Utilizing Load Shifting for Optimal Compressor Sequencing in Industrial Refrigeration

TL;DR

This paper explores how load shifting combined with compressor sequencing can significantly reduce energy consumption in industrial refrigeration, demonstrating potential savings of up to 20% based on real-world data.

Contribution

It introduces a novel approach integrating load shifting with compressor sequencing to enhance energy efficiency in industrial refrigeration systems.

Findings

Load shifting enables more efficient compressor operation.

Optimal compressor sequencing without load shifting often leads to inefficiencies.

Load shifting can reduce energy use by up to 20%.

Abstract

The ubiquity and energy needs of industrial refrigeration has prompted several research studies investigating various control opportunities for reducing energy demand. This work focuses on one such opportunity, termed compressor sequencing, which entails intelligently selecting the operational state of the compressors to service the required refrigeration load with the least possible work. We first study the static compressor sequencing problem and observe that deriving the optimal compressor operational state is computationally challenging and can vary dramatically based on the refrigeration load. Thus we introduce load shifting in conjunction with compressor sequencing, which entails strategically precooling the facility to allow for more efficient compressor operation. Interestingly, we show that load shifting not only provides benefits in computing the optimal compressor operational state, but also can lead to significant energy savings. Our results are based on and compared to real-world sensor data from an operating industrial refrigeration site of Butterball LLC located in Huntsville, AR, which demonstrated that without load shifting, even optimal compressor operation results in compressors often running at intermediate capacity levels, which can lead to inefficiencies. Through collected data, we demonstrate that a load shifting approach for compressor sequencing has the potential to reduce energy use of the compressors up to 20% compared to optimal sequencing without load shifting.