Optimizing Laboratory Exhaust Fan Performance and Efficiency at Cambridge University

Brad Cochran, PE, CPP, Inc.
Malcolm Tait, KJ Tait Engineers

The United Kingdom has significantly greater utility rates than in the U.S., and therefore the fume exhaust systems in the UK would appear to offer good opportunities for the adoption of sustainable strategies that can be applied to laboratory exhaust design to safely minimize energy usage. The University of Cambridge has commissioned a study to evaluate potential retrofits to the existing laboratory exhaust system on their Department of Chemistry Building. The Building is currently equipped with 29 No separate laboratory exhaust systems, which are a significant element of the building's total energy cost. A majority of these systems have redundancy in the fan motors but not in the fans themselves (two motors on a common fan belt). As such, there is no back-up if a fan belt breaks or a fan needs to be taken off-line for servicing. Also, trending data shows that some of the systems are overloaded while neighboring systems are significantly underutilized.

Therefore, the purpose of the study is to develop new exhaust strategies that will enhance the efficacy of the exhaust systems to meet the building demand in the event of a fan failure; to spread out the building demand between exhaust fans so as to increase the capacity is available to the areas in need; and employ a VAV exhaust strategy to minimize energy usage.

This presentation will provide detailed information on the various options that were evaluated for the retrofit. The feasibility of each option, along with its effectiveness at meeting the design goals, and their potential return on invest will be discussed. The objective is to provide the audience with information on how state-of-the-art VAV exhaust strategies can be used in conjunction with optimized equipment configurations to produce safe, efficient, and flexible laboratory exhaust systems even in a retrofit environment.

Biographies:

Brad Cochran is a registered Professional Engineer in the State of Colorado and has nearly 20 years of experience conducting wind-tunnel and mathematical modeling studies related to laboratory exhaust design. Brad is active in ASHRAE and is currently serving as the lead author of Chapter 9, Exhaust Stack Design, in the upcoming latest edition of the ASHRAE Laboratory Design Guide. He is a voting member of TC9.10 Laboratory Systems. During the past decade, Brad has focused on defining new design techniques to minimize the energy requirements for laboratory exhaust stacks. In 2005 Brad developed the first laboratory exhaust system that utilized local wind data to minimize exhaust fan horsepower requirements. He has authored and presented several papers on the subject of energy efficient laboratory exhaust design for ASHRAE, Labs 21, R&D Magazine, Lab Manager, LabWize, IFMA, AMCA, and AWMA.

Malcolm Tait is a Director with the firm of building services designers, KJ Tait Engineers. Malcolm graduated from South Bank University and then completed a Masters Degree in inter-disciplinary design at the University of Cambridge. He has been with KJ Tait Engineers for 23 years and has specialist design expertise in the field of Higher Education and the Bio-Tech Sectors. He has a good understanding of operational laboratory buildings, as the firm undertakes an array of minor works on the University of Cambridge's various laboratories. He is a regular attendee at Labs21 and the UK equivalent S-Labs.

 

Note: I2SL did not edit or revise abstract or biography text. Abstracts and biographies are displayed as submitted by the author(s).