Abstract: A vehicle includes a fuel-cell system having a fuel cell, a purge valve, and a drain line extending from the purge valve. A controller is programmed to open the purge valve according to a baseline purge routine when the drain line slopes away from the purge valve, and open the purge valve according to an enhanced purge routine when the drain line slopes towards the purge valve.

Abstract: This invention pertains to methods for controlling thermal aspects during operation of a solid oxide fuel cell (SOFC) system, including controlling target cathode and anode inlet stream temperatures and differential temperatures defined by the anode and cathode inlet and outlet streams. In one aspect, thermal management is achieved by controlling a combustion stream temperature and by employing one heat exchanger having two cold side pathways. In another aspect, thermal management is achieved by controlling a temperature of a combustion stream distributed through a cathode feed heat exchanger and an anode feed heat exchanger, optionally with bypassing a portion of the cathode air stream around the cathode feed heat exchanger. In another aspect, thermal management is achieved by employing a cathode feed heat exchanger to heat a cathode air stream and by employing an equalizer heat exchanger to equilibrate temperatures of the resulting heated cathode air stream and an anode fuel stream.

Abstract: A fuel cell stack includes: a first stack including: first unit cells stacked; and a first outer peripheral surface around a first stacking direction of the first unit cells; a second stack that is juxtaposed to the first stack including; second unit cells stacked along the first stacking direction of the first unit cells; and a second outer peripheral surface around a second stacking direction of the second unit cells; an external gas manifold that supplies and discharges a reactant gas to and from the first and second stacks; and an external coolant manifold that supplies and discharges a coolant to and from the first and second stacks.

Abstract: A fuel cell system includes a fuel cell stack, a gas liquid separator, a water level sensor, a drain valve, and a control unit. When a failure detection processing method is performed, a control unit makes a determination of main conditions where the water level sensor determines that water is present, a power generation current value of the fuel cell stack is not more than a predetermined current threshold value, a drain valve for discharging water in the gas liquid separator is open. Then, the control unit counts elapsed time when the main conditions are satisfied, and in the case where the main conditions are kept satisfied for the elapsed time which is larger than a time threshold value, the control unit determines that the water level sensor has a failure.

Abstract: A fuel cell system includes a fuel cell configured to be supplied with fuel and air to generate electricity, a reformer configured to reform the fuel to be supplied to the fuel cell, a heat source device configured to heat an off-gas discharged from the fuel cell to produce a heating gas and configured to heat the reformer, a fuel cell heating device configured to heat the air to be supplied to the fuel cell using the heating gas, a fuel cell temperature acquisition unit configured to acquire a temperature of the fuel cell, and a reformer temperature acquisition unit configured to acquire a temperature of the reformer.

Abstract: A system includes a fuel cell stack that receives a fluid, an actuator to increase or decrease a fluid temperature of the fluid, a pipe to facilitate flow of the fluid, and a memory designed to store a model of the fuel cell circuit. The system also includes an ECU that calculates mass flow values of the fluid through the fuel cell stack or the pipe based on a previously-determined mass flow value and the model of the fuel cell circuit. The ECU also calculates a plurality of pressure values corresponding to the fuel cell stack or the pipe based on the plurality of mass flow values and the model, controls the actuator position of the actuator to increase or decrease the fluid temperature based on at least one of the plurality of mass flow values and at least one of the plurality of pressure values.

Abstract: A fuel cell system includes: a first temperature sensor that measures the temperature of cooling water on the side of a cooling water outlet of a fuel cell; a second temperature sensor that measures the temperature of the cooling water on the side of a cooling water inlet of a water heater for heating the cooling water; a third temperature sensor that measures the temperature of the cooling water on the side of a cooling water outlet of the water heater; a cooling water pump that circulates the cooling water; and a control device. The control device is configured to determine that there is a cooling water leakage when the condition: “measurement temperature T1 measured by the first temperature sensor?measurement temperature T2 measured by the second temperature sensor” or the condition “no temperature difference ?T between measurement temperature T2 and measurement temperature T3 measured by the third temperature sensor” is met.

