A cylindrical header of a heat exchanger includes a central member, front-side and rear-side members extending longitudinally on front and rear sides of the central member to form front-side and rear-side spaces along with the central member. The central member has a first flange covering a front-side-member-first-end part and a rear-side-member-first-end part from outside when viewed in cross-section, and a second flange covering a front-side-member-second-end part and a rear-side-member-second-end part from outside when viewed in cross-section. The front-side member is joined to the central member with the front-side-member-first-end part facing an inner surface of the first flange, and the front-side-member-second-end part facing an inner surface of the second flange. The rear-side is joined to the central member with the rear-side-member-first-end part facing an inner surface of the first flange, and the rear-side-member-second-end part facing an inner surface of the second flange.

A heat transfer tube includes first flow paths aligned in the heat transfer tube. Each of the first flow paths includes a section with a rectangular shape that is elongated in a first direction parallel with an alignment direction of the first flow paths. Each of the first flow paths includes protrusions disposed on an inner surface. The section of each of the first flow paths has a long side having a first length and a short side having a second length, where a ratio of the first length to the second length is between 1.1 and 1.5.

A method for manufacturing a heat exchanger is provided. The heat exchanger includes a plurality of plate-like fins that are stacked with a predetermined fin pitch, and a plurality of flat heat exchanger tubes that are disposed with a predetermined spacing from one another along the longitudinal direction of the plate-like fins and extend through the plate-like fins along the stacking direction. The plate-like fins each have a plurality of notches provided in an end portion along the long side. The plate-like fins have a shape corresponding to the cross-sectional shape of the flat heat exchanger tubes, and the flat heat exchanger tubes are inserted into the notches. The manufacturing method includes disposing the flat heat exchanger tubes with a predetermined spacing from one another, and attaching the plate-like fins to the flat heat exchanger tubes one by one by inserting the flat heat exchanger tubes into the notches of each of the plate-like fins.

A refrigeration apparatus includes: a casing that includes first and second spaces; a heat exchanger housed in the casing and including a heat exchange portion and a header collecting tube. The heat exchange portion includes a plurality of heat transfer tubes through which a refrigerant flows, is disposed in the first space, and causes the refrigerant to exchange heat with an air flow. The header collecting tube is connected to the heat transfer tubes and disposed in the second space. The refrigeration apparatus also includes a wind shielding plate including a wind shielding surface that shields the second space from the air flow, where the header collecting tube includes a header body portion that extends in a longitudinal direction of the header collecting tube, and the wind shielding plate is fixed to the header collecting tube and fixed to the casing or a component disposed in the casing.

A heat exchanger includes: a header that extends in a first direction; and a plurality of heat transfer tubes that extend in a second direction crossing the first direction, each of which has one end connected to the header, and that are arranged in the first direction at intervals. The header includes: a header body having a tubular shape, a first member through which the one end of each of the heat transfer tubes extends, and a second member positioned between the header body and the first member in the second direction. The second member includes: a base portion that extends in the first direction, and a plurality of protruding portions that extend from the base portion toward the first member in the second direction.

A flat tube, a multi-channel heat exchanger, and an air conditioning and refrigeration system. The flat tube has n groups of flow channels extending in a length direction of the flat tube, and the n groups of flow channels are distributed to be spaced apart in a width direction of the flat tube; and a flow cross-sectional area of a first group of the flow channels is A1, . . . , a flow cross-sectional area of k.sup.th group of the flow channels is A.sub.k, . . . , a flow cross-sectional area of an n.sup.th group of the flow channels is An, 1<k≤n, A.sub.k≥1.2A.sub.k−1, and k is an integer greater than 1.

A heat exchanger having a heat exchanger core having at least two rows of tube and fin blocks, each tube and fin block contains an assembly of tubes and fins, wherein the tubes are aligned parallel to each other while the fins are located between adjacent tubes, each tube having a first tube end and a second tube end, each tube and fin block of the first tube and fin block and the second tube and fin block having a manifold tube, the manifold tubes having a row of openings for a fluid tight connection with tubes of a tube and fin block, wherein the first tube ends of the first tube and fin block are fluid tight connected to the openings of a first manifold and the first tube ends of the second tube and fin block are fluid tight connected to the openings of a second manifold.

A heat exchanger includes a plurality of heat transfer tubes arranged at predetermined intervals in a vertical direction, a tubular header that has a plurality of connection portions where the heat transfer tubes are connected to a side portion of the header and that communicates with each of the heat transfer tubes, a refrigerant pipe that communicates with the header at a middle portion of the header in the vertical direction, and a first bypass pipe having ends one of which communicates with a lower portion of the header and the other of which communicates with a middle portion of the refrigerant pipe. A distance between a communication position at which the first bypass pipe and the refrigerant pipe communicate with each other and an inner wall of the header is not more than double an inside diameter of the refrigerant pipe.

A heat exchanger includes: flat pipes arranged such that flat surfaces of the flat pipes are opposed to one another; and fins each including insertion parts that extend in an insertion direction that crosses a direction in which the flat pipes are disposed and a longitudinal direction of the flat pipes. At least part of each of the flat pipes is inserted into a corresponding one of the insertion parts. Each of the fins includes a cut-and-raised part that is cut and raised in a thickness direction between the insertion parts, and a rib disposed between the insertion part and the cut-and-raised part.

A heat exchanger includes: a plurality of flat tubes; a fin in which a plurality of notches are arranged side by side in a vertical direction, the fin having a plurality of intermediate portions and a connecting portion connecting the intermediate portions to each other; and a first bulging portion having an upper end edge and a lower end edge provided between a first notch and a second notch, the upper end edge being positioned in the intermediate portion and the lower end edge being positioned in the connecting portion. The upper end edge has a first upper end positioned on an intermediate portion side, and a second upper end positioned on a connecting portion side, the first upper end being positioned to be higher than the second upper end, or the first upper end being positioned at the same height as the second upper end.