An arrangement for operating a rail vehicle includes a DC voltage intermediate circuit which is connected to an energy supply network, at least one traction inverter which is connected at its DC voltage side to the DC voltage intermediate circuit and at its AC voltage side which is connected one or more traction motors of the rail vehicle. An auxiliary system inverter is connected at its DC voltage side to the DC voltage intermediate circuit and is connected at its AC voltage side to a primary side of an auxiliary system transformer. Auxiliary systems are connected to a secondary side of the auxiliary system transformer via an auxiliary line. Electrical energy generated by an electrical energy supply unit is transferred via the auxiliary line, the auxiliary system transformer and the auxiliary system inverter into the DC voltage intermediate circuit for operation of the at least one traction motor.

A transport vehicle equipped with a current collector, includes: a vessel to load a load; a current collector that extends to receive electric power from an overhead line and contracts and retracts so as to be disposed away from the overhead line; and a vehicle body that rotationally drives driving wheels by at least one of the electric power from the current collector and a self-propelled driving source and on which the vessel is placed; a pantograph position detector that detects a relative position of the current collector and the overhead line; and a control device that controls a driving direction of the vehicle body or gives an instruction of information with which a direction in which the vehicle body is to be operated can be recognized, so that the relative position is brought to a position where the current collector and the overhead line are connected.

A system for transferring energy to a vehicle, in particular a track bound vehicle, such as a light rail vehicle, wherein the system includes an electric conductor arrangement adapted to produce an electromagnetic field which can be received by the vehicle thereby transferring the energy to the vehicle the system further includes electric and/or electronic devices which are adapted to operate the electric conductor arrangement. The devices produce heat while operating the conductor arrangement and—therefore—are to be cooled. A cooling arrangement of the system includes a structure having a cavity in which at least one of the devices to be cooled is located. The structure includes a cover limiting the cavity at the top, wherein the device(s) to be cooled is/are located at a distance to the cover. The structure is integrated in the ground at the path of travel of the vehicle in such a manner that the cover forms a part of the surface of the ground.

The present invention is vehicle electric power supply system (A) that supplies electric power wirelessly to a vehicle (M) that is positioned within an electric power supply area (X). The vehicle electric power supply system (A) has: a power-receiving device (m1) that is provided in the vehicle; a plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, 1c3) that are provided at mutually different positions within the electric power supply area; a position detecting device (4) that detects the position of the power-receiving device within the electric power supply area; and a control device (4) that, based on detection results from the position detecting device, selects from among the plurality of power-transmitting devices the power-transmitting device that is located in a position that corresponds to the power-receiving device, and then causes power to be supplied wirelessly from the selected power-transmitting device.

In a catenary-based transportation system which is provided with integrated power supply equipment having an electricity storage unit which stores electricity regenerated by vehicles traveling by electricity received from a catenary and supplies electricity to the catenary and the other power supply system which is a power supply system different from the electricity storage unit concerned, the performance of a rectifier of the other power supply system is determined based on a power-supplying contribution ratio γ of the other power supply system so that the cost value of the integrated power supply equipment becomes lower than a target cost value.

The method according to the invention aims to optimize the operation of a reversible traction substation (Sk) of a power supply system (4) for railway vehicles, said reversible substation being able to be commanded in a traction operating mode or a braking mode. This method includes: determining a current value (Mc) of a favored operating mode;maximizing at least one optimization function (F) that depends on the current value of the favored operating mode, based on instantaneous values (G(t)) of multiple operating properties of the substation (Sk);computing optimized values (Popt(t)) for multiple configuration parameters of the substation (Sk) from maximized values (Gmax(t)) of the operating properties.

A cord storage apparatus includes an electric motor configured to retract a power reception cord to be connected to an external power supply and a control unit configured to determine whether or not the power reception cord is retracted away from the ground when the power reception cord is connected to the external power supply and control the electric motor to stop retracting the power reception cord when the power reception cord is retracted away from the ground.

A shaped block for positioning and/or holding a plurality of line sections of one or more electric lines along the track of a vehicle includes a plurality of recesses and/or projections. Edges of the recesses and/or the projections each delimit a space for the line sections into which one of the line sections can be introduced, so that said line section extends through the space in a longitudinal direction of the space. The longitudinal directions of the spaces delimited by the edges of the recesses and/or by the projections extend essentially mutually parallel in a common plane.

