Refrigeration cycle apparatus

A refrigeration cycle apparatus comprising:

• a first compressor;
• an expander;
• a second compressor directly connected to a rotation axis of said expander;
• a use side heat exchanger;
• a heat source side heat exchanger;
• a four-way valve;
• and
• said refrigeration cycle apparatus changing a cooling operation and a heating operation of said use side heat exchanger by means of said four-way valve,
• wherein a refrigeration cycle is constituted by sequentially connecting said first compressor, said four-way valve, said heat source side heat exchanger, said expander, said use side heat exchanger and said second compressor,
• wherein said refrigeration cycle is provided with a first expansion valve arranged between said expander and said heat source side heat exchanger, and a second expansion valve arranged between said expander and said use side heat exchanger, and
• wherein a rectifying means for always circulating a refrigerant in an inlet side of the expander is provided between said first and second expansion valves and said expander.

A refrigerant cycle apparatus comprising:

• a two-stage compressor having a first stage compression portion and a second stage compression portion;
• a use side heat exchanger;
• a pressure reducing apparatus;
• a heat source side heat exchanger;
• a four-way valve;
• and
• said refrigeration cycle apparatus changing a cooling operation and a heating operation of said use side heat exchanger by means of said four-way valve,
• wherein a discharge flow passage of the first stage compression portion of said two-stage compressor is branched, one is connected to a suction flow passage of said second stage compression portion, and another is connected to a flow passage changing means such as a three-way valve or the like for changing a flow passage to said use side heat exchanger and a flow passage to said heat source side heat exchanger.

A refrigerant cycle apparatus comprising:

• a compressor;
• a use side heat exchanger;
• a heat source side heat exchanger;
• and
• an expanding means,
• wherein the refrigeration cycle apparatus comprises:
• a refrigerant tank provided in parallel to said expanding means;
• two flow passages for taking in and out the refrigerant with respect to said refrigerant tank;
• valves respectively provided in said flow passages;
• a temperature detecting device provided in an outlet side of the heat source side heat exchanger at a time of a cooling operation, or in an outlet side of the use side heat exchanger at a time of a heating operation;
• a pressure detecting device for detecting a discharge pressure of said compressor;
• and
• a control apparatus for opening and closing said two valves or controlling opening ratio of said two valves on the basis of a temperature detected by said temperature detecting device, and a pressure detected by said pressure detecting device.