US-12624898-B2 - Heat exchanger, air-conditioning apparatus equipped with heat exchanger, and method of manufacturing heat exchanger

US12624898B2US 12624898 B2US12624898 B2US 12624898B2US-12624898-B2

Abstract

A heat exchanger includes: flat heat transfer tubes having refrigerant flow passages, extending in an up-down direction, spaced apart from each other in a lateral direction and arranged in two rows; and corrugated fins each provided between associated adjacent ones of the flat heat transfer tubes in the two rows, each joined to the associated adjacent flat heat transfer tubes from top to bottom in the up-down direction, and each having a protruding portion that protrudes forward relative to front-side end portions of the associated adjacent flat heat transfer tubes in a front-side one of the two rows. The position of the front-side end portion of each of the flat heat transfer tubes in the front-side row and the length of the protruding portion in the front-rear direction are not unchanged from top to bottom in the up-down direction.

Inventors

Takayuki KATSUMARU
Ryohei Kawabata
Tetsuji Saikusa
Keizo KAMADA
Yu TAMAKI
Mitsuhiro Ikeda

Assignees

MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date: 20260512
Application Date: 20220926
Priority Date: 20220407

Claims (8)

1 . A heat exchanger comprising: a plurality of flat heat transfer tubes each having refrigerant flow passages formed therein and allowing refrigerant to flow therethrough, the plurality of flat heat transfer tubes extending in an up-down direction that is a tube extending direction, the plurality of flat heat transfer tubes being spaced apart from each other in a lateral direction perpendicular to the up-down direction and a front-rear direction that is an flow direction of air, and being also arranged in two rows in the front-rear direction; and corrugated fins each of which is provided between associated adjacent ones of the flat heat transfer tubes in the two rows that are adjacent to each other in the lateral direction, each of which is joined to the associated adjacent ones of the flat heat transfer tubes in the two rows, from top to bottom in the up-down direction, and each of which has a protruding portion that protrudes forward relative to front-side end portions of the associated adjacent ones of the flat heat transfer tubes in the front-side row, wherein a position of a front-side end portion of each of the corrugated fins is unchanged from top to bottom in the up-down direction, a position of the front-side end portion of each of the flat heat transfer tubes in the front-side row is not unchanged from top to bottom in the up-down direction, and a length of the protruding portion in the front-rear direction is not unchanged from top to bottom in the up-down direction.
2 . The heat exchanger of claim 1 , wherein a relationship of L 1 <L 2 and L 3 <L 2 is satisfied, where L 1 is a length of the protruding portion at an upper part of the corrugated fin in the front-rear direction, L 2 is a length of the protruding portion at a central part of the corrugated fin in the front-rear direction, and L 3 is a length of the protruding portion at a lower part of the corrugated fin in the front-rear direction.
3 . The heat exchanger of claim 1 , wherein a relationship of L 1 >L 2 and L 3 >L 2 is satisfied, where L 1 is a length of the protruding portion at an upper part of the corrugated fin in the front-rear direction, L 2 is a length of the protruding portion at a central part of the corrugated fin in the front-rear direction, and L 3 is a length of the protruding portion at a lower part of the corrugated fin in the front-rear direction.
4 . The heat exchanger of claim 1 , wherein a relationship of L 1 >L 3 is satisfied, where L 1 is a length of the protruding portion at an upper part of the corrugated fin in the front-rear direction, and a length of the protruding portion at a lower part of the corrugated fin in the front-rear direction, and a length of the protruding portion gradually decreases from the upper part to the lower part of the corrugated fin.
5 . The heat exchanger of claim 1 , wherein a relationship of L 1 <L 3 is satisfied, where L 1 is a length of the protruding portion at an upper part of the corrugated fin in the front-rear direction, and L 3 is a length of the protruding portion at a lower part of the corrugated fin in the front-rear direction, and a length of the protruding portion gradually increases from the upper part to the lower part of the corrugated fin.
6 . An air-conditioning apparatus equipped with the heat exchanger of claim 1 .
7 . A method of manufacturing the heat exchanger of claim 1 , the method comprising: arranging the flat heat transfer tubes in a rear-side one of the two rows in the lateral direction on a reference plane; setting a spacer on an upper side of the flat heat transfer tubes in the rear-side row to ensure a space between the flat heat transfer tubes in the rear-side row and the flat heat transfer tubes in a front-side one of the two rows; arranging the flat heat transfer tubes in the front-side row in the lateral direction on the spacer; setting each of corrugated fins between associated adjacent ones of the flat heat transfer tubes in the two rows in the lateral direction; causing the corrugated fin to be compressed by the associated adjacent flat heat transfer tubes in the two rows; attaching headers to associated end portions of the flat heat transfer tubes; and joining the headers and the flat heat transfer tubes together by brazing and joining the corrugated fins and the flat heat transfer tubes together by brazing.
8 . The method of manufacturing the heat exchanger of claim 7 , wherein the spacer has an upper surface inclined relative to the reference plane.

