Absorption type cooling device

Abstract

The invention relates to an absorption type cooling device. The absorption cooling device of the present invention may comprise: an evaporator for evaporating a refrigerant; an absorber that mixes the refrigerant evaporated in the evaporator with an absorbent to generate an absorption liquid; a regenerator that heats the absorption liquid supplied from the absorber; a condenser to which the refrigerant generated in the regenerator is supplied; and a heat transfer tube disposed on at least one of the evaporator and the absorber and extending lengthwise, the heat transfer tube including a rib protruding from an inner surface of the heat transfer tube and extending lengthwise in a spiral shape in a longitudinal direction of the heat transfer tube. The width of the rib formed in the longitudinal direction of the heat transfer tube becomes smaller toward the direction in which the rib protrudes from the inner surface of the heat transfer tube.

Description

Technical Field

[0001] The present invention relates to an absorption type chiller, and more particularly, to an absorption type chiller having heat transfer tubes. Background Art

[0002] A cooling device supplies chilled water to a chilled water demand location, and can perform heat exchange between a refrigerant circulating in a refrigerant cycle and chilled water circulating at the demand location, thereby cooling the chilled water. Such a cooling device, as a large-capacity device, can be installed in a large-scale building or the like.

[0003] An absorption type chiller is a device that can perform refrigeration or heating by using the circulation operation of an absorbent and a refrigerant to perform heat exchange between the refrigerant and chilled water.

[0004] The absorption type chiller can perform refrigeration or heating by the following principle: the refrigerant evaporated in the evaporator is absorbed by the absorbent in the absorber, the absorbent liquid that has absorbed the refrigerant passes through the regenerator to evaporate the refrigerant, and the evaporated refrigerant is condensed through the condenser.

[0005] The absorption type chiller may include heat transfer tubes for the absorber and the evaporator. In the evaporator, the refrigerant outside the heat transfer tubes cools the water flowing inside the heat transfer tubes. In the absorber, the absorbent flows along the outer side surface of the heat transfer tubes while absorbing water particles in the air.

[0006] 'Heat transfer tubes for an absorption type chiller' disclosed in Korean Registered Patent No. 10-1786858 includes a plurality of ribs extending in a spiral direction along the inner surface, and the ribs project perpendicularly from the inner surface of the heat transfer tubes.

[0007] In the conventional heat transfer tubes, due to the ribs formed perpendicularly on the inner surface of the heat transfer tubes, there is a problem that the flow resistance increases due to the ribs interfering with the flow inside the heat transfer tubes.

[0008] In addition, due to the ribs formed perpendicularly in the flow direction, there is a problem that vortices are formed at the vertical ends on the downstream side of the ribs.

[0009] In addition, there is a problem that the pressure loss of the heat transfer tubes increases due to the formation of vortices and the increase in flow resistance.

[0010] In addition, there is a problem that the power consumption of the pump increases due to the increase in the pressure loss of the heat transfer tubes.

[0011] Existing Literature:

[0012] Patent Literature

[0013] Korean Registered Patent Gazette No. 10-1786858 (Publication Date: October 18, 2017) Summary of the Invention

[0014] An object of the present invention may be to provide an absorption cooling device with improved refrigeration and heating performance.

[0015] Another object of the present invention may be to provide an absorption cooling device with improved absorption performance of an absorber.

[0016] Another object of the present invention may be to provide an absorption cooling device with improved evaporation performance of an evaporator.

[0017] Another object of the present invention may be to provide an absorption cooling device with improved absorption efficiency of an absorbent that absorbs moisture.

[0018] Another object of the present invention may be to provide an absorption cooling device with reduced pressure loss of a heat transfer tube.

[0019] Another object of the present invention may be to provide an absorption cooling device with improved power efficiency.

[0020] Another object of the present invention may be to provide an absorption cooling device with improved pressure resistance of a heat transfer tube.

[0021] Another object of the present invention may be to provide an absorption cooling device with improved heat transfer performance of a heat transfer tube.

[0022] Another object of the present invention may be to provide an absorption cooling device with an increased heat transfer area of a heat transfer tube.

[0023] Another object of the present invention may be to provide an absorption cooling device with reduced manufacturing cost.

[0024] Another object of the present invention may be to provide an absorption cooling device with improved maintenance and management performance.

[0025] To achieve the above object, according to one aspect of the present invention, an absorption cooling device may include: an evaporator that evaporates a refrigerant; an absorber that mixes the refrigerant evaporated in the evaporator with an absorbent to generate an absorption liquid; a regenerator that heats the absorption liquid supplied from the absorber; a condenser to which the refrigerant generated in the regenerator is supplied; and a heat transfer tube disposed in at least one of the evaporator and the absorber and extending longitudinally. The heat transfer tube includes ribs that protrude from the inner side surface of the heat transfer tube and extend spirally and longitudinally in the length direction of the heat transfer tube. The width of the ribs formed in the length direction of the heat transfer tube becomes smaller as it approaches the direction in which the ribs protrude from the inner side surface of the heat transfer tube, so that the ribs protrude obliquely from the inner surface of the heat transfer tube.

[0026] The rib may include a first inclined surface that protrudes from the inner side surface of the heat transfer tube and extends obliquely with respect to the flow direction of the liquid, thereby reducing the space between the side surface of the rib where vortices are likely to form and the inner surface of the heat transfer tube.

[0027] The rib may include a second inclined surface that extends obliquely from the protruding surface toward the inner side surface of the heat transfer tube with respect to the flow direction of the liquid, thereby reducing the space between the side surface of the rib where vortices are likely to form and the inner surface of the heat transfer tube.

[0028] The rib may include a bulging surface that connects the first inclined surface and the second inclined surface and bulges toward the center of the heat transfer tube, thereby smoothly guiding the flow.

[0029] The length of the surface formed in the length direction of the heat transfer tube may be shorter than the lengths of the first inclined surface and the second inclined surface formed in the length direction of the heat transfer tube.

[0030] The rib may include a plurality of ribs that are spaced apart from each other in the circumferential direction of the heat transfer tube and extend longitudinally along the inner side surface of the heat transfer tube, thereby increasing the heat transfer area of the heat transfer tube.

[0031] The angle at which the plurality of ribs extend with respect to the flow direction of the liquid may be in the range of approximately 38 degrees to 48 degrees.

[0032] The number of the plurality of ribs may be in the range of 8 to 12.

[0033] The width of the ribs formed in the circumferential direction of the heat transfer tube may become smaller as it approaches the direction in which the ribs protrude from the inner side surface of the heat transfer tube.

[0034] The rib may include: a connection surface connected to the inner side surface of the heat transfer tube; and a surface spaced apart from the connection surface in the direction toward the center of the heat transfer tube, and a width of the connection surface formed in the circumferential direction of the heat transfer tube may be greater than a width of the surface formed in the circumferential direction of the heat transfer tube.

