Greg Jimmie

Track C: Infrastructure Renewal A Phenomenological Way to Save Energy
Fri/AM 10:30 AM - 11:00 AM
Energy Engineer
ETC Group
United States
Steps for Improving Air-Cooled and Water-Cooled Chiller Performance and Energy Efficiency

Presenters will discuss strategies to maximize air and water-cooled chiller performance, for example, using reset strategies to respond dynamically to cooling demand. A chiller’s efficiency is most important at non-peak conditions, where it usually runs. System pressure can be optimized by resetting pumps in response to AHU valve positions; chilled water temperature can be reset on the AHU’s collective ability to maintain setpoints. Condenser water should be as cold as weather conditions permit with a low limit dictated by the chiller manufacturer.

Air-cooled chillers are ‘packaged’ items so engineers rarely seek optimization opportunities. An understanding of their components and the refrigeration cycle might lead to efficiency improvements to beyond factory-rated performance. Compressor efficiency can be improved by maximizing the condenser surface used for condensing refrigerant. Presenters will showcase hardware and control modifications that maximize the condensing area, utilize de-superheating, or use pumps to maintain pressure through expansion devices.

Greg Jimmie is an Energy Engineer/Analyst at ETC Group. His main roles at ETC Group are the analysis and identification of energy efficiency opportunities. Greg works on a wide range of energy systems which include campus-wide, whole building, and small sub-systems. Greg is an expert in chiller plant sequencing and optimization. He works with engineers to troubleshoot and maximize plant performance. He also focuses on the building load side to enhance building performance.

Greg earned B.S. in Mechanical Engineering from the University of California, San Diego and completed ClimaCheck expert training in Europe. Greg is an active member of ASHRAE. He was recognized as 2020 AEE Region V Young Energy Professional of the Year.

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