Heat exchanger and refrigeration cycle apparatus
10801791 ยท 2020-10-13
Assignee
Inventors
Cpc classification
F28F19/002
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F17/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B39/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B39/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F1/32
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D1/0471
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D1/0478
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B2500/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D1/0476
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F1/325
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F19/006
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F2265/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F28F1/32
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F19/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D1/047
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F17/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B39/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
Provided is a heat exchanger that is capable of avoiding a bridge phenomenon caused by water droplets between a plurality of flat tubes and is easily manufactured. The heat exchanger includes a plurality of plate-like fins arranged in parallel at intervals, the plurality of flat tubes inserted into the plurality of plate-like fins, and at least one water-guiding member arranged between adjacent ones of the plurality of flat tubes projecting from at least one of both outermost ones of the plurality of plate-like fins and having both end portions held in contact with projecting flat surfaces of the adjacent ones of the plurality of flat tubes.
Claims
1. A heat exchanger, comprising: a plurality of plate-like fins arranged in parallel at intervals; a plurality of flat tubes inserted into the plurality of plate-like fins, the plurality of flat tubes being arranged in an up-and-down direction at intervals; and at least one water guide arranged between adjacent ones of the plurality of flat tubes projecting from both outermost ones of the plurality of plate-like fins and being in contact with a lower side of a projecting flat surface of an upper one of the adjacent ones of the plurality of flat tubes and an upper side of a projecting flat surface of a lower one of the adjacent ones of the plurality of flat tubes, the at least one water guide being located beyond both the outermost ones of the plurality of plate-like fins.
2. The heat exchanger of claim 1, wherein a projecting portion of each of the plurality of flat tubes is bent into a U-shape and the at least one water guide extends inside the U-shape.
3. The heat exchanger of claim 1, wherein the at least one water guide is arranged in a direction away from a center position of the projecting flat surfaces and the plurality of plate-like fins, in a longitudinal direction of the projecting flat surfaces.
4. The heat exchanger of claim 1, wherein a cross-sectional width of a contact portion of the at least one water guide in a transverse direction of the projecting flat surfaces is set to be equal to a cross-sectional width of the projecting flat surfaces in the transverse direction.
5. The heat exchanger of claim 1, wherein the at least one water guide comprises a member having a cylindrical shape, a polygonal columnar shape, or a polyhedral shape.
6. The heat exchanger of claim 1, wherein the at least one water guide comprises a member having a spherical shape.
7. The heat exchanger of claim 1, wherein the at least one water guide comprises a plurality of water guides fixed to a supporter.
8. The heat exchanger of claim 1, wherein the at least one water guide comprises a member made of the same material as materials of the plurality of flat tubes or a member made of a resin.
9. A refrigeration cycle apparatus, comprising the heat exchanger of claim 1.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
DETAILED DESCRIPTION
Embodiment 1
(8) The structure of a heat exchanger 1 according to Embodiment 1 of the present invention is described.
(9) In the drawings including
(10) The plate-like fins 2 each include a pair of plate surfaces 21 and a peripheral edge portion 22 located between sides of the pair of plate surfaces 21. In the heat exchanger 1, the plurality of plate-like fins 2 are arranged such that the pairs of plate surfaces 21 are arranged in parallel at intervals. The plurality of plate-like fins 2 arranged in parallel serve as a heat exchange part 10 configured to allow air to flow along the plate surfaces 21 and exchange heat with the refrigerant flowing through flat tubes 3. Further, although not illustrated, a heat-transfer promoting portion having peak portions and trough portions alternately arrayed may be formed on each of the plate surfaces 21 of each of the plate-like fins 2. In such a case, heat transfer in the plate-like fins 2 can be promoted.
(11) The flat tubes 3 each include a pair of flat surfaces 31, a pair of bent surfaces 32 having a semicircular shape in tube cross section, and one or more refrigerant flow passages 33. The one or more refrigerant flow passages 33 are located between the pair of flat surfaces 31, that is, inside the flat tube 3, and extend in a longitudinal direction of the pair of flat surfaces 31. The one or more refrigerant flow passages 33 are not illustrated in
(12) The flat tubes 3 each include a plurality of projecting flat surfaces 34 opposed to each other through an air gap 4. The plurality of projecting flat surfaces 34 are obtained by causing at least one side of longitudinal end portions of the pair of flat surfaces 31 to project outward from at least one side of the heat exchange part 10, that is, at least one of both outermost ones of the plate-like fins 2. That is, the plurality of projecting flat surfaces 34 are a part of the flat surfaces 31.