A method for producing process vapor and boiler feed steam in a heatable reforming reactor for producing synthesis gas. The sensible heat of a synthesis gas produced from hydrocarbons and steam can be used so that two types of vapor are produced during the heating and evaporation of boiler feed water and process condensate. The method also includes a conversion of the carbon monoxide contained in the synthesis gas. The method includes an optional heating of the boiler feed water using the flue gas from the heating of the reforming reactor. The sensible heat of the synthesis gas and of the flue gas originating from the heating can be used more efficiently. The disadvantages from the flue gas heating, which are caused by the fluctuating heat supply in the flue gas duct, are avoided. A system for practicing the method is also disclosed.

A method of controlling combustion of a gas appliance includes the following steps: a) Read a first burning data in a database; b) Burn gas according to the first burning data; c) Obtain a burning efficiency of the gas appliance; and d) Compare the burning efficiency with a predetermined value, and repeat the step b to the step d when the burning efficiency is higher than the value, or read a second burning data in the database and burn gas according to the second burning data when the burning efficiency is lower than the value. The present invention provides plural stages of burning according to the main component of the gas to be burned to increase the total burning efficiency.

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 novel 3-Input-3-Output (3×3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7×7) MFA control system is also described for controlling a combined 3-Input-3-Output (3×3) process of Boiler-Turbine-Generator (BTG) units and a 5×5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

A heating system comprising a fuel burner in co-operation with a primary heat exchanger, a reservoir for storing warmed water in, and a blending valve, and a controller wherein in use a user can signal to the controller to warm the water in the water store using a heater or by the primary heat exchanger, and when hot water is required water is removed from the water store and mixed with water from a cold main prior to being or after the water from the cold main has been admitted to a further heat exchanger for heating the water.

A steam generator includes a substantially horizontal gas conduit (1) to guide a heating gas flow (2) and an evaporator unit positioned at least partially in the horizontal gas conduit for transferring heat from the heating gas to a flow medium which flows through the evaporator unit. The heat transfer section of the evaporator unit of the steam generator is bottom fed, which means that the inlet conduit is arranged at a lower region of the heat transfer section. The outlet conduit is arranged at an upper region. The inlet conduit allows an once through operation of the evaporator section which is necessary to enable operation under supercritical circumstances. The evaporator unit includes at least two evaporator stages (3, 4) which are arranged in a cascade. Each evaporator stage includes a heat transfer section (12, 21) and a separator (14, 23). The presence of the separators (14, 23) subdivides the evaporator unit into evaporator stages (3, 4).

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 controller determines and adjusts system parameters, including cleanliness levels or sootblower operating settings, that are useful for maintaining the cleanliness of a fossil fuel boiler at an efficient level. Some embodiments use a direct controller to determine cleanliness levels and/or sootblower operating settings. Some embodiments use an indirect controller, with a system model, to determine cleanliness levels and/or sootblower settings. The controller may use a model that is, for example, a neural network, or a mass energy balance, or a genetically programmed model. The controller uses input about the actual performance or state of the boiler for adaptation. The controller may operate in conjunction with a sootblower optimization system that controls the actual settings of the sootblowers. The controller may coordinate cleanliness settings for multiple sootblowers and/or across a plurality of heat zones in the boiler.

A portable steam sauna includes a collapsible canopy which can be deployed in a use or storage configuration, allowing for easy deployment and transportation. The collapsible canopy has two flexible poles which provide a framework to the collapsible canopy. The collapsible canopy and flexible poles can be secured to a base sheet, which itself is attached to a flat surface such as a massage table. The collapsible canopy and base sheet each have elastic perimeters which allow them to be stretched over a flat surface, similar to how a sheet is fitted to a mattress. The base sheet includes attachment points which interface with the flexible poles and help to secure the collapsible canopy in a use configuration. Steam is supplied to the canopy by means of a steam generator, steam hose, and a steam connector which is inserted through a steam opening on the collapsible canopy.

A condensing fuel-fired appliance has a condensate trap that includes a trap body; a float; a flue gas inlet port for the introduction of flue gas into the interior region of the trap body; a condensate outlet port for the discharge of condensate from the interior region; and a flue gas outlet port for the discharge of flue gas from the interior region of the trap body. The float is configured to move in response to condensate collected in the interior region of the trap body to a position to substantially block the discharge of flue gas from the interior region through the flue gas outlet port. The float is also configured to move to a position to substantially block the discharge of flue gas from the interior region through the condensate outlet port when there is little or no condensate in the interior region of the trap body.

