Field Assessment of Refrigerated Display Cases Air Curtain Guiding Vanes

In January 2022 we completed a laboratory study (ET19SCE1110) on the proposed air vane technology under contract with the SCE ET&P group to investigate the benefits of installing air vanes on vertical open refrigerated display cases used in grocery stores.  In the lab assessment, a reduction of 17 W per linear foot of storage was realized for meat and produce temperatures. This corresponded to a 20-25% reduction in compressor power usage for meat and produce.  According to a prior SCE Air Vane study, there are an average of 330 linear feet of open display cases in a typical store, and an estimated 900,000 linear feet within the SCE service area alone savings could yield an average of 5.7 kW of load reduction per store, and 15.4MW grid reduction assuming market saturation.  It is expected that the field assessment will meet or exceed this savings reduction.    A real-world field assessment is needed to update the lab findings. Air vanes are thin rigid strips (either a single strip or two strips) attached to the end of each shelf. They are positioned perpendicularly across the air curtain of the display case and direct air flow down, strengthening the barrier reducing infiltration between the refrigerated space and the warm moist air outside of the display case. Performance benefits were quantified in the lab test by the reduction in infiltration load which accounts for approx. 85% of open display case energy use.     Considering the large presence of open vertical refrigerated display cases in Southern California Edison’s service territory*, the potential energy savings could have a large impact throughout CA for the commercial target market. The project will estimate this potential from the field assessed results. It is estimated that a medium sized 50,000 ft2 supermarket vanes could potentially save approximately 50,000 kWh annually. There is additional potential energy savings if large supermarkets and small convenience stores were also to adopt the measure.    This project is designed to field verify savings, which has not been done, and understand relevant market barriers to inform future tech transfer and utility program. Two air vane designs will be field tested at three locations in different climate zones with a representative sample of different display case configurations. Two typical temperature set points will be selected. One for merchandizing meat at discharge air temperature of 32°F and the other for merchandizing products at discharge air temperature of 37°F.     *Estimated at 10,760 stores in the SCE service territory based on CEUS.