KR102275301B1 - Heat transfer pipe and Heat exchanger for chiller - Google Patents

Abstract

The present invention is a refrigerant tube having a space in which the refrigerant flows; a plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including an upper surface having a step difference from the outer surface of the refrigerant tube; a main cavity formed between adjacent heat dissipation fins and having an inlet formed between upper ends of the plurality of heat dissipation fins; and a plurality of microcavities that are formed on the upper surface of the heat dissipation fins, have a height and a width smaller than that of the main cavity, and open upwards.

Description

{ Heat transfer pipe and heat exchanger for chiller }

The present invention relates to a heat transfer tube and a heat exchanger for a chiller.

In general, a chiller system supplies cold water to a cold water demander, and heat exchange is performed between a refrigerant circulating in a refrigeration system and cold water circulating between a cold water demander and a refrigeration system to cool the cold water. Such a chiller system is a large-capacity facility, and may be installed in a large-scale building.

A conventional chiller system is disclosed in Korean Patent Publication No. 10-1084477. In the prior art, a heat transfer tube is used to exchange heat between two refrigerants. The heat transfer tube has a space through which the first refrigerant passes, and the outer surface of the heat transfer tube is in contact with the second refrigerant to exchange heat between the two refrigerants.

Such a general heat transfer tube has a problem in that when the fluid passes into the heat transfer tube, a liquid or gas fluid passes through quickly without evenly contacting the inner surface of the heat transfer tube by 100% or more, so that the transfer with the external second refrigerant is reduced.

In particular, when R-134a, which is a refrigerant for a conventional chiller, is changed to R1233zd, which is an eco-friendly refrigerant (non-flammable, non-toxic), there is a problem that the performance of the heat transfer tube is greatly reduced (40%).

That is, there is a problem that a heat transfer tube having very excellent heat exchange efficiency is required to use an eco-friendly refrigerant.

Korean Patent Publication No. 10-1084477

An object of the present invention is to provide a heat transfer tube and a chiller system in which efficiency is not reduced while using an eco-friendly refrigerant.

Another object of the present invention is to provide a heat transfer tube that is easy to manufacture and maximizes heat transfer efficiency in the same tube diameter.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention is characterized in that it includes a main cavity and a microcavity smaller in size than the main cavity on the outer surface of the refrigerant tube.

Specifically, a refrigerant tube having a space in which the refrigerant flows; a plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including an upper surface having a step difference from the outer surface of the refrigerant tube; a main cavity formed between adjacent heat dissipation fins and having an inlet formed between upper ends of the plurality of heat dissipation fins; and a plurality of microcavities that are formed on the upper surface of the heat dissipation fins, have a height and a width smaller than that of the main cavity, and open upwards.

The heat dissipation fin includes a first portion having a lower end connected to the outer surface of the refrigerant tube, and a second portion connected to the upper end of the first portion and having a width wider than the first portion, and the upper surface is the It may be the upper surface of the second part.

The plurality of microcavities may be disposed along an edge of the top surface.

An upper width of the microcavity may be smaller than a lower width of the microcavity.

The width of the microcavity may decrease as it progresses from the top to the bottom.

The depth of the microcavity may be 0.01% to 10% of the depth of the main cavity.

The depth of the microcavity may be 5% to 90% of the width of the main cavity.

A depth of the microcavity may be greater than or equal to an entrance width of the microcavity.

The entrance width of the microcavity may be 5% to 50% of the entrance width of the main cavity.

The distance between the microcavities adjacent to each other may be 2 to 5 times the width of the entrance to the microcavities.

The entrance of the main cavity may be formed between the second portions adjacent to each other.

A lower width of the main cavity may be greater than an inlet width of the main cavity.

The lower width of the main cavity may be 2 to 4 times the width of the entrance of the main cavity.

The depth of the main cavity may be 5 to 10 times the width of the entrance of the main cavity.

A lower width of the main cavity may be 300 μm to 400 μm.

The depth of the main cavity may be 0.9 mm to 1.2 mm.

