A disclosed battery protecting circuit includes a battery protecting IC powered by a voltage of a secondary battery; another battery protecting IC powered by a voltage of another secondary battery connected to the secondary battery in series; and a constant voltage output unit which receives a maximum voltage obtained by adding voltages of the secondary battery and the other secondary battery in series and outputs a constant voltage upon receipt of a control signal from an output terminal of the battery protecting IC or the other battery protecting IC.

The present inventions, in one aspect, are directed to techniques and/or circuitry to adapt the charging of a battery using data which is representative of an overpotential or relaxation time (full or partial) of the battery. In another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of an overpotential or relaxation time (full or partial) of the battery. In yet another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of a state of charge of the battery using an overpotential or relaxation time (full or partial) of the battery.

A charging device with a battery management system which remains a rechargeable battery in full capacity during standby after being fully charged is disclosed. The charging device includes a charging module, electrically connected to a power source, for charging the rechargeable battery; a voltage detecting module, for detecting a voltage of the rechargeable battery; and a determination module, for instructing the charging module to charge the rechargeable battery with a supplementary current, when the voltage of the rechargeable battery detected by the voltage detecting module reduces to a first predetermined voltage, until the voltage of the rechargeable battery reaches a second predetermined voltage. A reduction of the voltage of the rechargeable battery is due to self-discharge of the rechargeable battery during standby after being fully charged.

Circuitry and techniques to measure, at the battery's terminals, characteristic(s) of the charging signal applied to the battery/cell during the recharging operation and, in response to feedback data which indicates the charging signal is out-of-specification, control or instruct the charging circuitry to adjust characteristic(s) of the recharging signal (e.g., the amplitude of the voltage of and/or current applied to or removed from the battery during the charging operation). For example, a rechargeable battery pack comprising a battery, and controllable switch(es), a current meter and voltmeter, all of which are fixed to the battery. Control circuitry generates control signal(s) to adjust a current and/or voltage of the charging signal using the feedback data from the current meter and/or voltmeter, respectively.

A method for operating a driverless, mobile assembly and/or material transport unit as a driverless transport system (DTS) with fixed assembly and/or warehousing stations. In this method, a system control device is used for the entire assembly process. The driverless, mobile assembly and/or material transport units comprises a travel device for the traveling movement of the unit, a drive device for the travel device, an energy storage device for providing the energy for the drive device and a control device for controlling the traveling movement in coordination with the system control device.

Systems and methods to determine cell capacities of a vehicle battery pack. Cell capacities may be determined using state of charge (SOC) estimates for the cells and a charge count for the battery pack. The SOC estimates may be determined when the SOC of the battery pack is below a lower threshold and above an upper threshold. Error values may also be generated for the cell capacity values.

A direct feeding apparatus for impedance matching of a wireless power transmission device includes a helical type resonator, and a feeding unit configured to directly feed power to a region having a relatively small current value as compared to a center of a conductive line of the resonator.

A system and method for digital management and control of power conversion from battery cells. The system utilizes a power management and conversion module that uses a CPU to maintain a high power conversion efficiency over a wide range of loads and to manage charge and discharge operation of the battery cells. The power management and conversion module includes the CPU, a current sense unit, a charge/discharge unit, a DC-to-DC conversion unit, a battery protection unit, a fuel gauge and an internal DC regulation unit. Through intelligent power conversion and charge/discharge operations, a given battery type is given the ability to emulate other battery types by conversion of the output voltage of the battery and adaptation of the charging scheme to suit the battery.

Systems and methods for in-vehicle charging of pallet jack batteries are provided. An example system allows using a power source of a host vehicle configured to provide power at voltage levels lower than the operating voltage of the pallet jack battery stack. The system may allow, for example, charging a 24 volts pallet jack battery stack from a 12 volts power source of the host vehicle. The system may further comprise an interconnecting circuit having a plurality of contactors electrically coupling the batteries in parallel for charging and serially for discharging. The system may further comprise a voltage monitoring circuit to detect whether the pallet jack is connected to the host vehicle power source for charging. Based on the detection, the voltage monitoring circuit may reconfigure the interconnecting circuit to electrically couple the pallet jack batteries in parallel.

A battery includes a first terminal, a second terminal, a first battery module, a second battery module, and a third batter module. The first battery module and the second battery module includes a first pole, a second pole, a plurality of battery cells, a charge and disconnect device, a disconnect device, and a bridging device. The third battery module includes a first pole, a second pole, a plurality of battery cells, a first disconnect device, a second disconnect device, and a bridging device. The first and second poles of the first battery module are connected in series with the first terminal and the first pole of the third battery module. The first and second poles of the second battery module are connected in series with the second terminal and the second pole of the third batter module.