[0035] The width of the connection surface relative to the width of the surface may be in a range of 2.0 to 2.5 times.

[0036] The rib may include an inclined surface that extends obliquely from the surface toward the inner side surface of the heat transfer tube.

[0037] A height at which the rib protrudes from the inner side surface of the heat transfer tube may be in a range of 0.18 to 0.28 millimeters.

[0038] The heat transfer tubes may be disposed in both the evaporator and the absorber.

[0039] The heat transfer tube may include a plurality of protrusions that protrude from the surface of the heat transfer tube and are arranged along the length direction and the circumferential direction of the heat transfer tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a conceptual diagram of an absorption cooling device according to an embodiment of the present invention.

[0041] Figure 2 is a perspective view of a heat transfer tube according to an embodiment of the present invention.

[0042] Figure 3 is an enlarged view of an outer side surface of a heat transfer tube according to another embodiment of the present invention.

[0043] Figure 4 is an enlarged view of an outer side surface of a heat transfer tube according to an embodiment of the present invention.

[0044] Figure 5 is Figure 2 an enlarged view of a part in

[0045] Figure 6 A and Figure 6 B are graphs showing experimental results of film thickness based on a residual angle according to an embodiment of the present invention.

[0046] Figure 7 is a graph showing experimental results comparing heat transfer areas according to an embodiment of the present invention.

[0047] Figure 8 is a graph showing experimental results comparing overall heat transfer coefficients according to an embodiment of the present invention.

[0048] Figure 9Is a perspective view of a heat transfer tube according to another embodiment of the present invention.

[0049] Figure 10 Is an enlarged view of the inner side of the heat transfer tube according to another embodiment of the present invention.

[0050] Figure 11 Is a view showing a longitudinal section of the heat transfer tube according to another embodiment of the present invention.

[0051] Figure 12 Is an enlarged view of a cross section of the heat transfer tube according to another embodiment of the present invention. Detailed Description of the Invention

[0052] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. Regardless of the reference numerals, the same or similar components are given the same reference numerals and repeated description thereof is omitted.

[0053] In the following description, the suffixes "module" and "unit" for components are given or mixed only for the ease of writing the specification, and they do not have meanings or functions that distinguish each other.

[0054] In addition, in the process of describing the embodiments disclosed in this specification, if it is considered that a detailed description of related well-known technologies will obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the accompanying drawings, and should be understood to include all changes, equivalents, and substitutes included in the concept and technical scope of the present invention.

[0055] Ordinal terms such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are only for the purpose of distinguishing one component from another.

[0056] When it is mentioned that a certain component is "connected" or "linked" to another component, it should be understood that it may be directly connected or linked to the other component, but there may also be other components in the middle. On the contrary, when it is mentioned that a certain component is "directly connected" or "directly linked" to another component, it should be understood that there are no other components in the middle.

[0057] Unless the context clearly indicates otherwise, the singular expression includes the plural expression.

[0058] The direction marks of up (U), down (D), left (Le), right (Ri), front (F), and rear (R) shown in the accompanying drawings are only for convenience of explanation, and the technical concept disclosed in this specification is not limited by this.

[0059] Reference Figure 1 , the structure and principle of the absorption cooling device 1 will be described.

[0060] <<Structure of the absorption cooling device 1>>

[0061] The absorption cooling device 1 may include a regenerator 11, a condenser 12, an absorber 14, and an evaporator 13. The refrigerant may circulate in the regenerator 11, the condenser 12, the absorber 14, and the evaporator 13 in sequence to perform heat exchange.

[0062] <Regenerator 11>

[0063] The absorption cooling device 1 may include a regenerator 11. The regenerator 11 may heat the absorption liquid. The absorption liquid may be a solution formed by mixing an absorbent and a refrigerant. The absorption liquid may be referred to as a dilute solution or a thin solution. For example, the absorption liquid may be an aqueous solution of lithium bromide.

[0064] The absorbent may absorb the refrigerant. The absorbent that absorbs the refrigerant may become the absorption liquid. When the regenerator 11 heats the absorption liquid, the absorbent and the refrigerant may be separated from each other. For example, the heated refrigerant may turn into a vapor state and separate from the liquid absorption liquid. The liquid from which the refrigerant is separated from the absorption liquid may be referred to as a concentrated solution or a concentrated solution. For example, the absorbent may be lithium bromide and the refrigerant may be water.

[0065] The absorption cooling device 1 may include a first pipe 110 connecting the regenerator 11 and the condenser 12. The refrigerant vapor separated from the absorption liquid may move along the first pipe 110 to the condenser 12. For example, water vapor as the refrigerant vapor may move through the first pipe 110 to the condenser 12.

[0066] The absorption cooling device 1 may include a fifth pipe 150 connecting the regenerator 11 and the absorber 14. The concentrated solution from which the refrigerant vapor is separated may move through the fifth pipe 150 to the absorber 14. The concentrated solution that moves to the absorber 14 may absorb the refrigerant vapor in the absorber 14.

[0067] <Condenser 12>

[0068] The condenser 12 may condense the refrigerant. The regenerator 11 may supply the refrigerant to the condenser 12. For example, the water vapor generated in the regenerator 11 may be supplied to the condenser 12.

[0069] The absorption cooling device 1 may include a cooling tower 16 that cools cooling water. The condenser 12 may be connected to the cooling tower 16. The cooling tower 16 and the condenser 12 may be connected through a sixth pipe 160. The cooling water may circulate between the cooling tower 16 and the condenser 12 through the sixth pipe 160. The cooling water may absorb heat energy when passing through the condenser 12 and release heat energy when passing through the cooling tower 16.

[0070] The refrigerant vapor supplied to the condenser 12 may be condensed by the cooling water. The cooling water may absorb heat energy from the refrigerant vapor to condense the refrigerant vapor. The refrigerant vapor may change phase into a refrigerant solution in the condenser 12. The refrigerant solution generated in the condenser 12 may be supplied to the evaporator 13.

[0071] The absorption cooling device 1 may include a second pipe 120 connecting the condenser 12 and the evaporator 13. The refrigerant solution may be supplied to the evaporator 13 through the second pipe 120.

[0072] <Evaporator 13>

[0073] The evaporator 13 may be connected to a cooler 17. The cooler 17 may cool the indoor space or supply cold water to the indoor space. Additionally, if the flow path is changed, the cooler 17 may also heat the indoor space or supply hot water to the indoor space. For ease of explanation, in the present invention, the cooler 17 for cooling is mainly described.

[0074] The absorption cooling device 1 may include a first heat transfer pipe 20a disposed in the evaporator 13. The first heat transfer pipe 20a may connect the evaporator 13 and the cooler 17. The water supplied to the indoor space may flow inside the first heat transfer pipe 20a. The water flowing inside the first heat transfer pipe 20a may have its temperature reduced when passing through the evaporator 13. The water may also circulate between the evaporator 13 and the cooler 17 through the first heat transfer pipe 20a.

