AIR CONDITIONING DEVICE

PROBLEM TO BE SOLVED: To improve reliability of a compressor by an accumulator supplying a proper amount of oil to the compressor.SOLUTION: A refrigerant and a refrigerating machine oil enclosed in a refrigeration cycle are composed with physical properties that a low temperature-side two-layer separation temperature is higher than -20°C in a state that an oil concentration to the refrigerant is within a range of 20-50%. An accumulator includes an oil inflow pipe to which oil separated by an oil separator flows, a refrigerant inflow pipe to which a refrigerant flows, an oil storage portion for storing oil flowing therein from the oil inflow pipe, a liquid refrigerant storage portion for storing a liquid refrigerant flowing therein from the refrigerant inflow pipe separately from the oil storage portion, an oil return pipe having an opening for sucking the oil stored in a bottom portion of the oil storage portion and allowing the oil to flow upward, and a refrigerant return pipe having an opening for sucking the liquid refrigerant stored in a bottom portion of the liquid refrigerant storage portion and allowing the liquid refrigerant to flow upward. The refrigerant return pipe and the oil return pipe are joined, and the refrigerant from the refrigerant inflow pipe flows to the refrigerant return pipe or the oil return pipe. 【課題】アキュムレータにより適切な量の油を圧縮機へ供給することで圧縮機の信頼性を向上する。【解決手段】冷凍サイクルに封入される冷媒と冷凍機油とが、冷媒に対する油濃度が２０〜５０％の範囲で低温側二層分離温度が−２０℃を上回るような物性で構成されるとともに、アキュムレータは、油分離器により分離された油が流入する油流入管と、冷媒が流入する冷媒流入管と、油流入管から流入する油を貯留する油貯留部と、油貯留部とは別に冷媒流入管から流入する液冷媒を貯留する液冷媒貯留部と、油貯留部の底部に貯留された油を吸いこむ開口部を有し、上方に油を流す油戻し管と、液冷媒貯留部の底部に貯留された液冷媒を吸い込む開口部を有し、上方に液冷媒を流す冷媒戻し管と、を備え、冷媒戻し管と油戻し管とを合流させ、冷媒流入管からの冷媒が冷媒戻し管又は油戻し管を流れる。【選択図】図３