Abstract: An integrated fuel cell system includes fuel cells, fuel heat exchangers, air heat exchangers, and tail gas oxidizers. The tail gas oxidizers oxidize a (second) portion of fuel received from the fuel cells with effluent that is output from the fuel cells. Fuel cell stacks are fluidly coupled with the fuel heat exchangers and the tail gas oxidizers such that the fuel that is output from the fuel cells is split into a first portion that is directed back into the fuel heat exchangers and a second portion that is directed into the tail gas oxidizers.

Abstract: The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

Abstract: Various examples are provided for operational control of fuel cells. In one example, among others, a system for controlling a fuel cell includes a stack temperature controller in cascade with a liquid level controller. The liquid level controller can provide a control output based at least in part upon an indication of a liquid level of a liquid fuel tank and a level reference. The stack temperature controller can provide a fan speed control output based at least in part upon an indication of a stack temperature of the fuel cell and the control output of the liquid level controller. In another example, a system for estimating methanol concentration of a fuel cell system includes a state observer that generates an estimate of the methanol concentration of fuel provided to a direct methanol fuel cell based upon a plurality of states of the fuel cell system.

Abstract: A power source includes a container, a hydrogen fuel disposed within the container, a fuel cell wrapped around the hydrogen fuel within the container, electronics supported within the container and coupled to receive current from the fuel cell, a sensor coupled to the electronics to provide data representative of a sensed condition, and a charge storage device within the container and coupled to provide current to the electronics.

Abstract: Provided is a solid electrolyte laminate comprising a solid electrolyte layer having proton conductivity and a cathode electrode layer laminated on one side of the solid electrolyte layer and made of lanthanum strontium cobalt oxide (LSC). Also provided is a method for manufacturing the solid electrolyte. This solid electrolyte laminate can further comprise an anode electrode layer made of nickel-yttrium doped barium zirconate (Ni—BZY). This solid electrolyte laminate is suitable for a fuel cell operating in an intermediate temperature range less than or equal to 600° C.

Abstract: A electrochemical battery including: a battery module including one or more metal air cells which use oxygen gas as a positive electrode active material; an air supply configured to supply air to the battery module and to adjust an oxygen concentration in air supplied to the battery module; and a control unit configured to control an oxygen concentration adjusting operation of the air supply unit. Also a method of operating the electrochemical battery including: supplying air to a battery module using an air supply unit, the battery module including one or more metal air cells which use oxygen in air as a positive electrode active material; and controlling the air supply unit to adjust an oxygen concentration in the air supplied to the battery module.

Abstract: A hydrogen fuel cell cartridge is provided. Furthermore, a non-transitory computer-readable storage medium is provided, which is configured to store a program for controlling a hydrogen fuel cell cartridge of a fuel cell. In addition, a hydrogen fuel cell system is provided, which includes a plurality of cartridge segments and a control unit.

Abstract: A geothermic heater system for heating a geological formation includes a fuel cell stack assembly disposed at the surface of the geological formation and includes a plurality of fuel cells which convert chemical energy from a fuel into electricity through a chemical reaction with an oxidizing agent, thereby producing an anode exhaust and a cathode exhaust. The geothermic fuel cell system also includes a combustor disposed within a bore hole of the geological formation. The combustor combusts a mixture at least one of the anode exhaust and the cathode exhaust to produce a heated combustor exhaust. The combustor discharges the heated combustor exhaust to heat the geological formation.

Abstract: A turbine engine includes a fan that provides an air flow to the turbine engine as compressor intake air and as compressor bypass air, a first stage compressor positioned to receive the compressor intake air and output a first stage compressed air, and a boiler positioned to cool the first stage compressed air using a fluid. A second stage compressor is positioned to receive the cooled first stage compressed air. A pump is configured to pump the fluid as a liquid into the boiler, extract energy from the first stage compressed air, and cause the cooling of the first stage compressed air.

Abstract: In various aspects, systems and methods are provided for integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process. The molten carbonate fuel cells can be integrated with a Fischer-Tropsch synthesis process in various manners, including providing synthesis gas for use in producing hydrocarbonaceous carbons. Additionally, integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process can facilitate further processing of vent streams or secondary product streams generated during the synthesis process.

