Patent ID: 8863545
Filing Date: 2014-10-21
Classification: F25B

Abstract:
1. A refrigeration apparatus comprising: a compression mechanism having a plurality of compression elements arranged and configured so that refrigerant discharged from a first-stage compression element of the plurality of compression elements is sequentially compressed by a second-stage compression element; a heat source-side heat exchanger arranged and configured to operate as a radiator or an evaporator of refrigerant; a usage-side heat exchanger arranged and configured to operate as an evaporator or a radiator of refrigerant; a switching mechanism arranged and configured to switch between a second-stage injection tube arranged and configured to branch off refrigerant, which has radiated heat in the heat source-side heat exchanger or the usage-side heat exchanger, and to return the refrigerant to the second-stage compression element; an intermediate heat exchanger an intermediate heat exchanger bypass tube connected to the intermediate refrigerant tube so as to bypass the intermediate heat exchanger, the intermediate heat exchanger bypass tube being arranged and configured to ensure that refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element is not cooled by the intermediate heat exchanger during a heating operation in which the switching mechanism is in the heating operation state, and an injection rate optimization control being performed to control a flow rate of refrigerant returned to the second-stage compression element through the second-stage injection tube on that an injection ratio is greater during the heating operation than during the cooling operation, the injection ratio being a ratio of flow rate of refrigerant returned to the second-stage compression element through the second-stage injection tube relative to flow rate of refrigerant discharged from the compression mechanism.