An apparatus for charging an automobile battery is presented. The device provides a surface charge with a time limited window in which to start a vehicle. Use of used batteries provides for environmentally effective manner in which to deal with the tremendous amount of used batteries that are discarded worldwide each year. The apparatus may optionally include a charging circuit to allow for recharging the used batteries. An LED display may be included to provide indication when a target battery has sufficient surface charge to warrant an attempt to start an engine. The apparatus is a small portable device that can be stored anywhere in a vehicle.

A standby battery box for an electric cylinder is electrically connected to a control box for driving the electric cylinder and includes a charge-discharge device and a rechargeable battery. The charge-discharge device includes a protection unit, a power conversion unit, a voltage detection unit, a control unit, a discharge unit, a display unit, and a switch unit. The rechargeable battery is electrically connected to the charge-discharge device. When a startup switch of the switch unit is pressed, the charge-discharge device delivers the electricity of the rechargeable battery into the control box. When a shutoff switch of the switch unit is pressed, the charge-discharge device does not supply power, thereby protecting the standby battery box from being exhausted.

A battery system is disclosed. The battery system includes a plurality of battery cells, and a battery cell balancing unit, configured to adjust voltages across each of the battery cells to reduce variation among the voltages across the battery cells. The battery cell balancing unit includes a controller configured to receive a DC reference current and to generate an AC current based on the DC reference current, a transformer, a rectifier circuit including a rectifier connected to the output coil, and a switching unit including a plurality of switches, each configured to selectively connect the rectifier to one of the battery cells.

Disclosed herein is a battery pack including a battery cell array including two or more battery cells, each of which has an electrode assembly of a cathode/separator/anode structure disposed in a battery case together with an electrolyte in a sealed state, arranged in a lateral direction, a protection circuit module (PCM) connected to an upper end of the battery cell array to control an operation of the battery pack, a pack case in which the battery cell array and the protection circuit module are disposed, and a plate-shaped reinforcing member mounted between the pack case and the battery cell array to increase mechanical strength of the pack case.

A belt battery charger includes a belt having a first end, a second end and an elongated central portion extending between the first and second ends. A plurality of electrically connected rechargeable batteries are carried by the central portion of the belt. A belt buckle located at the first end of the belt includes a frame that is secured to the central portion of the belt. The buckle further includes a prong in the form of an electrical connector electrically connected to the batteries and pivotally secured to the frame. The second end of the belt includes a number of spaced apart eyelets passing therethrough. The prong is shaped so as to be able to enter one of the eyelets to secure the second end of the belt to the buckle in the conventional manner. A second electrical connector is located adjacent the second end of the belt and is also connected to the batteries. One of said connectors is adapted to be connected to a cell phone for charging the same.

A battery fuel gauge apparatus comprises a current amplifier formed by a first transistor and a second transistor. Both transistors operate in the same operation conditions except that the second transistor has a smaller channel width in comparison with that of the first transistor. The first transistor is connected in series with a battery pack. The second transistor is connected in series with a sensing device. The sensing device comprises a first resistor and a second resistor connected in series. The first resistor has a positive temperature coefficient and the second resistor has a negative temperature coefficient.

There is provided a battery controller including a storing unit which stores an upper limit voltage and a lower limit voltage, each defining a first voltage range in which a battery is charged/discharged, and a second upper limit voltage and a second lower limit voltage, each defining a second voltage range which is wider than the first voltage range, and a charge/discharge regulation unit which temporarily changes, when charge/discharge is performed in the first voltage range and permission for charge/discharge in the second voltage is received, setting of the battery such that charge/discharge is performed in the second voltage range.

According to some embodiments, battery charge management using a scheduling application is disclosed. A first parameter may be received from a scheduling application running on a mobile computing device having a battery pack. Based on at least the first parameter and battery pack data, a required charge percentage for the battery pack may be determined and the remaining capacity of the battery pack may be determined. If the remaining capacity of the battery pack is less than the required charge percentage, a charge termination voltage may be determined and the battery pack may be charged to the charge termination voltage.

