Load Shifting for Compressor Sequencing in Industrial Refrigeration

The ubiquity and energy needs of industrial refrigeration has prompted several research studies investigating various control opportunities for reducing energy demand. This study focuses on one such opportunity termed compressor sequencing, which involves selecting the optimal operational state of compressors to fulfill the required refrigeration load efficiently. We first investigate the static compressor sequencing problem and highlight its computational complexity and load-dependent variability. To address these issues, we propose integrating load shifting with compressor sequencing, in which the facility is strategically pre-cooled to enhance compressor efficiency. Our results, based on real-world sensor data from an industrial refrigeration site of Butterball LLC® located in Huntsville, AR, demonstrate that without load shifting, even optimal compressor operation often results in inefficiencies due to compressors running at intermediate capacity levels. By implementing load shifting, we observe potential energy savings of up to 20% compared to optimal sequencing without load shifting.