Energy efficient heat pump with control system and compressor injection

An energy efficient heat pump, comprising:

• a working fluid circuit configured to circulate a working fluid, wherein the working fluid circuit comprises a compressor, a first heat exchanger, a second heat exchanger, a first expansion device, an economizer, and a reversing valve, wherein the reversing valve is configured to adjust a flow direction of the working fluid through the working fluid circuit;
• a first conduit of the working fluid circuit, wherein the first conduit extends between the first heat exchanger and the second heat exchanger, the economizer is disposed along the first conduit, and the first conduit is configured to direct the working fluid between the first heat exchanger and the second heat exchanger and through the economizer;
• and
• an injection conduit extending from the first conduit to an injection port of the compressor, wherein the injection conduit comprises a second expansion device, and the injection conduit is configured to direct a portion of the working fluid from the working fluid circuit, through the second expansion device, through the economizer, and to the injection port of the compressor to inject of the portion of the working fluid into the compressor.

An energy efficient heat pump, comprising:

• a working fluid circuit configured to circulate a working fluid, wherein the working fluid circuit comprises a compressor, a first heat exchanger, a second heat exchanger, a first expansion device, a second expansion device, an economizer, and a reversing valve, wherein the reversing valve is configured to adjust a flow direction of the working fluid through the working fluid circuit;
• a first conduit of the working fluid circuit, wherein the first conduit extends between the first heat exchanger and the second heat exchanger, the economizer is disposed along the first conduit, and the first conduit is configured to direct the working fluid between the first heat exchanger and the second heat exchanger and through the economizer;
• and
• an injection conduit extending from the first conduit to an injection port of the compressor, wherein the injection conduit comprises a third expansion device, and the economizer is disposed along the injection conduit;
• and
• a controller configured to control the first expansion device, the second expansion device, and the third expansion device based on an operating mode of the energy efficient heat pump, a pressure ratio of the compressor, and a speed of the compressor.