A latent heat recovery heat exchanger includes a case, a heat exchange portion, and a straightening vane. The heat exchange portion includes a plurality of heat transfer plates surrounded by a peripheral wall portion of the case and layered on one another, each of the plurality of heat transfer plates extending in a direction from an inlet toward an outlet. The straightening vane includes a top plate portion covering the plurality of heat transfer plates so as to close a space between the plurality of heat transfer plates in end portions of the plurality of heat transfer plates in a direction intersecting with a direction of layering of the plurality of heat transfer plates when the heat exchange portion is viewed from the inlet toward the outlet.

The heat exchanger comprises at least one gas flow channel, at least one water flow channel, and a metal wall delimiting the gas flow channel from the water flow channel. The at least one water flow channel comprises a number of consecutive parallel straight segments. Two consecutive parallel straight segments are separated by a wall and by a U-turn comprising an upstream section and a downstream section. The upstream and the downstream sections are defined as the sections of the U-turn delimited on the one hand by the plane of the wall separating the two consecutive parallel straight segments; and on the other hand by the plane through the end section of the wall separating the two consecutive parallel straight segments, the plane which is parallel with the width direction of the water flow channel and which is perpendicular to the plane of the wall separating the two consecutive parallel straight segments. In at least two U-turns the upstream section has a volume that is at least 20% lower than the volume of the downstream section.

The invention discloses a condensing gas water heater, a condensing heat exchanger as well as heat exchanger plates. The condensing heat exchanger comprises: a housing and at least one heat exchanger plate disposed in the housing; the heat exchanger plate comprises a first metal board and a second metal board butting each other, wherein a surface of the first metal board and a surface of the second metal board which butt each other are butting surfaces, and two outer surfaces opposite to the butting surfaces are a first surface and a second surface, respectively; at least one of the first metal board and the second metal board is formed with a convex flow guide portion along a direction away from the butting surface; the first metal board and the second metal board form a fluid passage via the flow guide portion; and the housing is provided with a flue gas inlet and a flue gas outlet. The condensing gas water heater, the condensing heat exchanger as well as the heat exchanger plates provided in the invention can increase heat exchange efficiency, reduce cost, realize a modular assembly and improve ease of mounting.

A heat exchanger tube assembly comprising a first tube sheet, a second tube sheet opposite the first sheet, a plurality of heat exchanger tubes, each independently connects the first tube sheet and the second tube sheet, wherein the tubes are in a staggered ring configuration that comprises a concentric sequence of rings of decreasing diameter wherein adjacent tubes on the same ring are separated by a fixed radial separation angle and adjacent tubes on adjacent rings are staggered by rotating all the tubes within an inner ring by a fixed radial index angle, IA, relative to the next outermost tube ring.

A fin-and-tube type heat exchanger includes: a plurality of plate fins arranged in a case side by side in a fore-and-aft direction of the case; and a heat transfer tube including a plurality of straight-type tubular bodies each passing through these plurality of plate fins. First and second plate fins arranged side by side in the right-and-left width direction of the case are provided as a plurality of plate fins. The heat transfer tube has a connection tubular body connecting the straight-type tubular bodies passing through the first and second plate fins. The heat transfer tube passes through areas in which the first and second plate fins are arranged.

According to the present invention, a heat exchanger comprises a fin having a plurality of through holes. The plurality of through holes include mutually adjacent first and second through holes disposed on a side closest to a heating gas's inlet side. The fin has a slit located between the first through hole and the second through hole and cut into the fin from an edge thereof located on the heating gas's inlet side to a side farther from the heating gas's inlet side than a reference line connecting a center of the first through hole and a center of the second through hole. Furthermore, the fin has at least one opening between the slit and the first and second through holes. The opening includes a first opening having a portion located on the side farther from the heating gas's inlet side than the reference line.

A plate-type heat exchanger includes a first heat transfer plate and a second heat transfer plate. The first heat transfer plate has a joint projection portion. The second heat transfer plate has a joint recess portion in which the joint projection portion is fitted. The joint projection portion and the joint recess portion are brazed to each other.

A fluid heating system including: a pressure vessel; an assembly comprising: a heat exchanger core including a second inlet and a second outlet; a first conduit having a first end connected to the second inlet of the heat exchanger core and a second end disposed outside of the pressure vessel; a second conduit having a first end connected to the second outlet of the heat exchanger core and a second end disposed outside of the pressure vessel; and a blower in fluid connection with the first end of the first conduit, wherein the fluid heating system satisfies the condition that a Bulk Heat Flux between the first end of the first conduit and the first end of the second conduit is between 45 kW/m.sup.2 and 300 kW/m.sup.2, and wherein the Pressure Drop between the first conduit and the second conduit is between 3 kiloPascals and 30 kiloPascals.

A heat exchange cell is described comprising a containment casing (11) comprising a rear wall (11d), a front wall (22) and a peripheral side wall (11c), a helically-shaped heat exchanger (13) comprising at least one tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis of the helix according to a plurality of coils and mounted in the containment casing (11); a feeding zone of a second heat transfer fluid, intended for the heat exchange with the first heat transfer fluid, defined in the casing (11) coaxially and internally with respect to the heat exchanger (13); a first chamber (15) for collecting the second heat transfer fluid externally defined with respect to the heat exchanger (13) between a radially outer wall thereof and the peripheral side wall (11c) of the containment casing (11); and a second chamber (16) for collecting the second heat transfer fluid at least partially delimited by at least one separating element (14). The separating element (14) is mounted at an axially external position with respect to the heat exchanger (13) in such a way as to define the second chamber (16) for collecting the second heat transfer fluid between the separating element (14), the peripheral side wall (11c) and the rear wall (11d) or the front wall (22) of the containment casing (11); in this way, the first (15) and the second (16) collection chambers are in fluid communication with each other by means of at least one passage (17a, 17a, 17b-17g; 14e) configured to allow a flow of the second heat transfer fluid substantially in parallel to the peripheral side wall (11c) of the casing (11) and in proximity thereto. The separating element (14) comprises a heat exchange portion in contact with at least one portion of an end coil of the heat exchanger (13) and configured to allow a heat exchange between the coil-shaped portion of the heat exchanger (13) and the second collection chamber (16), while the heat exchange cell (10) further comprises at least one second passage (35) allowing a fluid outlet from the second collection chamber (16) peripherally defined in the second chamber (16) between an axial end (11g) of the peripheral side wall (11c) and the rear wall (11d) or the front wall (22) of the containment casing (11).

A latent-heat exchanger comprising an upper heat exchange unit in which a plurality of circulating-heating-water heat exchange units having a circulating-heating-water flow channel formed therein and a lower heat exchange unit disposed on the lower side of the upper heat exchange unit, in which a plurality of direct-water heat exchange units having a direct-water flow channel formed therein is provided.