Description

CROSS REFERENCE TO RELATED APPLICATION This application is a U.S. national stage application of PCT/JP2022/035579 filed on Sep. 26, 2022, which is based on and claims the benefit of priority of the prior International Patent Application No. PCT/JP2022/017217 filed on Apr. 7, 2022, the contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a heat exchanger including flat heat transfer tubes and corrugated fins, an air-conditioning apparatus equipped with the heat exchanger, and a method of manufacturing the heat exchanger. BACKGROUND In the past, corrugated-fin-and-tube heat exchangers including flat heat transfer tubes and corrugated fins have been widely used. In an air-conditioning apparatus, the corrugated-fin-and-tube heat exchanger is provided in an outdoor unit. In a heating operation, this heat exchanger operates as an evaporator. When an outdoor air temperature falls to or below freezing point of water, a frosting phenomenon occurs in which moisture contained in the air changes into frost, which forms on the evaporator. When the frost forms on the heat exchanger, the heat transfer area of corrugated fins decreases and airflow passages narrows, thereby reducing the heating performance. In view of this point, a heat exchanger has been proposed in which a front-side end portion of each of corrugated fins protrudes forward relative to a front-side end portion of each of flat heat transfer tubes, that is, a windward-side end portion of the corrugated fin protrudes toward the windward side relative to a windward-side end portion of the flat heat transfer tube, thereby to reduce the likelihood that frost will form (see, for example, Patent Literature 1). PATENT LITERATURE Patent Literature 1: Japanese Patent Publication No. 6165360 In a heat exchanger disclosed in Patent Literature 1, a front-side end portion of each of corrugated fins protrudes forward relative to a front-side end portion of each of heat transfer tubes, thereby to improve a frost resistance. However, heat of high-temperature and high-pressure gas refrigerant does not easily transfer to the end portion of the corrugated fin that protrudes forward relative to the end portion of the flat heat transfer tube. Furthermore, once frost forms on the protruding portion of the corrugated fin, it is hard to defrost the protruding portion of the corrugated fins on which the frost forms. In addition, the corrugated fins have a further problem in which its strength is reduced at the protruding portion because the protruding portion protrudes forward relative to the front-side end portion of the flat heat transfer tube. SUMMARY The present disclosure is applied to solve the above problems, and relates to a heat exchanger that is improved in defrosting capability without reducing a frost resistance, and is also improved in strength of corrugated fins, and also to an air-conditioning apparatus equipped with the heat exchanger, and a method of manufacturing the heat exchanger. A heat exchanger according to an embodiment of the present disclosure includes: flat heat transfer tubes each of which has refrigerant flow passages formed therein, extends in an up-down direction that is a tube extending direction, and which are spaced apart from each other in a lateral direction perpendicular to the up-down direction and a front-rear direction that is an flow direction of air, and are arranged in two rows in the front-rear direction; and corrugated fins each of which is provided between associated adjacent ones of the flat heat transfer tubes in the two rows that are adjacent to each other in the lateral direction, each of which is joined to the associated adjacent ones of the flat heat transfer tubes in the two rows, from top to bottom in the up-down direction, and each of which has a protruding portion that protrudes forward relative to front-side end portions of the associated adjacent ones of the flat heat transfer tubes in a front-side one of the two rows. The position of the front-side end portion of each of the flat heat transfer tubes in the front-side row is not unchanged from top to bottom in the up-down direction, and the length of the protruding portion in the front-rear direction is not unchanged from top to bottom in the up-down direction. An air-conditioning apparatus according to another embodiment of the present disclosure is equipped with the above heat exchanger. A method of manufacturing a heat exchanger according to still another embodiment of the present disclosure is a method of manufacturing the above heat exchanger, and includes: arranging the flat heat transfer tubes in a rear-side one of the two rows in the lateral direction on a reference plane; setting a spacer on an upper side of the flat heat transfer tubes in the rear-side row to ensure a space between the flat heat transfer tubes in the rear-side row and the flat heat transfer tubes in a front-side one of the two rows; arranging the