Micro-combined heat and power heat pump defrost procedure
AssigneeTrane International Inc.
InventorStephen Stewart Hancock
Life of this patent
Estimating the term…
Abstract
Systems and methods are disclosed that may include recovering heat from a generator to defrost the heat exchanger by passing a heat transfer fluid from the generator through a recovery heat exchanger that is configured to promote heat transfer between the heat transfer fluid and a refrigerant flowing therethrough, reducing a restriction of the refrigerant, reducing an airflow through the heat exchanger, and delivering the heated refrigerant to the heat exchanger. Systems and methods may also include recovering heat from an exhaust of the generator to deter the formation of frozen condensate on the outdoor heat exchanger by diverting at least a portion of a hot exhaust fluid discharged by the generator onto the outdoor heat exchanger.
Claims19
A defrost mode for a heat pump heating, ventilation, and/or air conditioning (HVAC) system, comprising:
- a refrigerant circuit comprising a heat exchanger, wherein the heat exchanger is configured to receive a refrigerant in a first flow direction in the refrigerant circuit while operating the HVAC system in a heating mode;
- a generator coupled to the refrigerant circuit through a generator fluid circuit, wherein the generator is configured to produce heat as a function of operating the generator;
- a recovery heat exchanger coupled to the generator and the heat exchanger and configured to receive at least a portion of the heat from the generator through the generator fluid circuit;
- an exhaust vent in fluid communication with an exhaust of the generator and configured to receive heated exhaust air from the generator,
- a controller coupled to each of the generator and the HVAC, wherein the controller is configured to:
- operate the HVAC system in the defrost mode, wherein the defrost mode comprises operating the HVAC system in the heating mode;
- selectively divert the heated exhaust air from the generator to the heat exchanger;
- provide at least the portion of the heat from the generator to the recovery heat exchanger through the generator fluid circuit while reducing a restriction of flow of the refrigerant provided by a refrigerant restriction device to the heat exchanger;
- and
- reduce an airflow across the heat exchanger to increase a rate of heat transfer from the refrigerant to a frozen condensate in contact with the heat exchanger while continually providing heat to an indoor area conditioned by the HVAC system.
A method of operating a heat pump heating, ventilation, and/or air conditioning (HVAC) system in a defrost mode, comprising:
- providing a refrigerant circuit comprising a heat exchanger, wherein the heat exchanger is configured to receive a refrigerant in a first flow direction in the refrigerant circuit while operating the HVAC system in a heating mode;
- coupling a generator to the refrigerant circuit through a generator fluid circuit;
- providing an exhaust vent in fluid communication with an exhaust of the generator and configured to receive heated exhaust air from the generator;
- producing heat as a function of operating the generator;
- operating the HVAC system in the heating mode by flowing a refrigerant in a first flow direction through a heat exchanger;
- and
- operating the HVAC system in the defrost mode, wherein the defrost mode comprises:
- operating the HVAC system in the heating mode;
- selectively diverting the heated exhaust air from the generator to the heat exchanger;
- and
- providing at least the portion of the heat from the generator to a recovery heat exchanger while reducing a restriction of flow of the refrigerant provided by a refrigerant restriction device to the heat exchanger;
- and
- reducing an airflow across the heat exchanger to increase a rate of heat transfer from the refrigerant to a frozen condensate in contact with the heat exchanger while continually providing heat to an indoor area conditioned by the HVAC system.
Dependencies are inferred from the claim text.