This article originally appeared on HPAC Engineering
By Eric Toback, PE, LEED AP
Cool cash: Optimized chillers deliver ROI at Baylor University
Keeping students and faculty comfortable at a 172-year-old school deep in the heart of Texas is no easy task. But energy engineers have found sizable savings by optimizing an already well-run network of campus chillers
Challenge: Automating a heterogeneous plant
Prior to optimization, plant operators judged when to add or shed load based on demand. Their criteria were sound, but unfortunately they acted on critical decisions — such as shifting a building’s temperature or starting or stopping equipment — only once per shift. Human error made the plant even more inefficient. For example, operators could interpret criteria differently, resulting in inconsistent system adjustments.
Solution: Finding the ideal balance points
Optimum Energy’s OptimumLOOP is a closed-loop solution that reads data every 30 seconds and dynamically adjusts the chiller plant equipment in real time, in response to changing conditions. The company’s engineers had to find the balance point for each chiller, whether it was running concurrently with the others or individually. To do this with a valve table would have meant determining the ideal valve sequence — out of a possible 256 run combinations — that would enable the chillers to maintain appropriate water flows while operating as efficiently as possible. Since that was not a plausible approach, OptimumLOOP dynamically adjusts the control valves on all running chillers to maintain an equal percentage flow on each.
Result: Saving money, energy, and carbon emissions
OptimumLOOP is saving Baylor more than $460,000 a year (about 24 percent of electricity costs) and dramatically shrinking energy consumption. The university has also saved an average 5.8 million kilowatt-hours and 8.6 million pounds of CO2 per year.
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