Abstract: Provided is a solid oxide fuel cell module that is small in size and is capable of stably generating power. A plurality of power generation units and are located such that a first fuel cell and an oxidant gas preheater connected to a second fuel cell adjacent to the first fuel cell are adjacent to each other. A solid oxide fuel cell module includes a partition member. The partition member partitions a combustion chamber into a region including the first fuel cell and a region including the second fuel cell as well as into the region including the first fuel cell and a region including the oxidant gas preheater connected to the second fuel cell.

Abstract: A fuel cell system includes a fuel cell with an anode chamber and a cathode chamber. The fuel cell system also includes a recirculation device that recirculates anode exhaust gas to the anode input, which includes a discharge line for discharging liquid and/or gas from the region of the recirculation device, and an air conveying device for supplying the cathode chamber with a supply air flow. A water separator, which is connected to the discharge line and through which at least a portion of the supply air flow passes, is situated between the air conveying device and the cathode chamber in the area of the supply air flow.

Abstract: Various hot box fuel cell system components are provided, such as heat exchangers, steam generator and other components.

Abstract: The invention relates to a solid oxide fuel cell system, wherein planar fuel cells are arranged in stacked form and in this respect an integrated post-combustion of non-oxidized components, or of not fully oxidized components, in the exhaust gas can take place. The fuel cells of a system in accordance with the invention have a cathode-electrolyte-anode unit. A bipolar plate is arranged between two respective fuel cells and channels for the supply and removal of a fuel gas to anodes and of an oxidizing agent to cathodes are present. The exhaust gases at the anode side or at the cathode side are introduced via internal additional channels or directly into an afterburner in which a catalytic post-oxidizing of the exhaust gas mixture formed with the exhaust gas at the anode side and at the cathode side takes place.

Abstract: In various aspects, systems and methods are provided for integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process. The molten carbonate fuel cells can be integrated with a Fischer-Tropsch synthesis process in various manners, including providing synthesis gas for use in producing hydrocarbonaceous carbons. Additionally, integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process can facilitate further processing of vent streams or secondary product streams generated during the synthesis process.

Abstract: A power generation system includes a fuel cell unit, a combustion apparatus, and a controller. The fuel cell unit includes a fuel cell, a casing, a ventilation fan (an air supply device), and a temperature detector configured to detect the temperature of outside air supplied to the casing. An air supply passage through which the outside air is supplied to the casing, and a discharge passage through which a flue gas from the combustion apparatus is discharged, are configured in such a manner as to allow a medium flowing through the air supply passage and a medium flowing through the discharge passage to exchange heat with each other. When the fuel cell unit is to be started up, if the temperature detected by the temperature detector is lower than or equal to a predetermined first temperature and the combustion apparatus is not in operation, the controller refrains from causing the fuel cell unit to operate.

Abstract: Systems and methods provide for the thermal management of a high temperature fuel cell. According to embodiments described herein, a non-reactant coolant is routed into a fuel cell from a compressor or a ram air source. The non-reactant coolant absorbs waste heat from the electrochemical reaction within the fuel cell. The heated coolant is discharged from the fuel cell and is vented to the surrounding environment or directed through a turbine. The energy recouped from the heated coolant by the turbine may be used to drive the compressor or a generator to create additional electricity and increase the efficiency of the fuel cell system. A portion of the heated coolant may be recycled into the non-reactant coolant entering the fuel cell to prevent thermal shock of the fuel cell.

Abstract: The invention relates to a system having high-temperature fuel cells, for example SOFCs. A reformer connected upstream of the high-temperature fuel cells at the anode side, a start burner for the preheating of the cathodes of the high-temperature fuel cells, an afterburner and an operating heat exchanger are present at the system in accordance with the invention. Oxidizing agent can be supplied to the high-temperature fuel cell cathodes through the operating heat exchanger. In addition, it can be heated with the exhaust gas of the high-temperature fuel cells. Exhaust gas conducted through the operating heat exchanger can flow in an exhaust gas line together with environmental air and can then be conducted away into the environment as cooled exhaust gas.

Abstract: A fuel cell system includes a fuel cell stack, a heat exchanger, a reformer, and a combustor. The combustor is provided around the heat exchanger. A combustion gas path for supplying a combustion gas produced in the combustor to the heat exchanger and an exhaust gas path for supplying an exhaust gas discharged from the fuel cell stack after consumption in power generation reaction are merged at a merger section provided on an upstream side of a heat medium inlet of the heat exchanger.