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.

A robotic tubesheet walker having two rails connected by a central hinge, wherein the central hinge can be opened or closed by an actuation device. Upon each rail is mounted a carriage, wherein each carriage can move along its respective rail toward or away from the central hinge by means of a drive mechanism. Each carriage further contains at least two “gripper” attachment mechanisms, such as camlocks, to grip the tubesheet. The grippers either insert into tube holes within the tubesheet to fasten the respective carriage to the tubesheet, or retract to disengage. Further attached to the central hinge is a tool support fixture, and attached to the tool support fixture is a coupler that holds maintenance or inspection tools.

A buckstay connecting system includes a socket part that is fixed to the horizontal buckstay being separated from a lower end of the vertical buckstay between the lower end of the vertical buckstay and the horizontal buckstay, and an insertion part that is fixed to a lower portion of the vertical buckstay, is inserted into the socket part so as to be able to slide in a vertical direction, inhibits the horizontal buckstay from being inclined, and is allowed to be fastened to the socket part.

A fluid heating system for heating and dispensing fluid in a primary fluid flow path is disclosed, and may include a reservoir defining an interior for holding a quantity of a fluid, with the interior being in fluid communication with the primary fluid flow path such that the quantity of fluid in the interior is able to flow into the primary fluid flow path. A primary pump may be configured to pump fluid in the primary fluid flow path, the primary pump being in fluid communication with the primary fluid flow path. A fluid dispensing device may be configured to selectively dispense fluid from the primary fluid flow path. A steam injection apparatus may be in communication with the interior of the reservoir device to inject steam into the interior to heat fluid located in the interior of the reservoir.

An apparatus includes an inner rim, a base wall, a side wall and an outer rim. The inner rim has a first opening formed therein. The base wall extends outward from an inner edge of the inner rim and is integral with the inner rim. The side wall extends outward from an outer edge of the inner rim and is integral with the inner rim. The outer rim has a second opening formed therein and an inner edge integral with the side wall. The inner rim, base wall, side wall and outer rim are formed to prevent liquid seepage to one or more surrounding components of an appliance in which the apparatus is installed.

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 system providing for heat recovery from exhausted flue gas in a steam generator is described comprising a flue gas outlet conduit defining a flow path for flue gas from a flue gas outlet of a steam generator to a flue gas conduit junction point; a flue gas primary conduit defining a flow path for flue gas from the junction to a primary air preheater; a flue gas secondary conduit defining a flow path for flue gas from the junction to a secondary air preheater; wherein a steam generator process fluid heat exchanger is disposed within the flow path of the flue gas primary conduit upstream of the primary air preheater to recover some heat from the flue gas in advance of the primary air preheater. A method implementing the flow principles embodied in such a system is also described.

A steam boiler includes a boiler housing. A helical coil for boiling water and superheating the wet steam is disposed within the boiler housing. A burner emits combustion gases which heat a heat emitter which is disposed in the inner space of the helical coil. Combustion gases from the burner enter the internal cavity of the heat emitter and then pass through perforations in the heat emitter before contacting the helical coil. As such, the heat emitter is heated by the combustion gases and serves as a radiant heat source for the helical coil.

The building heat exchange system is suited for installation in areas having warmer seasonal climates. The system can include an external solar heated water supply, and an indoor water heater. An enclosure extends around the water heater, with indoor air flowing between the enclosure and water heater to a duct for distribution. During cooler conditions the water heater heats incoming water from the relatively cool external water supply, with the warmth of the water heater warming the air for distribution into the bathroom or other area as desired. In warmer times, the water supplied from the water supply can be sufficiently hot that additional heating is not needed, and can be hotter than desired. In such warmer conditions, the water heater can serve as a radiator, with heat radiated from the water heater being absorbed by air flowing past the water heater and expelled to the external environment.

A fuel-fired water heater is shut down when a predicted steady state combustion chamber temperature is below a known threshold. The predicted steady state temperature is based on combustion chamber temperatures during heat up of the burner and appliance.

A method of assembling a syngas cooler is provided. The method includes coupling a supply line within a cooler shell, coupling a heat transfer panel within the cooler shell, and coupling a heat transfer enclosure within the cooler shell such that the heat transfer enclosure substantially isolates the heat transfer panel from the cooler shell. A manifold is coupled in flow communication with the supply line, the heat transfer enclosure, and the heat transfer panel.

