Ferrous foundry group Waupaca Foundry Inc. has earned three awards from national, state, and industry groups recognizing its commitment to energy reduction, and to finding “smart” ways to use and protect natural resources. Its projects included overhauling an air-compressor system at Plant 1 in Waupaca, WI; installing a dehumidification system at Plant 5 located in Tell City, IN; and adopting a smart exhaust-fan system at Plant 2/3, also in Waupaca, WI.
Waupaca Foundry is a Hitachi Metals Ltd. holding that produces gray, ductile, compacted graphite, and austempered ductile iron castings for manufacturers in the automotive, commercial vehicle, agriculture and construction equipment, and other industrial markets. It lists its current melting capacity as 1.4 million tons/year.
The group operates four foundries in Wisconsin and one in Indiana, and it has plants for machining castings in Waupaca, WI, Effingham, IL, Ironwood, MI, and Etowah, TN.
Air compressor efficiency
An award from the U.S. Dept. of Energy's Better Plants program recognizes manufacturers for creating and implementing industrial energy and water efficiency projects, as well as renewable energy and energy resiliency projects. Waupaca Foundry was recognized for completing an extensive upgrade to Plant 1’s air-compressor system that increased energy efficiency and reduced annual energy and water usage.
It is the second time in two years that Waupaca Foundry has been recognized by the DoE for its environmental achievements.
At Plant 1 – which is a cupola-melting operation producing 300,000 tons/year of gray iron – outdated compressors were replaced with new, more efficient models in a new compressor room; piping layouts were improved; and waste heat-capture systems were installed, to provide heat to the building during colder months.
Finally, an ongoing compressor air-leak management program was implemented.
Air compressors are used by foundries to power pneumatic systems, robotic operations, and environmental control systems, and they represent one of the top energy-consuming functions for such plants. According to Waupaca, air-compressors represent 10% of Plant 1’s annual energy consumption. Maintaining efficient compressed-air systems is necessary to foundry productivity, as well as to energy and cost reduction, and to optimizing Plant 1’s environmental footprint.
The Plant 1 projects reduced overall system air pressure from 95 to 87 PSI. As a result of the improvements, plant operations and maintenance practices improved.
These projects increased overall energy efficiency by 13.5%; reduced energy usage by 18,000 MMBTU / year, the equivalent energy consumed by 20 U.S. single family homes annually; reduced water usage by 13 million gallons of water/year; eliminated 1,240 tCO2, or 1%, of GHG emissions; and energy usage was reduced by 1.1 million kWh.
Improving the plant atmosphere
The second award – the 2022 Green Foundry Sustainability Award – was presented by the American Foundry Society in recognition of the Waupaca Foundry Tell City, IN, plant’s new dehumidification system that significantly reduced energy consumption.
Reducing humidity from the plant atmosphere is another effective way to improve the efficiency of cupola melting. Waupaca had roof-mounted exhaust fans installed at the Tell City plant to run continuously – though temperature variations still affected the melting rate.
The improvement project involved installing a desiccant wheel to remove water vapor from plant’s ambient air, and a smart control system was installed that triggers fan use only when sensors detected elevated levels of humidity in the plant atmosphere.
The results of this system are more efficient cupola melting, decreased coke consumption, reduced CO2 emissions, and a decrease in overall plant energy usage.
Business and the environment
Last, the Wisconsin Manufacturers and Commerce (WMC) association recognized Waupaca Foundry’s environmental innovation with its “Business Friend of the Environment” award in the large business category. The award cites Waupaca Foundry Plant 2/3’s project to install smart controls, to improve efficiency of ventilation equipment.
Six roof-mounted exhaust fans were in place to remove heat and circulated air from the plant atmosphere during the summer months, although continuous operation did not address seasonal temperature variation.
Those existing fans were automated with sensors to monitor air temperature and carbon-monoxide contents, so they currently operate only when needed, as determined by targeted temperature and/or CO levels.
These modifications resulted in significant energy savings at Plant 2/3, reducing annual electricity and natural gas usage, improving workplace ventilation and worker comfort, and ensuring CO2 levels are actively monitored. Also, implementation costs for this project were low, Waupaca Foundry noted, making it business-friendly as well as environmentally responsible.
Waupaca Foundry continues to pursue projects that address its environmental and sustainability goals, which for 2023 are:
• To reduce energy intensity by 5%;
• To reduce the cumulative electrical consumption carbon footprint by 30%;
• To maintain air pollution-control systems considered as “best available” by the U.S. Environmental Protection Agency;
• To achieve a cumulative 80% beneficial reuse of spent foundry materials; and
• To reduce water use consumption by 10%.
“We have been on a corporate-wide mission of sustainability since 2009,” stated Waupaca Foundry director of Environmental Engineering, Bryant Esch. “Reducing our energy consumption and costs has a direct benefit to our customers, in terms of producing high-quality iron at a competitive price, with a reduced environmental footprint.”