Abstract: Wave-like concaves/convexes are formed on respective flat surfaces of a heat exchange tube, such that crest lines of continuing V shapes in a horizontal direction and trough lines of continuing V shapes in the horizontal direction are alternately arranged and that bends of the V shapes form curve lines. This configuration reduces the stress concentration at the bends in a press-forming process, compared with a configuration that crest lines and trough lines have bends formed in a shape of continuing sharply-angled V shapes in the horizontal direction. As a result, this configuration increases the yield in the press-forming process at a fixed amplitude of the wave-like concaves/convexes and increases the amplitude of the wave-like concaves/convexes at a fixed yield in the press-forming process.

Abstract: Each fin 30 is designed to have continuous lines of wave crests 34 and continuous lines of wave troughs 36 arranged at a preset angle in a specific angle range of 10 degrees to 60 degrees relative to the main stream of the air flow and symmetrically folded back about folding lines of a preset folding interval W along the main stream of the air flow. A ratio (a/p) of an amplitude ‘a’ of a waveform including one wave crest 34 and one adjacent wave trough 36 to a fin pitch ‘p’ satisfies a relation of 1.3×Re?0.5<a/p<0.2. A ratio (W/z) of the folding interval W to a wavelength ‘z’ of the waveform satisfies a relation of 0.25<W/z<2.0. A ratio (r/z) of a radius of curvature ‘r’ at a top of the wave crest 34 or at a bottom of the wave trough 36 to the wavelength ‘z’ of the waveform satisfies a relation of 0.25<r/z.

Abstract: A corrugated fin has flat plate sections each having a pair of lateral sides facing each other and a pair of end sides facing each other, and joining sections connecting with lateral sides of the flat plate sections. The flat plate sections and joining sections are alternately formed into a corrugated shape by bending. The joining section has an even surface joined to a tube through which a heat exchange medium flows, while the flat plate section includes a recess or protrusions in arbitrary sections taken along two directions including a direction in which the lateral sides are arranged and a direction in which the end sides are arranged, respectively.

Abstract: A heat exchanger assembled from multiple heat exchanging tubes. Each of the multiple heat exchanging tubes is formed as a flattened tube of 0.5 mm in thickness by press work or bending work of a stainless steel plate member having a thickness of 0.1 mm. Each of the multiple heat exchanging tubes is structured to have multiple lines of sequential wave crests and multiple lines of sequential wave troughs formed on each of flattened faces of the heat exchanging tube. The multiple lines of the sequential wave crests and the multiple lines of the sequential wave troughs are arranged to have a preset angle ? relative to a main stream of an air flow. The lines of the sequential wave crests and the lines of the sequential wave troughs are symmetrically folded back about folding lines arranged at a preset interval W along the main stream of the air flow.

Abstract: A plurality of heat-exchanger tubes, each of which has an inlet fin formed on a side surface on the air inlet side of a flattened hollow tube and extending upstream of air along the flow of air and an outlet fin formed on the side surface on the air outlet side of the hollow tube and extending downstream of the air along the flow of the air are arranged at regular intervals in such a manner that their oblong planes face one another, an upper header which supplies a first heat exchange medium is attached on top of the heat-exchanger tubes, and an lower header which collects the first heat exchange medium is attached at the bottom of the heat-exchanger tubes to form a heat exchanger.

Abstract: A plurality of heat-exchange tubes 30 each including a flat pipe including a groove 36 and wavelike depression-and-projection portions 33, 34 are arranged in parallel in such a manner that each of respective longitudinal directions thereof is a vertical direction, and a heat exchange medium is made to flow from an inlet 31 at each lower portion to an outlet 32 at each upper portion. Guide walls 43, 44 are provided in a shell 40, and exhaust gas is made to flow an inlet 41 at an upper portion to an outlet 42 at a lower portion, thereby making the exhaust gas meander in flow paths 46a to 46d and a space between the plurality of heat-exchange tubes 30.

