A plate (1) for a heat exchange arrangement has a first heat transferring surface (A) with a protrusion (7) forming a continuous and closed ridge. This ridge divides said surface into a closed inner region (A1) and an outer region (A2). The inner region (A1) encloses a first inlet porthole (2) and a first outlet porthole (5) for a first medium. The outer region (A2) has a second inlet porthole (3) and a second outlet porthole (6) for the first medium. A heat exchange arrangement comprises a stack of first and second plates of the above type. The protrusions (7) on the first heat transferring surfaces (A) of said plates are connected to each other to separate first channels into first and second flow paths for the first medium. Each first flow path is configured to direct the first medium from a first inlet to a first outlet inside the inner region (A1) and each second flow path is configured to direct the first medium from a second inlet to a second outlet in the outer region (A2), said inlets and outlets being defined between said inlet and outlet portholes (2, 3 and 5, 6 respectively).

A heat exchanger for hot water supply (21) is comprised of: a first heat exchanging unit (21) a that heats the water, which is supplied from a second communication section x.sub.1 to the hollow portions of hollow plates P.sub.1 to P.sub.5 and reaches a first communication section y, by a combustion exhaust gas that circulates through the gaps among the hollow plates P.sub.1 to P.sub.5; and a second heat exchanging unit (21b) that heats the water, which is supplied from the first communication section y to the hollow portions of the hollow plates P.sub.6 to P.sub.8 below the hollow plates P.sub.1 to P.sub.5 and reaches a third communication section x.sub.2, by a heat medium that circulates through the gaps among the hollow plates P.sub.6 to P.sub.8.

The heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The secondary heat exchanger is disposed to overlap the primary heat exchanger in a vertical direction in a state in which the heat exchange device is installed. The secondary heat exchanger includes a plurality of first pipes and a plurality of second pipes. Each of the plurality of first pipes and the plurality of second pipes extends in a zigzag manner in the vertical direction by a plurality of linear portions being connected to a plurality of curved portions in series. Each of the plurality of linear portions of each of the plurality of second pipes is disposed to be displaced from each of the plurality of linear portions of each of the plurality of first pipes in the vertical direction.

A domestic boiler preheater includes a flue box including 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 includes a condenser including 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 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 includes connections that enable the condenser to be connected to preheated fluid supply pipework from a source of preheated fluid, the preheated fluid including fluid heated by heat from at least one of the combustion gas and a renewable energy source.

A hot water apparatus includes a burner, a latent heat recovery heat exchanger, a housing, a fixing member, an attachment member, and a straightening vane. The fixing member is configured to fix the latent heat recovery heat exchanger to the housing. The attachment member is configured to attach the fixing member to a case. The straightening vane is arranged in the case. The attachment member protrudes into the case. The straightening vane includes a top plate portion arranged upstream from the attachment member in a direction of flow of the heating gas in the case.

A header of a heat exchanger including a first wall connected with a plurality of heat transfer tubes of the heat exchanger, a second wall facing the first wall with an interval therebetween, and a circumferential wall connecting outer circumferential edges of the first and the second walls in such a manner that an area between the first and the second walls constitutes a chamber for inflow of fluid, the chamber communicating with each of the heat transfer tube. At least one of the first and the second walls is configured to curve in such a manner that a central area of the wall is positioned close to an inside of the chamber than an outer circumferential area of the wall. The thickness of the header is reduced and enough strength of the header is obtained, thereby preferably enduring repeating water hammer.

A heat exchanger including (a) a fluid conductor including a heat exchange tubing including a first end and a lumen; and (b) a first connecting tubing including an outer surface, a lumen and a first sealing ring disposed about the outer surface of the first connecting tubing, wherein the first connecting tubing is configured for insertion into the lumen of the heat exchange tubing at the first end such that the first sealing ring comes in sealing engagement with the first connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the first connecting tubing and a fluid flow is confined within a lumen formed of the lumen of the first connecting tubing and the lumen of the heat exchange tubing.

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 heat exchanger plate for a plate heat exchanger (12) includes a first side, a second side and a center point (P) through which an imaginary center axis (A) extends in a direction perpendicular to a plane of the plate. The plate comprises a first port for a first medium, and at least a second port and a third port for a second medium. The plate further comprises a first sealing arranged on the second side around the first port, a second sealing arranged on the second side at a circumference of the plate, and a closed third sealing arranged between the first and second sealings to form a first heat transfer area and a second heat transfer area separated from the first heat transfer area. The second port is arranged in the first heat transfer area and the third port is arranged in the second heat transfer area.

A condensation heat exchanger having dummy pipes is provided in which a plurality of condensation heat exchange pipes are connected with water housings so as to recover latent heat while the water is circulating, and, by having the dummy pipes, penetrating the water housings, arranged in between the condensation heat exchange pipes, the pressure applied to the water housings is distributed and smooth flow of water is facilitated.