Radiative Sky Cooling-Enabled Efficiency Improvements on Commercial Cooling Systems 

Project Result

This project was completed in 2024. SkyCool installed its energy-saving, capacity-improving panel array at two supermarkets in California. The first site was in Red Bluff, California, where an array was used to add modular heat rejection capacity to an underperforming condenser. SkyCool’s array increased the heat rejection of the refrigeration cycle by 35 kilowatts (34 percent) and lowered the discharge pressure of the condenser by up to 50 pounds per square inch, gauge. As a result of the added capacity, the power demand for the refrigeration system was reduced by 5 to 7 kilowatts, and a maximum energy savings of 15 percent was achieved.

At the second site in Milpitas, California, SkyCool demonstrated an array that could both subcool, adding efficiency during cooler times of the year, and precool, adding condensing capacity during the hotter times of the year. The array increased the heat rejection of the refrigeration system by 25 kilowatts (27 percent) and lowered the electrical demand of the medium-temperature compressors by 3 kilowatts. When the ambient temperature was lower than 75 degrees Fahrenheit (24 degrees Celsius), SkyCool’s array was able to add between 10 to 25 degrees Fahrenheit (6 to 14 degrees Celsius) of additional subcooling, which improved the efficiency of the refrigeration system by 14 percent. The net benefit of SkyCool’s panels saved nearly 20,000 kilowatt-hours per year.