Abstract: A corrugated fin has flat plate sections each having a pair of lateral sides facing each other and a pair of end sides facing each other, and joining sections connecting with lateral sides of the flat plate sections. The flat plate sections and joining sections are alternately formed into a corrugated shape by bending. The joining section has an even surface joined to a tube through which a heat exchange medium flows, while the flat plate section includes a recess or protrusions in arbitrary sections taken along two directions including a direction in which the lateral sides are arranged and a direction in which the end sides are arranged, respectively.

Abstract: A heat exchanger has multiple laminated fins 30. Each fin 30 has multiple tops 34 and multiple bottoms 36 arranged to have a preset acute angle ? (for example, 30 degrees) to an air flow line at an air inlet and to make an air flow in a cavity region behind each of multiple heat transfer tubes 22a to 22c in an air flow direction at an air outlet. This design of the fins 30 produces effective secondary flows of the air to improve the heat transfer efficiency and makes an additional contribution to heat exchange, due to the air flow in the cavity region behind each of the heat transfer tubes 22a to 22c in the air flow direction. This arrangement effectively prevents separation of the air flow and a local speed increase of the air flow, while improving the overall heat exchange efficiency by production of the effective secondary flows of the air.

Abstract: A plurality of flat tubes formed as a tube having notches by linearly cutting upper and lower parts from a hollow flat circular doughnut shape are stacked to structure a tube laminate. It is attached to a case so that a notch aligns with the notch and faces upward by an exhaust inflow end plate and that a notch aligns with the notch and faces downward by an exhaust outflow end plate. A cutoff valve is provided at an exhaust outflow end of an exhaust communication tube passing through the center of the tube laminate by heat insulation. While an internal combustion engine is warming up, the cutoff valve is closed to cause the exhaust to flow in gaps of the respective flat tubes from upward to downward as a whole and also a heat exchange medium is caused to flow in the respective flat tubes from downward to upward as a whole to have heat exchanged between the exhaust and the heat exchange medium to recover the exhaust heat.

Abstract: A plurality of flat tubes formed as a tube having notches by linearly cutting upper and lower parts from a hollow flat circular doughnut shape are stacked to structure a tube laminate. It is attached to a case so that a notch aligns with the notch and faces upward by an exhaust inflow end plate and that a notch aligns with the notch and faces downward by an exhaust outflow end plate. A cutoff valve is provided at an exhaust outflow end of an exhaust communication tube passing through the center of the tube laminate by heat insulation. While an internal combustion engine is warming up, the cutoff valve is closed to cause the exhaust to flow in gaps of the respective flat tubes from upward to downward as a whole and also a heat exchange medium is caused to flow in the respective flat tubes from downward to upward as a whole to have heat exchanged between the exhaust and the heat exchange medium to recover the exhaust heat.

Abstract: A heat exchanger assembled from multiple heat exchanging tubes. Each of the multiple heat exchanging tubes is formed as a flattened tube of 0.5 mm in thickness by press work or bending work of a stainless steel plate member having a thickness of 0.1 mm. Each of the multiple heat exchanging tubes is structured to have multiple lines of sequential wave crests and multiple lines of sequential wave troughs formed on each of flattened faces of the heat exchanging tube. The multiple lines of the sequential wave crests and the multiple lines of the sequential wave troughs are arranged to have a preset angle ? relative to a main stream of an air flow. The lines of the sequential wave crests and the lines of the sequential wave troughs are symmetrically folded back about folding lines arranged at a preset interval W along the main stream of the air flow.

