Energy-smart industrial architecture
Today’s factories and warehouses are different from the designs of only 20 years ago. Evolving industrial building codes, increased robotic operations, heightened ventilation requirements, and new energy technologies have changed the look and feel of these facilities. Further, many owners are looking not only at improving operating efficiency, but also at reducing the building carbon emission profile. Changes have been evolutionary, but the result has been a new industrial architectural standard.
Rooftop energy systems in newer buildings
Newer manufacturing facilities are usually built on a single level to allow linear lift-truck or conveyor movement of materials and products. Often this means that HVAC equipment is located on building rooftops, which usually means packaged systems. This includes heating, electric cooling, plus dehumidification and sometimes humidification functions.
Most commonly, new building heating systems in North America use natural gas as a primary fuel, sometimes with an assist from solar collectors. In some cases, process waste heat can also be used for space heating. The use of natural gas means that less energy usage and equipment is necessary for emission control than with coal or heavy petroleum fractions as fuel.
Increased ventilation brings energy challenges
For a manufacturing plant, a primary function is building ventilation. ASHRAE Standard 62 sets acceptable indoor air quality standards and prescribes appropriate ventilation rates. The standard has been in place since 1973, and has periodically been modified, each time usually with lower acceptable contamination levels and greater ventilation requirements. The ASHRAE standard is often adopted as code by state and local agencies. This tightened regulation of the indoor working environment necessitates dramatically more workplace ventilation.
Local, state or provincial, and federal occupational health agencies also set additional strict specific standards for air contaminants, including carbon monoxide, ozone, volatile organics, formaldehyde, silicone, glues, epoxies and other air contaminants of special concern. These tightened requirements result in enormous amounts of building air being exhausted rather than recirculated, with a consequent potential penalty of building heat or cooling loss. Often air contaminants are also routed through a thermal oxidizer to eliminate harmful emissions.
Engineers and architects are specifying exchanger systems for thermal recovery from these exhausts. Process ventilation exhausts are frequently combined and routed through heat exchangers for this temperature recovery, with a counterflow of building makeup ventilation air. This temperature recovery function can either be on the operating floor level in a mechanical space, suspended from the ceiling, or on the rooftop.
Onsite electric generation increasing
Because of rising energy costs, high electric demand charges, and a desire for improved supply reliability, owners increasingly ask building planners to include combined heat and power (CHP) systems in building plans. This option is particularly attractive in industrial operations where significant process heat is needed and can be provided by a natural gas-fired engine or gas turbine generator set. CHP is most attractive when it can be incorporated in the actual building design, putting the generation byproduct heat close to the process application.
Another option is to use the byproduct heat from electric generation to supply an absorption chiller for space or process cooling purpose. This approach is discussed in another article in this issue. With CHP, total energy utilization can approach 90% thermal efficiency. Even with a reliable CHP system, most industrial buildings are also designed for a utility interconnection, both for purposes of redundant supply, and possible sale of surplus site power back to the utility.
Lighting is another area where building designs are changing. In some ways, the newest industrial buildings harken back to early 20th century designs because they use extensive rooftop or window daylighting to supplement high-efficiency lighting systems that utilize LED or halogen lighting equipment. Sophisticated lighting controls often switch lighting on only when the area is occupied, and are programmed to adjust for varying light levels and needs through the day.
An important influence for evolving industrial building practices is the U.S. Green Building Council (USGBC), a non-profit organization that was formed in 1973 with a goal of transforming the way buildings are designed and operated. In Canada, the Canada Green Building Council fulfills the same role. The Councils sponsor the influential Leadership in Energy and Environmental Design (LEED) certification program. The program has developed standards for new buildings that encompass a wide range of energy and environmental issues. In the beginning, many LEED projects were commercial, institutional, or office facilities, but over the years many industrial facilities have also become involved in the LEED design, construction and scoring process.
Growing involvement with LEED process
According to Stefanie Young, Director, Technical Solutions for USGBC, there is growing interest in the LEED process and standards by the industrial sector. "USGBC is seeing a substantial uptake from the manufacturing sector in addressing the need to create greener, healthier, more efficient manufacturing facilities." She notes that accelerating this trend are organizations that understand the connection between business sustainability and environmental sustainability.
Young indicates that ten years ago, there were fewer than 100 industrial or manufacturing facilities registered under the LEED green building rating system. She says, "Today there are over 2,300 projects registered or certified, indicating a large positive shift in the design and operations of these buildings. These include many buildings owned and operated by brands we interact with on a daily basis: Coca-Cola, PepsiCo, Mars, Kraft, Boeing, Hewlett Packard, Intel Corp., Colgate-Palmolive, Armstrong and Johnson Controls." She indicates that all of these companies are using LEED to certify their buildings’ design and ongoing operations while seeing a quick return on their investment.
Corporations make efficiency a policy priority
Young points out that while some manufacturers are building more efficient units or investing in retrofits simply in response to current or anticipated government regulations, many are making better building practices part of their corporate policy. She notes, "This can be attributed to increasing demand from savvy consumers that are drawn to brands that promote strong sustainability policies, as well as the tremendous leadership of forward-looking executives across an increasing number of industries."
Young points out that there is a growing understanding that improved facilities can significantly reduce a company’s carbon emission impact. "It used to be that purchasing green power RECs or carbon offsets were the only ways." She explains that for industries that are genuinely interested in making an improvement, there’s a growing appreciation that improved mechanical plants, building envelopes, and a rigorous commissioning process are important.
She adds, "Additional LEED measures implemented at the site level can include designs to encourage carpooling, biking to work, and electric vehicle charging. This allows them to address impacts created by their employees and visitors traveling to the sites, which tend to be in remote, industrial areas away from public transit and residential neighborhoods."
DOE Better Buildings program
Another institutional force for building efficiency improvement is the U.S. DOE’s Better Buildings Initiative, which recruits energy users, including industrial users, to become partners in a program of committing to building energy improvements, and publication of their progress along this road. An example of this program is Cummins Inc. a global leader in power systems. Cummins committed to a 25% reduction in its energy usage (per revenue dollar) by 2015, and has reached that goal.
At its Jamestown, NY, engine plant, the company undertook a comprehensive energy rework. The project included a 2 MWe solar installation capable of generating about one-third of the plant’s energy requirement on sunny days. The project also included installing three regenerative dynamometers, capable of generating electric power sufficient to supply surplus to the nearby city. The Jamestown project has reduced plant energy usage by 33%.
Another Better Buildings showcase project has been done by Better Buildings partner J.R. Simplot, a large national food and agribusiness company. The project is a new 420,000 square foot state-of-the-art potato processing plant that will incorporate multiple energy saving technologies while processing millions of pounds of potato products annually.
Improvements include advanced refrigeration systems, improved pipe insulation, and improved methods for compressed air operations. A new regenerative thermal oxidizer, boiler stack, and fryer exhaust system will recover byproduct heat. It is anticipated that this plant will contribute significantly to the company’s overall goal of reducing energy usage by 25%.
Facilities designed for efficiency
Whether the facility is processing potatoes, building engines, or performing nearly any other industrial task, energy efficiency is increasingly a high priority. The achievement of this goal is within reach for most industries, and the solutions are often a combination of reduction of energy waste, upgrading process equipment, capturing byproduct energy and prudent use of renewable energy resources. Clean natural gas often plays a major role. The result is industrial buildings that look differently, contribute less to the global carbon load, and help reduce the cost of production by using less energy. It’s a changed and still-changing world.
This article originally appeared in the Gas Technology Summer 2015 issue.