Turndown for What!?! Laboratory Exhaust Fan Energy Optimization without Sacrificing Safety

Laboratory exhaust fans consume significant amounts of energy compared with other building systems. Depending on the initial mechanical design, architectural configuration, and meteorological site conditions, operators can achieve significant energy savings by running laboratory exhaust fans at a reduced volume flow rate. However, these systems must continue to support the health, safety, and comfort of laboratory users and occupants of nearby spaces. How can laboratory exhaust fan turndown be safely achieved?

This presentation will explain a methodology for effectively implementing laboratory exhaust fan turndown in both new and existing projects. The speakers will cover how to identify candidate laboratory buildings, assess potential energy savings, model exhaust plume dispersion through numerical analysis or physical wind tunnel testing, and conduct on-site testing and commissioning of installed laboratory exhaust fan systems.

The presentation will discuss two approaches to laboratory exhaust fan turndown: wind-responsive turndown using a local wind sensor and simple turndown. The session will explore challenges and successes in implementing laboratory exhaust fan turndown on science and technology campuses, with specific examples from recent projects.

Learning objectives:

1. Describe the process for evaluating, designing, and implementing laboratory exhaust fan turndown while maintaining appropriate environmental conditions for laboratory users, adjacent occupants, and ongoing research activities.
2. Evaluate existing and planned laboratory exhaust systems to identify suitable candidates for turndown, considering mechanical system configuration, building characteristics, site conditions, operational requirements, and potential energy savings.
3. Differentiate between variable air volume operating strategies for laboratory exhaust systems, including their control approaches, performance characteristics, and implications for airflow, occupant conditions, and overall system operation.
4. Apply strategies for implementing laboratory exhaust fan turndown in new and existing facilities, including exhaust plume dispersion analysis, system controls, monitoring, testing, and commissioning to support reliable and efficient operation.