[0075] The refrigerant solution supplied to the evaporator 13 may be evaporated. The refrigerant solution may exchange heat with the water inside the heat transfer pipe 20. The refrigerant solution may exchange heat with the water inside the heat transfer pipe 20 and change phase into refrigerant vapor. For example, the refrigerant solution may absorb heat energy from the water inside the heat transfer pipe 20 and evaporate, and the water inside the heat transfer pipe 20 may have its heat energy taken away by the refrigerant, resulting in a temperature drop.

[0076] The absorption cooling device 1 may include a third pipe 130 connecting the evaporator 13 and the absorber 14. The refrigerant vapor evaporated in the evaporator 13 may be supplied to the absorber 14 through the third pipe 130.

[0077] <Absorber 14>

[0078] The refrigerant evaporated in the evaporator 13 can move to the absorber 14. The concentrated solution generated in the regenerator 11 can be supplied to the absorber 14 through the fifth pipe 150.

[0079] The absorption cooling device 1 can include a second heat transfer pipe 20b disposed in the absorber 14. The second heat transfer pipe can be connected to the cooling tower 16. The cooling water supplied from the cooling tower 16 can flow in the second heat transfer pipe. The cooling water can circulate between the cooling tower 16 and the absorber 14 through the second heat transfer pipe.

[0080] The concentrated solution supplied through the fifth pipe 150 can flow toward the second heat transfer pipe 20b. The concentrated solution can flow downward along the outer side surface of the second heat transfer pipe 20b. The refrigerant vapor generated in the evaporator 13 can be supplied to the absorber 14 through the third pipe 130, and the concentrated solution can absorb the refrigerant vapor. The refrigerant vapor and the concentrated solution can meet in the absorber 14 and become a dilute solution.

[0081] The absorption cooling device 1 can include a fourth pipe 140 connecting the absorber 14 and the regenerator 11. The absorbent solution generated in the absorber 14 can move again to the regenerator 11 through the fourth pipe 140. The absorbent solution supplied to the regenerator 11 can be reheated and separated into a concentrated solution and refrigerant vapor.

[0082] Refer to Figure 2 for an explanation of the outer shape of the heat transfer pipe 20.

[0083] <Heat transfer pipe 20>

[0084] The heat transfer pipes 20 can be respectively disposed in the evaporator 13 and the absorber 14. The shape of the heat transfer pipe 20 disposed in the evaporator 13 can correspond to the shape of the heat transfer pipe 20 disposed in the absorber 14. For example, a single heat transfer pipe 20 can be applicable to both the evaporator 13 and the absorber 14.

[0085] Water can flow inside the heat transfer pipe 20. Cold water or cooling water can flow inside the heat transfer pipe 20. The heat transfer pipe 20 can include a first heat transfer pipe 20a disposed in the evaporator 13. Cold water can flow inside the first heat transfer pipe 20a. The heat transfer pipe 20 can include a second heat transfer pipe 20b disposed in the absorber 14. Cooling water can flow inside the second heat transfer pipe 20b.

[0086] <Direction definition - DR1, DR2>

[0087] The heat transfer pipe 20 can extend long. The first direction DR1 can be a direction parallel to the length direction of the heat transfer pipe 20. The length direction of the heat transfer pipe 20 can correspond to the pipe axis direction of the heat transfer pipe 20.

[0088] The second direction DR2 may represent the circumferential direction of the heat transfer tube 20. The second direction DR2 may intersect the first direction DR1. Regardless of the cross-sectional shape of the heat transfer tube 20, the circumferential direction may be the same. For example, if the cross-sectional shape of the heat transfer tube 20 is circular, the circumferential direction may be the circumferential direction of the circle. For example, if the cross-sectional shape of the heat transfer tube 20 is quadrilateral, the circumferential direction may be the circumferential direction of the circle concentric with the quadrilateral.

[0089] <Base tube 21>

[0090] The heat transfer tube 20 may include a base tube 21 that forms a framework. The base tube 21 may include an outer side surface and an inner side surface. The base tube 21 may include an internal space 200 for fluid flow. The internal space 200 of the base tube 21 may be surrounded by the inner side surface. The base tube 21 may extend along the first direction DR1.

[0091] <Protrusion 22>

[0092] The heat transfer tube 20 may include a plurality of protrusions 22 protruding from the surface 220. The plurality of protrusions 22 may protrude from the outer side surface of the base tube 21. The plurality of protrusions 22 may be formed on the outer side surface of the base tube 21. The plurality of protrusions 22 may be arranged in a grid pattern on the outer side surface of the base tube 21. The plurality of protrusions 22 may be adjacent to each other or spaced apart from each other. The plurality of protrusions 22 may be connected to each other.

[0093] Thus, the heat transfer area of the heat transfer tube can be increased.

[0094] Refer to Figure 3 and Figure 4 to describe the structure in which the plurality of protrusions 22 are arranged on the outer side surface of the heat transfer tube 20.

[0095] <Arrangement of the plurality of protrusions 22>

[0096] The plurality of protrusions 22 may be arranged along the length direction of the heat transfer tube 20. The plurality of protrusions 22 may be arranged along the circumferential direction of the heat transfer tube 20. For example, the plurality of protrusions 22 may be spaced apart from each other at a predetermined interval along the first direction and the second direction and arranged in a grid pattern.

[0097] <First flow path 242>

[0098] The heat transfer tube 20 may include a first flow path 242 extending along the circumferential direction of the heat transfer tube 20. The first flow path 242 may be formed between a plurality of protrusions 22 spaced apart from each other along the length direction of the heat transfer tube 20. That is, the first flow path 242 may be the interval between the plurality of protrusions 22 arranged along the first direction. The first flow path 242 and the plurality of protrusions 22 arranged along the circumferential direction of the heat transfer tube 20 may be alternately arranged along the length direction of the heat transfer tube 20.

[0099] The first flow path 242 may include a plurality of first flow paths 242 arranged along the length direction of the heat transfer tube 20. The plurality of first flow paths 242 may be spaced apart from each other in the length direction of the heat transfer tube 20. The plurality of protrusions 22 may be located between the plurality of first flow paths 242 spaced apart from each other.

[0100] The first flow path 242 may extend along the flow direction of the liquid flowing on the surface 220 of the heat transfer tube 20. The concentrated solution distributed through the fifth pipe 150 may move in the second direction. The second direction may be parallel to the up-down direction. The concentrated solution may flow downward along the periphery of the heat transfer tube 20.

[0101] <Second flow path 244>

[0102] The heat transfer tube 20 may include a second flow path 244 extending along the length direction of the heat transfer tube 20. The second flow path 244 may be formed between the plurality of protrusions 22 spaced apart from each other along the circumferential direction of the heat transfer tube 20. That is, the second flow path 244 may be the space between the plurality of protrusions 22 arranged in the second direction. The second flow path 244 and the plurality of protrusions 22 arranged along the length direction of the heat transfer tube 20 may be alternately arranged with each other along the circumferential direction of the heat transfer tube 20.

