The Impact of Existing Building Commissioning Measures on Peak Electric Demand

This paper investigates the independent impact of several different existing building commissioning (EBCx) measures on peak electric demand, to help understand measures to prioritize based on peak demand savings along with the usually-assessed energy consumption savings. The investigation involves developing separate EnergyPlusT models for each EBCx measure, and comparing the peak electric demand generated by each model with a baseline model. The pre-EBCx and post-EBCx models are based on a community college campus which underwent an EBCx project between 2014 and 2015, resulting in an average of 34% savings in energy consumption and peak demand. The total peak demand reduction determined from the individual EBCx measures was only 26% compared to the measured reduction of 34%. Applying an outside air temperature reset schedule to AHUs' supply air temperature (SAT) setpoints reduced peak demand by an average of 16.7%, mainly due to the reduction of unnecessary cooling and reheating, especially in winter. The optimization of AHU control schedules, which minimized the unnecessary operation of some units during peak hours produced peak demand savings of 6%, while the optimization of space temperature setpoints contributed another 3%. While other measures impact electric demand during non-peak hours, none produced peak electric demand reduction greater than 1%. Other measures did not generate peak demand savings while still generating energy consumption savings, mainly for the reason of not having an impact during peak hours.