REFRIGERATION DEVICE

PROBLEM TO BE SOLVED: To provide a refrigeration device capable of improving cooling capacity and efficiency by controlling a high pressure-side pressure of a low stage-side refrigerant circuit to an optimum value.SOLUTION: In a refrigeration device 1 which includes a high stage-side refrigerant circuit 4, first and second low stage-side refrigerant circuits 6A, 6B, and cascade heat exchangers 43A, 43B for cooling a high pressure-side refrigerant of the low stage-side refrigerant circuits 6A, 6B by evaporating a refrigerant in the high stage-side refrigerant circuit 4, and in which carbon dioxide is sealed in the refrigerant circuits 4, 6A, 6B as the refrigerant, a pressure regulation expansion valve 31 is disposed for regulating a high pressure-side pressure of the low stage-side refrigerant circuits 6A, 6B. 【課題】低段側冷媒回路の高圧側圧力を最適な値に制御して、冷却能力と効率を向上させることができる冷凍装置を提供する。【解決手段】高段側冷媒回路４と、第１、第２の低段側冷媒回路６Ａ、６Ｂと、高段側冷媒回路４の冷媒を蒸発させて低段側冷媒回路６Ａ、６Ｂの高圧側冷媒を冷却するカスケード熱交換器４３Ａ、４３Ｂとを備え、各冷媒回路４、６Ａ、６Ｂには二酸化炭素を冷媒として封入して成る冷凍装置１において、低段側冷媒回路６Ａ、６Ｂの高圧側圧力を調整するための圧力調整用膨張弁３１を設けた。【選択図】図１