Abstract: Each fin 30 is designed to have continuous lines of wave crests 34 and continuous lines of wave troughs 36 arranged at a preset angle in a specific angle range of 10 degrees to 60 degrees relative to the main stream of the air flow and symmetrically folded back about folding lines of a preset folding interval W along the main stream of the air flow. A ratio (a/p) of an amplitude ‘a’ of a waveform including one wave crest 34 and one adjacent wave trough 36 to a fin pitch ‘p’ satisfies a relation of 1.3×Re?0.5<a/p<0.2. A ratio (W/z) of the folding interval W to a wavelength ‘z’ of the waveform satisfies a relation of 0.25<W/z<2.0. A ratio (r/z) of a radius of curvature ‘r’ at a top of the wave crest 34 or at a bottom of the wave trough 36 to the wavelength ‘z’ of the waveform satisfies a relation of 0.25<r/z.

Abstract: A heat exchanger has multiple laminated fins 30. Each fin 30 has multiple tops 34 and multiple bottoms 36 arranged to have a preset acute angle ? (for example, 30 degrees) to an air flow line at an air inlet and to make an air flow in a cavity region behind each of multiple heat transfer tubes 22a to 22c in an air flow direction at an air outlet. This design of the fins 30 produces effective secondary flows of the air to improve the heat transfer efficiency and makes an additional contribution to heat exchange, due to the air flow in the cavity region behind each of the heat transfer tubes 22a to 22c in the air flow direction. This arrangement effectively prevents separation of the air flow and a local speed increase of the air flow, while improving the overall heat exchange efficiency by production of the effective secondary flows of the air.

Abstract: There is disclosed a ceiling embedded type indoor unit which is reduced in height to provide a compact unit body size and which provides a large cooling/heating capability. The ceiling embedded type indoor unit comprising two air blowoff ports and embedded in a ceiling comprises a heat exchanger formed in a U-shape with sides of the U-shape being disposed on long sides of a unit body and connected to a header pipe for circulating a coolant at one end of an open side of the U-shape, air blowoff ports disposed to extend from a bottom side the U-shape, and a centrifugal blower disposed aside to the bottom side of the U-shape relative to a substantial center of a length direction of the sides of the U-shape.

Abstract: There is disclosed a ceiling embedded type indoor unit which is reduced in height to provide a compact unit body size and which provides a large cooling/heating capability. The ceiling embedded type indoor unit comprising two air blowoff ports and embedded in a ceiling comprises a heat exchanger formed in a U-shape with sides of the U-shape being disposed on long sides of a unit body and connected to a header pipe for circulating a coolant at one end of an open side of the U-shape, air blowoff ports disposed to extend from a bottom side the U-shape, and a centrifugal blower disposed aside to the bottom side of the U-shape relative to a substantial center of a length direction of the sides of the U-shape.

Abstract: There is disclosed a ceiling embedded type indoor unit which is reduced in height to provide a compact unit body size and which provides a large cooling/heating capability. The ceiling embedded type indoor unit comprising two air blowoff ports and embedded in a ceiling comprises a heat exchanger formed in a U-shape with sides of the U-shape being disposed on long sides of a unit body and connected to a header pipe for circulating a coolant at one end of an open side of the U-shape, air blowoff ports disposed to extend from a bottom side the U-shape, and a centrifugal blower disposed aside to the bottom side of the U-shape relative to a substantial center of a length direction of the sides of the U-shape.

Abstract: A heat exchanger composed by overlapping a plurality of heat exchanger units each of which is formed by inserting a plurality of fins over one or a plurality of heat transfer tubes. The fins are worked so that a pair of opposed fins of the overlapped heat exchanger units are brought into contact with each other at one or more points. This heat exchanger constitutes an air conditioner when the heat exchanger units are overlapped in a direction of gravity.

Abstract: A heat exchanger, in which a plurality of fins formed on either an internal or an external face of a heat transfer tube, wherein each of the plurality of fins has a first portion including a fin top and a second portion including a fin root, and wherein the first portion has a ridgeline formed in a raised and recessed shape, or in a wave-like or corrugated shape, and the second portion has a substantially straight outline in a fin longitudinal direction in a cross section parallel to either the internal or the external face on which the plurality of fins are formed.