(13) The heat exchanger 1 according to Embodiment 1 includes a plurality of water-guiding members 5 arranged in the air gaps 4 each between the projecting flat surfaces 34. Both end portions of each of the plurality of water-guiding members (or water guide) 5 are held in contact with the projecting flat surfaces 34 on sides close to the projecting flat surfaces 34. In
(14)
(15) In
(16) In
(17)
(18) Also in the heat exchanger 1 in
(19) The water-guiding member 5 only needs to have such a shape that the both end portions of the water-guiding member 5 on the sides close to the projecting flat surfaces 34 are held in contact with the projecting flat surfaces 34. For example, the water-guiding member 5 can have a spherical shape, a cylindrical shape, a polygonal columnar shape, or a polyhedral shape. The water-guiding member 5 has such a shape as to be held in contact with the projecting flat surfaces 34 at both the end portions of the water-guiding member 5 on the side of the projecting flat surfaces 34. Thus, formation of a bridge of water droplets between the projecting flat surfaces 34 can be avoided, and the drainage performance can be enhanced accordingly.
(20) Further, as a material of the water-guiding member 5, there may be used a metal material having high heat conductivity, such as aluminum and aluminum alloy, or a resin material such as plastic. In a case where a metal material is used for the water-guiding member 5, to prevent corrosion due to contact between metals of different kinds, namely, galvanic corrosion, as the metal material of the water-guiding member 5, there is used the same metal material as the material of the flat tube 3 or a metal material selected from metal materials having a small potential difference from the material of the flat tube 3.
(21) The coupling portions between the plate-like fins 2 and the flat tubes 3 and the contact portions between the flat tubes 3 and the water-guiding members 5 are joined to each other by, for example, brazing. For example, in a case where the material of the flat tube 3 is aluminum, the water-guiding member 5 is formed by using a clad material of aluminum, and the flat tubes 3 and the water-guiding members 5 are integrated by brazing, and the drainage performance can be enhanced accordingly. Methods other than brazing may be used as the method of joining the coupling portions and the contact portions as long as the heat conductivity at the coupling portions and the contact portions can be maintained. For example, the coupling portions and the contact portions may be joined by welding or bonding.
(22) Next, a refrigeration cycle apparatus including the heat exchanger 1 according to Embodiment 1 is described with reference to
(23) As illustrated in
(24) In
(25) The compressor 110 is a fluid machine configured to compress sucked low pressure refrigerant and discharge the refrigerant as high pressure refrigerant.
(26) The refrigerant flow switching device 120 is configured to switch a direction of a flow of refrigerant in the refrigeration cycle for the cooling operation and the heating operation. For example, a four-way valve is used as the refrigerant flow switching device 120.
(27) The heat source-side heat exchanger 130 is a heat exchanger that acts as an evaporator during the heating operation and acts as a condenser during the cooling operation. In the heat source-side heat exchanger 130, heat is exchanged between refrigerant flowing through the heat source-side heat exchanger 130 and outdoor air sent by the heat source-side air-sending fan 160. In the air-conditioning apparatus 100, the evaporator may be referred to as a cooler, and the condenser may be referred to as a radiator.
(28) The pressure reducing device 140 is configured to decompress high pressure refrigerant into low pressure refrigerant. As the pressure reducing device 140, for example, a linear electronic expansion valve (LEV) adjustable in opening degree is used.
(29) The load-side heat exchanger 150 is a heat exchanger that acts as a condenser during the heating operation and acts as an evaporator during the cooling operation. In the load-side heat exchanger 150, for example, heat is exchanged between indoor air and refrigerant flowing through the load-side heat exchanger 150. Although not illustrated in
(30) In this case, the heating operation refers to an operation of feeding high-temperature and high-pressure refrigerant to the load-side heat exchanger 150, and the cooling operation refers to an operation of feeding low-temperature and low-pressure refrigerant to the load-side heat exchanger 150. In
(31) Next, a drainage operation of the heat exchanger 1 during the heating operation in a case where the heat exchanger 1 according to Embodiment 1 is used as the heat source-side heat exchanger 130 in the air-conditioning apparatus 100 according to Embodiment 1 is described with reference to
(32) In the air-conditioning apparatus 100, when the heating operation is continued for a long period of time, dew condensation water, that is, condensed water is generated on a surface of the heat source-side heat exchanger 130 that acts as the evaporator, that is, the heat exchanger 1. In the heat exchange part 10 of the heat exchanger 1, the condensed water is drained due to the gravity through the plate-like fins 2 serving as water-guiding passages.
