A hot water appliance includes a housing defining an inner space; a heat source arranged in the inner space of the housing and comprising at least one burner; a flue gas discharge arranged in the inner space of the housing and configured to discharge combustion gases of the at least one burner therethrough; and a heat exchanger arranged in the inner space of the housing and associated with the flue gas discharge. The combustion gases of the at least one burner form a first heat exchanging fluid of the heat exchanger associated with the flue gas discharge. A flue gas discharge for a hot water appliance and a method for heating a fluid are also described.

The present invention is to resolve a problem such as the above, the purpose being providing a heat exchanger capable of improving heat exchange efficiency by allowing the amount of heating medium flowing through heat medium channels, which are in multiple layers between a plurality of plates, to be evenly distributed. The present invention comprises a heat exchange part having heating medium channels, through which heating medium flows, and combustion gas channels, through which combustion gas burned in a burner flows, adjacently disposed in alternation in the spaces between the plurality of plates, the heat exchange part being provided in multiple numbers in a stacked structure, and having a heating medium distribution part for narrowing the channel at points where the flow direction of the heating medium is switched in adjacently located heating medium channels.

A domestic boiler preheater includes a flue box having a combustion gas inlet to receive hot combustion gas from a boiler, and a combustion air inlet to receive air for combustion in a boiler. The preheater further includes a condenser having a mains cold water inlet and a mains water outlet arranged such that mains water flows through the condenser prior to being supplied to a boiler combustion chamber. The condenser further includes a central heating water return and a central heating water flow outlet arranged such that central heating water flows through the condenser prior to being supplied to the boiler combustion chamber. The condenser further includes connections that enable the condenser to be connected to preheated fluid supply pipework from a source of preheated fluid, the preheated fluid having fluid heated by heat from at least one of the combustion gas and a renewable energy source.

A heat exchanger for an apparatus including a burner has at least one tube extending along a centerline from an inlet end adjacent the burner to an outlet end. A plurality of indentations is formed in the tube adjacent the inlet end and extend radially inward towards the centerline. The indentations are formed in opposing pairs extending towards one another to a depth sufficient to create turbulent fluid flow through the inlet end of the tube.

A heat exchanger, comprising at least a double shell, wherein the lower portion of the inner space of the inner shell is filled with liquid phase change medium, and at least one coiler is provided in the upper portion. The heated fluid flows in the coiler. After the downstream side pipe of the coiler is pierced through the inner shell, at least one surrounding pipe is formed in the cavity between the double shells. The bottom heat exchange plate of heat exchanger of the inner shell is located above the heat source. The cavity between the two shells forms the flue gas passage. After bottom heat exchange plate of the inner shell is heated by the heat source, the flue gas rises from the bottom of perimeter of the inner shell along the flue gas passage and the heat is transferred to the heated fluid in the surrounding pipe. The heat device using the heat exchanger according to the present invention can significantly improve the efficiency of heat utilization.

A heat exchanger tube for transferring a heat of an exhaust gas to a fluid to be heated includes a turn-back portion formed in an intermediate portion of the heat exchanger tube and a reciprocating conduit portion. The reciprocating conduit portion includes a conduit portion leading from a starting end of the heat exchanger tube to the turn-back portion, and a conduit portion leading from the turn-back portion to a terminal end of the heat exchanger tube. A space equal to or greater than the outer diameter of the conduit portions is provided between these conduit portions.

A tube for a thermal transfer device can include at least one wall having an inner surface and an outer surface, where the inner surface forms a cavity. The inner surface can be non-cylindrical. The cavity can be configured to receive a fluid that flows continuously along a length of the at least one wall.

An apparatus and system for efficiently and safely transferring heat from a masonry heater to an external heating device using coil pipes and a liquid circulation pump. Circulation of a heat transfer liquid in the apparatus and system is controlled based on the measured temperature of the heat transfer liquid in the coil pipe on a return side of the masonry heater. Two additional sensors near the external heating device are used to control the flow rate of the circulation of the heat transfer liquid in the apparatus and system, thereby controlling the amount of heat actually transferred to the external heating device.

A tube sheet for a thermal transfer device can include a body having a plurality of apertures that traverse therethrough, where the plurality of apertures are configured to receive a plurality of tubes of the thermal transfer device. The tube sheet can also include an outer perimeter defining the body, where the outer perimeter has at least one first recess feature disposed therein. The at least one first recess feature can have a first shape and a first size, where the first shape is any shape aside from a semi-circle.

A boiler includes a chamber designed to receive and conduct hot exhaust gases, the chamber being enclosed by two plate elements which have an angled design and are arranged relative to one another in a sandwich-like manner, and the chamber being connected to a flow guide that is designed between the plate elements and used to cool the hot exhaust gases. The flow guide is designed in the form of a flat gap channel which fully encloses the periphery of the chamber.