Optimization of Refrigeration Defrost Schedules for Demand Shifting in Commercial Buildings

The share of intermittent energy resources is increasing year over year in electric utility energy portfolios. From an operational perspective, power grid operators need to utilize flexible generation and consumption resources to maintain system reliability while preserving supply and demand balance. This paper presents a practical optimization framework to unlock the load shifting capabilities of commercial refrigeration system to benefit end-users as well as electric utilities. The study focuses specifically on finding optimal defrost schedules for coordinated food store refrigeration units while accounting for predicted building electricity consumption, electricity prices, and the physics of commercial refrigeration systems. While the findings directly address commercial refrigerators and freezers operating in the territory of Southern California Edison (SCE), the results apply to other utility service territories and electric loads beyond refrigeration.