Heat recovery apparatus and methods of increasing energy efficiency of hybrid heating systems using the apparatus

A hybrid heating system comprising a heat pump and a furnace, the hybrid heating system comprising:

• a heat recovery apparatus in fluid communication with the heat pump and the furnace, the heat recovery apparatus configured to (i) recover heat from flue gas discharged from the furnace, and (ii) transfer the recovered heat to a stream of refrigerant in the heat pump, the heat recovery apparatus comprising:
• a shell disposed in fluid communication with the furnace and configured to allow the flue gas to flow therethrough in a first direction;
• and
• one or more tubes disposed in fluid communication with the shell and the heat pump, the one or more tubes configured to allow a stream of refrigerant to flow therethrough in a second direction, wherein the second direction of the flow of stream of refrigerant is different from the first direction of the flow of the flue gas;
• one or more valves configured to regulate access between the heat recovery apparatus and the stream of refrigerant in the heat pump;
• and
• a control unit in communication with the one or more valves and configured to regulate access between the heat recovery apparatus and the heat pump during a heating mode based on one or more operating parameters of the hybrid heating system.

A method of increasing energy efficiency of a hybrid heating system during a heating mode, the hybrid heating system comprising a heat pump and a furnace, the method comprising:

• contacting a heat recovery apparatus with a stream of flue gas discharged from the furnace and a stream of refrigerant in the heat pump, wherein the heat recovery apparatus comprises a shell and one or more tubes disposed in contact with the shell;
• directing the flue gas to flow through the shell in a first direction;
• directing the stream of refrigerant to flow through the one or more tubes in a second direction, wherein the one or more tubes are fluidly communicated with a stream of refrigerant in the heat pump, and wherein the second direction of the flow of the stream of refrigerant is different from the first direction of the flow of the flue gas;
• and
• introducing, via the heat recovery apparatus, a stream of refrigerant to the stream of refrigerant in the heat pump during the heating mode and a defrosting mode.