The invention provides a water tank heating method and unit, an electronic device and a solid oxide fuel cell (SOFC) system. Before the SOFC system is started, ice in a water tank has been heated up, so after the SOFC system is started, the heating time of the heated ice, i.e., the thawing time of the water tank, will be shortened. Further, in the ice heating process, a pre-set needed SOFC thawing time determined according to current stack outlet temperature is used as a heating control parameter. As the stack outlet temperature is a key factor influencing the starting time of the SOFC system, the heating control will be more accurate if the pre-set needed SOFC thawing time corresponding to the stack outlet temperature is used as a heating control parameter.

The invention provides a water tank heating method and unit, an electronic device and a solid oxide fuel cell (SOFC) system. Before the SOFC system is started, ice in a water tank has been heated up, so after the SOFC system is started, the heating time of the heated ice, i.e., the thawing time of the water tank, will be shortened. Further, in the ice heating process, a pre-set needed SOFC thawing time determined according to current stack outlet temperature is used as a heating control parameter. As the stack outlet temperature is a key factor influencing the starting time of the SOFC system, the heating control will be more accurate if the pre-set needed SOFC thawing time corresponding to the stack outlet temperature is used as a heating control parameter.

A device, system, and a method are provided for notifying a user to replace a sacrificial anode in a pool or spa system. The device is provided in the form of a body defining a cavity, a sacrificial anode, and a sensor. The sacrificial anode substantially surrounds the cavity when the sacrificial anode is coupled to the body. The sensor is at least partially received into the cavity and is in communication with a pool automation system. The sensor is designed to transmit a signal to the pool automation system when the sensor detects water within the cavity. The signal is processed by the pool automation system, and the pool automation system may then transmit a notification to a user that the sacrificial anode is depleted.

A device, system, and a method are provided for notifying a user to replace a sacrificial anode in a pool or spa system. The device is provided in the form of a body defining a cavity, a sacrificial anode, and a sensor. The sacrificial anode substantially surrounds the cavity when the sacrificial anode is coupled to the body. The sensor is at least partially received into the cavity and is in communication with a pool automation system. The sensor is designed to transmit a signal to the pool automation system when the sensor detects water within the cavity. The signal is processed by the pool automation system, and the pool automation system may then transmit a notification to a user that the sacrificial anode is depleted.

Methods and systems are provided for remotely controlling a plurality of heating devices in one or more sites having a fossil fuel-based heating device and an electrical heating device. An example method involves operating a management processor to determine whether a current system supply is greater than a current system demand. In response to determining that the current system supply is greater than the current system demand, the management processor identifies at least one site to receive an opportunity to use electrical heating and transmits an opportunity signal to the local controller of the at least one site. The method can also involve operating each local controller to receive the opportunity signal from the management processor and generate one or more signals to control an operation the fossil fuel-based heating device or the electrical heating device of the site based in part on the opportunity signal.

Methods and systems are provided for remotely controlling a plurality of heating devices in one or more sites having a fossil fuel-based heating device and an electrical heating device. An example method involves operating a management processor to determine whether a current system supply is greater than a current system demand. In response to determining that the current system supply is greater than the current system demand, the management processor identifies at least one site to receive an opportunity to use electrical heating and transmits an opportunity signal to the local controller of the at least one site. The method can also involve operating each local controller to receive the opportunity signal from the management processor and generate one or more signals to control an operation the fossil fuel-based heating device or the electrical heating device of the site based in part on the opportunity signal.

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.

Systems and methods for integrating photovoltaic (PV) energy into water heater systems are disclosed. The disclosed technology includes determining whether a current water temperature is less than a first PV heat point that is greater than a normal heat point, and if so, outputting instructions for PV energy to be transferred from a PV system to a heating device of the water heater. If the current water temperature falls below a second PV heat point that is less than the normal heat point, the disclosed technology includes outputting instructions for energy to be transferred from a utility system to the heating device.