[0103] The second flow path 244 may include a plurality of second flow paths 244 arranged along the circumferential direction of the heat transfer tube 20. The plurality of second flow paths 244 may be spaced apart from each other in the circumferential direction of the heat transfer tube 20. The plurality of protrusions 22 may be located between the plurality of second flow paths 244 spaced apart from each other.

[0104] The second flow path 244 may extend along a direction intersecting the flow direction of the liquid flowing on the surface 220 of the heat transfer tube 20. The concentrated solution distributed through the fifth pipe 150 may move in the first direction DR1. The first direction DR1 may intersect the up-down direction. The concentrated solution may diffuse in the length direction of the heat transfer tube 20.

[0105] <Relationship between the first flow path 242 and the second flow path 244>

[0106] The width of the first flow path 242 may be greater than the width of the second flow path 244. The width of the first flow path 242 may be formed in the length direction of the heat transfer tube 20. The width of the second flow path 244 may be formed in the circumferential direction of the heat transfer tube 20. The width of the second flow path 244 may be smaller than the width of the first flow path 242.

[0107] Thus, the fluidity of the concentrated solution flowing circumferentially along the outer side surface of the heat transfer tube can be improved.

[0108] <Specific shape of each protrusion 22 - surface, inclined surface, slit>

[0109] The plurality of protrusions 22 may include a surface 220 protruding from the base pipe 21. The surface 220 of the plurality of protrusions 22 may be spaced apart from the surface 220 of the base pipe 21. For example, the surface 220 of the plurality of protrusions 22 may be spaced apart from the surface 220 of the base pipe 21 in the radial direction.

[0110] The plurality of protrusions 22 may include a first inclined surface 221 extending obliquely along the circumferential direction of the heat transfer tube 20. The first inclined surface 221 may extend from the surface 220 of the plurality of protrusions 22 toward the base tube 21.

[0111] The first inclined surface 221 can connect the circumference of the surface 220 ( Figure 3 The upper end and the lower end) of the heat transfer tube 20 are connected to the base tube 21 and are inclined relative to the radial direction of the heat transfer tube 20. The radial direction of the heat transfer tube 20 is a direction orthogonal to the axial direction (length direction) of the heat transfer tube 20.

[0112] The first inclined surface 221 may include an upstream first inclined surface 221a extending from the surface 220 of the protrusion 22 to the upstream side of the heat transfer tube 20 in the circumferential direction ( Figure 3 The first inclined surface 221 may include a downstream first inclined surface 221b, which extends from the surface 220 of the protrusion 22 to the downstream of the circumference of the heat transfer tube 20. The upstream first inclined surface 221a and the downstream first inclined surface 221b may be opposite to each other. A second flow path 244 may be formed between the upstream first inclined surface 221a and the downstream first inclined surface 221b.

[0113] The plurality of protrusions 22 may include a second inclined surface 222 extending obliquely in the length direction of the heat transfer tube 20. The second inclined surface 222 may extend from the surface 220 of the plurality of protrusions 22 toward the base tube 21. The second inclined surface 222 may extend from the surface 220 of the plurality of protrusions 22 toward the first flow path 242.

[0114] The second inclined surface 222 may include a second inclined surface 222a on one side, which extends from the surface 220 of the protrusion 22 to one side in the length direction of the heat transfer tube 20. The second inclined surface 222 may include a second inclined surface 222b on the other side, which extends from the surface 220 of the protrusion 22 to the other side in the length direction of the heat transfer tube 20. The second inclined surface 222a on one side and the second inclined surface 222b on the other side may be opposite to each other. A first flow path 242 may be formed between the second inclined surface 222a on one side and the second inclined surface 222b on the other side.

[0115] The distance between the first inclined surfaces 221 can be shorter than the distance between the second inclined surfaces 222. The distance between the first inclined surfaces 221 can be formed in the circumferential direction of the heat transfer tube 20. The distance between the second inclined surfaces 222 can be formed in the longitudinal direction of the heat transfer tube 20.

[0116] The plurality of protrusions 22 may include a slit 226 formed between the first inclined surfaces 221. The slit 226 may be located between the upstream first inclined surface 221a and the downstream first inclined surface 221b.

[0117] <Arrangement interval of the plurality of protrusions 22 - longitudinal direction and circumferential direction, g1 > g2>

[0118] The interval between the plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 can be smaller than the interval between the plurality of protrusions 22 arranged in the longitudinal direction of the heat transfer tube 20. The second flow path 244 can be formed between the plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20. The first flow path 242 can be formed between the plurality of protrusions 22 arranged in the longitudinal direction of the heat transfer tube 20. For example, the interval g2 between the plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 can be about 0.1 mm or less. For example, the interval g1 between the plurality of protrusions 22 arranged in the longitudinal direction of the heat transfer tube 20 can be in the range of about 0.2 mm to 0.4 mm.

[0119] <Relationship between the width and length of each protrusion 22>

[0120] The protrusion 22 can extend long in the longitudinal direction of the heat transfer tube 20. The protrusion 22 can extend in the circumferential direction of the heat transfer tube 20. The length of the protrusion 22 can be formed in the longitudinal direction of the heat transfer tube 20. The width of the protrusion 22 can be formed in the circumferential direction of the heat transfer tube 20. The protrusion 22 can be formed in a quadrilateral shape.

[0121] <a1 > b1>

[0122] The length of the plurality of protrusions 22 extending in the longitudinal direction of the heat transfer tube 20 can be greater than the width of the plurality of protrusions 22 extending in the circumferential direction of the heat transfer tube 20. For example, the protrusion 22 can be formed in a rectangular shape with one side longer than the other. For example, the length of the protrusion 22 can be formed to be about 0.45 mm or less. For example, the width of the protrusion 22 can be formed to be about 0.35 mm or less. However, it is not limited thereto, and the protrusion 22 can also be formed in various shapes such as a triangle, a square, a circle, etc.

[0123] <a1 > g1>

[0124] The interval between a plurality of protrusions 22 arranged in the longitudinal direction of the heat transfer tube 20 may be smaller than the length of the plurality of protrusions 22 extending in the longitudinal direction of the heat transfer tube 20. The width of the first flow path 242 may be smaller than the length of the protrusions 22. For example, the width of the first flow path 242 may be in the range of about 0.15 mm to 0.45 mm.

[0125] <b1>g2>

[0126] The interval between a plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 may be smaller than the width of the plurality of protrusions 22 extending in the circumferential direction of the heat transfer tube 20. The width of the second flow path 244 may be smaller than the width of the protrusions 22. For example, the width of the second flow path 244 may be formed to be about 0.15 mm or less.