Abstract: An operating method is provided for a fuel cell system, in particular a fuel cell system in a motor vehicle. The system includes a cooling system via which waste heat of fuel cells of the fuel cell system is ultimately dissipated into the surrounding air, and a tank withstanding an internal pressure of the order of 150 bar and more. In the tank, fuel for the fuel cell system is stored in the cryogenic state, in particular as a cryogen, which tank has a heat exchanger in its storage volume, via which, in order to compensate for the pressure reduction resulting from the removal of fuel from the tank, heat can be supplied to the stored fuel in a controlled manner by way of a heat transfer medium.

Abstract: The invention provides a thermal management system for a fuel cell, a fuel cell system and a vehicle equipped with the fuel cell system. The thermal management system for a fuel cell comprises: a cooling system (100) for recovering the waste heat produced by the fuel cell system, a heat supply system (15) connected with the cooling system (100) to supply heat using the waste heat recovered by the cooling system (100). The fuel cell system comprises a fuel cell stack and the aforementioned thermal management system for a fuel cell.

Abstract: A method of controlling a concentration of a fuel to be supplied to a stack of a fuel cell system, the method including determining a reference concentration of the fuel to be supplied to the stack when the stack is in a normal mode, monitoring temperature of the stack, and controlling the concentration of the fuel to be supplied to the stack, based on a result of the monitoring the temperature of the stack.

Abstract: The multi-section cathode air heat exchanger (102) includes at least a first heat exchanger section (104), and a fixed contact oxidation catalyzed section (126) secured adjacent each other in a stack association. Cool cathode inlet air flows through cool air channels (110) of the at least first (104) and oxidation catalyzed sections (126). Hot anode exhaust flows through hot air channels (124) of the oxidation catalyzed section (126) and is combusted therein. The combusted anode exhaust then flows through hot air channels (112) of the first section (104) of the cathode air heat exchanger (102). The cool and hot air channels (110, 112) are secured in direct heat exchange relationship with each other so that temperatures of the heat exchanger (102) do not exceed 800° C. to minimize requirements for using expensive, high-temperature alloys.

Abstract: A heat exchanger for operating at an outlet of a hot fuel cell feeding the heat exchanger with oxidizer gas and with fuel gas, the heat exchanger including: a first flow circuit for oxidizer gas; a second flow circuit for fuel gas; a pre-mixer chamber fed both with oxidizer gas and with fuel gas from at least the second circuit; a combustion chamber fed with the gaseous mixture from the pre-mixer chamber and with oxidizer gas from the first circuit; and a flow circuit for flue gas, receiving the flue gas coming from the combustion chamber. The first flow circuit for oxidizer gas, the second flow circuit for fuel gas, the combustion chamber, and the flow circuit for flue gas are immersed in a common cooling fluid.

Abstract: A fuel cell vehicle air-conditioning apparatus includes: a cooling system that adjusts a temperature of a fuel cell; a waste heat collection unit that collects at least a part of waste heat from the fuel cell and uses the collected waste heat to heat a cabin interior of the fuel cell vehicle; and a heat creation unit that creates heat for heating the fuel cell vehicle. The fuel cell vehicle air-conditioning apparatus calculates a fuel consumption amount required for the fuel cell to generate a total power generation amount, which is a sum of a heating power generation amount and a travel power generation amount, calculates an optimum temperature, which is a temperature of the fuel cell at which the fuel consumption amount reaches a minimum, and controls the cooling system such that the temperature of the fuel cell reaches the optimum temperature.

Abstract: Solid oxide fuel cell that comprises a cell core and a thermal exchanger suitable for supplying said cell core with a fluid at a given temperature required for its operation, wherein the exchanger comprises a cold fluid circuit and provides a thermal interface with a hot fluid circuit, the cold fluid circuit supplying the fluid inlet of the cell core and the hot fluid circuit being supplied by the fluid outlet of the cell core, characterized in that the thermal exchanger is provided concentrically relative to the cell core.

Abstract: A fuel cell system for a vehicle includes a burner for producing a heat flow by combustion of a fuel gas which reacts with an oxidant. A heating heat exchanger provided to heat a vehicle passenger compartment is arranged in a coolant circuit of the fuel cell system, and is externally heated, at least at times, by the burner.