An apparatus for minimizing self-discharge of a smart battery pack is provided. During initial storage of the smart battery pack (100), prior to be being charged, a self-discharge protection circuit (110) disables smart battery circuitry (130). A minimal current drain is maintained while the smart battery circuitry (130) is disabled. Upon coupling of the smart battery pack (100) to a charger, the protections circuit (110) enables the smart battery circuitry (130). Battery packs having to be shipped with partially drained cells as part of shipping precaution requirements are no longer faced with the additional drainage problem previously caused by the smart battery circuitry (130) during storage.

A semiconductor device for battery control includes a CPU, a first bus coupled to the CPU, a second bus not coupled to the CPU, and a protective function circuit for protecting a battery from stress applied thereto. The semiconductor device also includes a non-volatile memory storing trimming data, a trimming circuit to perform trimming required to allow the protective function circuit to exert a protective function, and a bus control circuit capable of selectively coupling the first bus and the second bus to the non-volatile memory. The semiconductor device further includes a transfer logic circuit which causes, by making the bus control circuit select the second bus, a trimming data transfer path leading from the non-volatile memory to the trimming circuit to be formed and the trimming data stored in the non-volatile memory to be transferred to the trimming circuit without involving the CPU.

A battery pack and an electronic device are disclosed. The battery pack includes a battery for storing electric energy, and a non-contacting discharging unit for receiving the stored electric energy from the battery and for transferring the stored electric energy to a power receiving unit in a non-electrically contacting manner. The electronic device includes a main body and the battery pack. The main body includes a power receiving unit. The battery pack is for mounting to and supplying power to the main body.

There is provided a battery module including: a power storage unit storing power; a first authentication unit carrying out first authentication via a first authentication route; a second authentication unit carrying out second authentication via a second authentication route; and a discharging control unit controlling discharging from the power storage unit to an external appliance, wherein the first authentication unit is operable, when the first authentication has succeeded, to share key information to be used in the second authentication with an authentication party for the second authentication, the second authentication unit carries out the second authentication using the key information shared with the authentication party, and the discharging control unit is operable, when the second authentication has succeeded, to permit discharging from the power storage unit.

A battery voltage detector includes, but is not limited to: a voltage detection circuit; and a voltage processor. The voltage detection circuit includes, but is not limited to: a capacitor configured to be charged by a battery cell; a pair of output terminals; an output switch; and a voltage processor. While the capacitor is charged, the output switch is configured to be off-state and insulate the capacitor from the pair of the output terminals. After the capacitor is charged, the output switch is configured to be on-state and connect the capacitor to the pair of the output terminals. The voltage processor is configured to obtain, as a cell voltage, a voltage between the output terminals of the voltage detection circuit while the output switch is on-state. A high-potential output terminal of the pair of the output terminals is connected to a power line via a pull-up resistor.

An charging device includes: capacitors connected in series; a charging unit that charges the capacitors; bypass units, each respectively connects in parallel to each capacitors, wherein each bypass unit causes, when a charged voltage of any capacitor has reached a set voltage, a charging current to bypass the capacitor whose charged voltage has reached the set voltage; and a control unit that controls the charging unit to charge the capacitors in such a manner that, when a charging voltage of the any capacitor has reached the set voltage, the control unit causes the charging unit to reduce the charging current, and if a predetermined period has elapsed since the charging voltage has reached the set voltage, and if a charging voltage of any of the other capacitors has not reached the set voltage after the predetermined period, the control unit causes the charging unit to increase the charging current.

A generator system includes a generator having a stationary portion and a rotating portion. The generator includes a permanent magnet based exciter with permanent magnets disposed on the stationary portion. A first channel includes a first main field winding and a first main field power converter disposed on a rotating portion. The first main field power converter selectively delivers voltage from the exciter winding to the first main field winding. A second channel includes a second main field winding and a second main field power converter disposed on the rotating portion. The second main field power converter selectively delivers voltage from the exciter winding to the second main field winding. A generator control unit is connected to the first channel and the second channel. The generator control unit monitors an output voltage at each of the first channel and the second channel and generates the first and second control signals based on the output voltage.

A generator airgap monitoring system includes a first proximity sensor disposed in a first location of a stator and configured to transmit a first signal representative of a first distance between the first proximity sensor and a plurality of rotor poles of a rotor, and a controller communicatively coupled to the first proximity sensor. The controller is configured to derive a first plurality of instantaneous airgaps based on the first signal and to determine a difference between a first instantaneous airgap of the first plurality of instantaneous airgaps and a second instantaneous airgap of the first plurality of instantaneous airgaps. The first plurality of instantaneous airgaps includes a first plurality of measurements of airgaps between the stator and the plurality of rotor poles when the rotor is rotating. The first instantaneous airgap and the second instantaneous airgaps include measurements for respective rotor poles.