[0127] <Arrangement interval of a plurality of protrusions 22 - Direct connection>

[0128] A plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 may be connected to each other. That is, a plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 may not be spaced apart from each other. For example, the interval between a plurality of protrusions 22 arranged in the circumferential direction of the heat transfer tube 20 may be 0. The width of the second flow path 244 may be 0.

[0129] Thus, the external shape of the heat transfer tube can be simplified.

[0130] In addition, the drainage and fluidity of the heat transfer tube can be improved.

[0131] In addition, the thickness of the liquid flowing along the outer side surface of the heat transfer tube, that is, the thickness of the thin film, can be thinned.

[0132] In addition, the thickness of the thin film can be made uniform.

[0133] Refer to Figure 5 , and the structure of the cross-section of the heat transfer tube 20 will be described.

[0134] <h1>h2>

[0135] The thickness of the heat transfer tube 20 may be greater than the height by which the plurality of protrusions 22 protrude. The thickness of the heat transfer tube 20 may be the thickness of the base tube 21. The thickness of the heat transfer tube 20 may be the thickness of the tube excluding the plurality of protrusions 22. For example, the thickness h1 of the heat transfer tube 20 may be in the range of about 0.28 mm to 0.45 mm. For example, the height h2 by which the plurality of protrusions 22 protrude may be formed to be about 0.28 mm or more.

[0136] Thus, the pressure resistance of the heat transfer tube can be improved.

[0137] <h2>g2>

[0138] The height by which a plurality of protrusions 22 protrude can be greater than the interval between the plurality of protrusions 22 arranged circumferentially along the heat transfer tube 20. For example, the plurality of protrusions 22 can protrude by about 0.28 mm or more, and the interval g2 between the plurality of protrusions 22 arranged circumferentially along the heat transfer tube 20 can be formed to be about 0.12 mm or less.

[0139] <h2>b1>

[0140] The height by which a plurality of protrusions 22 protrude can be less than the width of the plurality of protrusions 22 extending circumferentially along the heat transfer tube 20. For example, the plurality of protrusions 22 can protrude by about 0.28 mm or more, and the width b1 of the plurality of protrusions 22 extending circumferentially along the heat transfer tube 20 can be formed to be about 0.32 mm or less.

[0141] Refer to Figure 6 A and Figure 6 B to describe the thickness of the thin film formed according to an embodiment of the present invention.

[0142] Refer to Figure 6 A to describe an embodiment according to the present invention.

[0143] <Comparison between X1 and X2 - Number, size, interval of protrusions, size relative to the thickness of the heat transfer tube 20>

[0144] It can be represented by X1 Figure 6 The embodiment on the left side of A. It can be represented by X2 Figure 6 The embodiment on the right side of A. The size of the protrusions 22 in X2 can be smaller than the size of the protrusions 22 in X1. For example, the length of the protrusions 22 in X2 can be shorter than the length of the protrusions 22 in X1. For example, the width of the protrusions 22 in X2 can be shorter than the width of the protrusions 22 in X1. The number of the plurality of protrusions 22 in X2 can be more than the number of the plurality of protrusions 22 in X1. The width of the first flow path 242 in X2 can be narrower than the width of the first flow path 242 in X1. The number of the first flow paths 242 in X2 can be more than the number of the first flow paths 242 in X1. The width of the second flow path 244 in X1 and X2 can be 0. The protruding height of the protrusions 22 in X2 can be lower than the protruding height of the protrusions 22 in X1.

[0145] In X1, the thickness of the heat transfer tube 20 relative to the width of the plurality of protrusions 22 can be in the range of about 0.2 times to 0.8 times. The width of the plurality of protrusions 22 can be formed in the circumferential direction of the heat transfer tube 20. For example, in X1, the thickness of the heat transfer tube 20 relative to the width of the plurality of protrusions 22 can be in the range of about 0.4 times to 0.65 times.

[0146] In X2, the thickness of the heat transfer tube 20 can be in the range of about 0.8 times to 1.6 times relative to the width of the plurality of protrusions 22. The width of the plurality of protrusions 22 can be formed in the circumferential direction of the heat transfer tube 20. For example, in X2, the thickness of the heat transfer tube 20 can be in the range of about 0.95 times to 1.45 times relative to the width of the protrusion 22.

[0147] <Residual angle>

[0148] Figure 6 B is a diagram showing the thickness of the thin film based on the residual angle with respect to the cross section of the heat transfer tube 20.

[0149] The concentrated solution or absorbent supplied to the absorber 14 can move from the upper end to the lower end of the heat transfer tube 20. The absorbent distributed at the upper end of the heat transfer tube 20 with a circular cross section can flow circumferentially along the outer side surface of the heat transfer tube 20 and move to the lower end of the heat transfer tube 20. At this time, if the residual angle at the upper end on the uppermost side of the heat transfer tube 20 is set to 0 degrees, the residual angle at the lower end on the lowermost side of the heat transfer tube 20 can be regarded as 180 degrees. When the absorbent flows circumferentially along the outer side surface of the heat transfer tube 20, the residual angle can gradually increase from 0 degrees to 180 degrees.

[0150] The thinner the thickness of the thin film formed on the outer side surface of the heat transfer tube 20, the more excellent the heat transfer performance of the heat transfer tube 20 may be. The more uniform the thickness of the thin film formed on the outer side surface of the heat transfer tube 20, the more excellent the heat transfer performance of the heat transfer tube 20 may be.

[0151] X1 will be described based on the experimental result diagram. The thickness of the thin film formed on the outer side surface of the heat transfer tube 20 may be the highest at the residual angles near 0 degrees and 180 degrees. The thickness of the thin film can be formed to be the thinnest in the residual angle range between 0 degrees and 30 degrees. The thickness of the thin film can gradually increase in the residual angle range between 30 degrees and 60 degrees. That is, when the absorbent flows, it may stagnate on the outer side surface of the heat transfer tube 20, and the thickness of the thin film may become thicker.

[0152] X2 will be described based on the experimental result diagram. The thickness of the thin film formed on the outer side surface of the heat transfer tube 20 can be the highest at the residual angles near 0 degrees and 180 degrees. The thickness of the thin film can be formed to be uniform in the residual angle range between 0 degrees and 150 degrees.

[0153] The thickness of the thin film formed in X2 can be thinner than the thickness of the thin film formed in X1 as a whole. In addition, the thickness of the thin film formed in X2 can be more uniform than the thickness of the thin film formed in X1.

[0154] Thereby, the heat transfer performance of the heat transfer tube can be improved.

[0155] In addition, the mass transfer performance and heat transfer performance in the absorber can be improved, thereby improving the absorption efficiency.

[0156] In addition, the heat transfer performance in the evaporator can be improved, thereby improving the evaporation efficiency.

[0157] Refer to Figure 7 and describe the heat transfer area according to an embodiment of the present invention.