(33) Meanwhile, in a case where the projecting flat surfaces 34 of the flat tubes 3 are exposed to outside air, when the outside air is cooled down to a dew-point temperature, water droplets of condensed water are also generated on the projecting flat surfaces 34 of the flat tubes 3. The projecting flat surfaces 34 are located on an outer side of the heat exchange part 10, that is, the outer side of the plate-like fins 2 arranged on both the ends. Thus, the water droplets generated on the projecting flat surfaces 34 may not be drained through the plate-like fins 2 serving as the water-guiding passages. In
(34) Water droplets of condensed water generated on the first projecting flat surface 34a are drained due to the gravity through the plate-like fins 2 serving as the water-guiding passages in a case where the water droplets of condensed water are generated close to the heat exchange part 10. Further, in a case where water droplets are generated close to the bent surface 32, the water droplets flow along the bent surface 32 due to the gravity to reach the second projecting flat surface 34b. Meanwhile, water droplets generated close to a first arc surface 35a serving as an outer arc surface of the flat tube 3 having a U-shape flow along the first arc surface 35a due to the gravity to reach the fourth projecting flat surface 34d. No drainage passage is provided in a part of the fourth projecting flat surface 34d located on the side of the first arc surface 35a. Consequently, due to the surface tension of water droplets, a stagnation part 7a of the condensed water is liable to be generated.
(35) Further, water droplets of condensed water generated on the second projecting flat surface 34b are drained due to the gravity through the plate-like fins 2 serving as the water-guiding passages in the case where the water droplets of condensed water are generated close to the heat exchange part 10. Further, water droplets generated close to a second arc surface 35b, which is an inner arc surface of the flat tube 3 having a U-shape, flow along the second arc surface 35b due to the gravity to reach the third projecting flat surface 34c. Meanwhile, water droplets generated between the heat exchange part 10 and the raised position of the second arc surface 35b are not drained through any of the plate-like fins 2 and the second arc surface 35b. Consequently, a stagnation part 7b of the condensed water is liable to be generated due to the surface tension of the water droplets. Consequently, in the case where the heat exchanger 1 includes no water-guiding member 5, part of the condensed water stagnates on the projecting flat surface 34 due to the surface tension of the water droplets or other causes.
(36) Consequently, the water-guiding member 5 is arranged in a direction away from a center position of the projecting flat surface 34 and the heat exchange part 10, that is, the plate-like fins 2, in a projecting direction of the flat tube 3, that is, in a longitudinal direction of the projecting flat surface 34. With this configuration, the drainage of the condensed water can be promoted. For example, the crossing portion between the heat exchange part 10 and the projecting flat surfaces 34 in the longitudinal direction of the projecting flat surface 34 is defined as a reference point 0. A length of the projecting portion of the flat tube 3 is defined as L, and a radius of the first arc surface 35a is defined as R. A center position of the water-guiding member 5 in the longitudinal direction of the projecting flat surface 34 is defined as X. In this case, the water-guiding member 5 is arranged such that the center position X of the water-guiding member 5 satisfies Expression (1). With this configuration, the stagnation of the condensed water can be avoided to promote the drainage of the condensed water.
(LR)/2<x<L(1)
(37) In Embodiment 1, even when the projecting flat surfaces 34 are exposed to outside air at 0 degrees Celsius or less or refrigerant at 0 degrees Celsius or less is present inside the flat tube 3, the drainage is promoted by the water-guiding member 5. Thus, formation of ice pieces from the condensed water can be avoided.
(38) Consequently, a risk of causing breakage of the flat tube 3 and leakage of a fluid in the flat tube 3 to the outside due to the formation of ice pieces from the condensed water can be avoided. Further, through the promotion of the drainage of the condensed water, the frequency of an operation for defrosting can be reduced, and the amount of energy consumption of the air-conditioning apparatus 100 as a whole can be reduced accordingly.
(39) Next, a drainage operation for water droplets flowing from the first projecting flat surface 34a or the third projecting flat surface 34c along the bent surface 32 to reach the second projecting flat surface 34b or the fourth projecting flat surface 34d is described with reference to
(40) In
(41) As described above, the heat exchanger 1 according to Embodiment 1 includes the plurality of plate-like fins 2 arranged in parallel at intervals, the plurality of flat tubes 3 inserted into the plate-like fins 2, and the water-guiding members 5 each arranged between adjacent ones of the flat tubes 3 projecting from at least one of the plurality of plate-like fins 2 arranged on both the ends and having both end portions held in contact with the flat surfaces 31 of the adjacent ones of the flat tubes 3.