The entrance width of the microcavity may be 10 μm to 50 μm.

In addition, the present invention is a case having a heat exchange space; a first refrigerant supply pipe connected to the case to supply a first refrigerant to the heat exchange space; a first refrigerant discharge pipe connected to the case to discharge the first refrigerant in the heat exchange space; and a plurality of heat transfer tubes disposed in the heat exchange space of the case and through which a second refrigerant that exchanges heat with the first refrigerant flows, the heat transfer tube comprising: a refrigerant tube having a space in which the refrigerant flows; a plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including an upper surface having a step difference from the outer surface of the refrigerant tube; a main cavity formed between adjacent heat dissipation fins and having an inlet formed between upper ends of the plurality of heat dissipation fins; and a plurality of microcavities that are formed on the upper surface of the heat dissipation fin, have a height and a width smaller than those of the main cavity, and open upward.

The details of other embodiments are included in the detailed description and drawings.

According to the heat exchanger for a heat transfer tube and a chiller of the present invention, there are one or more of the following effects.

First, in the present invention, since the liquid refrigerant of the heat transfer tube has a structure in which it is difficult to penetrate into the microcavity and the main cavity due to surface tension, a gaseous refrigerant is always present inside the microcavity, and the gaseous refrigerant inside the microcavity is a liquid There is an advantage in that the refrigerant acts as a phase change nucleus for phase change into a gaseous refrigerant, thereby accelerating the boiling of the liquid refrigerant.

Second, there is an advantage that the main cavity and the microcavity are different from each other because they have different sizes, so that the bubbles generated in the main cavity merge with the bubbles generated in the microcavities so that the bubbles can easily escape from the refrigerant tube.

Third, since it has a main cavity and a fine cavity, there is an advantage of improving the heat exchange efficiency of the heat transfer tube.

Fourth, the present invention has the advantage of having a structure that is simple and easy to manufacture.,

Fifth, the present invention has the advantage that the efficiency of the chiller is not lowered while using an eco-friendly refrigerant.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 shows a chiller system in one embodiment of the present invention.
2 illustrates a structure of a compressor according to an embodiment of the present invention.
3 is a diagram illustrating a case in which the compressor according to an embodiment of the present invention does not generate a surge.
4 is a diagram illustrating a case in which the compressor according to an embodiment of the present invention generates a surge condition.
5 is a perspective view of a heat transfer tube according to an embodiment of the present invention.
Figure 6 is an enlarged view of the entrance of the main cavity of Figure 5;
7 is a cross-sectional view of the heat transfer tube of FIG. 5 .

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between components and other components. Spatially relative terms should be understood as terms including different orientations of components in use or operation in addition to the orientation shown in the drawings. For example, when a component shown in the drawings is turned over, a component described as “beneath” or “beneath” of another component may be placed “above” of the other component. can Accordingly, the exemplary term “below” may include both directions below and above. Components may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" means that a referenced component, step and/or action excludes the presence or addition of one or more other components, steps and/or actions. I never do that.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly specifically defined.

In the drawings, the thickness or size of each component is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size and area of each component do not fully reflect the actual size or area.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Hereinafter, the present invention will be described with reference to the drawings for explaining a chiller system according to embodiments of the present invention.

1 shows a chiller system of the present invention. Meanwhile, the compressor 100 according to an embodiment of the present invention not only functions as a part of a chiller system, but may also be included in an air conditioner, and may be included in any device that compresses gaseous substances.

Referring to FIG. 1 , a chiller system 1 according to an embodiment of the present invention includes a compressor 100 configured to compress a refrigerant, and a condenser 200 for condensing the refrigerant by exchanging heat with the refrigerant compressed in the compressor 100 and cooling water. ), an expander 300 for expanding the refrigerant condensed in the condenser 200, and an evaporator 400 formed to heat-exchange the refrigerant expanded in the expander 300 with the cold water to cool the cold water together with the evaporation of the refrigerant.

