Refrigeration Capacity Load Matching

Commercial and industrial refrigeration systems frequently use fixed-speed compressors that operate inefficiently under variable load conditions, contributing to elevated energy consumption and greenhouse gas (GHG) emissions. In California, refrigerated warehouses consume over 2,600 GWh annually, underscoring the need for scalable efficiency solutions aligned with the state’s decarbonization goals.This study evaluates a retrofit emerging technology (ET) comprising a smart compressor control (SCC) system, a variable frequency drive (VFD), and temperature sensors. Unlike traditional pressure-based modulation, the SCC algorithm dynamically adjusts compressor operation based on suction and discharge temperatures, enabling more precise load matching. Field demonstrations were conducted at two refrigerated produce warehouses located in disadvantaged communities within California Climate Zones 9 and 10. The retrofit included four 40 horsepower (HP) compressors at Site 1 and four 25 HP compressors at Site 2, which were all fixed-speed reciprocating units. Compressor real power, compressor run time, outside air temperature (OAT), and space temperature were monitored during the summer season. Performance was normalized using temperature bins and regression modeling.Site 1 exhibited consistent improvements, achieving normalized energy savings of 20 percent to 22 percent, peak demand reductions of 25 percent to 30 percent, and annual GHG reductions of 10 to 11 metric tons of CO₂e per compressor. Site 2 yielded mixed results, two compressors demonstrated 12 percent to 22 percent energy savings, peak demand reductions of 5 percent to 7 percent, and annual GHG reductions of 4 to 7 metric tons of CO₂e per compressor, while the other two compressors showed increased energy use due to unadjusted defrost cycles. Simple payback periods ranged from 1.7 to 2.0 years for compressors with positive savings. Although the customer at Site 2 reported pre-existing defrost issues, customers at both sites reported no operational or performance issues after ET installation.These findings indicate that the ET offers a viable pathway to enhance refrigeration system efficiency and support broader energy and climate policy objectives.