| abstract |
To provide a refrigerating unit using ammonia as a refrigerant,nwhich uses a lubricant that is excellent in the compatibility withnan ammonia refrigerant as well as in the lubricity and the stability. n An ammonia refrigerating unit formed by a refrigerating cyclenincluding a refrigeration compressor, a condenser, an expansionnvalve and an evaporator, wherein a working is circulated in saidnrefrigerating cycle, the working fluid including ammonia and anlubricant that contains a polyether compound represented by onenof the following formula (1) or (2):n X {-O-(AO) n -H} p n X {-O-(AO 1 ) a -(AO 2 ) b -H} p n[wherein X represents a residue resulting from removing a hydroxylngroup from a monool or a polyol; (AO) n represents an AO chainnconstituted by copolymerization of EO and C3 or more AO; (AO 1 ) a nrepresents an AO chain constituted by copolymerization of EO andnPO and/or BO; AO 2 represents C3 or more AO; and in the formula (1),nthe number of the secondary hydroxyl groups from among hydroxylngroups at the structural terminal is 50% or more of the total numbernof the hydroxyl groups]. |