A circuit for generating electrical energy is disclosed. The circuit uses a pulse generator in combination with a tube having a cavity therein. The tube can have material therein, such as solid material or fluid passing therethrough. A thyristor or other negative resistance is in series with the tube to increase a change of voltage with respect to time. A resultant energy applied to a load is larger than the energy supplied by the pulse generator due to the absorption of external energy by the tube.

A safety system and method to prevent water within a top portion of a tank of an electric water heater to drop below a safe temperature during a load shedding period, other than a full emergency grid failure, by a power provider whereby to prevent the propagation of harmful bacteria in a top portion the tank. A control device monitors the water temperature in the top portion of the tank by the use of a temperature sensor. If the control device detects a temperature of the water in the top portion of the tank inferior to 140 degrees F., it will by-pass the instructions of the power provider and connect power to one or more of the resistive heating elements of the tank until a predetermined temperature above 140 degrees F. is attained before switching off the resistive heating elements.

A control system for controlling a heater includes a power converter, a sensor circuit, and a controller. The power converter supplies an adjustable power to the heater, and the sensor circuit is configured to measure an electrical characteristic of the heater. The controller is coupled to the power converter to control the power to the heater, and is configured to select a state model control, as an operation state of the heater, from among a plurality of defined state model controls. The controller controls the power supplied to the heater based on the operation state of the heater and on the electrical characteristics of the heater.

The present disclosure is directed toward a control system for controlling a heater that includes at least one heating element. The control system includes a power converter operable to supply an adjustable voltage output to the heater, a sensor circuit that measures an electrical characteristic of the heating element of the heater, a reference temperature sensor that measures a reference temperature of a reference at the heater, and a controller. The controller is configured to calculate a primary temperature of a heater element based on the electrical characteristic and determines the voltage output to be applied to the heater based on at least one of the reference temperature and the primary temperature. The controller is configured to operate in at least one of an operation mode and a learn mode, and execute protection protocols when voltage is being supplied to the heater.

A tankless water heater system (100), with a heat exchanger device (20) comprising at least one hollow chamber (21, 22, 23, 24 ) and at least one electrical heating element (52, 53, 54), and: a controller device (30) with a temperature control unit (35), a tap event counter unit (32), a down-time counter unit (33) and a time delay unit (34); an electrical switching element (41, 42, 43) for connecting or disconnecting one or several heating elements (52, 53, 54) to/from a power supply; an outlet temperature sensor (27) linked with the temperature control unit (35); a flow rate sensor (29); wherein: the tap counter unit (32) is connected to the flow rate sensor (29) and is triggered when water flow rate exceeds a tap indication threshold {dot over (V)}.sub.0 the down-time counter unit (33) is triggered and retriggered by the tap counter unit (32) and both provide a down-time event signal after any inactivity period with no water flow and records the duration of inactivity; the time delay unit (34) is connected to and triggered by the tap counter unit (32) starting a delay period t.sub.OFF which duration is switched from a short default delay period to a long delay period by the down-time signal provided by the down-time counter unit (33); and the switching elements (41, 42, 53) are triggered by the time delay unit (34) only after the delay period has elapsed.

A water heater including an inflow terminal for connecting a tankless water heater to a cold water supply and an outflow terminal for connecting the tankless water heater to a tap. A fluid channel proves a fluid connection from the inflow terminal to the outflow terminal. A heat element arrangement is arranged at or within at least a section of the fluid channel for transferring heat to fluid present within the fluid channel. An electronic controller is configured to control a heating power provided to the heat element arrangement. A flow sensor is arranged at or within the fluid channel downstream the heat element arrangement. The electronic controller is further configured to detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor and to adapt the heating power provided to the heat element arrangement in reaction to the determination of air bubbles.

A safety system and method to prevent water within a top portion of a tank of an electric water heater to drop below a safe temperature during a load shedding period, other than a full emergency grid failure, by a power provider whereby to prevent the propagation of harmful bacteria in a top portion the tank. A control device monitors the water temperature in the top portion of the tank by the use of a temperature sensor. If the control device detects a temperature of the water in the top portion of the tank inferior to 140 degrees F., it will by-pass the instructions of the power provider and connect power to one or more of the resistive heating elements of the tank until a predetermined temperature above 140 degrees F. is attained before switching off the resistive heating elements.

An electric tankless water heater for heating a continuous supply of water. The electric tankless water heater includes a heater assembly having a water inlet, a water outlet and a heating chamber defining a water flow path there between. A flow sensing device is coupled to the water flow path and configured to detect an ultra-low flow condition of water within a heating chamber of the heater assembly. In response to the detection of an ultra-low flow condition, or higher flow conditions, a controller regulates the amount of electrical current flowing through to achieve the desired temperature of water at the water outlet.

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.

An electric water heater tank adapted for connection to a controller, the tank including one or more electrical heating elements temperature sensing means mounted on the exterior of the tank wall and adapted to obtain a measurement of the temperature of the water in the tank, the temperature sensing means and each heating element being connected to an externally accessible connection means. The tank can include one or more heating element control means each connected to a corresponding one of the heating elements. The element control means can be connected to the externally accessible connection means.