Abstract: The cogeneration system includes: a cogeneration apparatus which generates electric power using supplied fuel gas and supplies the electric power and heat; a heat accumulator which accumulates the heat supplied by the cogeneration apparatus; a controller which controls at least start and stop of the cogeneration apparatus; and a display unit that displays a remaining power generation duration which is a length of time for which the cogeneration apparatus can continue power generation. The controller further calculates the remaining power generation duration based on a remaining heat accumulation capacity which is a difference between (a) a maximum accumulable heat amount which is the amount of heat the heat accumulator is capable of accumulating and (b) a current accumulated heat amount that is the amount of heat currently accumulated in the heat accumulator, and causes the display unit to display the calculated remaining power generation duration.

Abstract: A fuel cell stack module includes a plurality of fuel cell stacks, a base supporting the plurality of fuel cell stacks, and a metal shell located over the base and the fuel cell stacks. The metal shell contains an integrated heat exchanger.

Abstract: A fuel cell stack (1) includes a plurality of stacked power generation cells (3), a heat exchange unit (7) provided between adjacent two of the power generation cells, a fuel gas supply path arranged to supply the power generation cells with a fuel gas, and an oxidant gas supply path (3, 7, 33, 34, 38) arranged to supply the power generation cells with an oxidant gas, wherein the fuel gas supply path includes in series a first path (7, 31) passing through the heat exchange unit (7), a second path (3, 32, 35, 37) passing through some of the plurality of power generation cells (3) in parallel, and a third path (3, 32, 36) passing through the other power generation cells in parallel.

Abstract: A highly efficient combined cooling, heating, and power (CCHP) system is capable of providing 100% utilization of an energy generator used by the system by distributing thermal and electrical outputs of the energy generator to loads and/or other storage apparatuses. The CCHP system includes an energy generator, which can be a fuel cell and a waste heat recovery unit that assists in recovering thermal energy from the energy generator and returning it to the energy generator, and/or providing it to a thermal load, or a storage as needed or desired.

Abstract: A fuel cell power plant includes a cell stack assembly having an anode and a cathode. A component is arranged in fluid connection with at least one of the anode and cathode. The component has a first shut-down cooling rate. A heat exchanger is arranged in fluid communication with and between the component and one of the anode and cathode. The heat exchanger has a second shut-down cooling rate greater than the first shut-down cooling rate. Water vapor within the fuel cell power plant outside of the cell stack assembly will condense and freeze in the heat exchanger rather than the component, avoiding malfunction of the component upon start-up in below freezing environments.

Abstract: An evaporative humidifier for a polymer electrolyte membrane fuel cell system including a fuel cell stack, comprising: a condensation channel to which exhaust gas from the fuel cell stack is introduced; an evaporation channel to which supply gas for the fuel cell stack is introduced; a partition wall for separating the condensation channel and the evaporation channel from each other; and a water distribution unit for supplying water into the evaporation channel, wherein the water is condensed in the condensation channel by heat exchange between the exhaust gas and the supply gas.

Abstract: A fuel cell system including: a fuel cell stack including plural fuel cells sandwiched between two end plates; a fuel supply system supplying a stream of fuel gas to the fuel cell stack; an oxidizer supply system supplying a stream of oxidizer gas to the fuel cell stack; a closed loop coolant circulation system driving a cooling liquid through the fuel cell stack so that the cooling liquid enters the fuel cell stack, absorbs heat from the fuel cells, and exits the fuel cell stack. The coolant circulation system includes a circulation pump driving the cooling liquid, a heat exchanger removing heat from the cooling liquid and for at least partially transferring the heat to the stream of fuel gas and/or the stream of oxidizer gas.

Abstract: A fuel cell system includes a fuel cell stack, a heavy hydrocarbon fuel source, and a fractionator configured to separate light ends from heavy ends of a heavy hydrocarbon fuel provided from the heavy hydrocarbon fuel source.

