Balancing Act: Safety, Energy Efficiency and Aesthetics of Laboratory Exhaust Systems

Jeffrey Abramson, Payette
Ruth McMath, Rowan Williams Davies & Irwin Inc.

Achieving a safe, effective and energy efficient laboratory ventilation system involves a broad array of considerations. Reducing energy use and cost are only one side of the equation and must be considered from an aesthetic perspective. Through the lens of a single project, this session addresses the question: Is it possible to reduce energy use and cost while maintaining a healthy environment in and around the building as well as aligning with the design aesthetic of the project?

This session, co-presented by Payette and RWDI, explores the range of ventilation design challenges and successful strategies applied to the New Science Center at Amherst College. Charged with responding to the environmental challenges with an efficient and responsible project, the design team sought to decrease energy use through reducing laboratory airflow when conditions allowed. A key component of this efficiency measure was the control of exhaust air systems to allow for variable air flow resulting in reduced heating, cooling and fan energy.

Set at the base of a hillside below the historic campus quad, the New Science Center roof-scape is often the first visual point of reference for the project, which challenged the team to limit the size of the penthouse and any highly visible equipment located on the roof. Application of a wind-responsive system was proposed in order to not only achieve energy reduction, but also decrease stack height and limit rooftop equipment.

The speakers will share project-specific conditions and exhaust dispersion criteria which drove the design process. Participants will be guided through the key aspects of the system including fan design and control as well as exhaust stack and anemometer siting. The session will cover how results from wind tunnel modeling influenced the final design and quantify improved performance through energy model analysis.

Learning Objectives

• Participants will learn the best approaches for quantifying re-entrainment criteria and evaluate mitigation options early in the design process.
• Participants will be able to identify the importance of fine-tuning exhaust stack and building intake locations in reducing fan energy.
• At the end of the session, participants will better understand active control strategies such as wind monitoring, variable fan flow rates, individual fan turndown and staged fan turnoff.
• Participants will be able to recognize the measurable energy savings when the ability to vary lab ventilation based on occupancy is coupled with variable air volume exhaust system.

Biographies:

Since joining Payette in 2003, Jeff has been particularly instrumental in the design, technical development and graphic documentation of highly complex envelope systems. Jeff believes architecture today must harmoniously balance both building performance and aesthetics. He has leveraged his work on high performance envelopes to focus more broadly on developing and implementing sustainable design strategies specifically for undergraduate teaching and research science facilities.

Ruth is a technical coordinator at Rowan Williams Davies & Irwin Inc. (RWDI). She has provided guidance on exhaust dispersion and intake designs in the context of the local microclimate, for a wide range of laboratory, health care and other facilities. When consulting on projects, Ruth strives to adopt a holistic view of building design, providing advice that helps facilities to achieve safe, comfortable, efficient environments for their users.

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