A method for controlling reheating of a tank-style water heater having an upper heating element and a lower heating element is described. The method identifies whether the upper heating element, and optionally whether the lower heating element, or neither of the upper heating element and the lower heating element, is energized when electrical power is supplied to the water heater. The method determines whether to continue supply of electrical power to the water heater based on which of the upper heating element, or optionally the lower heating element, or neither of the upper heating element and the lower heating element is energized when electrical power is supplied to the water heater. The method may be implemented by a controller adapted to selectively permit and deny supply of electrical power to the water heater, where the controller executes program logic for implementing the method.

A method for controlling reheating of a tank-style water heater having an upper heating element and a lower heating element is described. The method identifies whether the upper heating element, and optionally whether the lower heating element, or neither of the upper heating element and the lower heating element, is energized when electrical power is supplied to the water heater. The method determines whether to continue supply of electrical power to the water heater based on which of the upper heating element, or optionally the lower heating element, or neither of the upper heating element and the lower heating element is energized when electrical power is supplied to the water heater. The method may be implemented by a controller adapted to selectively permit and deny supply of electrical power to the water heater, where the controller executes program logic for implementing the method.

A controller provides power to a water heater having upper and lower heating elements. Various options for measurement units to measure electrical parameters reflecting the state of the water heater are implemented to provide sensing of a desired parameter, whether the controller is powering the heating elements or not. A power relay is operably connected to power a testing or sensing circuit in one embodiment whenever the relay switches away from powering the water heater. In another embodiment, sensing circuits operate both during powered operation or non-powered condition for heating elements. Component damage and wear is greatly reduced, while also providing the controller an ability to assess the state of the heating elements, assure hot water, and override conservation methods like off-peak use, voluntary load shedding, and the like, in favor of guaranteed hot water output, based on measurements even in “power-off” conditions.

A controller provides power to a water heater having upper and lower heating elements. Various options for measurement units to measure electrical parameters reflecting the state of the water heater are implemented to provide sensing of a desired parameter, whether the controller is powering the heating elements or not. A power relay is operably connected to power a testing or sensing circuit in one embodiment whenever the relay switches away from powering the water heater. In another embodiment, sensing circuits operate both during powered operation or non-powered condition for heating elements. Component damage and wear is greatly reduced, while also providing the controller an ability to assess the state of the heating elements, assure hot water, and override conservation methods like off-peak use, voluntary load shedding, and the like, in favor of guaranteed hot water output, based on measurements even in “power-off” conditions.

Methods and systems for water heater system receiving electrical power from an electrical grid. The system includes an electronic processor configured to monitor an average water temperature of the water within a water tank of the system based on a first and second signal from an upper and lower temperature sensor, operate an upper heating element heating an upper portion of the tank and a lower heating element heating a lower portion of the tank in a first operation mode, receiving, via a transceiver, either an add load command or a shed load command from a grid controller, operating the upper heating element and lower heating element in a second mode in response to receiving the add load command, and operating the upper heating element and lower heating element in a third mode in response to receiving the shed load command.

A method of operating a water heater in a load shed mode can include detecting that an upper water heater thermostat control module in a water heater is calling for heat to be provided via an upper heating element of the water heater while the water heater is in a load shed mode of operation wherein a first leg of power to the water heater is decoupled from an input to the upper water heater thermostat control module and responsive to the upper water heater thermostat control module calling for heat, transmitting a signal to end the load shed mode of operation at the water heater so that the first leg of power to the water heater is coupled to the input of the upper water heater thermostat control module so that the upper heating element of the water heater is enabled to heat water responsive to the upper water heater thermostat control module calling for heat.

Embodiments of the present disclosure provide a system for disinfecting water for hydronic space conditioning and domestic hot water. The system includes a thermal storage tank, a disinfecting device and a control unit. The control unit monitors an outlet temperature of water exiting the thermal storage tank. Further, the control unit calculates a temperature difference between a temperature threshold limit associated with the disinfecting device and the outlet temperature. The control unit transmits a first signal to the disinfecting device when the temperature difference is a positive value. The first signal operates the disinfecting device in the activation mode for heating the water to provide anti-bacterial sanitation. The control unit transmits a second signal to the disinfecting device for deactivating the disinfecting device when the temperature difference is a negative value. The sanitized water from the disinfecting device is used for conditioning an enclosure and a domestic hot water.

A water heater appliance, as provided herein, may include a casing, a tank, an inlet conduit, an electric heating system, and a controller. The tank may be disposed within the casing, the tank defining an inlet and an outlet. The inlet conduit may be mounted to the tank at the inlet of the tank. The electric heating system may be in thermal communication with the tank to heat water within the tank. The controller may be in operative communication with the electric heating system. The controller may be configured to initiate a responsive-heating cycle. The responsive heating cycle may include detecting expiration of a dormant event at the water heater appliance, initiating a randomized delay period in response to detecting expiration of the dormant event, and initiating activation of the water heater appliance following the delay period.

A water heater that includes a cylindrical storage tank and at least one heating element, is modeled using a one-dimensional model that includes: a vertical stack of disks representing the water volume in the cylindrical storage tank, and a stack of annular segments surrounding the vertical stack of disks. Various temperature measurements are determined via resistance calculations of the at least one heating element. The stack of annular segments represents the cylindrical wall of the cylindrical storage tank. The one-dimensional model may be used by a condition-based maintenance system comprising an electronic data processing device configured to detect a failure mode present in the water heater based on an output of the water heating model component. Some illustrative failure modes include insulation disturbance, heating element failure, excessive sediment buildup, or a drip tube rupture.

A system and method for controlling power to a water heater. The method comprises providing the water heater in a locked state, wherein at least one heating element of the water heater is inoperable when the water heater is in the locked state, coupling a digital key module to a communications port of the water heater, and receiving a digital key from the digital key module through the communications port. The method comprises coupling an electrical grid controller to the water heater through the communications port and placing the water heater in an unlocked state, wherein the at least one heating element of the water heater is operable when the water heater is in the unlocked state.