In addition, the chiller system 1 according to an embodiment of the present invention includes a cooling water unit 600 that heats the cooling water through heat exchange between the refrigerant compressed in the condenser 200 and the cooling water, and the expanded in the evaporator 400 . It further includes an air conditioning unit 500 for cooling the cold water through heat exchange between the refrigerant and the cold water.

The condenser 200 provides a place for exchanging the high-pressure refrigerant compressed in the compressor 100 with the coolant flowing in from the cooling water unit 600 . The high-pressure refrigerant is condensed through heat exchange with the cooling water.

The condenser 200 may be configured as a shell-tube type heat exchanger. Specifically, the high-pressure refrigerant compressed in the compressor 100 is introduced into the condensing space 230 corresponding to the internal space of the condenser 200 through the condenser connection passage 150 . In addition, the inside of the condensing space 230 includes a cooling water passage 210 through which the cooling water flowing in from the cooling water unit 600 can flow. The condenser 200 includes a condensation chamber 201 having a condensation space 230 therein.

The cooling water flow path 210 includes a cooling water inflow path 211 through which cooling water is introduced from the cooling water unit 600 and a cooling water discharge path 212 through which the cooling water is discharged to the cooling water unit 600 . The cooling water flowing into the cooling water inlet flow path 211 exchanges heat with the refrigerant inside the condensing space 230 and then passes through the cooling water connection flow path 240 provided at one end inside or outside the condenser 200 to the cooling water discharge flow path 212 . is brought in

The cooling water unit 600 and the condenser 200 are connected via the cooling water tube 220 . The cooling water tube 220 may be made of a material such as rubber to not only become a passage through which the cooling water flows between the cooling water unit 600 and the condenser 200 but also to prevent leakage to the outside.

The cooling water tube 220 includes a cooling water inlet tube 221 connected to the cooling water inlet passage 211 and a cooling water discharge tube 222 connected to the cooling water discharge passage 212 . Looking at the flow of the cooling water as a whole, the cooling water after heat exchange with air or liquid in the cooling water unit 600 is introduced into the condenser 200 through the cooling water inlet tube 221 . The cooling water introduced into the condenser 200 passes through the cooling water inlet passage 211, the cooling water connection passage 240, and the cooling water discharge passage 212 provided in the condenser 200 in turn. After heat exchange with the refrigerant, it flows back into the cooling water unit 600 through the cooling water discharge tube 222 .

Meanwhile, the cooling water that has absorbed heat of the refrigerant through heat exchange in the condenser 200 may be air-cooled in the cooling water unit 600 . The cooling water unit 600 includes a cooling water inlet pipe 610, which is an inlet through which the cooling water that has absorbed heat through the main body 630 and the cooling water discharge tube 222, and the cooling water unit 600 are cooled inside and then the cooling water is discharged. It is composed of a cooling water discharge pipe 620 which is an outlet.

The cooling water unit 600 may use air to cool the cooling water introduced into the main body 630 . Specifically, the main body 630 is provided with a fan for generating a flow of air and includes an air outlet 631 through which air is discharged, and an air inlet 632 corresponding to an inlet through which air is introduced into the main body 630 . do.

Air discharged after heat exchange at the air outlet 631 may be used for heating. The refrigerant after heat exchange in the condenser 200 is condensed and collected in the lower portion of the condensing space 230 . The accumulated refrigerant flows into the refrigerant box 250 provided in the condensing space 230 and then flows into the expander 300 .

The refrigerant box 250 flows into the refrigerant inlet 251 , and the introduced refrigerant is discharged through the evaporator connection passage 260 . The evaporator connection passage 260 includes an evaporator connection passage inlet 261 , and the evaporator connection passage inlet 261 may be located below the refrigerant box 250 .

The evaporator 400 includes an evaporation chamber 401 having an evaporation space 430 in which heat exchange occurs between the refrigerant expanded in the expander 300 and the cold water. The refrigerant that has passed through the expander 300 in the evaporator connection passage 260 is connected to the refrigerant injection device 450 provided in the evaporator 400, and the refrigerant injection hole 451 provided in the refrigerant injection device 450 is connected to the It is then spread evenly into the evaporator 400 .