(42) Further, the air-conditioning apparatus 100 according to Embodiment 1 includes the above-mentioned heat exchanger 1.
(43) With this configuration according to Embodiment 1, the water-guiding members 5 are arranged between the flat tubes 3 to be held in contact with the projecting flat surfaces 34. Thus, the bridge phenomenon caused by the water droplets between the projecting flat surfaces 34 can be avoided, with the result that the drainage of the water droplets adhering on the projecting flat surfaces 34 is promoted. Further, the plurality of water-guiding members 5 are arranged between the projecting flat tubes 3, and hence the manufacturing method is simple. Consequently, with this configuration according to Embodiment 1, there can be provided the heat exchanger 1 that is capable of avoiding the bridge phenomenon caused by the water droplets and is easily manufactured, and the air-conditioning apparatus 100.
(44) Further, in the heat exchanger 1 according to Embodiment 1, the projecting portions of the flat tubes 3 are each bent into a U-shape. The refrigerant tubes each having a U-shape are used as the flat tubes 3. Thus, a header portion joined to terminal ends of the refrigerant tubes each having a U-shape can be arranged in the same direction, with the result that the downsizing of the heat exchanger 1 can be achieved.
(45) Further, in the heat exchanger 1 according to Embodiment 1, the water-guiding members 5 can each be arranged in the direction away from the center position of the projecting flat surface 34 and the plate-like fins 2, in the longitudinal direction of the projecting flat surface 34. Further, the cross-sectional width of the contact portion of the water-guiding member 5 in the transverse direction of the projecting flat surface 34 can be set to be equal to the cross-sectional width of the projecting flat surface 34 in the transverse direction. With this configuration, the drainage of the condensed water can further be promoted.
(46) Further, in the heat exchanger 1 according to Embodiment 1, the water-guiding members 5 can be formed by members each having a cylindrical shape, a polygonal columnar shape, or a polyhedral shape. Further, the water-guiding members 5 may be formed by members each having a spherical shape. Further, the water-guiding members 5 can be formed by members made of the same material as those of the flat tubes 3 or by members made of a resin. The water-guiding members 5 can be formed by various materials into various shapes. Thus, the manufacture can be simplified.
Embodiment 2
(47) The structure of a heat exchanger 1 according to Embodiment 2 of the present invention is described.
(48) In the heat exchanger 1 according to Embodiment 2, each of the water-guiding members (or water guides) 5 is fixed to a support member (or supporter) 8. Other structures of the heat exchanger 1 are similar to those of the above-mentioned heat exchanger 1 according to Embodiment 1, and hence description of the other structures is omitted.
(49) The support member 8 is only required to to be able to fix the water-guiding members 5. For example, the support member 8 can be formed by a plate-like member having a rectangular shape. Further, the support member 8 can be formed by a member made of the same material as those of the water-guiding members 5 or by a member made of a resin. Further, the support member 8 may be increased in width in the longitudinal direction of the projecting flat surfaces 34 to be used as a windshield member.
(50) In Embodiment 2, all of the water-guiding members 5 can be mounted to the heat exchanger 1 at a time by fixing each of the water-guiding members 5 to the support member 8. Thus, the water-guiding members 5 are easily mounted to the heat exchanger 1. Further, the strength of the projecting flat surfaces 34 can be increased by mounting each of the water-guiding members 5 to the support member 8. That is, the water-guiding members 5 also serve as reinforcing members.
Other Embodiment
(51) The present invention is not limited to the above-mentioned embodiments, and various modifications may be made to any of the embodiments without departing from the gist of the present invention. For example, in the embodiments described above, the air-conditioning apparatus 100 is given as an example of the refrigeration cycle apparatus. However, the present invention is also applicable to refrigeration cycle apparatus other than the air-conditioning apparatus 100, such as a water heater.
(52) Further, a plurality of water-guiding members 5 may be provided in the same air gap 4. For example, in the heat exchanger 1, an amount of drainage is larger on the lower side. Consequently, a larger number of water-guiding members 5 may be arranged in the flat tube 3 that are located on the lower side.
(53) Further, the embodiments described above may be carried out in various combinations.