William P. Bahnfleth, Ph.D., P.E.
Department of Architectural Engineering
The Pennsylvania State University
1426 South Pugh Street
University Park, PA 16801
United States
(814) 863-2076
Region: III
Honorarium: None

William Bahnfleth is a professor of architectural engineering at the Pennsylvania State University (Penn State) in University Park, PA, where he has been employed since 1994. Previously, he was a Senior Consultant for ZBA, Inc. in Cincinnati, OH and a Principal Investigator at the U.S. Army Construction Engineering Research Laboratory in Champaign, IL. He holds BS, MS, and PhD degrees in Mechanical Engineering from the University of Illinois, where he also earned a bachelor of music degree in instrumental performance. His is a registered professional engineer. At Penn State, Dr. Bahnfleth teaches undergraduate courses in HVAC fundamentals, HVAC system design, and controls and graduate courses in chilled water systems, hot water and steam systems, and indoor air quality. His research interests cover a wide variety of indoor environmental control topics including chilled water pumping systems, stratified thermal energy storage, protection of building occupants from indoor bioaerosol releases, ultraviolet germicidal irradiation systems, and others. He is the author or co-author of more than 170 technical papers and articles and 14 books and book chapters. He consults on the design of chilled water thermal energy storage systems and has been involved in more than 20 projects world-wide.

Dr. Bahnfleth is a fellow of ASHRAE, the American Society of Mechanical Engineers (ASME) and the International Society for Indoor Air Quality and Climate (ISIAQ). He has served ASHRAE in a variety of capacities, including Student Branch Advisor, Chapter Governor, Technical Committee and Standing Committee Chair, and as Director-at-Large, Vice President, Treasurer, and 2013-14 Society President. His honors include a 1st place ASHRAE Technology Award, Transactions Paper Award, Distinguished Service and Exceptional Service Awards, The Louise and Bill Holladay Distinguished Fellow Award, the E.K. Campbell Award of Merit and the F. Paul Anderson Award. He is also a recipient of the Penn State Engineering Alumni Society’s World-Class Engineering Faculty Award.

The ASHRAE Building Energy Labeling Program

Whether voluntary or mandatory, the rating of the energy use and indoor environmental quality of buildings is a growing trend worldwide. In 2009, ASHRAE introduced its own "Building Energy Quotient" (bEQ) labeling program for new and existing buildings and is now in the process of implementing it. It is a comprehensive and rigorous program comprising not only an energy use performance scale, but also tools and procedures for performing ratings and certifications for the qualified energy modelers and building assessors who will use them. This presentation provides an overview of the bEQ program, compares it to other building certification programs, identifies the benefits of certification, and summarize the current status of the bEQ program and plans for the future.

Integrating Indoor Air Quality and Energy Efficiency in Buildings

Buildings are one of the largest energy end use sectors in countries around the globe. Concerns for the availability of energy supplies and the impact of energy use on the environment are driving a worldwide focus on energy end use reduction. In this push for dramatic changes in the energy use intensity of the building sector, it is essential that the fundamental importance of indoor environmental quality, particularly indoor air quality, not be lost. This presentation addresses: 1) the significance of indoor air quality in terms of its impact on health and productivity and associated costs; 2) the inseparable linkage between indoor air quality and building energy demands, including examples of efficient technologies for maintaining good indoor air quality; and 3) the need for an approach to building research, design, and operation that recognizes this connection.

Fundamentals of Ultraviolet Germicidal Irradiation for Air and Surface Disinfection

Germicidal radiation produced by low pressure mercury vapor lamps and other sources is seeing increasing application both for air disinfection and for control of biological growth on surface.  This presentation provides an overview of the fundamentals of ultraviolet germicidal irradiation (UVGI) including principles of operation, component characteristics, system types, applications, and published evidence of effectiveness.

Variable Primary Flow Chilled Water Systems

Variable primary flow is being adopted in chilled water system design with increasing frequency as a lower cost, more efficient alternative to primary/secondary design that is not as susceptible to low delta T syndrome.  Subtopics include a review of variable primary flow and primary/secondary system types; causes and effects of low delta T syndrome and potential remedies; design considerations for variable primary flow, and, comparisons of variable primary flow and primary/secondary flow taken from case study and research literature.

Thermal Energy Storage in the Era of Sustainability

During the 1980s and 1990s, cool thermal energy storage (TES) was a key technology in US utility demand-side management (DSM) programs.  Interest in TES declined steeply as incentives disappeared during utility deregulation.  Today, the focus of design has shifted from energy cost savings toward sustainability and it is reasonable to ask whether TES has anything to offer in this environment.  This presentation will review the essentials of cool thermal energy storage and examine its relevance to sustainable design.  Specific issues examined will include the impact of TES on site and source energy consumption, the economic case for TES without the incentives of the DSM era and the role of TES in achieving net zero energy buildings and communities.

HVAC and Risk from Airborne Hazards

Interest in protection of building occupants from airborne chemical and biological agents was strongly stimulated by several terrorist incidents early in the 21st century. The discussion generated by these incidents brought to the forefront the concept of formal risk assessment for airborne hazards, which few building designers or owners undertake. Over time, the discussion of HVAC security has declined without significant changes having been made to either design requirements or procedures, yet the issue remains and is more important than is generally acknowledged, since accidental exposures have the potential to be just as harmful as intentional ones. This presentation provides an overview of the key issues relating to protection of building occupants from chemical and biological releases including: HVAC system and building characteristics that affect exposure, the spectrum of available countermeasures and their characteristics, risk assessment processes, and metrics for describing the level of risk and degree of improvement achieved by a risk reduction strategy.

HVAC and Airborne Infectious Diseases

Concern regarding the risk of hospital acquired infections and the effect of the built environment on epidemics of drug-resistant diseases is increasing. The well-educated designer and owner needs to understand the mechanisms by which infectious disease is transmitted indoors, the extent to which HVAC system characteristics affect probability of infection, available means for controlling risk with demonstrated effectiveness. These topics are presented and discussed using the ASHRAE Board of Directors-approved Position Document Airborne Infectious Diseases as a framework. Pertinent scientific knowledge about modes of disease transmission is reviewed, its practical implications for control are discussed, and the three HVAC-related control methods identified by the Position Document: ventilation, particulate filtration, and ultraviolet germicidal irradiation, are presented and compared. General recommendations for reducing risk are provided and knowledge gaps that need to be filled are identified.