In addition, the evaporator 400 is provided with a cold water passage 410 including a cold water inlet passage 411 through which cold water flows into the evaporator 400 and a cold water discharge passage 412 through which cold water is discharged to the outside of the evaporator 400 . do.

The cold water is introduced or discharged through the cold water tube 420 in communication with the air conditioning unit 500 provided outside the evaporator 400 . The cold water tube 420 includes a cold water inlet tube 421 that is a passage for the cold water inside the air conditioning unit 500 to the evaporator 400 and a passage for the cold water after heat exchange in the evaporator 400 to the air conditioning unit 500 . It is composed of a phosphorus cold water discharge tube (422). That is, the cold water inlet tube 421 communicates with the cold water inlet passage 411 , and the cold water discharge tube 422 communicates with the cold water discharge passage 412 .

Looking at the flow of cold water, the cold water connection passage 440 provided at the inner end of the evaporator 400 or the outside of the evaporator 400 through the air conditioning unit 500, the cold water inlet tube 421, and the cold water inlet passage 411. ), the cold water is introduced back into the air conditioning unit 500 through the discharge passage 412 and the cold water discharge tube 422 .

The air conditioning unit 500 cools the cold water through the refrigerant. The cooled cold water absorbs heat from the air in the air conditioning unit 500 to enable indoor cooling. The air conditioning unit 500 includes a cold water discharge pipe 520 communicating with the cold water inlet tube 421 and a cold water inlet pipe 510 communicating with the cold water discharge tube 422 . The refrigerant that has undergone heat exchange in the evaporator 400 flows back into the compressor 100 through the compressor connection passage 460 .

2 illustrates a centrifugal compressor 100 (aka, turbocompressor) according to an embodiment of the present invention.

Compressor 100 according to FIG. 2 is one or more impellers 120 for sucking refrigerant in the axial direction (Ax) and compressing it in the centrifugal direction, the impeller 120 and the motor 130 for rotating the impeller 120 are connected. A bearing unit 140 including a plurality of magnetic bearings 141 supporting the rotating shaft 110 and the rotating shaft 110 to be rotatable in the air and a bearing housing 142 supporting the magnetic bearing 141, the rotating shaft 110 ) and a gap sensor 70 for sensing the distance and a thrust bearing 160 for limiting vibration of the rotation shaft 110 in the axial direction Ax.

The impeller 120 is generally composed of one stage or two stages, and may be composed of a plurality of stages. It rotates by the rotating shaft 110, and serves to make the refrigerant into a high pressure by compressing the refrigerant flowing in the axial direction (Ax) by rotation in the centrifugal direction.

The motor 130 has a rotation shaft 110 and a separate rotation shaft 110 and may have a structure for transmitting rotational force to the rotation shaft 110 by a belt (not shown), but in the case of an embodiment of the present invention, the motor ( 13) is composed of a stator (not shown) and a rotor 112 to rotate the rotating shaft 110 .

The rotating shaft 110 is connected to the impeller 120 and the motor 13 . The rotation shaft 110 extends in the left-right direction of FIG. 2 . Hereinafter, the axial direction Ax of the rotation shaft 110 means a left-right direction. The rotating shaft 110 preferably includes a metal so as to be movable by the magnetic force of the magnetic bearing 141 and the thrust bearing.

In order to prevent vibration in the axial direction (Ax) (left and right) of the rotation shaft 110 of the assembly of the thrust bearing 160, it is preferable that the rotation shaft 110 has a constant area in a plane perpendicular to the axial direction (Ax). . Specifically, the rotary shaft 110 may further include a rotary shaft blade 111 that provides sufficient magnetic force to move the rotary shaft 110 by the magnetic force of the thrust bearing 160 . The rotary shaft blade 111 may have a larger area than the cross-sectional area of the rotary shaft 110 in a plane perpendicular to the axial direction Ax. The rotary shaft wing 111 may be formed to extend in the rotational radial direction of the rotary shaft 110 .

