PURPOSE: To improve durability of a compressor by providing in a passage for refrigerant composed of halogenated hydrocarbon compounds a drier charged with a desiccant composed of synthetic zeolite and an acid removing device, thereby removing inorganic acid in a refrigeration system to prevent the synthetic zeolite from being crushed.

CONSTITUTION: Refigerant compressed at a compressor 11 is delivered through a condenser 14 and a drier 15, and the pressure thereof is reduced in a capillary tube 18 and then is fed into an evaporator 19 to evaporate it, thereby generating cold air. The evaporated refrigerant is returned to the compressor 11 via an accumulator 20. In such a refigeration system, desiccants 16 comprising spherically formed synthetic zeolite are charged into the drier 15. An acid removing device 2 charged with adsorbents 3 prepared by forming alkaline activated alumina into spherical bodies, 5mm in diameter, is provided downstream of the accumulator 20, where an inorganic acid contained in the refrigerant is removed, whereby degradation and crushing of synthetic zeolite constituting the desiccants 16 can be avoided.