Durr Industries’ 240,000-sq-ft North American headquarters and manufacturing plant replaced its 20-yr-old heating system with roof-mounted industrial space heaters. Energy consumption was reduced by 23%.

Every company wants to save energy and get a little bit greener. Converting to a more energy efficient and environmentally friendly heating/ventilating system is one way to make a big impact in this area. The Durr Industries, North American headquarters and manufacturing plant in Plymouth, MI, is a perfect case in point.
Durr decommissioned their steam boiler heating system during 2006. They replaced it with Cambridge direct gas-fired Blow-Thruì space heaters for the plant and a Raypak hydronic boiler system for the office. After this conversion, the average annual natural gas consumption for this plant was reduced by 6,697 MCF (66,970 Therms). From an environmental standpoint, this means an annual CO2 emissions reduction of 393 tons.

Replacing Steam

Durr is a global supplier of painting systems and air pollution control equipment for the automotive, aerospace, and other industrial markets. Gordon Harbison, CEM, is leader of Durr’s project development team. His normal job is reducing energy consumption and the cost of operations for their customers. So Durr management, said, “If you can do it for them, then do it for us.”

In the spring of 2005, Harbison launched a plan to decommission the gas-fired steam boiler at their 240,000-sq-ft facility. The 20-yr-old boiler had a steam capacity of 10,350 lb/hr and was in good working order, but was expensive to operate due to rising energy and maintenance costs.

The boiler was used to heat a large manufacturing area with a combination of fancoil and unit heaters distributed around the plant. The office had hydronic heating coils, hydronic baseboard radiation, a hydronic snow melting system, and a combination of air handlers both hydronic and indirect gas-fired. All of this would have to be replaced. Durr also wanted to address cold dock door areas, achieve more even temperatures throughout the building, and provide more ventilation with outside air to address a negative air pressure problem.

Weighing the Options

The 180,000-sq-ft production area with 25-ft ceilings posed heating challenges because of its uneven roofline, mixture of high and low bay areas, lots of hanging lights, many windows, and dock door area that was difficult to heat.

Roof mounted Blow-Thru industrial space heaters manufactured by Cambridge Engineering became the obvious choice in the eyes of the team. This direct gas-fired heating equipment enjoys 100% combustion efficiency because there are no flue or heat exchanger losses. One hundred percent of the available heat is delivered to the heated/ventilated space. The equivalent AFUE rating, or thermal efficiency (Et) is 92%.

With the old steam system, the 60,000-sq-ft office space was prone to overheating in the afternoon, affecting worker productivity. Performance Engineering Group, a Michigan-based company, was selected to provide the new heating equipment. Alan Deal, president of Performance Engineering, said, “The challenge for upgrading the office heating system was finding a new location for the gas-fired hydronic boilers, and figuring out a way to vent the products of combustion.”

The final solution was to install three Raypak boilers outdoors. Two 1,800 Mbtuh boilers were put on the roof, and one 500 Mbtuh boiler was located on grade level. The boilers have an 87% combustion efficiency - the highest available for this application. A 120oF minimum inlet water temperature allowed for greater energy savings. The system was also part of a separate snowmelt application that required the use of glycol.

Goals Accomplished

The new heating systems were installed in January 2006. The facility was occupied at the time, but the conversion went so well that no temporary heating was required. Dave Williams, with Kropf Service Co. (the local contractor used by Durr to service their HVAC equipment) confirmed, “The new heating system improved ventilation for the plant solved the negative air problem and provided more even temperatures with increased comfort levels throughout the plant and office areas.”

Improved productivity was noted in the office and plant because of more effective temperature control. Best of all, a significant reduction in natural gas was documented during the first year of operation. This was determined by a heating degree-day (HDD) annual gas consumption analysis that accounts for year-to-year changes in the weather.

Before the conversion, this Durr facility averaged 4.48 MCF/HDD annual gas consumption for the steam boiler system. After the conversion, gas consumption was reduced by 23% to 3.44 MCF/HDD. “The energy savings and reduced maintenance costs enabled us to meet our payback goal for the conversion,” Harbison said. ES