Designing industrial, manufacturing, and warehouse facilities: Sustainability and energy efficiency
- Andy Campbell, CEng, MCIBSE Senior Refrigeration Engineer Leo A Daly Minneapolis
- David Crutchfield, PE, LEED AP Principal RMF Engineering Charleston, S.C.
- George Isherwood, PE Vice President Peter Basso Associates Troy, Mich.
- Tommy Lane, PE Department Head, Electrical Engineering Spencer Bristol Peachtree Corners, Ga.
CSE: What unusual systems or features are owners requesting to make their facilities more efficient?
Campbell: In designing zero-carbon warehouses and factories, some things I’ve specified include rainwater harvesting for truck washing, reed beds to filter greywater, and condensate-wastewater recovery from refrigeration. I’ve also done projects with wind power, solar thermal, solar photovoltaics (PVs), and CHP (combined heat and power) using low-carbon-impact fuels like fish oil and wood chips.
Crutchfield: Exterior shading elements are effective at reducing the building’s cooling and heating load. They are incorporated into an architectural design element, but the main function is shading the envelope. When done well, glare can also be controlled while still allowing views to the outside that are important for workers in large buildings.
CSE: What types of sustainable features or concerns might you encounter on such facilities that you wouldn’t on other projects?
Crutchfield: Due to the fact that these facilities have large roof areas, it is convenient to place PVs on the roof. Most facilities we design in the Southern U.S. have some sort of PV on the roof.
Campbell: Corporate social responsibility is driving companies’ earnest commitment to sustainable design. From what I can see, CEOs understand the environmental impacts of their businesses and set aggressive targets. People may dismiss it as greenwashing, but it’s not trivial for a company to become sustainable. It takes a serious commitment, and from what I can tell, they’re serious. In the U.S., it’s increasingly important for companies to have a reputation for taking sustainability seriously. In Europe, it’s even more important because the cost of energy is significantly higher. Depending on the country, there can be a faster return on investment (ROI) for investments in sustainability in Europe. In the U.S., ROI depends a lot on backing from local and national governments.
CSE: What types of renewable or alternative energy systems have you recently specified to provide power? This may include PVs, wind turbines, etc. Describe the challenges and solutions.
Campbell: I’ve specified wind turbines, passive solar, solar PV, and CHP systems. One of the most important considerations when specifying wind is to consider flight paths. When you start to look into wind, you discover how many local airports and flying clubs there are. When you’re putting up big wind turbines, it’s very important to survey for flight paths and apply for permissions from local airports and the military. It’s critical to do this well in advance, before planning. Another important consideration is to enlist consultants early, to get a realistic picture of how viable wind is on your specific site. I’ve found that, no matter what the wind-harvest map says, there are always pockets where the wind is weak. If your wind harvest isn’t worthwhile, you won’t get your ROI and the project will be a failure. Surveying the quality of wind is a very cheap fix to a very expensive problem.
Isherwood: A significant number of manufacturing facilities have been using natural ventilation since Henry Ford started the assembly line. Opening windows on the exterior of the building and exhausting in the centers has been a consistent design concept and is still used in facilities today. Large amounts of equipment have impacted the comfort and expectations of the team members that work on the factory floors, and conditioning the space has become more normal. Most of these systems have not been designed using energy recovery because the high level of particulates in the exhaust air will clog the energy-recovery device. Energy recovery is common on individual pieces of infrastructure, such as process chillers, cooling towers, air compressors, etc. These recovery systems are commonplace in industrial facilities.
Crutchfield: PVs are easier to accommodate in a design. Wind turbines in this area of the country are not as desirable with our hurricane potential.
CSE: What are some of the challenges or issues when designing for water use in such facilities? Large-scale production facilities may have high water needs-how have you addressed this?
Isherwood: Most facilities have onsite water storage that helps with water usage. Most projects also have onsite waste treatment to prevent hazardous waste from leaving the facility. Our experience has been that facility owners have become very conscious about the environment and care about the impact their facilities make.
Campbell: It’s a struggle to reduce water consumption, but it’s highly important to clients, especially in the U.S., where water is expensive. To start, we target reducing water use by designing systems with less need for water in the first place, such as using adiabatic condensers instead of evaporative. After the system has been optimized, we get into reclaiming water from condensate, reed beds, and rainwater harvesting.
CSE: How has the demand for energy-recovery technology influenced the design of these kinds of projects?
Crutchfield: We feel that every facility should attempt to reclaim as much energy as possible from any available source. From energy-recovery coils in the HVAC system’s exhaust airstreams to energy recovery of heat from wastewater, we present every energy-recovery option to the owner. As part of this, we provide the analysis on the economics of pursuing the option so that the owner can understand not only the first cost, but also the long-term operating cost, maintenance cost, and potential savings.
Campbell: We always look to reduce energy use from the beginning of the design, and then look to energy recovery where it makes sense. In refrigerated warehouses, we use energy recovery in various places, including from wastewater to subcool refrigeration liquid lines, which increases the efficiency and capacity of the refrigeration system. We use heat from refrigeration to heat floors and office spaces. No matter what, we always do a thermodynamic evaluation of the whole energy system to establish how to reuse energy.
CSE: High-performance design strategies have been shown to have an impact on the performance of the building and its occupants. What value-add items are you adding to these kinds of facilities to make the buildings perform at a higher and more efficient level?
Campbell: Every warehouse we design is high-performance. These are buildings with low profit margins, so performance is an integral part of our standard design process.
CSE: What level of performance are you being asked to achieve, such as WELL Building Standards, LEED certification, net zero energy, Passive House, or other guidelines? Describe a project and its goals.
Campbell: I’ve been involved in warehouses designed to LEED, net zero energy, and zero waste during construction. The most common goal is LEED, although our clients often choose not to pursue certification despite sustainability being baked into the design. If tasked to LEED Gold, we try to overshoot and hit Platinum. One recent LEED Gold project of ours is the Ben E. Keith distribution center in Houston. This project is designed with cost-saving, energy-efficient features like rainwater harvesting, reuse of harvested water for landscape irrigation and refrigeration condenser make-up water, low-flow plumbing fixtures, bio-based foam insulation, heat island effect-reducing roof, showers and bicycle storage, light-pollution-reducing site lighting fixtures, and energy-recovering air handlers.