A heat exchanger according to the present invention comprises a heat exchange portion in which heating medium flow paths, where a heating medium flows through a space between a plurality of plates, and combustion gas flow paths through which a combustion gas combusted in a burner flows are adjacently and alternatingly formed, wherein the heat exchange portion comprises a sensible heat portion, which surrounds the outside of a combustion chamber and comprises an area on one side of the plates, for heating the heating medium using the sensible heat of the combustion gas generated by combustion of the burner, and a latent heat portion, which comprises an area on the other side of the plates, for heating the heating medium using the latent heat of water vapors in the combustion gas which has completed heat exchanging in the sensible heat portion, wherein a connection passage for the heating medium is formed between the sensible heat portion and the latent heat portion, the plates are formed in a vertical structure so that the sensible heat portion is positioned on the top part and the latent heat portion is positioned on the bottom part, and wherein the burner has a cylindrical shape and is assembled by being inserted laterally from the front surface of a space in the combustion chamber.

Provided is an instantaneous hot water circulation unit with a scale cleaning function which can easily perform pipe cleaning for removing scale. The instantaneous hot water circulation unit which includes a hot water supply inlet portion connected to a hot water discharge unit of a hot water supply device, a hot water supply outlet portion connected to an external hot water supply unit, a hot water returning unit, a hot water outgoing unit, a hot water supply pipe, a hot water pipe, and a circulation pump, and a bypass pipe, which drives the circulation pump to perform an instantaneous hot water circulation operation when stoping hot water supply, wherein a storage tank configured to store a cleaning agent used in a cleaning operation of cleaning an inside of the pipe of the hot water supply device is provided at the bypass pipe.

A hot water supply system decouples an intelligent hot water storage system from a water heating engine system. The water heating engine system includes a plurality of instantaneous water heaters that provide for redundant operation for improved reliability. The intelligent hot water storage system includes a storage tank that encloses a volume for storage of water. The intelligent hot water storage system includes a recirculation loop driven by an integrated pump and operated by an integrated controller. By positioning the tank recirculation outlet and inlet farther apart from each other, additional usable volume of hot water is provided by the intelligent hot water storage system. Isolation valves positioned on the input and output of a recirculation pump in the recirculation loop facilitate repair or replacement of the recirculation pump. The hot water system provides for increased capacity while providing redundant heating engines in a smaller floor space than conventional systems.

Apparatuses of an energy efficient water heater and methods for controlling the same are disclosed. In one embodiment, a water heater may include a water inlet configured to receive input water, an input water temperature sensor configured to detect a temperature of the input water, a user interface unit configured to receive an output water temperature setting selected by a user, a controller configured to determine a flow rate of an output water based on the input water temperature and the output water temperature setting, a heating unit configured to heat the input water to produce the output water, the controller is further configured to control the heating unit and a proportional flow restrictor to produce the flow rate of the output water, and a water outlet configured to transfer the output water at the flow rate of the output water.

Systems and methods for controlling the output water temperature of a water heater are disclosed herein. The water heater preferably has a water inlet, heating unit, and water output. The system comprises a proportional flow restrictor placed near the water output and a controller which is configured to direct the heating unit to heat the water and the proportional flow restrictor to produce a flow rate of the output water. Temperature sensors may be used to control the proportional flow restrictor. The proportional flow restrictor can also be controlled based on the amount of heat energy applied to the heating unit.

Mobile water heating systems for producing hot water are disclosed herein. In one embodiment, a mobile water heating system includes a water heater having an oval-cylindrical shape. The water heater includes a shell, a lid and a water reservoir having a screen. A first heating coil and a second heating coil can extend between the screen and a first cone and a second cone, respectively. A first burner and a second burner can be configured to mix and combust fuel and air and direct the resulting flames through the heating coils. Pall rings can at least partially fill an interior volume of the water heater and the combustion of the fuel and air can heat the heating coils and the pall rings. Water can be heated by being directed through the heating coils and through a water manifold positioned to spray water on the pall rings.

A multi-temperature output fluid heating system including an input for receiving a fluid supply, a single heating source, a first output, a second output and a bypass path. The first output is fluidly connected to the input, where the first output is adapted for control by a first control device and to receive heat from the single heating source to achieve a first temperature at the first output. The bypass path fluidly connects the input and the second output. The input is adapted to empty a first portion of the fluid supply into the first output and a second portion of the input into the bypass path. The second output is adapted to receive an output from the first output and an output from the bypass path to achieve a second temperature.

A liquid heating system includes an instantaneous heater (18) having an inlet (20) connected to a reservoir (62). The outlet (22) of the heater is connected to fixtures (72) which use the heated liquid, and is also connected through a return connection (30) to the reservoir. In an idle mode, a pump 40 draws liquid from the reservoir (62), so that the liquid circulates through the heater and back to the reservoir. A controller (52) actuates the heater to heat the liquid to a first setpoint temperature, so that the liquid in the reservoir stabilizes at the first setpoint temperature. In a supply mode, some or all of the heated liquid flows from the outlet to the fixtures (72). Cold liquid is admitted from a supply (60) to the reservoir, and cold liquid desirably also is supplied to the heater inlet along with liquid from the reservoir, so that the heater inlet receives a combination of these. The controller controls the proportion of cold liquid to liquid from the reservoir in the combination, so as to maintain the heater at a setpoint heating rate while also maintaining the temperature of liquid discharged from the heater outlet at or near a setpoint temperature.

Provided is an instantaneous hot water circulation unit with a scale cleaning function which can easily perform pipe cleaning for removing scale. The instantaneous hot water circulation unit which includes a hot water supply inlet portion connected to a hot water discharge unit of a hot water supply device, a hot water supply outlet portion connected to an external hot water supply unit, a hot water returning unit, a hot water outgoing unit, a hot water supply pipe, a hot water pipe, and a circulation pump, and a bypass pipe, which drives the circulation pump to perform an instantaneous hot water circulation operation when stoping hot water supply, wherein a storage tank configured to store a cleaning agent used in a cleaning operation of cleaning an inside of the pipe of the hot water supply device is provided at the bypass pipe.

A heat exchanger according to the present invention comprises a heat exchange portion in which heating medium flow paths, where a heating medium flows through a space between a plurality of plates, and combustion gas flow paths through which a combustion gas combusted in a burner flows are adjacently and alternatingly formed, wherein the heat exchange portion comprises a sensible heat portion, which surrounds the outside of a combustion chamber and comprises an area on one side of the plates, for heating the heating medium using the sensible heat of the combustion gas generated by combustion of the burner, and a latent heat portion, which comprises an area on the other side of the plates, for heating the heating medium using the latent heat of water vapors in the combustion gas which has completed heat exchanging in the sensible heat portion, wherein a connection passage for the heating medium is formed between the sensible heat portion and the latent heat portion, the plates are formed in a vertical structure so that the sensible heat portion is positioned on the top part and the latent heat portion is positioned on the bottom part, and wherein the burner has a cylindrical shape and is assembled by being inserted laterally from the front surface of a space in the combustion chamber.