The magnetic bearing 141 and the thrust bearing 160 are made of a conductor, and a coil 143 is wound thereon. The current flowing in the wound coil 143 acts like a magnet.

A plurality of magnetic bearings 141 are provided to surround the rotary shaft 110 with the rotary shaft 110 as a center, and the thrust bearing 160 is provided to extend in the rotational radial direction of the rotary shaft 110 and provided with rotary shaft blades 111 . provided adjacent to

The magnetic bearing 141 allows the rotation shaft 110 to rotate without friction in a state in which it is levitated in the air. To this end, at least three magnetic bearings 141 should be provided around the rotation shaft 110 , and each magnetic bearing 141 should be installed in a balanced manner around the rotation shaft 110 .

In the case of an embodiment of the present invention, four magnetic bearings 141 are provided to be symmetrical about the rotation axis 110 , and the rotation axis 110 by the magnetic force generated by the coil wound on each magnetic bearing 141 . It will float in the air. As the rotating shaft 110 is lifted and rotated in the air, energy lost due to friction is reduced, unlike the conventional invention in which a bearing is provided.

Meanwhile, the compressor 100 may further include a bearing housing 142 supporting the magnetic bearing 141 . A plurality of magnetic bearings 141 are provided, and are installed with a gap so as not to contact the rotation shaft 110 .

The plurality of magnetic bearings 141 are installed at least at two points of the rotation shaft 110 . The two points correspond to different points along the longitudinal direction of the rotation shaft 110 . Since the rotation shaft 110 corresponds to a straight line, the rotation shaft 110 must be supported at at least two points to prevent vibration in the circumferential direction.

Looking at the flow of the refrigerant, the refrigerant introduced into the compressor 100 through the compressor 100 connection passage 460 is compressed in the circumferential direction by the action of the impeller 120 and then discharged to the condenser connection passage 150 . The compressor 100 connection passage 460 is connected to the compressor 100 so that the refrigerant flows in a direction perpendicular to the rotation direction of the impeller 120 .

The thrust bearing 160 limits the movement of the rotary shaft 110 in the axial direction (Ax) vibration, and when the surge occurs, the rotary shaft 110 moves in the impeller 120 direction, and It prevents the rotation shaft 110 from moving.

Specifically, the thrust bearing 160 is composed of a first thrust bearing 161 and a second thrust bearing 162 , and is disposed to surround the rotary shaft wing 111 in the axial direction Ax of the rotary shaft 110 . That is, the first thrust bearing 161 , the rotary shaft blade 111 , and the second thrust bearing 162 are disposed in the axial direction Ax of the rotary shaft 110 .

More specifically, the second thrust bearing 162 is located closer to the impeller 120 than the first thrust bearing 161 , and the first thrust bearing 161 is farther from the impeller 120 than the second thrust bearing 161 . at least a portion of the rotating shaft 110 is positioned between the first thrust bearing 161 and the second thrust bearing 162 . Preferably, the rotary shaft blade 111 is positioned between the first thrust bearing 161 and the second thrust bearing 162 .

Therefore, the first thrust bearing 161 and the second thrust bearing 162 may minimize the vibration of the rotary shaft 110 in the direction of the rotary shaft 110 by the operation of the rotary shaft blade 111 and magnetic force having a large area. It works.

The gap sensor 70 measures the movement in the axial direction (Ax) (left and right) of the rotation shaft 110 . Of course, the gap sensor 70 may measure the movement of the rotation shaft 110 in the vertical direction (direction orthogonal to the axial direction Ax). Of course, the gap sensor 70 may include a plurality of gap sensors 70 .

For example, the gap sensor 70 includes a first gap sensor 710 that measures the vertical movement of the rotation shaft 110 and a second gap sensor 720 that measures the left and right movement of the rotation shaft 110 . . The second gap sensor 720 may be disposed to be spaced apart from one end in the axial direction Ax of the rotation shaft 110 in the axial direction Ax.

