Commercial and industrial refrigeration systems consume asignificant portion of U.S. electrical energy. In this research,advanced expansion valve and control algorithms are evaluatedto quantify the potential energy savings due to improved systemregulation and efficient start-up of vapor-compression refrigerationsystems. The performance of the new micro-electromechanicalsystem (MEMS) actuators with different controlstrategies is compared with that of the standard mechanicalvalves and a commercially available superheat controller. Additionally,this research includes a comprehensive set of experimentaltests that identify the most effective elements of advanced valvecontrol strategies, including the impact of refrigerant migrationcontrol strategies. The experimental results confirm that 30% to50% improvements in cyclic coefficient of performance (COP)are possible using improved expansion valve controls, while thebenefits of preventing refrigerant migration do not outweigh theadditional cooling achieved if refrigerant continues to flowthrough the expansion valve during the compressor OFF period.