Provided is a fuel cell system. The fuel cell system comprises: a reformer that reforms fuel; a reformed fuel storage unit that receives the reformed fuel from the reformer and stores same; a fuel cell stack that generates electric power and heat by using the reformed fuel; a boiler unit that provides heating by using heating water, a battery unit that stores the electric power generated in the fuel cell stack; and a control unit that controls the operations of the reformer, the reformed fuel storage unit, the fuel cell stack, the boiler unit, and the battery unit, wherein the control unit controls the reformer to operate using the heating water of the boiler unit when the temperature of the heating water of the boiler unit is higher than a first baseline and the stored amount of the reformed fuel stored in the reformed fuel storage unit is equal to or less than a second baseline.

Provided is a fuel cell system. The fuel cell system comprises: a reformer that reforms fuel; a reformed fuel storage unit that receives the reformed fuel from the reformer and stores same; a fuel cell stack that generates electric power and heat by using the reformed fuel; a boiler unit that provides heating by using heating water, a battery unit that stores the electric power generated in the fuel cell stack; and a control unit that controls the operations of the reformer, the reformed fuel storage unit, the fuel cell stack, the boiler unit, and the battery unit, wherein the control unit controls the reformer to operate using the heating water of the boiler unit when the temperature of the heating water of the boiler unit is higher than a first baseline and the stored amount of the reformed fuel stored in the reformed fuel storage unit is equal to or less than a second baseline.

A water heating system can include a water heater having a tank, an inlet line, and an outlet line, where the inlet line provides unheated water to the tank, and where the outlet line draws heated water from the tank. The water heating system can also include multiple sensing devices, where each sensing device of the plurality of sensing devices measures a parameter associated with the tank. The water heating system can further include a controller communicably coupled to the plurality of sensing devices, where the controller determines an amount of heated water in the tank based on measurements made by the plurality of sensing devices.

System and method for grid load-up dual set point. The invention provides a method of operating a water heater having a tank configured to store water. The method includes heating, via a first heating element, a first portion of the water to a first temperature set point. The method also includes heating, via a second heating element, a second portion of the water to a second temperature set point, the second temperature set point being greater than the first temperature set point. The method additionally includes receiving a load-up signal from a grid controller, and heating, via the first heating element, the first portion of the water to the second temperature set point upon receiving he load-up signal.

A hot water supply apparatus has: a thermo-sensitive valve which is connected in parallel to a cold water delivery pipe and a hot water delivery pipe and which is closed when the hot water temperature to flow inside the valve is above a predetermined temperature to thereby shut off communication between the cold water delivery pipe and the hot water delivery pipe; and a circulation pump. By operation of the circulation pump, water circulation takes place from a heat exchanger through the hot water delivery pipe, a return pipe, the circulation pump, and a cold water supply pipe back to the heat exchanger. When the thermo-sensitive valve is open, water circulation takes place also through the thermo-sensitive valve. Instantaneous hot water supply operation is finished when an amount detected by a flow sensor falls below a predetermined amount during the instantaneous hot water supply operation.

A method and system of providing hot water efficiently. A cost of heating a volume of water to a predetermined temperature in a first water heater is determined. A cost of transferring a volume of hot water from a second water heater of a network of interconnected water heaters to the first water heater is determined. Upon determining that the cost of transferring the volume of hot water from the second water heater is lower than the cost of heating the volume of water of the first water heater, the second water heater transfers at least part of the volume of hot water to the first water heater. Otherwise, the volume of water is heated to the predetermined temperature in the first water heater.

A fluid heating apparatus according to an embodiment disclosed herein may include a burner, a heat exchanger, a first flow rate sensor that detects a flow rate of a fluid supplied to the heat exchanger, a temperature sensor that detects a temperature of a fluid discharged from the heat exchanger, and a controller that controls a first pump provided in an internal circulation flow path on the basis of the flow rate detected by the first flow rate sensor to manage the flow rate of the fluid supplied to the heat exchanger and controls an operation of the burner on the basis of the temperature detected by the temperature sensor.

A fluid heating apparatus according to an embodiment disclosed herein may include a burner, a heat exchanger, a first flow rate sensor that detects a flow rate of a fluid supplied to the heat exchanger, a temperature sensor that detects a temperature of a fluid discharged from the heat exchanger, and a controller that controls a first pump provided in an internal circulation flow path on the basis of the flow rate detected by the first flow rate sensor to manage the flow rate of the fluid supplied to the heat exchanger and controls an operation of the burner on the basis of the temperature detected by the temperature sensor.

A hot water supply device includes a heater, a water channel, a mixing valve unit, and a circulation mechanism. The mixing valve unit has a valve member and a drive unit configured to drive the valve member to change a mixing ratio of supply water heated by the heater and unheated water. The circulation mechanism has: a connection passage that connects the water channel to the heater by being branched from a part of the water channel between the mixing valve unit and the heater; an on-off valve that opens and closes the connection passage; and a pump configured to return the supply water remaining in the water channel through the connection passage to the heater. A drive amount acquisition unit acquires a drive amount of the drive unit, and a controller controls the circulation mechanism based on the drive amount acquired by the drive amount acquisition unit.

The present disclosure provides a water heating system for efficient heating of water for immediate use that fits either to industrial applications or household applications. The water heating system is suitable to be combined with a solar heating unit and it can be operated on electric power or on gas-based heating units for providing hot water to multiple consumers for household or industrial utilization. Furthermore, the system can be stand-alone, operating without any additional water heating system and can provide an immediate stream of hot water, e.g. it can be installed within a water supplying appliance. The water can operate in two modes: (1) heating for immediate use of hot water; and (2) heating water to be contained in a reservoir for later use. The system uses a two (bi) directional flow valve.