The force of the thrust bearing 160 is inversely proportional to the square of the distance and proportional to the square of the current. When a surge occurs in the rotating shaft 110 , a thrust is generated in the impeller 120 direction (right direction). The force generated in the right direction must be pulled with the maximum force by using the magnetic force of the thrust bearing 160, so that the position of the rotating shaft 110 is located in the middle of the two thrust bearings 160 (the reference position C0). If it is, it is difficult to quickly move the rotary shaft 110 to the reference position C0 in response to the sudden axis movement.

Since the force of the thrust in the direction of the impeller 120 generated on the rotating shaft 110 is quite strong, when it is located at the reference position C0, the amount of current supplied to increase the magnetic force of the thrust bearing 160 is increased, or the thrust bearing There is a problem in that the size of (160) needs to be increased.

Therefore, the present invention is to position the rotation shaft 110 in advance in an eccentric direction opposite to the direction in which the thrust is generated when the surge is expected to occur.

Specifically, the control unit 700 determines the surge generation condition based on the information received from the gap sensor 70 . The control unit 700 may determine the surge generation condition when the position of the rotation shaft 110 measured by the gap sensor 70 is out of the normal position range (-C1 to +C1). In addition, when the position of the rotation shaft 110 measured by the gap sensor 70 is located within the normal position range (-C1 to +C1), the control unit 700 may determine that the surge does not occur.

Here, the normal position range (-C1 to +C1) of the rotation shaft 110 means an area within a predetermined distance in the left and right direction with respect to the reference position C0 of the rotation shaft 110 . The normal position range (-C1 to +C1) of the rotating shaft 110 is such that the rotating shaft 110 vibrates in the axial direction (Ax) by various environmental and peripheral factors when the rotating shaft 110 rotates. This is the range in which vibration is judged to be in a steady state. This normal position range (-C1 ~ +C1) is an experimental value, and the value of the normal position range (-C1 ~ +C1) is based on the kurtosis or skewness of the position of the rotation shaft 110 . You can also set There is no limit to the method of determining the normal position range (-C1 to +C1).

When the surge generation condition is satisfied, the control unit 700 adjusts the amount of current supplied to the thrust bearings 160 so that the rotating shaft 110 is eccentric from the reference position C0 to the impeller 120 in the opposite direction. can be positioned. The position at which the rotating shaft 110 is eccentric means that the rotating shaft wing 111 is located between the first thrust bearing 160 and the reference position C0.

Therefore, after a surge occurs, the rotation shaft 110 may have a buffer time to rapidly move in the impeller 120 direction, and the rotation shaft 110 may be moved to the normal position range (-C1 to +C1) due to an increase in the small amount of current. ) to make it easier to control.

Specifically, when the surge generation condition is satisfied, the controller 700 may supply current only to the first thrust bearing 161 among the first and second thrust bearings 162 . As another example, when the surge generation condition is satisfied, the controller 700 may control the amount of current supplied to the first thrust bearing 161 to be greater than the amount of current supplied to the second thrust bearing 162 .

The control unit 700 may control the position of the rotating shaft 110 to be fixed to the eccentric position for a predetermined time after the surge generating condition is satisfied, eccentrically eccentric the rotating shaft 110 in the opposite direction of the impeller 120 . That is, when a surge occurs after the rotation shaft 110 is eccentric in the opposite direction to the impeller 120 , the controller 700 may increase the amount of current supplied to the first thrust bearing 161 . After the rotation shaft 110 is eccentric in the opposite direction to the impeller 120 , the controller 700 moves the rotation shaft 110 back to the reference position C0 when the vibration width is maintained below a certain standard based on the eccentric position. may do it

When the surge non-occurrence condition is satisfied, the controller 700 may adjust the amount of current supplied to the first thrust bearing 161 and the amount of current supplied to the second thrust bearing 162 to be the same. Alternatively, when the surge non-occurrence condition is satisfied, the control unit 700 adjusts the amount of current supplied to the upper first thrust bearing 161 and the second thrust bearing 162 so that the rotating shaft 110 moves to the reference position ( It can be controlled to be located in C0).