An inverter generator used in combination with a motor and an ECU generating a pulse at each predetermined rotation angle of the motor is comprised of: an electric generator driven by the motor configured to generate alternating current electric power; estimating means for estimating an electrical angle of alternating voltage of the alternating current electric power from the pulse, the estimating means being electrically connected with the ECU; a converter configured to convert the alternating current electric power into direct current electric power, the converter electrically connected with the electric generator and the estimating means; and an inverter configured to convert the direct current electric power into alternating current output electric power, the inverter electrically connected with the converter.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated by extracting thermal energy from a gas to condense the gas into a liquid and transferring the thermal energy to the electrically polarizable material. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material in thermal communication with a heat source, wherein the heat source is a condenser. An apparatus is also described which comprises a chamber, one or more conduits inside the chamber for conveying a cooling fluid and an electrically polarizable material sandwiched between electrodes on an outer surface of the conduit. A gas introduced into the chamber condenses on the conduits and thermal energy is thereby transferred from the gas to the electrically polarizable material.

A dip in the output voltage of a motor-vehicle alternator, owing to a connecting of a load or a change in speed, is compensated with the aid of an alternator regulator which provides a control signal that has a duty factor and increases the excitation current of the motor-vehicle alternator. After the occurrence of the voltage dip, in a first step, the duty factor of the control signal is increased by a differential amount, and in a subsequent second step, the rate of correction is limited. After the occurrence of the voltage dip, parameters describing the instantaneous working point of the motor-vehicle alternator are determined, and in the first step, the differential amount is set as a function of the working point.

A self-excited alternator for generating electrical energy. The alternator includes a stator, a rotor, and an exciter. The rotor includes conductors which are integrated within the rotor via one of a casting process, a welding process, or a fastening process. The exciter includes a magnet producing a static magnetic field, and a rotatable conductive member coupled to the shaft and electrically coupled to the one or more conductors. The rotatable conductive member is operable to output the direct current to the one or more conductors upon rotation within the static magnetic field, thus exciting the alternator.

A generator includes a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft. The main generator is configured to produce a voltage output. A generator control unit includes a circuit configured to provide current from the permanent magnet generator to the exciter. A switch is provided in the circuit and is configured to change between open and closed conditions. The switch is configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition. An overvoltage limit controller is programmed to determine an amount of overvoltage of the output voltage exceeding a desired voltage. Either a fixed reference threshold is used or a reference threshold voltage is calculated based upon the duration in over voltage condition, and the switch is modulated between the open and closed conditions according to error between the actual output voltage and the reference threshold voltage to limit the output voltage to the desired reference threshold voltage.

A generator system includes a generator having a stationary portion and a rotating portion. An exciter field winding and a main armature winding are disposed on the stationary portion. An exciter armature winding and a main field winding are disposed on the rotating portion. A frequency demodulator is configured to extract a frequency modulated control signal from the exciter armature winding and to demodulate the frequency modulated control signal to generate a demodulated control signal. The generator includes a main field rotating power converter to selectively control current in the main field winding in response to the demodulated command signal. The generator system includes a generator control unit in electrical communication with the generator to monitor the output voltage at the main armature winding and to output an exciter current including the frequency modulated control signal to the exciter field winding based on the output voltage.

The regulator/brush-holder assembly (1) comprises a support (2) and an electrical circuit (5, 6) comprising a regulating element (5) connected by microwires to a trace circuit (6). The electrical circuit further includes a filtering circuit (10) separate from the regulating element and connected by microwires to the trace circuit. According to one particular embodiment, the filtering circuit comprises an insulating substrate (11) and surface-mounted components (C1, C2, S1, S2, V). A ground plane (19) and/or one or more ground pads may be provided for connection to a ground trace of the trace circuit. The filtration frequencies of the filter circuit extend from 100 kHz to 1 GHz.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated using thermal energy obtained from: a combustion reaction; solar energy; a nuclear reaction; ocean water; geothermal energy; or thermal energy recovered from an industrial process. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material. The heat source used to heat the material can be: a combustion apparatus; a solar thermal collector; or a component of a furnace exhaust device. Alternatively, the heat exchanger can be a device for extracting thermal energy from the earth, the sun, ocean water, an industrial process, a combustion reaction or a nuclear reaction. A vehicle is also described which comprises an apparatus for converting heat to electrical energy connected to an electric motor.

