OAKLAND, Calif. -- Safeway here has seen a 5% to 8% reduction in refrigerated systems' energy use from its pilot test of hydrofluorocarbon 407-A coolant. bon R-502 it replaced. The test was conducted in the Menlo Park store's ice cream and frozen food display cases. Several different temperature settings were used and project engineers said the gas performed well at both medium and low temperatures. The HFCs used in the test are manufactured by ICI Klea, Wilmington, Del.