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Laboratory Plug Load Diversity - Right-Sizing Equipment and Risk Management

William J. Starr, Jr., University of California-Davis
Paul A. Mathew, Ph.D., Lawrence Berkeley National Laboratory
David Frenze, PE
Susanna See, PE, Flack + Kurtz Inc

Heat gain from laboratory plug load is the dominant cooling load in most laboratories. Understanding the loads themselves and the diversity of the loads both in time and by laboratory area is critical to right-sizing mechanical systems. Lab designers and engineers are often encouraged to make recommendations based on input from the lab users/building owners that is relatively unspecific and relative. Owners are asked to approve the recommendations without being able to fully understand the risk/benefit balance with any immediate context. This inclines the designers and users to avoidance of an unknown risk without understanding its quantity.

UC Davis worked with lab planners and engineers to develop sampling protocols and installed data loggers on the electrical panels serving the plug loads of multiple existing functioning laboratories. This enabled the University to obtain key information about the peak loads and load diversity of labs in operation. By combining this information with user information about lab activity level and photographs of the relative density of the lab equipment, the loads can be discussed with laboratory users and designers in both a relative and absolute context.

The peak and average plug loads varied significantly from lab to lab within the sample group. The majority of labs had peak and average loads significantly below the original design loads and, in most cases, still below current design values.

Panel Discussion:
How can this information best be used to balance risk between the lab owner and the designers? How much latitude do HVAC designers take when gauging their air-system diversities. Is the industry ready to embrace a "risk-based approach"? If a design includes deep diversity factors for system sizing, how does the same design also mitigate post occupancy liability related to potential over/under design? How can the owner update this information to expand the time horizon to better understand lab use changes over time? How applicable is this information to other institutions?

Labs21 Connection:

By looking at real data on load values and diversity this approach informs right-sizing that directly applies to the Labs21 goal of optimizing whole building efficiency on a life-cycle basis. In addition, by collecting real data from functioning labs this approach sets the foundation for the University to track performance and share results with other institutions for continuous improvement. For example, by using the current information for a baseline, we will be able to see the direct implications of replacing standard lab refrigerators with higher efficiency models.


Bill Starr is a Senior Architect and Project Manager with the University of California, Davis office of Architects & Engineers (A&E). He is managing the Tahoe Center for Environmental Sciences, the Veterinary Medicine Instructional Facility and the Veterinary Medicine 3B Laboratory Building projects. All three projects are targeting LEED™ Silver certification or higher. Bill co-authored his office's sustainable design policy and the Davis campus' LEED™ baseline. His particular interests are the program-embedded energy conservation and the visual quality of the indoor environment.

Paul Mathew is a Staff Scientist at Lawrence Berkeley National Laboratory, where he works on applied research in energy efficiency and environmental sustainability in the built environment. His current work is focused on high performance, sustainable laboratory design for the Labs21 program, as well as risk analysis in energy efficiency projects for the Federal Energy Management Program. He has a Bachelor's degree in Architecture, and a Ph.D. in Building Performance and Diagnostics from Carnegie Mellon University. His work experience includes technical research, tool development, and training in energy efficiency, sustainable design, and risk management. Prior to joining LBNL, he worked at Enron Energy Services and the Center for Building Performance at Carnegie Mellon University.

David Frenze, PE, has over 20 years of business leadership, senior project management, and mechanical engineering experience, primarily in the chempharma, biopharma and university research marketplace. He maintains that delivering value in design and construction begins with dialogue-rich programming and planning sessions. Guiding principles include communication, accountability, project pre-planning, defined outcomes and genuine teamwork. Frenze, a strong believer in being a life long learner as well as educator, maintains active membership and committee involvement with ISPE, ASHRAE, PMI and Labs21. His credentials include a BSME from The Ohio State University and the LEED™ Accredited Professional Designer designation.

Susie See is a Senior Vice President and has been with Flack + Kurtz San Francisco for over eighteen years. Susie is the electrical engineer-of-record on many of F+K's largest and most challenging projects, establishing engineering concepts, selecting systems, and ensuring quality as the projects move through the design and production phases. As a LEED™ Accredited Professional Designer, Susie provides a high level technical understanding that ensures effective design, in energy efficiency, capacity and flexibility. Her designs have been recognized for their uniqueness and exhibit high operating efficiency at minimum energy cost, while ensuring attractive environments. Susie holds a Bachelors of Science in Architectural Engineering from the University of Colorado.

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