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.

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.

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.

A boiler includes a tank, a gas circuit that includes a main combustion chamber in the tank and branch tubes in the tank that extend off of the main combustion chamber, and a water circuit fluidly isolated from the gas circuit. The water circuit includes a first manifold and water tubes that extend off of the first manifold. Each water tube extends through a respective one of the branch tubes, which may serve to preheat the water prior to discharge of the water into the tank.

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.

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.

A shell-and-tube heat exchanger according to the present invention comprises: an outer barrel having a cavity provided therein such that heating water flows along the same; a lower tube plate that covers an opening near one end of the outer barrel; an upper tube plate that covers an opening near the other end of the outer barrel, the upper tube plate providing an inner space in which a heat source is positioned; a plurality of flues for guiding combustion gas from the upper tube plate to the outside of the lower tube plate; and a main diaphragm arranged across a reference direction between the lower tube plate and the upper tube plate, a plurality of through-holes being formed in the main diaphragm such that the flues penetrate the same, wherein at least some of the through-holes constitute a large-width through-hole (single hole) that at least two of the flues penetrate together.

The present invention relates to a boiler with a heating blower, the boiler being able to improve heat exchange efficiency without an additional boiler. According to the present invention, there is provided a heating blower that supplies high-temperature hot wind to a flame guide tube outside a storage tub, so it is possible to improve heat exchange efficiency of the flame guide tube and flue tube without an additional boiler.

The present invention relates to a boiler with a heating blower, the boiler being able to improve heat exchange efficiency without an additional boiler. According to the present invention, there is provided a heating blower that supplies high-temperature hot wind to a flame guide tube outside a storage tub, so it is possible to improve heat exchange efficiency of the flame guide tube and flue tube without an additional boiler.

The objective of the present invention is to provide a tubular heat exchanger capable of improving heat exchange efficiency and preventing deformation and damage thereof even in a high water-pressure environment. To this end, the present invention includes an outer jacket through which a heat medium is introduced and discharged; a combustion chamber coupled to the inside of the outer jacket so that a heat medium passage is formed between the combustion chamber and the outer jacket, and configured to perform combustion of a burner; a plurality of tubes formed in a flat shape for allowing combustion gas, which is generated in the combustion chamber, to flow along the inside of the combustion chamber and exchange heat with the heat medium; and a turbulator coupled to the inside of the tubes so as to induce generation of turbulence in a flow of the combustion gas.