[0158] According to the experimental result graph, the heat transfer area in X2 can be increased compared to the heat transfer area in X1. For example, the heat transfer area in X2 can be increased by about 1.4 times compared to the heat transfer area in X1. That is, the larger the number of the plurality of protrusions 22, the more the heat transfer area can be increased. In addition, the smaller the size of the plurality of protrusions 22, the more the heat transfer area can be increased. In addition, the smaller the ratio of the width of the protrusion 22 to the thickness of the heat transfer tube 20, the more the heat transfer area can be increased.

[0159] Thereby, the heat transfer performance of the heat transfer tube 20 can be improved.

[0160] In addition, the heat transfer performance can be improved, thereby improving the evaporation efficiency in the evaporator 13.

[0161] Refer to Figure 8 and describe the overall heat transfer coefficient according to an embodiment of the present invention.

[0162] According to the experimental result graph, the overall heat transfer coefficient (hereinafter referred to as "heat transfer coefficient") in X2 can be increased compared to the heat transfer coefficient in X1. For example, the heat transfer coefficient in X2 can be increased by about 1.5 times compared to the heat transfer coefficient in X1. That is, the larger the number of the plurality of protrusions 22, the more the heat transfer coefficient can be increased. In addition, the smaller the size of the plurality of protrusions 22, the more the heat transfer coefficient can be increased. In addition, the smaller the ratio of the width of the protrusion 22 to the thickness of the heat transfer tube 20, the more the heat transfer coefficient can be increased.

[0163] Refer to Figure 9 and describe the inner shape of the heat transfer tube 20.

[0164]

[0165] The heat transfer tube 20 may include ribs 26 protruding from the inner surface. The ribs 26 may protrude from the inner surface of the heat transfer tube 20 toward the central axis of the heat transfer tube 20. For example, the ribs 26 may protrude from the inner surface of the base tube 21 in a direction opposite to the radial direction (the central direction of the base tube 21).

[0166] The ribs 26 may extend long. The ribs 26 may extend helically along the length direction DR1 of the heat transfer tube 20. The ribs 26 may rotate along the circumferential direction DR2 of the heat transfer tube 20 and extend long along the length direction DR1. For example, the ribs 26 may extend long along the length direction DR1 of the heat transfer tube 20 and extend helically along the inner surface of the base tube 21.

[0167] The ribs 26 may include a plurality of ribs 26 that extend longitudinally in the length direction DR1 along the inner side surface of the heat transfer tube 20. The plurality of ribs 26 may be spaced apart from each other in the circumferential direction DR2 of the heat transfer tube 20. The plurality of ribs 26 may protrude from the inner side surface of the heat transfer tube 20 toward the center of the heat transfer tube 20 and be arranged on the inner side surface in the circumferential direction DR2 of the heat transfer tube 20. The plurality of ribs 26 arranged on the inner side surface of the heat transfer tube 20 in the circumferential direction DR2 may extend helically in the length direction DR1 of the heat transfer tube 20. For example, the heat transfer tube 20 may include 7 to 13 ribs 26 that are spaced apart from each other in the circumferential direction DR2 on the inner side surface and extend longitudinally in the length direction DR1.

[0168] Refer to Figure 10 to describe the angles at which the plurality of ribs 26 are formed.

[0169] <Angles of the plurality of ribs 26>

[0170] The plurality of ribs 26 may extend obliquely on the inner side surface of the heat transfer tube 20. The plurality of ribs 26 extending obliquely may be spaced apart from each other in the length direction DR1 of the heat transfer tube 20. The ribs 26 extending helically along the inner side surface of the heat transfer tube 20 may form an angle with the length direction DR1 of the heat transfer tube 20. The angles at which the plurality of ribs 26 extend may be inclined with respect to the length direction DR1 of the heat transfer tube 20. The angles at which the plurality of ribs 26 extend may be inclined with respect to the flow direction LF of the liquid. For example, the plurality of ribs 26 may form a first angle (theta1) with the flow direction LF of the liquid. For example, the plurality of ribs 26 may form a first angle (theta1) with the length direction DR1 of the heat transfer tube 20. For example, the first angle (theta1) may be in the range of 35 degrees to 50 degrees.

[0171] Refer to Figure 11 to describe the structure of the longitudinal section of the heat transfer tube 20.

[0172] <Shape of the rib 26>

[0173] The width of the rib 26 may be smaller the closer it is to the protruding direction. The width of the rib 26 may be smaller the closer it is to the center of the heat transfer tube 20. The width of the rib 26 may extend in the length direction DR1 of the heat transfer tube 20. The width of the rib 26 may extend in the flow direction LF of the liquid. For example, the width of the rib 26 formed in the length direction DR1 of the heat transfer tube 20 may be smaller the closer it is to the protruding direction.

[0174] <Inclined surface>

[0175] The rib 26 may include a first inclined surface 261 protruding from the heat transfer tube 20. The first inclined surface 261 may be a surface of the rib 26 protruding from the inner side surface of the heat transfer tube 20. The first inclined surface 261 may protrude from the inner side surface of the heat transfer tube 20. The first inclined surface 261 may extend obliquely from the protruding surface 260 in a direction opposite to the liquid flow direction LF. The first inclined surface 261 may extend obliquely with respect to the liquid flow direction LF. The first inclined surface 261 may form an angle with the length direction DR1 of the heat transfer tube 20. The first inclined surface 261 may form an angle with the liquid flow direction LF. For example, the first inclined surface 261 may form a second angle (theta2) with the length direction DR1 of the heat transfer tube 20.

[0176] The rib 26 may include a second inclined surface 262 protruding from the heat transfer tube 20. The second inclined surface 262 may be another surface of the rib 26 protruding from the inner side surface of the heat transfer tube 20. The second inclined surface 262 may protrude from the inner side surface of the heat transfer tube 20. The second inclined surface 262 may extend obliquely from the protruding surface 260 in the liquid flow direction LF. The second inclined surface 262 may extend from the protruding surface 260 toward the inner side surface of the heat transfer tube 20. The second inclined surface 262 may form an angle with the length direction DR1 of the heat transfer tube 20. The second inclined surface 262 may form an angle with the liquid flow direction LF. The angle formed by the second inclined surface 262 and the length direction DR1 of the heat transfer tube 20 may correspond to the angle formed by the first inclined surface 261 and the length direction D1R of the heat transfer tube 20.

[0177] <Surface 260>

[0178] The rib 26 may include a surface 260 connecting the first inclined surface 261 and the second inclined surface 262. The surface 260 may connect the first inclined surface 261 and the second inclined surface 262 in a curved manner. The surface 260 may bulge toward the center of the heat transfer tube 20.

[0179] The length of the surface 260 may be shorter than the length of the first inclined surface 261 and / or the second inclined surface 262. The length that the surface 260 extends may be shorter than the length that the first inclined surface 261 extends. The length that the surface 260 extends may be shorter than the length that the second inclined surface 262 extends. For example, the length of the surface 260 extending along the length direction DR1 of the heat transfer tube 20 may be shorter than the length of the first inclined surface 261 and / or the second inclined surface 262 extending along the length direction DR1 of the heat transfer tube 20.