A method of operating a converter of a wind turbine for providing electric energy to a utility grid includes determining a grid voltage. If the grid voltage is between a nominal voltage and a first voltage threshold, i.e. higher than the nominal voltage, a normal procedure for lowering the grid voltage is performed. If the grid voltage is above the first voltage threshold, another procedure for keeping the wind turbine connected is performed, wherein the other procedure is different from the normal procedure. Further a corresponding arrangement is described.

A generator drive system for the generator (3) of an internal combustion engine (1), including a flexible drive having a traction mechanism (5) which is guided across a generator pulley (6) driving the generator (3). The generator (3) is configured and electrically wired such that the generator (3) can be temporarily driven as a motor, and the generator (3) is coupled to the generator pulley (6) or the crankshaft pulley (7) is coupled to the crankshaft (8) via an overrunning clutch (4) which allows the generator (3), when operated as a motor, running faster than the generator pulley (6) or, taking into consideration a gear ratio, the crankshaft (8).

Systems and methods for reducing current imbalance between parallel bridge circuits used in a power converter of a doubly fed induction generator (DFIG) system are provided. A control system can monitor the bridge current of each of the bridge circuits coupled in parallel and generate a feedback signal indicative of the difference in bridge current between the parallel bridge circuits. Command signals for controlling the bridge circuits can then be developed based on the feedback signal to reduce current imbalance between the bridge circuits. For instance, the pulse width modulation of switching devices (e.g. IGBTs) used in the bridge circuits can be modified to reduce current imbalance between the parallel bridge circuits.

A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

An arrangement adapted for letting water pass by electrical conductors and their contact surfaces related to a track of a system adapted for electrically driving a vehicle along a roadway. The vehicle is provided with a current collector which is displaceable up and down and sideways in relation to the direction of transportation, in order to be brought into mechanical and electrical contact with elongated tracks positioned below the roadway and comprising a conductor adapted to be supplied with current and put under voltage. At least two or three tracks are disposed parallel to each other in a common rail structure, with at least two of these tracks being adapted to support and contain individual electrical conductors with contact surfaces put under voltage, and wherein at least one track is disposed closer to the highest point of the roadway and adjacent to a track containing one of said conductors with contact surfaces, which may be put under voltage.

A vehicle-related system adapted for electrically driving a vehicle along a road-way. The vehicle has three sources of power: a vehicle-related power generator, a set of batteries and vehicle-external electric stations. The vehicle is provided with a current collector which is displaceable up and down and sideways in relation to the direction of transportation, in order to be brought into mechanical and electrical contact with elongated tracks positioned below the roadway and comprising a conductor adapted to be connected with an electric station. A circuit, determining instantaneous power content of the set of batteries, is adapted to connect the vehicle-external power source via a switch belonging to the electric station, in order to charge the set of batteries and/or to supply power to the vehicle motor via a control circuit, when the power content of the set of batteries is at a predetermined level of power, lying below a maximum power content, and a supply of power or voltage from the vehicle-external power source is available.

The upper lateral collection structure (8) is mounted on a land vehicle (1), notably an urban public transport vehicle, and cooperates, for the purpose of overhead electrical power supply to the vehicle, with fixed contact slippers (16) located along its route. This structure comprises: a conducting track (14) arranged longitudinally (NEW) the upper lateral part of the vehicle and comprising a contact region (15) for the contact slipper; an electrical connection connecting the conducting track to the electrical circuit of the vehicle; an insulating support (24) on which the conducting track is mounted; a means of mechanical connection of the collecting structure to the vehicle; and a damping device which damps out the shocks resulting from the contact slipper and ensures satisfactory contact between the conducting track and the contact slipper. This invention is of benefit to the manufacturers of electrically powered public transport vehicles.

Systems and methods for controlling exhaust steam temperatures from a finishing superheater are provided. In certain embodiments, the system includes a controller which includes control logic for predicting an exhaust temperature of steam from the finishing superheater using model-based predictive techniques (e.g., based on empirical data or thermodynamic calculations). Based on the predicted exhaust temperature of steam, the control logic may use feed-forward control techniques to control the operation of an inter-stage attemperation system upstream of the finishing superheater. The control logic may determine if attemperation is required based on whether the predicted exhaust temperature of steam from the finishing superheater exceeds a set point temperature as well as whether the inlet temperature of steam into the finishing superheater drops below a set point temperature of steam. The attemperation system may include a characterizing function to linearize the valve operation controlled by the control logic to inject cooled, high-pressure feedwater into the steam upstream of the finishing superheater, which may, in turn, control the exhaust temperature of steam from the finishing superheater. The disclosed embodiments may also be applied to any systems where an outlet temperature of a fluid from a heat transfer device may be controlled.