A waste heat steam generator for a gas and steam turbine power plant is provided. The generator has economizer, evaporator and superheater heating surfaces which form a flow path and through which a flow medium flows. An overflow line branches off from the flow path and leads to injection valves arranged downstream at a flow side of a superheater heating surface in the flow path. The overflow line permits a brief power increase of a downstream steam turbine without resulting in an excessive loss in efficiency of the steam process. The brief power increase is permitted independently of the type of waste heat steam generator. The branch location of the overflow line is arranged upstream of an evaporator heating surface at the flow medium side and downstream of an economizer heating surface.

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.

A steam generation boiler having a reaction chamber formed by a bottom portion in a lower portion, a roof portion at an upper portion, and walls extending vertically between the bottom portion and the roof portion. The walls include vertical end walls having a tapering wall section that tapers symmetrically with respect to its middle axis towards the bottom portion, in which (i) a first group of steam pipes in the tapering wall section including steam pipes on both sides of the middle axis, pass at an angle with respect to the middle axis in a wall plane of the tapering wall section, and from the wall plane into the reaction chamber, and (ii) a second group of steam pipes arranged to pass to the bottom portion along the wall plane.

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.

A control method for boiler outlet temperatures includes predictive control of SH and RH desuperheater systems. The control method also includes control and optimization of steam generation conditions, for a boiler system, such as burner tilt and intensity, flue-gas recirculation, boiler fouling, and other conditions for the boiler. The control method assures a proportional-valve control action in the desuperheater system, that affects the boiler system.

An improved method of making a baked pastry, particularly, a shell or wrap for a samosa from a pastry dough in a convection baking oven having a convection atmosphere, the method comprising baking the dough in the oven at a baking temperature for a baking period of time, the improvement having the convection atmosphere with a sufficiently moist atmosphere for the duration of the baking time to prevent the pastry from becoming dry.

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.

This invention relates to a heating/cooling system operating on the basis of a novel SPLIT BUFFER TANK; representing an efficiency improvement alternative to HVAC systems functioning with existing commercial buffer tanks. Currently, commercial buffers have the heat source provider (HSP)-return and system-return discharging to a common buffer/vessel. Novel SPLIT BUFFER is provided with a SEPARATION DISK placed inside the tank as mechanical way of separating the hot water inflow from the HSP from the warmer water inflow from system return. The disk moves up and down along the tank driven by demanded water supply and return. Pump-1 circulates hot water from the hot section of the buffer to the secondary system claiming for heat. Pump-2 circulates warmer water from the warmer section of the buffer through the HSP where it is reheated, and subsequently stored in the hot section of the buffer to reinitiate this cycle again.

A method of controlling a water heater is provided. The method comprises evaluating the fitness of solutions associated with a plurality of individuals in a population for a current operating environment of the water heater. Each of the plurality of individuals comprises a dominant genotype and a recessive genotype. Each genotype represents a solution for controlling the water heater. A fitness function is applied to the dominant genotype of each individual. The fitness function is based on at least one of water flow demand data and energy price data. The method further comprises storing previously encountered genotypes in the recessive genotypes of the individuals. The method further comprises selecting a solution for controlling operation of the water heater based on the fitness evaluation.

A system includes a gas turbine engine that includes a compressor section configured to generate compressed air and a combustor coupled to the compressor section. The combustor is configured to combust a first mixture comprising the compressed air and a first fuel to generate a first combustion gas. The gas turbine engine also includes a turbine section coupled to the combustor. The turbine section is configured to expand the first combustion gas to generate an exhaust gas. The gas turbine engine also includes a boiler coupled to the turbine section. The boiler is configured to combust a second mixture comprising a portion of the first combustion gas and a second fuel to generate a second combustion gas that is routed to the turbine section. In addition, the boiler generates a first steam from heat exchange with the second combustion gas.

A water heater includes a bypass that is formed, on the side of a water supply pipe, branching from a main water path and bypassing a part of the main water path, and a flow path switching unit (a valve and a stepping motor) that is formed at a branching portion of the main water path and the bypass. The flow path switching unit is controlled by a controller and that can selectively switch a flow path between the main water path and the bypass. A microbubble generator generating microbubbles is provided on the bypass, the microbubble generator including a water agitator portion, a compression portion and a decompression portion. When the controller determines that scale has built up, the flow path is switched to the bypass by the flow path switching unit, and water containing microbubbles is caused to flow inside the water heater.