[0180] <Relationship between the height of the rib 26 and the tube thickness>

[0181] The rib 26 can protrude from the inner side surface of the heat transfer tube 20. The height by which the rib 26 protrudes from the heat transfer tube 20 can be in the range of 0.1 mm to 0.3 mm. For example, the height by which the rib 26 protrudes from the inner side surface of the heat transfer tube 20 can be in the range of 0.15 mm to 0.3 mm.

[0182] <Relationship between rib 26 and protrusion - position, height>

[0183] The rib 26 can be located between a plurality of protrusions 22. The plurality of protrusions 22 can be arranged to be spaced apart from each other along the longitudinal direction DR1 of the heat transfer tube 20, and the plurality of ribs 26 can be located at positions corresponding to the intervals by which the plurality of protrusions 22 are spaced apart from each other, based on the longitudinal direction DR1 of the heat transfer tube 20.

[0184] The height by which the plurality of protrusions 22 protrude from the heat transfer tube 20 can be higher than the height by which the plurality of ribs 26 protrude from the heat transfer tube 20. The plurality of protrusions 22 can protrude radially from the heat transfer tube 20, and the plurality of ribs 26 can protrude inwardly from the heat transfer tube 20. That is, the plurality of protrusions 22 and the plurality of ribs 26 can protrude from the heat transfer tube 20 in directions opposite to each other.

[0185] <Inclined surfaces 261, 262 of rib 26 and inclined surface 222 of protrusion>

[0186] The angle by which the inclined surface 222 of the plurality of protrusions 22 is inclined with respect to the longitudinal direction DR1 of the heat transfer tube 20 can be greater than the angle by which the inclined surfaces 261, 262 of the rib 26 are inclined with respect to the longitudinal direction DR1 of the heat transfer tube 20. For example, the first inclined surface 222 of the protrusion 22 formed on the outer side surface of the heat transfer tube 20 can form a third angle (theta3) with the longitudinal direction DR1 of the heat transfer tube 20. For example, the first inclined surface 261 of the rib 26 formed on the inner side surface of the heat transfer tube 20 can form a second angle (theta2) with the longitudinal direction DR1 of the heat transfer tube 20. The third angle (thata3) formed by the first inclined surface 222 of the protrusion 22 with the longitudinal direction DR1 of the heat transfer tube 20 can be greater than the second angle (theta2) formed by the first inclined surface 261 of the rib 26 with the longitudinal direction DR1 of the heat transfer tube 20.

[0187] Refer to Figure 12 , the structure of the cross-section of the heat transfer tube 20 will be described.

[0188] <Cross-sectional shape of rib 26>

[0189] The width of the rib 26 can be smaller the closer it is to the protruding direction. The rib 26 on the cross-section of the heat transfer tube 20 can have a trapezoidal cross-sectional shape. For example, the width W of the rib 26 formed along the circumferential direction DR2 of the heat transfer tube 20 can be smaller the closer it is to the protruding direction.

[0190] <Connection surface 264>

[0191] The rib 26 may include a connection surface 264 connected to the heat transfer tube 20. The connection surface 264 may be connected to the inner side surface of the heat transfer tube 20.

[0192] The surface 260 may be spaced apart from the connection surface 264. The surface 260 may be spaced apart from the connection surface 264 in the central direction of the heat transfer tube 20. The surface 260 and the connection surface 264 may be spaced apart from each other in the radial direction of the heat transfer tube 20. The inclined surfaces 261, 262 may connect the surface 260 and the connection surface 264. The first inclined surface 261 and the second inclined surface 262 may connect the surface 260 and the connection surface 264 in an inclined manner.

[0193] The connection surface 264 of the rib 26 may be one end of the rib 26 closest to the base tube 21, and the surface 260 of the rib 26 may be the other end of the rib 26 farthest from the base tube 21.

[0194] <Length ratio of the rib 26>

[0195] The width of the connection surface 264 may be greater than the width of the surface 260. The width of the connection surface 264 may extend in the circumferential direction DR2 of the heat transfer tube 20. The width of the surface 260 may extend in the circumferential direction DR2 of the heat transfer tube 20. For example, the width W1 of the connection surface 264 formed in the circumferential direction DR2 of the heat transfer tube 20 may be greater than the width W2 of the surface 260 formed in the circumferential direction DR2 of the heat transfer tube 20. The width of the connection surface 264 may be more than 1.5 times the width of the surface 260. For example, the width of the connection surface 264 relative to the width of the surface 260 may be in the range of 2.0 to 2.5 times.

[0196] Refer to Figures 1 to 12 , according to an aspect of the present invention, an absorption cooling device may include: an evaporator that evaporates a refrigerant; an absorber that mixes the refrigerant evaporated in the evaporator with an absorbent to generate an absorption liquid; a regenerator that heats the absorption liquid supplied from the absorber; a condenser to which the refrigerant generated in the regenerator is supplied; and a heat transfer tube disposed in at least one of the evaporator and the absorber and extending long.

[0197] According to another aspect of the present invention, the heat transfer tube may include ribs that protrude from the inner side surface of the heat transfer tube and extend long in a spiral shape along the length direction of the heat transfer tube.

[0198] According to another aspect of the present invention, the width of the rib formed in the length direction of the heat transfer tube may be smaller the closer it is to the direction in which the rib protrudes from the inner side surface of the heat transfer tube.

[0199] According to another aspect of the present invention, the rib may include a first inclined surface that protrudes from the inner surface of the heat transfer tube and extends obliquely with respect to the flow direction of the liquid.

[0200] According to another aspect of the present invention, the rib may include a second inclined surface that extends obliquely with respect to the flow direction of the liquid from the protruding surface toward the inner surface of the heat transfer tube.

[0201] According to another aspect of the present invention, the rib may include a bulging surface that connects the first inclined surface and the second inclined surface and bulges toward the center of the heat transfer tube.

[0202] According to another aspect of the present invention, the length of the surface formed in the longitudinal direction of the heat transfer tube may be shorter than the lengths of the first inclined surface and the second inclined surface formed in the longitudinal direction of the heat transfer tube.

[0203] According to another aspect of the present invention, the rib may include a plurality of ribs that are spaced apart from each other in the circumferential direction of the heat transfer tube and extend longitudinally along the inner surface of the heat transfer tube.

[0204] The angle at which the plurality of ribs extend with respect to the flow direction of the liquid may be an acute angle.

[0205] According to another aspect of the present invention, the angle at which the plurality of ribs extend with respect to the flow direction of the liquid may be in the range of 38 degrees to 48 degrees.

[0206] According to another aspect of the present invention, the number of the plurality of ribs may be in the range of 8 to 12.

