Exterior of the Andersen facility near the river. At the right foreground you can see the crane installing the wood-fired boilers.

ST. PAUL, Minn. - TKDA, an employee-owned engineering, architecture, and planning firm, has received a national award for its design of an innovative, environmentally friendly steam generating facility for Andersen Corp. The award was given by the American Council of Engineering Companies (ACEC) at an event held in Washington, D.C.

“It is a privilege to be honored by ACEC, which recognizes excellence in engineering and new technologies that enhance business and protect the environment,” said William E. Deitner, CEO of TKDA. “Our team developed a unique system that will serve Andersen’s needs now and into the future, and we are extremely proud of the work that we did to make this project a reality.”

The project was initiated in 2005, when Andersen was notified by Xcel Energy that steam energy provided by its nearby plant would no longer be available for use at Andersen’s 63-acre campus. Andersen, which is Minnesota’s largest window manufacturer, chose to utilize this opportunity to minimize the impact of a new steam facility to their community (the businesses and residents of Bayport, Minn.) and the adjacent St. Croix Riverway.

TKDA planned and engineered the design of the $22 million steam generating facility at Andersen’s Bayport campus, which enables Andersen to produce 100 percent of its required steam and heat from renewable energy to heat and cool the campus. The facility also eliminates Andersen’s reliance on coal-based steam and allows the company to control its current and future energy requirements by using new, state-of-the-art equipment.

TKDA worked with the company to develop a system of wood-fired boilers that utilize the facility’s wood waste products and substantiates Andersen’s commitment to landfill avoidance. The wood-fired boilers are equipped with low nitrogen oxide burners. If needed, flue gas may also be recirculated to further reduce nitrogen oxide emissions. Flue gases pass through an electrostatic precipitator to remove particulate matter emissions. Wood fuel used in the burners is a byproduct from Andersen’s own wood milling operations. The boilers were designed to accept the sawdust fuel as a fine powder, which ensures complete combustion and minimal ash generation. An ash utilization program for soil enhancement by local crop farmers is being planned to replace a previous waste landfill program.

In addition, a warm water recovery system is used to heat outside or fresh air brought into the facility. This system recycles the condenser cooling water discharged from the neighboring power plant for heating purposes.

Four large air-handling units reduce fugitive air infiltration by approximately two-thirds, which eliminates the need for an additional 40,000-lb./hr. boiler and reduces Andersen’s dependence on fuel burning. Additionally, utilizing heat energy from a portion of the discharge water also reduces thermal loading into the nearby St. Croix River.

Shown are the wood-fired boilers.

Special low nitrogen oxide burners were also installed as a backup heat source to the warm water. This was the first time low nitrogen oxide burners have been used in this manner outside of California. The design provides reduced energy consumption, improved performance, and a longer life for the system.

The steam generating facility, which was fully operational May 1, 2007, was constructed by the design/build team assembled by TKDA that included Pioneer Power, Siegfried Construction, and Hunt Electric. The facility adheres to Andersen’s environmental performance guidelines for both manufacturing products and process.

TKDA has earned three other awards for this project from industry peer groups in Minnesota including the 2008 Engineering Excellence Grand Award from the Minnesota Chapter of ACEC; the 2008 Minnesota Society of Professional Engineers Seven Wonders Award; and the 2007 Minnesota Environmental Initiative Award.

While TKDA has long provided clients with solutions when it comes to improving their heating and cooling systems, the company recently dedicated a team to focus solely on providing energy-saving designs and plans. The team will specifically work with clients to provide energy-efficient alternatives for facility heating, power, and cooling for a variety of building types and infrastructure.

For more information, visit www.tkda.com.

Publication date:08/03/2009