Provided is a cogeneration system that includes a plurality of fuel cell devices capable of supplying heat and power to a heat load and a power load and a control device connected to the fuel cell devices. The control device determines an operation mode on the basis of at least one of a heat demand value and a power demand value. The control device controls a power generation efficiency and a heat recovery efficiency by controlling the fuel cell devices on the basis of the operation mode determined.

A plant includes a fuel supply line for supplying high-pressure fuel gas; and at least one expander disposed in the fuel supply line and configured to extract power from the high-pressure fuel gas by expanding the high-pressure fuel gas.

Various designs and configurations of and methods of operating fuel cell units, fuel cell systems and combined heat and power systems are provided that permit efficient thermal management of such units and systems to improve their operation.

A fuel cell device includes: a fuel cell; and a controller configured to provide a notification to a user and to control a first electronic device configured to make hot water that is heated with exhaust heat of the fuel cell be discharged in response to an operation of the user, in which the controller is configured to, when the fuel cell is in an inactive state, make the first electronic device display a notification that the fuel cell is inactive, and is configured to, when the fuel cell is not reactivated after display of the notification and the user operates the first electronic device, make the first electronic device provide a notification with at least one of a warning sound and warning display.

A proton-conducting solid oxide fuel cell system includes a proton-conducting solid oxide fuel cell including an anode through which a flow of fuel is directed, and a cathode through which a flow of air containing 9% to 100% oxygen is directed, and a water recovery portion. The water recovery portion includes an anode water recovery unit to recover anode water from anode products output from the anode, and a cathode water recovery unit to recover cathode water from cathode products output from the cathode.

A carbon dioxide recovery system for collecting carbon dioxide from an exhaust gas generated in a facility including a combustion device includes: a first exhaust gas passage through which the exhaust gas containing carbon dioxide flows; a fuel cell including an anode, a cathode disposed on the first exhaust gas passage so that the exhaust gas from the first exhaust gas passage is supplied to the cathode, and an electrolyte transferring, from the cathode to the anode, a carbonate ion derived from carbon dioxide contained in the exhaust gas from the first exhaust gas passage; and a second exhaust gas passage diverging from the first exhaust gas passage upstream of the cathode so as to bypass the cathode. A part of the exhaust gas is introduced to the second exhaust gas passage.

A power management server controls a fuel cell system including a power generator. The power management server includes at least one processor. The processor is configured to execute a reception process and control process. The reception process incudes a reception process of receiving a massage including an information element indicating an operation state of the fuel cell system. The control process includes a control process of controlling the fuel cell system which the operation state is a power generating state, in preference to the fuel cell system which the operation state is a starting up state, stopping state, and stop operating state, in a control target period.

Embodiments of the present invention provide a single coolant loop (40) that can be used for cooling at least two systems (100, 26) that are generally operable at two different temperatures. Rather than providing two separate cooling loops that can provide the two different cooling temperatures, there is provided a single cooling loop (40) that can route, harness, and mix heated coolant so that the two system can be served by a single loop.

Various designs and configurations of and methods of operating fuel cell units, fuel cell systems and combined heat and power systems are provided that permit efficient thermal management of such units and systems to improve their operation.

Provided are a low-cost electrochemical device and the like that have both durability and high performance as well as excellent reliability. The electrochemical device includes at least one metal material, and the metal material is made of a Fe—Cr alloy that contains Ti in an amount of more than 0.10 mass % and 1.0 mass % or less.