How to engineer manufacturing, industrial buildings: Energy efficiency
- C. Erik Larson, PE, LEED AP BD+C, Principal, Industrial Systems, Wood Harbinger, Bellevue, Wash.
- Ronald R. Regan, PE, Principal, Triad Consulting Engineers, Morris Plains, N.J.
- John Schlagetter, NCARB, PMP, CSI, CCS, CCCA, LEED Green Associate, Senior Architect, Process Plus, Cincinnati
- Wallace Sims, SET, NICET Fire Alarm Level IV, Lead Life Safety Engineer, CH2M Hill, Portland, Ore.
CSE: Many aspects of sustainability (power, HVAC, maintenance, etc.) require building personnel to follow certain practices in order to be effective. What, if anything, can you as an engineer do to help increase chances of success in this area?
Larson: You have to engage the building personnel in the design process, so you can build the design around what they’re willing to do. If they don’t buy-in up front, there’s very little chance it’s going to happen the way it should. Don’t give up if it’s hard to get an audience, and make sure you’re really talking to the people that are going to make it happen down the road.
Schlagetter: When employed to provide commissioning, we help ensure the requirements for operations and maintenance documentation, and demonstration and training, are satisfied.
Regan: We feel that the most significant impact in achieving sustainability goals is seen in companies that take time to promote the green or sustainable design features to their personnel. Whether it’s a monthly e-mail that shows how much energy has been reduced or signage throughout the building highlighting and explaining certain design features, awareness is key. If motion detection is somehow disabled or high-end trim on lighting is reset without the engineer’s knowledge, the features don’t accomplish the intention for having installed them. As engineers we work with management to monitor and track the effectiveness of these sustainable design features so they can, in turn, keep their personnel aware of the impact they have. The best results we see are in facilities engaged in the process, from the management and maintenance personnel down to each employee.
CSE: Could you share a success story in which you were able to deliver a highly sustainable project to a manufacturing/industrial facility client? Statistics on energy savings and other supporting evidence would be helpful.
Larson: Sustainable construction is a goal of many building owners, and we have benefitted from working with owners that truly want to demonstrate sustainability in the built environment. Using dedicated outside air systems with or without heat recovery, variable volume exhaust, and with proper system level zoning to match actual occupancy periods, we have been able to provide many facilities that achieve excellent performance. Heat recovery chillers, water-side economizer, and high-efficiency low-temperature heating water systems should all be on the table for consideration. For example, in our region, an appropriate system selection can result in savings for LEED EA Credit 1 of 30% to 40% (10 to 15 points). You can go for more, but complexity comes quickly, and systems are tough to keep running like they should be if they’re too hard for the average mechanic to figure out. Of course, don’t forget that the building envelope has a big impact, and lighting control strategies must be aggressive. Look for opportunities to integrate lighting system occupancy sensors into the HVAC system to avoid spending energy on ventilating non-occupied space.
CSE: Could you please share any experience you have using sustainable heating/cooling tech, such as geothermal systems or ground source heat pumps?
Larson: The moral to the story is that if you’re generating heat inside your facility, find someplace to use it. Strategies that take advantage of this include variable refrigerant flow (VRF) systems, water-source heat pump systems, and heating water systems that use heat recovered from generating chilled water for cooling. If you truly have a balanced load, your building will be the heat sink, and you won’t need to go drilling a field full of pits. That being said, ground source heat pumps are incredibly effective, and we have completed several projects that use large, open areas (such as a football field next to a high school) for the wells. If you’re looking at work over water, the body of water can also be your heat sink, but make sure your local environmental authorities don’t object with you rejecting your heat to their favorite swimming hole.
CSE: Please describe your experience with high-performance building projects in the manufacturing/industrial arena.
Larson: The Aeroman hangar in El Salvador is a great example of sustainable industrial construction. The hangars themselves are arranged to capture the prevailing winds, and channel this air across the hangar floor up large air induction chimneys that pull air all the way to the back of the hangar. This system, coupled with a translucent membrane roof, provides much higher levels of comfort for the occupants. Initially, the thought of a translucent roof in a tropical environment was hard to accept—100% shade is better than 97% shade, right? Wrong! The traditional insulated metal panel roof construction can reach a temperature of 150 F on the inside surface. The membrane roof was never more than a degree or two above ambient. This provided a much cooler roof surface, and allowed the mechanics to move out from under the heat lamp they had worked under in their older structures.