Abstract: In one embodiment, a membrane electrode assembly of a fuel cell has an anode aspect and a cathode aspect. A fuel distribution structure is disposed adjacent to the anode aspect. The fuel distribution structure has a fuel feed port configured to receive and inject liquid fuel to a flow field plate. The flow field plate has flow channels formed therein that split and spread from the fuel feed port to exit ports. The flow channels are configured to convey heat to fuel passing there through to substantially convert the liquid fuel to vaporous fuel within the flow channels. The exit ports are configured to deliver the resulting vaporous fuel to the anode aspect to substantially uniformly distribute fuel across the anode aspect. Further, an enthalpy exchanger and heat spreader assembly is in thermal contact with the fuel distribution structure and configured to provide to it heat from fuel cell operation.

Abstract: A fuel cell system includes a first heating mechanism and a second heating mechanism. The first heating mechanism directly heats a reformer using some of an exhaust gas discharged from a fuel cell stack. The second heating mechanism supplies the remaining exhaust gas to a heat exchanger and indirectly heats the reformer by the heat generated in the heat exchanger. The reformer performs preliminary reforming to produce a reformed gas. The reformed gas is supplied to an anode. At the anode, water produced in the power generation is present as a water vapor. The reformed gas is further reformed by steam reforming to produce a hydrogen gas.

Abstract: A fuel cell system for use with an endothermic fuel generator including a fuel cell stack having a primary fuel cell stack having a first thermal mass and a secondary fuel cell stack having a second thermal mass smaller than the first, the fuel cell system further including a first thermal coupling mechanism configured to thermally couple waste heat from the secondary fuel cell stack to the primary fuel cell stack, and a second thermal coupling mechanism configured to thermally couple waste heat from the fuel cell stack to the endothermic fuel generator.

Abstract: A fuel cell system includes a plurality of fuel cells arranged into a stack. A combustor receives a cathode exhaust flow from the fuel cell cathodes and a flow of fuel. The fuel is oxidized in the combustor by the cathode exhaust to produce a mixed exhaust flow. A cathode air flow path extends between a fresh air source and the fuel cell cathodes. An air preheater is arranged along the cathode air flow path, cathode air passing through the air preheater being heated therein by a flow of uncombusted anode exhaust from the fuel cell anodes. A cathode recuperator is arranged along the cathode air flow path, cathode air passing through the cathode recuperator being heated therein by the mixed exhaust flow. Water passing through a vaporizer is converted to steam by heat from the mixed exhaust flow and directed from the vaporizer to the fuel cell anodes.

Abstract: An electricity storage system comprising a reversible fuel cell having a first electrode and a second electrode separated by an ionically conducting electrolyte, and at least two chambers adapted to hold fuel and/or a reaction product, wherein the system is substantially closed and at least one reactant for discharge is hydrogen or oxygen.

Abstract: A control unit operates a fuel-cell power generation apparatus efficiently according to power consumption and supplied hot-water heat consumption which are different in each home. A generated-power command-pattern creation section creates a plurality of generated-power command patterns which are obtained from a combination of a start time and a stop time of the fuel-cell power generation apparatus, based on a power-consumption prediction value. A hot-water storage-tank heat-quantity calculation section calculates a stored hot-water heat quantity for a predetermined period in a hot-water storage tank, based on a supplied hot-water heat-consumption prediction. A fuel-cell system-energy calculation section calculates fuel-cell system energy which indicates the energy of a fuel required in hot-water supply equipment and electricity required in electric equipment when the fuel-cell power generation apparatus is operated in each generated-power command pattern.

Abstract: A fuel cell system (1) is provided and includes a fuel cell stack (3), a cathode recuperator heat exchanger (33) adapted to heat an air inlet stream using heat from a fuel cell stack cathode exhaust stream, and an air preheater heat exchanger (39) which is adapted to heat the air inlet stream using heat from a fuel cell stack anode exhaust stream.

Abstract: A fuel cell system includes a fuel cell module and a condenser apparatus. The condenser apparatus includes a first condenser using an oxygen-containing as a coolant, and a second condenser using hot water stored in a hot water tank as the coolant. Further, the fuel cell system includes a control device for controlling at least one of a flow rate of the exhaust gas supplied to the first condenser and a flow rate of the exhaust gas supplied to the second condenser based on at least any of a water level of the hot water in the hot water tank, a temperature of the hot water in the hot water tank, and a water level of the condensed water in the condenser apparatus.