Various embodiments of the teachings herein include a mixer disposed in a fuel gas combustion system and mixing air and fuel gas to form flammable mixed gases. The mixer may include: a Venturi tube having an air inlet, a fuel gas inlet, a gas mixture outlet, a central axis direction, and a throat positioned between the air inlet and the gas mixture outlet in the central axis direction, wherein the fuel gas inlet is disposed at the throat; and an adjustment component disposed in the Venturi tube downstream of the throat, the adjustment component drivable to move towards or away from the throat in the central axis direction, thereby changing a flow area of gas in the Venturi tube. The adjustment component comprises a conical valve plug with a conical outer surface thereof at a side facing towards the throat and fitting an inner surface of the Venturi tube.

A method of improving an endothermic process in a furnace utilizing steps a) calibrating the simplified physical model of step c3) by measuring one or more tube temperature for at least a tube impacted by the throttling of a burner in standard and in throttled state, b) acquiring information on a tube temperature for the tubes present in the furnace with all the burners present in the furnace under standard non-throttled conditions, c) getting a map of burners to throttle including c1) choosing at least one parameter representative of the performances of the furnace with a target of improvement, c2) choosing at least one or more power ratio for the burner throttling; c3) utilizing the information of step b) and a simplified physical model of the impact of throttling a burner on the tube temperature, c4) getting a map of burners to throttle, step d) throttling the burners.

A fluid heating system including a burner unit is operated based on feedback control loops. The fluid heating system comprises a burner unit configured to heat a fluid, a sensor configured to sense a characteristic of the appliance, and a controller coupled to the burner unit and the sensor. The controller includes an electronic processor and a memory. The controller is configured to receive a first signal corresponding to the characteristic from the sensor, determine, based on the first signal, a first feedback loop control, control combustion of the burner unit based on the first feedback loop control, determine, based on the first feedback loop control, a second feedback loop control, and control combustion of the burner unit based on the second feedback loop control.

A method for controlling a gas furnace that performs a heating operation by receiving a first heating signal; calculating a certain heating capacity smaller than a maximum heating capacity of the gas furnace, according to the first heating signal; and operating a heating of the gas furnace with the calculated certain heating capacity. The calculating of the certain heating capacity includes calculating the certain heating capacity according to a difference between an intake air temperature sucked into the gas furnace and a reference temperature.

In some examples, a method for operating a gas burner appliance includes determining, on basis of a nominal burner-load and on basis of a mixing ratio of gas and air of a gas/air mixture or a λ-value of the gas/air mixture, a nominal air mass flow in order to provide the nominal burner-load. The method further comprises determining the ambient air pressure and the ambient air temperature of the ambient air, determining, on basis of the ambient air pressure and on basis of the ambient air temperature, the atmospheric density of the ambient air, determining on basis of the nominal air mass flow, on basis of the determined atmospheric density of the ambient air, and on basis of a system resistance of the gas burner appliance, the fan speed of the fan in order to provide the nominal burner-load.

A cooking appliance and method control the power consumption of a plurality of electrical loads in response to an ambient temperature sensed by a temperature sensor to maintain a combined power consumption within a temperature-dependent output capability of a low voltage power supply used in the cooking appliance.

In some examples, a method for operating a gas burner appliance includes determining, on basis of a nominal burner-load and on basis of a mixing ratio of gas and air of a gas/air mixture or a λ-value of the gas/air mixture, a nominal air mass flow in order to provide the nominal burner-load. The method further comprises determining the ambient air pressure and the ambient air temperature of the ambient air, determining, on basis of the ambient air pressure and on basis of the ambient air temperature, the atmospheric density of the ambient air, determining on basis of the nominal air mass flow, on basis of the determined atmospheric density of the ambient air, and on basis of a system resistance of the gas burner appliance, the fan speed of the fan in order to provide the nominal burner-load.

A heat controlled oven system includes a plurality of oven levels, including an oven belt and gas burners; a gas flow network, including a gas supply line, a variable flow control valve, and on/off flow control valves; and a heat control unit, including a processor, a non-transitory memory, and input/output component, a heat modeler, a heat manager, a feedback controller, and a valve controller, such that the heat control unit is configured to calculate an estimated heat demand to adjust to a temperature set point, based on a heat model of the at least one oven level, and further calculates an optimized heat demand using a control loop feedback algorithm. Also disclosed is a method of heat calculation for an oven, including defining a heat model, calculating and optimizing the estimated heat demand, calculating and setting a variable valve position for the gas burners.

A burner system for use in a gas cooking grill has a primary burner in a firebox providing heat to a cooking surface above the primary burner and a secondary burner in the firebox selectively providing heat to a cooking grate such that ignition of the secondary burner provides an additional degree of heat to the cooking surface above the primary burner.

An improved gas fireplace hearth provides a controller and can perform new features. A pressure sensor may be provided to communicate to the controller to warn of a drop of inlet gas pressure to indicate a problem with gas service rather than the hearth. An ambient temperature sensor can provide an input to the controller for various features including a safety feature to shut off gas flow if the hearth becomes too hot. The hearth can be made more efficient by having the controller implement a zero voltage alternating current system to adjust the speed of the fan, flame height, lighting, BTU output or other feature.