Energy efficient heat pump systems and methods

An energy efficient heat pump, comprising:

• a working fluid circuit;
• a first compressor disposed along the working fluid circuit, wherein the first compressor is configured to direct a working fluid along the working fluid circuit in a first direction in a first operating mode of the energy efficient heat pump;
• a second compressor disposed along the working fluid circuit, wherein the second compressor is configured to direct the working fluid along the working fluid circuit in a second direction in a second operating mode of the energy efficient heat pump, wherein the first compressor and the second compressor are arranged in parallel with one another relative to a flow of the working fluid along the working fluid circuit, and wherein the first direction is opposite the second direction;
• and
• a controller configured to operate the first compressor and the second compressor, wherein the controller is configured to execute a time delay subsequent to suspending operation of the first compressor and prior to initiating operation of the second compressor, execute the time delay subsequent to suspending operation of the second compressor and prior to initiating operation of the first compressor, or both.

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

• a first compressor disposed along a working fluid circuit and configured to direct a working fluid through the working fluid circuit in a first direction;
• a second compressor disposed along the working fluid circuit and configured to direct the working fluid through the working fluid circuit in a second direction, opposite the first direction, wherein the first compressor and the second compressor are arranged in parallel with one another relative to a flow of the working fluid along the working fluid circuit;
• and
• a controller configured to:
• operate the first compressor and suspend operation of the second compressor in a cooling mode of the energy efficient heat pump;
• operate the second compressor and suspend operation of the first compressor in a heating mode of the energy efficient heat pump;
• and
• operate the first compressor and suspend operation of the second compressor in a defrost mode of the energy efficient heat pump to adjust flow of the working fluid through the working fluid circuit from the second direction to the first direction.