[0207] According to another aspect of the present invention, the width of the rib formed in the circumferential direction of the heat transfer tube may be smaller as it gets closer to the direction in which the rib protrudes from the inner surface of the heat transfer tube.

[0208] According to another aspect of the present invention, the rib may include: a connecting surface connected to the inner surface of the heat transfer tube; and a surface spaced apart from the connecting surface in the direction toward the center of the heat transfer tube.

[0209] According to another aspect of the present invention, the width of the connecting surface formed in the circumferential direction of the heat transfer tube may be greater than the width of the surface formed in the circumferential direction of the heat transfer tube.

[0210] According to another aspect of the present invention, the width of the connecting surface with respect to the width of the surface may be in the range of 2.0 to 2.5 times.

[0211] According to another aspect of the present invention, the rib may include an inclined surface that extends obliquely from the surface toward the inner side surface of the heat transfer tube.

[0212] According to another aspect of the present invention, the height by which the rib protrudes from the inner side surface of the heat transfer tube may be in the range of 0.18 to 0.28 millimeters.

[0213] According to another aspect of the present invention, the heat transfer tubes may be disposed in both the evaporator and the absorber.

[0214] According to another aspect of the present invention, the heat transfer tube may include a plurality of protrusions that protrude from the surface of the heat transfer tube and are arranged along the length direction and the circumferential direction of the heat transfer tube.

[0215] According to another aspect of the present invention, the plurality of protrusions may be arranged to be spaced apart from each other along the length direction of the heat transfer tube, and the rib may be located between the plurality of protrusions with respect to the length direction of the heat transfer tube.

[0216] According to another aspect of the present invention, the plurality of protrusions may include an inclined surface that extends obliquely from the protruding surface toward the length direction of the heat transfer tube.

[0217] According to another aspect of the present invention, the rib may include: a surface that protrudes from the inner side surface of the heat transfer tube; and an inclined surface that obliquely connects the surface to the inner side surface of the heat transfer tube.

[0218] According to another aspect of the present invention, the angle formed by the inclined surface of the plurality of protrusions with the length direction of the heat transfer tube may be greater than the angle formed by the inclined surface of the rib with the length direction of the heat transfer tube.

[0219] According to at least one embodiment of the present invention, the rib may protrude obliquely from the inner surface of the heat transfer tube such that the rib causes flow chaos inside the heat transfer tube, thereby increasing the turbulent kinetic energy but reducing the disturbance.

[0220] According to at least one embodiment of the present invention, the rib may protrude obliquely from the inner surface of the heat transfer tube, thereby reducing the space between the side surface of the rib where vortices are likely to form and the inner surface of the heat transfer tube. Thereby, the formation of vortices can be reduced, and the heat transfer performance of the heat transfer tube can be improved.

[0221] According to at least one embodiment of the present invention, the rib may protrude obliquely from the inner surface of the heat transfer tube, thereby increasing the heat transfer area of the heat transfer tube. Thereby, the heat transfer performance and the heat transfer coefficient of the heat transfer tube can be increased.

[0222] According to at least one embodiment among the embodiments of the present invention, ribs may protrude obliquely from the inner surface of the heat transfer tube, making the flow inside the heat transfer tube smoother, thereby reducing the pressure loss. As a result, the power consumption of the pump that forms the flow inside the heat transfer tube can be reduced.

[0223] According to at least one embodiment among the embodiments of the present invention, by forming a plurality of ribs on the inner surface of the heat transfer tube, the heat transfer area of the heat transfer tube can be increased. As a result, the refrigeration and heating performance of the absorption cooling device can be improved.

[0224] The effects of the present invention are not limited to the effects mentioned above, and those skilled in the art can clearly understand other effects not mentioned according to the description of the scope of the claims.

[0225] Certain embodiments or other embodiments of the present invention described above are not mutually exclusive or different from each other. Any or all of the elements in the embodiments of the present invention described above can be combined with each other or combined in terms of composition or function.

[0226] This means that, for example, component A described in one embodiment and / or drawing and component B described in another embodiment and / or drawing can be combined with each other. That is to say, it means that they can be combined even without directly stating the combination between the components, unless it is stated that they cannot be combined.

[0227] The above detailed description should not be construed restrictively in all aspects and should be regarded as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims

1. An absorption cooling device, comprising: Evaporator, evaporates the refrigerant; an absorber for mixing the refrigerant evaporated in the evaporator with an absorbent to generate an absorption liquid; a regenerator for heating the absorption liquid supplied from the absorber; a condenser to which the refrigerant generated in the regenerator is supplied; as well as a heat transfer tube disposed in at least one of the evaporator and the absorber, The heat transfer tube includes a rib, which protrudes from the inner side of the heat transfer tube and extends long and spirally along the length direction of the heat transfer tube. The width of the rib formed in the length direction of the heat transfer tube decreases as it approaches the center of the heat transfer tube.

2. The absorption cooling device according to claim 1, wherein: The rib includes a first inclined surface that protrudes from an inner side surface of the heat transfer tube and extends obliquely with respect to a flow direction of the liquid.

3. The absorption cooling device according to claim 2, wherein: The rib includes a second inclined surface extending from the protruding surface toward the inner side surface of the heat transfer tube and extending obliquely with respect to the flow direction of the liquid.

4. The absorption cooling device according to claim 3, wherein: The rib includes a bulging surface that connects the first inclined surface and the second inclined surface and bulges toward a center of the heat transfer tube.

5. The absorption cooling device according to claim 4, wherein: The length of the surface formed in the length direction of the heat transfer tube is shorter than the length of the first inclined surface and the length of the second inclined surface formed in the length direction of the heat transfer tube.

6. The absorption cooling device according to claim 1, wherein: The rib includes a plurality of ribs that are spaced apart from each other in a circumferential direction of the heat transfer tube and extend long in a length direction along an inner side surface of the heat transfer tube.

7. The absorption cooling device according to claim 6, wherein: The angle at which the plurality of ribs extend relative to the flow direction of the liquid is an acute angle.

8. The absorption cooling device according to claim 6, wherein: The angle at which the plurality of ribs extend relative to the flow direction of the liquid is in a range of 38 to 48 degrees.

9. The absorption cooling device according to claim 8, wherein: The number of the plurality of ribs ranges from 8 to 12.

10. An absorption cooling device, comprising: Evaporator, evaporates the refrigerant; an absorber for mixing the refrigerant evaporated in the evaporator with an absorbent to generate an absorption liquid; a regenerator for heating the absorption liquid supplied from the absorber; a condenser to which the refrigerant generated in the regenerator is supplied; as well as a heat transfer tube disposed in at least one of the evaporator and the absorber, The heat transfer tube comprises: a base pipe, in which a fluid flows, and which extends along a first direction; as well as a rib protruding from the inner side of the base tube and extending helically along the first direction, The width of the rib formed in the first direction decreases as it approaches the center of the base pipe.

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