The analysis of change of refrigerating of АRМ is carried out at use for overcooling of liquid ammonia of reversible cycles, and also the compressor refrigerating machine working on R134a. A values of optimum temperatures of overcooling of ammonia before throttling, answering to maximum of refrigerating efficiency of АRМ are found. It is offered to use for overcooling of ammonia in a range from 30 °С up to 7 °С the absorption lithium bromide refrigerating machine, and from 7 °С up to –10 °С — the compressor refrigerating machine. The refrigerating efficiency of such combined ammoniac refrigerating machine will be raised on 12,6 %.