| abstract |
A refrigerator oil which can inhibit precipitation attributable to a working oil remaining in a refrigeration system, a hydraulic fluid for a refrigerator, and a method for lubricating a refrigeration system. The refrigerator oil comprises a polyhydric alcohol ester compound as a lube base oil and 0.5 to 4.5 % by weight of at least one polyoxyalkylene compound. The hydraulic fluid comprises the refrigerator oil and a hydrofluorocarbon coolant. The lubrication method comprises using the above hydraulic fluid in the lubrication of a refrigeration system wherein a metal working oil containing a component sparingly soluble in a polyhydric alcohol ester compound or a hydrofluorocarbon coolant, or a metal working oil containing a component having a high reactivity with a polyhydric alcohol ester compound or a hydrofluorocarbon coolant. The precipitation in a refrigeration system, particularly in the tubing in the system, can be inhibited. |