Specifying systems for energy efficiency in manufacturing, warehouse buildings
Warehouse, manufacturing and logistics facilities need engineering experts to specify various systems to achieve energy efficiency and sustainability
- Jarron Gass, PE, CFPS, Fire Protection Discipline Leader, CDM Smith, Pittsburgh
- Mike Morder, PE, CPD, Design Engineer II, Southland Industries, Dulles, Va.
- Bryce Vandas, PE, Mechanical Group Lead, CRB, St. Louis
- John Gregory Williams, PE, CEng, Vice President – Design Studio, Harris, Oakland, Calif.
What level of performance are you being asked to achieve, such as WELL Building Standards, U.S. Green Building Council LEED certification, net zero energy, Passive House or other guidelines?
Mike Morder: Many owners are taking more sustainable approaches to their manufacturing processes and building construction. As owners leverage Lean construction strategies to look for opportunities to reduce waste in the building process and improve facility operations, these often lead to engineering solutions that boost energy efficiency, with some of my recent projects earning U.S. Green Building Council LEED and LEED Silver certifications.
Bryce Vandas: There was an influx of LEED project a few years ago, but the wave has recently subsided. There are still a fair number of LEED or other energy efficient projects, but typically they are targeted toward office or ‘nonprocess’ buildings as opposed to the actual process areas.
John Gregory Williams: We’ve seen a couple of “entry level” LEED submissions, such as Certified or Silver. More often we are seeing a need for speed of delivery, rather than meeting the needs of LEED or another rating tool. What we are seeing more is elements of a sustainable process being considered based on the function of the process, such as high–efficiency systems, improved commissioning, etc.
What unusual systems or features are being requested to make such projects more energy efficient?
Bryce Vandas: Higher levels of recirculated air in high volume spaces, going to large makeup air handling units, then specifying many smaller recirc units that treat only a few rooms at a time to “final cool” to reduce cooling and reheating costs while still maintaining required humidity levels. Also finding unique ways to recover more energy off exhaust streams that may be contaminated such as lab exhaust or process room exhaust. A lot of runaround coils. Determining which streams can be used to recover energy and in what method is important for both the energy use in the building as well as the protection of all personnel and products.
Describe a recent project in which the building envelope was complex or unique.
Bryce Vandas: We had a recent project where a modular clean room system was used with exceptionally tight gasketed doors. The lack of leakage actually presented more issues, because of large fluctuations in pressure when doors were opened. Also, the amount of makeup air to maintain these pressures was not sufficient to adequately ventilate the space. Additional exhaust had to be specified into each unit to ensure that the spaces could maintain a tight pressure cascade control when not enough air was able to leave the spaces. These spaces were also very tricky for final balancing because a CFM here or there could cause wide fluctuations. With a little bit looser space, a few cfm doesn’t affect the space as much.
What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects?
Bryce Vandas: Test and balance in these types of facilities can take an excessive amount of time. The level of pressurization controls and the way that all of these systems work together, all the way down to the accuracy at which air is distributed from one space to the next. It makes it difficult in the first place, then you add in things like economizer modes where the balance of outside air and exhaust air begins to shift and maintaining very tight and consistent pressure control is at risk. When even momentary blips in that control can cause a batch to be put into quarantine, specific attention must be paid to every BAS/EMS operation that occurs in the facility
John Gregory Williams: Facilities are often being developed in areas with limited or unsuitable utility infrastructure for the processes being considered. We’ve recently worked on a number of facilities with issues regarding limited water supply, gas supply and/or power supply.
This resource limitation often engages considerations for the design which are usually associated around sustainable development practices such as water or energy conservation measures.
What types of renewable or alternative energy systems have you recently specified to provide power?
Bryce Vandas: In the life sciences industry, they are more reluctant than most to make the jump to renewables. Because every step in a products manufacturing must be tested, validated, documented and approved, even minor changes to building construction can trigger a complete retesting of the product. Some owners push forward, but many are still reluctant to make that kind of jump.
How has the demand for energy recovery technology influenced the design for these kinds of projects? Describe a mixed-use building in which the heat from the manufacturing section of the plant was used in other portions of the building.
Bryce Vandas: Energy recovery technologies are put into place but unlike other facilities, in the life sciences, the extra level of controls needed can be very expensive. Because of the tight and consisted control needed 24/7 year-round in these manufacturing spaces, even momentary issues when a system switches (e.g., temperature reset on chilled water) that causes a product to go out of spec could be devastating. To achieve energy efficiency, a lot of buildings separate their building services from the manufacturing space. This allows them to use the new technologies in the building services to recover and conserve as much energy as possible, while not putting the product purity or stability at risk.
What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?
Bryce Vandas: Creative solutions on energy recover. Helping owners identify where energy can be saved without putting products at risk. Diving into the operational details of every step of ever sequence to show where potential risks are and having plans to mitigate them. These are areas that most owners are not familiar with. The utility guy may know how the utilities operate, the process guy knows how the process has to operate and it falls to the engineer to design a system that satisfies both needs while integrating new codes and energy standards.
How have energy recovery products evolved to better assist in designing these projects?
Bryce Vandas: Products, yes. Codes and standards, no. There are many ways to recover energy or reduce usage that are not directly called out in codes and standards. There are many good products and methods on the market. As these technologies come along and you don’t have to sacrifice performance to achieve the end result, it is becoming increasingly easy to sell the technology to a client.