The efficiencies of illustrative embodiments of vertical center flue type fuel-fired base water heaters are improved by installing in the water heaters variously configured tubular condensing type secondary heat exchangers of smaller diameters than the associated center flues. The efficiency increases are achieved with components and manufacturing processes similar to those utilized in the base water heaters and secondary heat exchanger materials similar to those in the tank portions of the base water heaters.

A water heater includes a water pipe form by bending a pipe. The entire water pipe leans related to a vertical plane to expose all the section to a burner thereunder. All the sections of the water pipe lean downwards related to a horizontal plane. It will make the water in the water in the water pipe flows backwards when no water is supplied to the water heater. Therefore, there will never be water remaining in the water pipe to get rid of the jam problem.

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 (31) 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 stored hot water over at least a determination time for prohibiting the use of stored hot water, 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.

Disclosed is a hot water supply system provided with a tank which holds a high-temperature liquid, and a heating means for generating the high-temperature liquid which is stored in the aforementioned tank. In the lower portion of the aforementioned tank is provided a water-heating heat exchanger which heats the water to be supplied to a hot water terminal by means of the liquid present in the lower portion of the aforementioned tank. Further, a hot water supply circuit is provided which conducts water to the aforementioned hot water supply terminal. The aforementioned hot water supply circuit splits into a water-heating path passing through the aforementioned water-heating heat exchanger, and a bypass path bypassing the aforementioned water-heating heat exchanger, and is provided with a hot water supply circuit control mechanism which controls the circulation state of the water in the aforementioned water-heating path and the aforementioned bypass path.

A circulating fluidized bed boiler includes a rectangular furnace having multiple particle separators connected to an upper portion of each of a front wall and a back wall of the furnace. Each particle separator includes a gas outlet, and a flue gas duct system connected to the gas outlets for conducting cleaned flue gas to a back pass. The particle separators are arranged in pairs. Each pair includes a front separator arranged adjacent to the front wall and a back separator arranged adjacent to the back wall. The flue gas duct system includes cross over ducts, each duct connecting the gas outlet of a front separator of a pair of particle separators, across and over the furnace, to the gas outlet of the back separator of the same pair of particle separators, and to the back pass, which back pass is arranged on the back wall side of the furnace.

A water heater in which by applying pulsation of a liquid to be heated which circulates between a tank and a heat exchanger, scale that has been deposited on the inner wall (heat-transfer surface) of a to-be-heated liquid flow channel in a heat exchanger is detached, and the number of times of circulation of the liquid to be heated which circulates between the tank and the heat exchanger is controlled to be three times or less. The number of times of circulation is determined, based on the entire volume of the to-be-heated liquid stored in the tank, a boiling time to be taken for the entire volume of the to-be-heated liquid in the tank to reach a predetermined temperature, and the flow rate of the to-be-heated liquid which passes through the to-be-heated liquid flow channel.

A domestic combined heat and power system including a power unit, a heat-storage tank which receives waste heat of the power unit for storing heat in direct water, and a main heat exchanger connected to the heat-storage tank, being heated by a burner so as to use the water as hot water. A waste-heat heat exchanger filled with a heat-transfer medium is installed between the power unit and the heat-storage tank such that a waste-heat pipe is arranged in the form of a coil at one side inside the waste-heat heat exchanger, and a heat-storage pipe of the heat-storage tank is arranged in the form of a coil at the other side. Waste heat of the power unit is indirectly heat exchanged to the heat-storage tank through the heat-transfer medium. Costs and waste of energy consumption are reduced, and there is sharing of functions that are duplicated across the heat-storage tank.

A tube disposed in the combustion chamber of a standing pilot type fuel-fired water heater is used to increase the overall efficiency of the water heater by improving the heat transfer from the pilot flame to the tank during standby periods by funneling the standing pilot flame upwardly through the tube in a manner concentrating the pilot flame heat against an underside portion of the bottom head of the water heater tank. To further increase water heater efficiency, the pilot burner is of a dual input type. Various pilot burner operational algorithm modes are disclosed for causing the pilot burner to operate at a high firing rate during main burner operation, and at a low firing rate during standby periods.