The present invention provides a fine bubble generating apparatus capable of generating fine bubbles efficiently. The present invention includes a fluid flow passage that includes a narrow portion in at least a part thereof, a heating part capable of heating a liquid flowing through the fluid flow passage, and a controlling unit that controls the heating part. The controlling unit controls the heating part to generate film boiling in the liquid to generate ultrafine bubbles.

A variable power water heater is disclosed. In embodiments, the variable power water heater includes a water tank, a heating element, a power supply circuit, a switch, and a controller. The heating element may be disposed within or coupled to the water tank. The power supply circuit may be configured to generate a power signal for the heating element. The switch may be configured to couple the power supply circuit to the heating element, and the controller may be configured to toggle the switch according to a pulse width modulation (PWM) scheme to control a duty cycle of the power signal transmitted from the power supply circuit to the heating element.

A heater system includes a heater bundle. The heater bundle includes a plurality of heater assemblies. Each heater assembly includes a plurality of heater units and an insulating material, and each heater unit defines at least one independently controlled heating zone. The heater bundle includes power conductors electrically connected to each of the independently controlled heating zones in each of the heater units. The heater bundle includes a power supply device configured to modulate power to each of the independently controlled heater zones of the heater units through the power conductors. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

A heater system is provided, which includes a plurality of heaters, a controller for supplying power to the plurality of heaters, a plurality sets of auxiliary wires extending from the plurality of heaters, and a wire harness for connecting the plurality sets of auxiliary wires to the controller. Each set of auxiliary wires includes three wires, two of the three wires being made of different materials and being joined to form a thermocouple junction, such that each of the plurality of heaters is operable to function as both a heater and a temperature sensor.

A water heater appliance is provided that includes a control panel assembly that has features that facilitate mounting of a control panel of the control panel assembly to a curved surface of the water heater appliance. For instance, the curved surface may be an outer surface of a wrapper or a shroud of the water heater appliance. Particularly, the control panel assembly includes features that permit mounting of the control panel assembly to surfaces of variable radii. Moreover, the control panel assembly includes features that facilitate access to the electrical components of the control panel during assembly and servicing of the control panel assembly. Specifically, the control panel assembly includes features that allow the control panel to hinge downward to permit easy access to the electrical components during assembly and service.

A tankless water heater includes a heater assembly, a temperature sensor, a flow sensor, a first heating element, a second heating element, and a controller. The heater assembly includes a water inlet, a water outlet, and a heating chamber defining a water flow path between the water inlet and the water outlet. The temperature sensor measures the temperature of water flowing through the heating chamber. The flow sensor measures a flow condition of water within the heating chamber. The first and second heating elements are located in the heating chamber and include first and second wattages, respectively. The second wattage is different from the first wattage. The controller is coupled to the first and second heating elements and the temperature and flow sensors. The controller is configured to regulate the amount of electrical current flowing through the first and second heating elements in response to the flow condition.

A water heater system includes a water tank and a flow-through heating assembly. The water tank contains heated water. The flow-through heating assembly may extend into the water tank and heats water as water is passed through an interior channel of the flow-through heating assembly. In one embodiment, the flow through heater assembly is a thermosiphonic heater having a hollow body and a heating element extending therein such that an annular recess is defined between an interior surface of the hollow body and the external surface of the heating element.

The heating system for a sauna comprises an oven and an accumulator. The heating system is electrically connectable to a mains which provides a first electrical power. The accumulator is provided to provide a second electrical power. The oven is operable with the first and second electrical powers to increase the thermal power.

A method of controlling a heating system is provided that includes having at least one heater assembly, the heater assembly comprising a plurality of heater units, each heater unit defining at least one independently controlled heating zone, supplying power to each of the heater units through power conductors electrically connected to each of the independently controlled heating zones in each of the heater units, and modulating power supplied to each of the independently controlled heating zones. A voltage is selectively supplied to each of the independently controlled heating zones such that a reduced number of independently controlled heating zones receives the voltage at a time, or at least a subset of the independently controlled heating zones receive a reduced voltage at all times.

A sensor is driven at a first heating power value. The sensor generates a sensing signal that is indicative of a sensed entity. A possible onset of a sensor contamination condition is detected as a function of the sensing signal generated by the sensor. If such detecting fails to indicate onset of a sensor contamination condition, the sensor continues to be driven at the first heating power value. However, if such detecting indicates onset of a sensor contamination condition, a protection mode is activated. In the protection mode, the sensor is driven at a second heating power value for a protection interval, where the second heating power value is lower than the first heating power value. Furthermore, the operation may refrain from supplying power to the sensor for a further protection interval, wherein the further protection interval is longer than the protection interval.