Integrating Energy Conservation and Occupant Safety

John Duffy, Affiliated Engineers, Inc.
Bryan Schanely, Duke University

Designed in 2017 and now in construction, the engineering building at Duke University's Pratt School of Engineering is organized around three research 'neighborhoods': health innovation, computing and intelligent systems, and environmental health. Integrated with these neighborhoods are a traditional mix of academic spaces and 5,700 SF maker space. Three guiding principles drove the design philosophy:

  1. Flexible building systems that can evolve over time.
  2. Superior energy stewardship and sustainability.
  3. A 24x7x365 facility that can be safely maintained.

Planners and designers know there are frequent changes in lab requirements including conversion of non-lab spaces into lab spaces. Duke's engineering program is in a constant state of evolution. So much that a research floor is generically populated for future flexibility that could include a bio medical component.

A decoupled 100%-outside-air system with 4 pipe chilled beams for space conditioning provides maximum flexibility. This approach allows the building to adapt to any combination of lab, office, or seminar/conference space without the need to replace or modify the major HVAC infrastructure.

The energy penalty for this flexibility would be substantial if not for a commitment to high performance. Energy use is optimized by:

  • Chilled beams.
  • Wrap-around heat pipes.
  • Combined heat recovery / preheat.
  • 1,200 FPM lab air exhaust velocity optimized by wind tunnel testing.
  • High efficiency heat recovery for building and domestic water heating.
  • High performance fume hoods.
  • Reduced lab ventilation rates using a facility monitoring system.
  • Low-flow fixtures in the restrooms.
  • 0.62 W/SF lighting power density.
  • Occupancy sensors.
  • Electrical design that is configured to accept a microturbine.
  • Integrated commissioning.

The anticipated energy reduction is 30%. The expected EUI is 222 kBTU / GSF rather than 345 kBTU / GSF for a comparable code building.

There is significant redundancy in traditional equipment that allows one piece of equipment to be serviced while systems remain operable. Uninterrupted building operation extends to the electrical design in two unique ways. First, there are the two independent electrical services to the building. Second, alternating branches of the electrical distribution system serve the mechanical equipment from multiple power sources in multiple configurations. This allows for concurrent electrical maintenance without shutting down major building systems.

Learning Objectives

  • Understand the importance of wind-wake studies on determining opportunities for reducing exhaust stack velocities and energy usage without adversely impacting health and safety;
  • Identify strategies for reducing air change rates in engineering wet lab spaces while retaining the ability to actively respond to adverse air quality events;
  • Identify unique opportunities to provide system level redundancy utilizing two independent electrical utility services in combination with traditional equipment level redundancy to allow safe and secure building operation during power outages and major equipment maintenance events; and
  • Understand the value of making decisions for high performance buildings while maximizing occupant safety.


John Duffy has served as Project Manager on a variety of state-of-the-art science facilities including facilities with programs for Chemistry, Biology, Math and Physics, Marine Biology, Psychology, Chemical, and Electrical and Mechanical Engineering. These facilities have included spaces for BSL-2 and BSL-3 labs, animal holding, clean rooms, electron microscopes, imaging equipment, laser labs, and hazardous production labs.

Bryan is the DUES (Utility & Engineering Services) representative for the Pratt Engineering building at Duke University. Before coming to Duke, Bryan worked as an engineering consultant and as a project engineer / estimator for a mechanical contractor on a wide variety of MEP projects.


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