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 heated water device is disclosed. The heated water device includes a cold water tank configured to receive cold water from a cold water source and a hot water tank configured to receive water from a hot water source and discharge water to the cold water source. The heated water device includes a pump configured to selectively pump water from the hot water source and to the hot water tank and a valve configured to selectively permit water to flow from the hot water tank to the cold water source. The heated water device includes a thermoelectric generator configured to generate electrical energy from a water temperature differential between cold water in the cold water tank and heated water in the hot water tank.

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 heated water device is disclosed. The heated water device includes a cold water tank configured to receive cold water from a cold water source and a hot water tank configured to receive water from a hot water source and discharge water to the cold water source. The heated water device includes a pump configured to selectively pump water from the hot water source and to the hot water tank and a valve configured to selectively permit water to flow from the hot water tank to the cold water source. The heated water device includes a thermoelectric generator configured to generate electrical energy from a water temperature differential between cold water in the cold water tank and heated water in the hot water tank.

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 cogeneration system includes, at least, a biomass-burner assembly, a water-heater assembly, a heating-assembly, a compression-tank assembly, and an electricity-generator assembly. Additionally, in some embodiments, the cogeneration further includes a cooling-assembly and a thermoelectric-generator assembly. The cogeneration system burns/combusts a biomass material, preferably wood, to generate wood gas. The wood gas is used to provide heating, cooling and electricity to an area, such as a building or off-the-grid areas such as campgrounds.

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.

Various disclosed embodiments include combined heating and power modules and combined heat and power devices. In an illustrative embodiment, a combined heat and power device includes a heating system including: at least one burner; at least one igniter configured to ignite the at least one burner; a fluid motivator assembly including an electrically powered prime mover; and a heat exchanger fluidly couplable to the fluid motivator assembly. At least one alkali metal thermal-to-electricity converter (AMTEC) has a high pressure zone and a low pressure zone, the high pressure zone being thermally couplable to the at least one burner, the low pressure zone being thermally couplable to the heat exchanger.

Various disclosed embodiments include combined heating and power modules and combined heat and power devices. In an illustrative embodiment, a combined heat and power device includes a heating system including: at least one burner; at least one igniter configured to ignite the at least one burner; a fluid motivator assembly including an electrically powered prime mover; and a heat exchanger fluidly couplable to the fluid motivator assembly. At least one thermophotovoltaic converter has a photon emitter and at least one photovoltaic cell, the photon emitter being thermally couplable to the at least one burner, the at least one photovoltaic cell being thermally couplable to the heat exchanger.