A hot water supply system includes a first tank for storing hot water for heating; a second tank for storing hot water to be supplied to a hot water tap; a heater circulation path for supplying the hot water of the first tank to a heater; a first path that includes a first heat transfer portion surrounding the exposed portion of the second tank to the inside of the first tank and that connects the first tank to a forward portion of the heater circulation path so that the hot water of the first tank can be supplied to the heater through the first heat transfer portion; and a second path that includes a second heat transfer portion disposed along the first heat transfer portion, and that allows heat exchange between the hot water of the second tank and the hot water flowing through the first heat transfer portion due to the flow, in the second heat transfer portion, of the hot water of the second tank.

A water delivery system is provided, comprising at least one faucet device with a cold water faucet part and a hot water faucet part, a cold water line to the at least one faucet device, a tankless heater device for heating water, a hot water line having a first portion running from an outlet of the tankless heater device to the at least one faucet device and having a second portion running from the at least one faucet device to an inlet of the tankless heater device, and a circulatory pump arranged in the second portion of the hot water line, wherein the circulatory pump has a prefixed first performance level and a prefixed second performance level, wherein the first performance level causes a finite water flow in the hot water line which is below an operation threshold value of the tankless heater device.

There are provided a generator internal pipe section that extends in the horizontal direction inside a steam generator; and a communication pipe section that is connected to the generator internal pipe section and is provided with a communication path, wherein one end of the communication path is connected to the pipe path at an upper end of a cross-section perpendicular to the flow direction of the cooling water in the pipe path and the other end of the communication path is positioned at the downside in the vertical direction in relation to one end of the communication path, and wherein one end side and the other end side of the communication path are connected at a position existing at the upside in the vertical direction in relation to one end.

A catalytic tank heater includes a catalytic heating element supported on an LPG tank by a support structure that holds the element in a position facing the tank. Vapor from the tank is provided as fuel to the heating element, and is regulated to increase heat output as tank pressure drops. The heating element is internally separated into a pilot heater and a main heater, with respective separate fuel inlets. The pilot heater remains in continual operation, but the main heater is operated only while tank pressure is below a threshold. Operation of the pilot heater keeps a portion of the catalyst hot, so that, when tank pressure drops below the threshold, and fuel is supplied to the main heater, catalytic combustion quickly expands from the area surrounding the pilot heater to the remainder of the catalyst.

A water heater system comprises a water tank, a burner plenum, a flue, a blower, a combustion air passageway, a dilution air passageway, an upstream manifold, and a downstream manifold. The upstream manifold divides air from the blower so that some air flows through the combustion air passageway to the burner plenum and some air flows through the dilution air passageway to the downstream manifold. The downstream manifold combines the air from the dilution air passageway with combustion products from the flue.

Disclosed is a masterless control system for controlling a plurality of fluidly and operably connected water heaters to meet a hot water demand such that overall efficiency is maximized and usage disparity between water heaters is minimized. There is further disclosed a method for detecting a small system demand in said network by adjusting the setting of each flow limiting valve of each water heater. There is still further disclosed a method for enabling seamless addition or removal of a heater in service and heating load distribution to water heaters.

An on demand tankless water heater system that is capable of quickly delivering water within a desired temperature range. The tankless water heater provides a hybrid heating method that contains a primary heating system and a secondary heating system disposed in a buffer tank that cooperate to facilitate control of output water temperature during water usage. A pressure differential switch detects low flow demand and allows the secondary heating system to provide immediate heating to the water. This secondary heating system provides a faster temperature response and fine tuning of output water temperature.

When a detection temperature by a hot-water tank thermister (42) has been equal to or lower than a re-heating determination temperature over at least a re-heating determination time, a tank controller (50) performs a sterilization process by heating hot water within a hot-water tank (30) by means of a heat pump unit (60); and when the detection temperature by the hot-water tank thermister (42) has been equal to or lower than a determination temperature for prohibiting the use of hot water in the hot-water tank over at least a determination time for prohibiting the use of hot water in the hot-water tank, the tank controller (50) performs only a temperature regulation control via heating while keeping a hot-water flow regulation valve (34) in a closed state.