Green Manufacturing Comes of Age
The green lifestyle is about making choices based on the ecological consequences of one’s decisions. With so much media coverage on the topic of environmental ethics in the past few years, more and more companies are joining the movement toward a greener way of business. According to Larry Bliss, a Leadership in Energy and Environmental Design (LEED) accredited professional working for G...
The green lifestyle is about making choices based on the ecological consequences of one’s decisions. With so much media coverage on the topic of environmental ethics in the past few years, more and more companies are joining the movement toward a greener way of business.
According to Larry Bliss, a Leadership in Energy and Environmental Design (LEED) accredited professional working for General Motors, green manufacturing is about reducing or eliminating any negative impact on the environment by a company’s facilities. It also includes “looking for new ways to increase energy efficiency, creating healthier spaces for our employees, minimizing our site disturbance, and constructing with materials that are more beneficial to the environment.”
Designing and manufacturing a product that has the least impact on resources and the environment can also yield both economic and environmental benefits for the company, said Chris Tall, engineer for special projects at NRG Systems. The company built a completely new facility in Hinesburg, VT, incorporating environmentally sustainable practices and materials. NRG’s products are designed to help create electricity from wind energy. The company makes complete wind assessment systems, tilt-up towers, instruments, and sensors that measure and analyze wind speed, direction, and other environmental data used in siting and operating wind energy projects.
The company’s owners, David and Jan Blittersdorf, wanted to “walk the talk” of the energy industry and do the most to create a sustainable building and processes for their company. For example, occupancy sensors are used to minimize lighting needs. Overall, the building only uses one-fourth the energy of a typical building of its size, according to the couple. On a yearly basis, NRG produces about 53% of its own electricity through solar photovoltaics and a wind turbine behind the facility.
NRG’s building is “LEED Gold Certified” and is one of only five or six industrial buildings like it in the world. LEED is the nationally accepted standard for the design, construction, and operation of high performance buildings developed by the U.S. Green Building Council, and gold level certification recognizes a high level of performance.
The GM Lansing Delta Township Assembly Plant in Lansing, MI, was the first LEED Gold Certified automotive manufacturing plant in the world. Over the first 10 years of operations, the facility is expected to save over 40 million gallons of water and 30 million kwh of electricity, compared to traditional construction.
At NRG, “we have utilized 'smarter’ production equipment that automates processes,” said Tall. “For example, machinery only runs during the [manufacturing] process and is in a 'no-power’ state otherwise.”
Smart controls on the paint spray booths allow for automatic operation of the lights and exhaust fan, said Tall. Booths have multiple doors to allow for staged operation. A technician opens the door and the light turns on and the fan runs up to a preset speed based on the number of doors open. When the technician closes the door, the lights turn of and the fan runs at a minimum level for a preset time to allow for curing before shutting off completely.
GM Lansing’s strategies
At the GM plant in Lansing, energy efficiency was designed into every system, resulting in energy costs that are 45% lower than industry standards, with a projected savings of $1 million each year. Water use has been reduced by 45%, for example, in part through the collection of roof rainwater that is stored in cisterns above restrooms. This is used instead of potable water to flush toilets.
“Plant lighting is controlled by an energy management system tied into production scheduling,” said Jim Konkle, senior electrical engineer at GM. “Lighting panels have microprocessors which communicate with the energy management system, allowing lights to be turned off during non-production hours. Overall exterior lighting is controlled in a similar way.”
The plant air handling system consists of roof mounted air supply houses (ASHs) and associated ventilation fans. The ASHs are also tied into the plant-wide energy management system and controlled based on temperature and occupancy.
Opto22 tackles HVAC
Automation vendor Opto 22 also noticed the buzz surrounding sustainable lifestyles and decided to overhaul its facilities to save money on rising energy costs and to be more environmentally aware.
“Opto 22 made a conscious decision to do its part to ensure that we, as a manufacturer, offset our carbon footprint and have production and corporate processes and policies that are environmentally friendly and promote recycling, sustainability, and the conservation of energy and natural resources,” explained David Crump, marketing communications manager.
In addition to putting in place rules about turning off computers at night and recycling paper, the company used its own products to control air conditioning and lighting. Snap PAC systems (with controllers, I/O modules, racks, and software) were used to connect to and more efficiently monitor, control, and gather data from heating, ventilation and air conditioning (HVAC) equipment and processes, lighting, and water-related systems.
The first steps in Opto 22’s process of saving energy was examining the current HVAC and lighting equipment. Engineers created a list of failed or malfunctioning HVAC devices, components, and equipment: fans that wouldn’t turn on, others that would stay on constantly, broken fan belts, failed fan coils, and burned-out motors.
Checking valves and sensors
The team found that some HVAC valves in the ceiling were not opening to deliver the cold water and glycol mixture for the air conditioning, wasting energy. Besides repairing broken equipment, the team created new strategies for controlling the valves.
The company’s Mistic hardware had previously used PID loops to continually adjust valve positions to change the amount of water flow, but the process was imprecise because temperature set points were based on temperatures from sensors taken from return air ducts. To correct this, sensors were hung from the ceiling and valves now open and close fully.
Fans in the corporate side of the building were running all day to maximize cooling, using far too much energy at peak pricing times. The project team created a control strategy that would turn fans on and off only enough to cool down each area to its predefined set point. The facility also uses integrated circuit temperature detector (ICTD) probes connected to analog input modules on the I/O rack to take periodic outdoor temperature readings every morning. If the temperature is below a certain point, the Snap PAC executes a pre-cool strategy and opens the dampers completely, flushing out the stale air in the building to give the facility a running start on cooling.
The company’s efforts have resulted in a 29% reduction in Opto 22’s carbon footprint—the measure of the amount of CO2 emitted through the combustion of fossil fuels. The company is now offsetting the remaining carbon emissions by buying Green-e certified Green Tags from the Bonneville Environmental Foundation (see sidebar).
Crump advises those “going green” for the first time to remember that every little effort helps. “You’re not going to save the planet single-handedly or ever get to a point where you can self-righteously declare yourselves 'green,’” he said. “Take small steps and begin with things you can do right away, leading toward other, more involved activities and initiatives. It is more of a process and culture that evolves and progresses over time.”
When starting a building from scratch, NRG’s Tall said to “spend 90% of your time designing and 10% constructing. The level of detail to design to before breaking ground [for green building] is counter to what has been the norm for the architectural and construction industry.”
Lisa Sutor is a contributing writer to Control Engineering.
Green Tags offset carbon emissions and fund clean energy
Bonneville Environmental Foundation, a non-profit organization, sells Green Tags to help businesses, public utilities, government agencies, and individuals offset their carbon emissions. The revenues from these renewable energy certificates help replace traditional polluting sources of electricity with clean, secure, and sustainable renewable sources of energy that come from solar and wind power.
One Green Tag represents enough renewable energy to offset a typical home for a month and is equal to 1,500 miles of offsetting emissions from a standard car. The purchase of them supports the development of renewable energy on power grids, solar power systems for schools and public buildings, and wind power systems for farms, ranches, and communities.
Green Tags from BEF are Green-e certified, meaning that an independent third-party certified that the renewable energy meets the Green-e program’s strict consumer protection and environmental standards. The Green-e program is administered by the Center for Resource Solutions and its logo is a nationally recognized symbol for certified renewable energy.