A baffle for a fluid collection portion of a thermal transfer device can include a body having an inner perimeter, an outer perimeter, and an asymmetric feature, where the asymmetric feature is configured to create a pressure drop within the fluid collection portion of the thermal transfer device. The inner perimeter can be configured to be at least as large as an inner surface of a first wall that forms the fluid collection portion of the thermal transfer device. The outer perimeter can be configured to be no larger than an outer surface of a second wall that forms the fluid collection portion of the thermal transfer device.

A U-bend pipe type heat exchanger includes: a heat exchanger main body surrounded by a front side plate, a back side plate, a left side plate, and a right side plate, and having open upper and lower portions through which a heat source passes; a plurality of U-bend pipes inserted between the left side plate and the right side plate, each of the plurality of U-bend pipes including two heat exchange pipes arranged in parallel with each other and a U-shaped pipe connecting one end portions of the two heat exchange pipes; and a plurality of water jackets attached to at least one of outward surfaces of the left side plate and the right side plate, and connecting open end portions of two adjacent heat exchange pipes such that a low-temperature water circulates along the plurality of U-bend pipes.

A diffuser plate for a thermal transfer device can include a body having a number of first apertures and a second aperture that traverse therethrough, where the first apertures are asymmetrically arranged with respect to the second aperture. The first apertures can have a first shape and a first size, and where the first apertures are configured to receive a plurality of tubes. The second aperture has a second size, where the second size is larger than the first size.

The plate-type heat exchanger includes blocks stacked on each other, each of the blocks including a heat exchanger body configured to exchange heat between a first fluid and a second fluid. A connection passage for the first fluid is formed between blocks adjacent to each other of the plurality of blocks, the connection passage allowing the outlet of one of the blocks adjacent to each other and the inlet of the other of the blocks adjacent to each other to communicate with each other, the first fluid in the blocks adjacent to each other having different flow directions between the blocks adjacent to each other, and a second connection passage is provided between at least one pair of blocks adjacent to each other among the plurality of blocks, the second connection passage being configured to cause the first fluid to flow to a position different from the connection passage.

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.

A heat exchanger including more than one fluid conductor, each of the fluid conductors is configured to receive a distinct flow of fluid and heat from only one heat source, wherein the coils are configured to be interleaved to form a structure of a single-sized lumen in which the heat source is disposed.

A baffle for a fluid collection portion of a thermal transfer device can include a body having an inner perimeter, an outer perimeter, and an asymmetric feature, where the asymmetric feature is configured to create a pressure drop within the fluid collection portion of the thermal transfer device. The inner perimeter can be configured to be at least as large as an inner surface of a first wall that forms the fluid collection portion of the thermal transfer device. The outer perimeter can be configured to be no larger than an outer surface of a second wall that forms the fluid collection portion of the thermal transfer device.

A heat exchange cell includes a casing, a heat exchanger in which a first heat transfer fluid flows, a feeding zone, and first and second collection chambers for a second heat transfer fluid. The casing can include rear, front, and peripheral side walls. The heat exchanger can be helically-shaped, mounted in the casing, and include at least one tubular duct for the flow of the first heat transfer fluid. The tubular duct can be coiled about a longitudinal axis and define a helix. The feeding zone of the second heat transfer fluid can be defined in the casing coaxially and internally with respect to the helix. The first chamber can be defined externally with respect to the heat exchanger by a radially outer wall thereof and the peripheral side wall. The second chamber can be at least partially delimited by at least one separating element.

An aspect of the present disclosure provides a flow channel cap plate that constitutes a combustion chamber assembly including a combustion chamber and a plurality of insulating pipelines disposed on left/right side surfaces of the combustion chamber, the flow channel cap plate forming an insulating flow channel by covering the front surface of the combustion chamber, the flow channel cap plate including an inlet part including an inlet, and an inlet flow channel cap covering the front surface of the combustion chamber, an inlet space part is formed by covering the front surface of the combustion chamber with the inlet flow channel cap, the inlet is an entrance of the insulating flow channel, the plurality of insulating pipelines include a plurality of inlet insulating pipelines, and the inlet space part is a space that communicates the inlet with the plurality of inlet insulating pipelines.

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.