Patent ID: 12262638

DESCRIPTION OF EMBODIMENT

Embodiment of the present invention will now be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiment. Further, the present invention may be changed without departing from the scope of effects brought about by the present invention.

FIG.1andFIG.2are diagrams illustrating a structure of a tubular heat exchanger with a thermoelectric power generation function (hereinafter, simply referred to as “heat exchanger”), according to an embodiment of the present invention.FIG.1is an external perspective view of the heat exchanger, with a part thereof cut away to show an internal structure of the heat exchanger.FIG.2is a cross-sectional view taken perpendicularly to an axial direction of the heat exchanger. The “axial direction” herein refers to a center axis direction of a heat exhaust tube1.

As illustrated inFIGS.1and2, the tubular heat exchanger according to the present embodiment includes: a thermoelectric power generation module2mounted on an outer circumferential surface of the heat exhaust tube1; and a cooling pipe3mounted on an outer circumferential surface of the thermoelectric power generation module2. The cooling pipe3is for allowing a cooling material4such as cooling water to flow therethrough. The thermoelectric power generation module2performs thermoelectric power generation by using the outer circumferential surface of the heat exhaust tube1as a high-temperature source and using the inner circumferential surface of the cooling pipe3as a low-temperature source.

In a part of the thermoelectric power generation module2relative to the circumferential direction, there is a gap8extending along the axial direction. The cooling pipe3is a double cooling pipe including an inner pipe3aand an outer pipe3b. The inner pipe3aand the outer pipe3bare welded at their axial ends. Reference numeral5in the drawing denotes a welded portion. Alternatively, the axial ends of the inner pipe3aand the outer pipe3bmay be sealed with a resin6.

The inner pipe3ais tightly wound around the outer circumferential surface of the thermoelectric power generation module2. This way, the cooling pipe3is in tight attachment to the outer circumferential surface of the thermoelectric power generation module2. As a result, in the thermoelectric power generation module2, heat loss is reduced and a temperature differential can be increased, which improves power generating efficiency.

Both wound ends of the inner pipe3ain the circumferential direction are welded along the axial direction at the position of the gap8. This way, it is possible to avoid an adverse effect on the thermoelectric power generation module2due to heat generated when welding the inner pipe3a.

For example, when three thermoelectric power generation modules2of 10 cm square are wound around the heat exhaust tube1whose outer circumference is 34 cm, a gap8of 3 cm is formed. Around the outer circumferential surface of the thermoelectric power generation module2, the inner pipe3amade of a stainless plate of 0.1 mm in thickness is tightly wound, and laser welding is performed above the gap8. Around the outer circumferential surface of the inner pipe3a, the outer pipe3bmade of a stainless plate of 0.1 mm in thickness is wound, leaving a space of 2 cm, or an existing pipe is inserted, and ends of the inner pipe3aand the outer pipe3bin the axial direction are welded or sealed with resin. This way, the double cooling pipe3is formed.

According to the present embodiment, it is possible to achieve a tubular heat exchanger with a thermoelectric power generation function, which has a small heat loss and a high power generating efficiency. Further, in a case where the cooling pipe3is structured as a double cooling pipe having the inner pipe3aand the outer pipe3b, an adverse effect on the thermoelectric power generation module2due to heat generated when welding the inner pipe3acan be avoided by welding both wound ends of the inner pipe3aat the position of the gap8formed in the thermoelectric power generation module2.

While the present invention has been described with reference to the preferred embodiment, such description is not intended to limit the present invention, and various changes are possible.

For example, the thermoelectric power generation module2may be attached to the outer circumferential surface of the heat exhaust tube1with a thermal conductive sheet (not shown) interposed therebetween. Further, as illustrated inFIG.2, a heat transfer sheet7may be provided between the thermoelectric power generation module2and the cooling pipe3. This allows further reduction of the heat loss from the heat exhaust tube1to the cooling pipe3, in relation to the attachment of the thermoelectric power generation module. As a result, a temperature differential in the thermoelectric power generation module2can be further increased, and the power generating efficiency can be further improved.

For example, the thermal conductive sheet may a silicone sheet having a heat transfer rate of 10 W/mK and a thickness of 0.1 mm. For example, the heat transfer sheet7may be a flexible carbon sheet having a heat transfer rate of 30 W/mK and a thickness of 0.1 mm. Alternatively, the heat transfer sheet7may be a flexible porous metal film, a metal-plated fabric, or the like. The thermal conductive sheet and the heat transfer sheet7also serve as a cushion for the thermoelectric power generation module2, at a time of attaching the thermoelectric power generation module2and tightly winding the inner pipe3a.

Further, as illustrated inFIG.3, the thermoelectric power generation module2may be attached to the outer circumferential surface of the heat exhaust tube1with a heat collector9interposed therebetween. This makes heat collection from the heat exhaust tube1efficient, and further raises the temperature at the high-temperature source of the thermoelectric power generation module. As a result, a temperature differential in the thermoelectric power generation module2can be further increased, and the power generating efficiency can be further improved. For example, the heat collector9may be a copper plate of 0.2 mm in thickness.

Further, the thermoelectric power generation module2may be attached to the outer circumferential surface of the heat exhaust tube1with a heat transfer sheet interposed therebetween. For example, the heat transfer sheet may be a flexible carbon sheet having a heat transfer rate of 30 W/mK and a thickness of 0.1 mm. Note that the heat collector9and the heat transfer sheet may be used in combination.

DESCRIPTION OF REFERENCE CHARACTERS

1Heat Exhaust Tube2Thermoelectric Power Generation Module3Cooling Pipe3aInner Pipe3bOuter Pipe5Welded Portion4Cooling Material6Resin7Heat Transfer Sheet8Gap9Heat Collector