Gothic-style building, nearly a century old, which was originally designed to burn coal. The boiler room is small and very narrow, and it was not an option to modify the space. Second, the building has two large historic brick stacks, and the auxiliary boilers had to be custom-designed to utilize these original exhaust structures.

In addition, due to the tight boiler room quarters, there was not enough real estate for a conventional Forced-Draft Fan located adjacent to each boiler. Cleaver-Brooks engineers worked closely with the university’s engineering firm to devise a creative solution. The fan system was designed to sit on the mezzanine level above the boiler room. This approach allowed for the necessary ductwork and flue gas recirculation equipment to be designed to provide proper air flow conditions, thus ensuring ultra-low emissions burner performance.  

In the summer of 2009, the university issued formal project specifications, largely based upon the input and boiler blueprints Cleaver-Brooks engineers had submitted over the previous year. The design called for a pair of 100,000 lb/hr O-type industrial watertube boilers with ultra-low NOx burners. The O-style boiler was specified due to the building’s space constraints in order to optimize the system footprint and combustion air fan’s power consumption. Cleaver-Brooks Nebraska Boilers and Natcom Burners were identified in the specification as the basis of design.  

In March 2010, the university awarded the project to Cleaver-Brooks following an in-depth evaluation period which included numerous on-site meetings and discussions with the university, their engineering firm and mechanical contractor. As the sole manufacturer of boilers, burners and controls, Cleaver-Brooks single-source approach was judged to be the ideal solution.  

“We were extremely honored that our design was deemed as state-of-the-art by this prestigious Ivy League institution,” said Jason Jacobi, sales manager for the Engineered Boiler Systems division of Cleaver-Brooks. “We won this job against formidable competition, including the incumbent.”  

Cleaver-Brooks completed and shipped the boilers from its manufacturing facility in Lincoln, Neb., in March 2011. The Blake Group, an authorized Cleaver-Brooks representative, oversaw the start-up of the boilers in late 2011. Both dual fuel-fired boilers were commissioned and placed online in January 2012.  

“Our integrated boiler/burner system met all contract guarantees, including achieving <9 ppm NOx right out of the box,” said Jacobi. “This project included many technical challenges and the experienced engineering and manufacturing teams at both our Lincoln and Montreal facilities faced it head on. The equipment’s performance, and ultimately the project’s success, is a direct result of their efforts.”

Rick Fiorenza, vice president of sales for Natcom, added, “As shown in this case, building one-of-a-kind systems is our specialty. We excel at designing integrated, custom-fit solutions. We provide designs that allow for rapid system startup and commissioning that meet our ongoing goal of exceeding customers’ expectations.”