Energy efficient heat pump systems and methods

An energy efficient heat pump for a heating, ventilation, and air conditioning (HVAC) system, comprising:

• a compressor disposed along a working fluid circuit, wherein the compressor comprises a suction port configured to receive a first flow of working fluid from the working fluid circuit and a plurality of injection ports configured to receive a second flow of working fluid from an injection conduit extending from the working fluid circuit to the plurality of injection ports, wherein the plurality of injection ports is disposed along the compressor downstream of the suction port relative to a flow direction of working fluid through the compressor;
• an expansion device disposed along the injection conduit, wherein the expansion device is configured to reduce a temperature and a pressure of the second flow of working fluid directed to the plurality of injection ports;
• a sensor configured to detect an ambient temperature;
• and
• a controller communicatively coupled to the sensor and to the expansion device, wherein the controller is configured to:
• receive feedback from the sensor indicative of the ambient temperature;
• compare the ambient temperature to a set point temperature;
• in response to a first determination that the ambient temperature is equal to or greater than the set point temperature, adjust the expansion device toward an open position;
• and
• in response to a second determination that the ambient temperature is less than the set point temperature, adjust the expansion device toward a closed position.

An energy efficient heat pump for a heating, ventilation, and air conditioning (HVAC) system, comprising:

• a working fluid circuit;
• a compressor disposed along the working fluid circuit, wherein the compressor is configured to direct a working fluid along the working fluid circuit, and the compressor comprises a suction port, a discharge port, and an injection port disposed between the suction port and the discharge port relative to a flow of the working fluid through the compressor;
• an injection conduit extending from the working fluid circuit to the injection port, wherein the injection conduit comprises an expansion device, and the injection conduit is configured to direct a portion of the working fluid from the working fluid circuit to the injection port;
• a reversing valve disposed along the working fluid circuit, wherein the reversing valve is adjustable to direct the working fluid along the working fluid circuit in a first direction and to direct the working fluid along the working fluid circuit in a second direction, opposite the first direction;
• a sensor configured to detect an ambient temperature;
• and
• a controller communicatively coupled to the sensor and to the expansion device, wherein the controller is configured to:
• receive feedback from the sensor indicative of the ambient temperature;
• compare the ambient temperature to a set point temperature;
• in response to a first determination that the ambient temperature is equal to or greater than the set point temperature, adjust the expansion device toward an open position;
• and
• in response to a second determination that the ambient temperature is less than the set point temperature, adjust the expansion device toward a closed position.