A system for combined heat and electric power generation, preferably including a heat reservoir and one or more electric generators, each preferably including a heat source and an energy converter. A method for combined heat and electric power generation, preferably including activating an electric generator, deactivating the electric generator, and/or providing heat from a heat reservoir.

An apparatus for recovering heat in an ablutionary or plumbing system includes first and second pipes for carrying fluids at different temperatures. A first heat transfer element is configured to be thermally coupled to the first pipe and a second heat transfer element configured to be thermally coupled to the second pipe, with each having an elongate portion extending in a direction away from the associated pipe. The elongate portions of the first and second heat transfer elements at least partially overlap. A thermoelectric device is provided that includes one or more thermoelectric elements located between the elongate portions, the thermoelectric element(s) being in thermal communication with the elongate portion of the first heat transfer element and the elongate portion of the second heat transfer element and being arranged to generate electricity from a temperature differential between the elongate portions of the first and second heat transfer elements.

A water heater control system the water heater system comprising a rechargeable and non-rechargeable power source. In one or more examples, a controller such as a microcontroller of the water heater system is configured to receive power from the non-rechargeable power source and does not receive power from the rechargeable power source. Various other components of the water heater system are configured to receive power from the rechargeable power source. The system may comprise an energy storage system electrically connected to a pilot valve operator and electrically isolated from a main valve operator. The controller may be configured to recognize a call for main burner operation and may also be configured to check an available voltage of the energy storage system against a setpoint.

An apparatus and method for producing heat and electricity including a burner to produce radiant heat. A thermal-to-electric conversion device is integrated with the burner and proximate to the radiant heat. The conversion device provides a first side disposed toward the radiant heat and a second side disposed toward a cooling fluid flow path, such as combustion air for the burner or a media to be heated by the burner.

A gas-fired instantaneous water heater including a thermoelectric generator (TEG) and a heat pump that is powered by the TEG to improve efficiency compared to existing water heaters. Water to be heated is circulated through the heat pump, TEG heat exchanger, and primary heat exchanger to produce a stream of heated water. An adjustable firing rate permeable matrix radiant burner is included, in which natural gas and air are combusted to produce combustion products, including heat. The combustion products are condensed in a condensing system to produce cooled and dry exhaust gas.

A flame powered intermittent pilot combustion controller may include a first power source and a second power source separate from the first power source, a thermal electric and/or photoelectric device, an igniter and a controller. The thermal electric and/or photoelectric device may charge the first power source when exposed to a flame. The controller and the igniter may receive power from the first power source when the first power source has sufficient available power, and may receive power from the second power source when the first power source does not have sufficient available power.

A water heater may include a water tank, a burner, a pilot for igniting the burner, an ignitor for igniting the pilot, a thermoelectric device in thermal communication with a flame of the pilot, a controller for controlling an ignition sequence of the pilot using the ignitor, and a rechargeable power storage device for supplying power to the ignitor and the controller. The rechargeable power storage device may be rechargeable using the energy produced by the thermoelectric device. The controller is configured to selectively run only the pilot for at least part of a heating cycle to increase the recharge time of the rechargeable power storage device while still heating the water in the water heater.

A flame powered intermittent pilot combustion controller may include a first power source and a second power source separate from the first power source, a thermal electric and/or photoelectric device, an igniter and a controller. The thermal electric and/or photoelectric device may charge the first power source when exposed to a flame. The controller and the igniter may receive power from the first power source when the first power source has sufficient available power, and may receive power from the second power source when the first power source does not have sufficient available power.

Apparatus and methods for a gas furnace are disclosed. The gas furnace includes a variable combustion control which monitors the temperature of the burner and modifies one of the amount of combustion air supplied and the amount of gas fuel supplied to the mixing chamber. The described systems can dynamically accommodate differences in air quality and gas fuel supply to provide an optimum BTU output irrespective of differences in geographic location of usage. The gas furnace can include a dynamic response unit which predicts an optimum rate of heating to maintain a target room temperature, thereby preventing unnecessary shut down and costly re-ignition sequences, and maintaining the gas furnace at an optimum BTU output level.

A water heater may include a water tank, a burner, a pilot for igniting the burner, an ignitor for igniting the pilot, a thermoelectric device in thermal communication with a flame of the pilot, a controller for controlling an ignition sequence of the pilot using the ignitor, and a rechargeable power storage device for supplying power to the ignitor and the controller. The rechargeable power storage device may be rechargeable using the energy produced by the thermoelectric device. The controller is configured to selectively run only the pilot for at least part of a heating cycle to increase the recharge time of the rechargeable power storage device while still heating the water in the water heater.