The heat exchanger for a chiller of the present invention includes a case having a heat exchange space, a first refrigerant supply pipe connected to the case to supply a first refrigerant to the heat exchange space, a first refrigerant discharge pipe connected to the case to discharge the first refrigerant in the heat exchange space, It may include a plurality of heat transfer tubes disposed in the heat exchange space of the case and through which a second refrigerant that exchanges heat with the first refrigerant flows.

The heat exchanger for the chiller may include the above-described evaporator and/or condenser. For example, the heat exchanger for a chiller includes a case having a heat exchange space, a first refrigerant supply pipe connected to the case to supply a first refrigerant to the heat exchange space, and a first refrigerant discharge pipe connected to the case to discharge the first refrigerant in the heat exchange space , which is disposed in the heat exchange space of the case and may include a plurality of heat transfer tubes through which a second refrigerant exchanging heat with the first refrigerant flows.

When the heat exchanger for the chiller is a condenser, the case is the condensation chamber 201, the first refrigerant supply pipe is the condenser connection flow path 150, the first refrigerant discharge pipe is the evaporator connection flow path 260, and the heat transfer pipe is the cooling water inflow path ( 211) and/or the coolant discharge passage 212 .

When the heat exchanger for the chiller is an evaporator, the case is the evaporation chamber 401, the first refrigerant supply pipe is the evaporator connection flow path 260, the first refrigerant discharge pipe is the compressor connection flow path 460, and the heat transfer pipe is the cold water inflow path ( 411 ) and/or the cold water discharge passage 412 , or at least a part of the cold water inlet passage 411 and/or the cold water discharge passage 412 .

Here, the first refrigerant may be water, and the second refrigerant may be any one of Freon, R-134a, and R1233zd.

A general heat pipe has a problem in that when the fluid passes into the inside of the heat pipe, the fluid, which is a liquid or gas, passes quickly without contacting 100% or more of the inner surface of the heat pipe evenly, so that the transfer with the external second refrigerant is reduced.

In addition, since the fluid moves at a constant speed without obstruction of the heat transfer tube when passing through the heat transfer tube, heat transfer of the fluid is not completely achieved with the surface, so sufficient heat exchange has not been achieved, and when the fluid moves, some of it flows ( Since it passes through the inside of the heat transfer tube as it is without the occurrence of heat, the heat flowing inside the fluid could not be effectively transferred.

In particular, there is a problem in that the performance of the heat transfer tube 20 is greatly reduced (40%) when R-134a, which is a refrigerant for a conventional chiller, is changed to R1233zd, which is an eco-friendly refrigerant (non-flammable, non-toxic).

Accordingly, the heat transfer tube 20 of the present invention has a configuration in which the above-described problems are solved, and the efficiency is excellent, and an environment-friendly refrigerant can be used.

Hereinafter, the heat transfer tube 20 of the present invention will be described in detail.

5 is a perspective view of a heat pipe 20 according to an embodiment of the present invention, FIG. 6 is an enlarged view of the inlet 38 of the main cavity 30 of FIG. 5, and FIG. 7 is a view of the heat pipe 20 of FIG. It is a cross section.

5 to 7 , the heat transfer tube 20 of the present invention has a space therein and protrudes from the outer surface of the refrigerant tube 21 extending in the first direction, the refrigerant tube 21, and the refrigerant tube 21 A plurality of heat dissipation fins 23 including an outer surface and a top surface 23c having a step difference, are formed between the heat dissipation fins 23 adjacent to each other, and an inlet is formed between the upper ends of the plurality of heat dissipation fins 23 ( 30) and a plurality of microcavities 40 formed on the upper surface of the heat dissipation fins 23 and having a smaller height and width than the main cavity 30, and opened upwards.

The refrigerant tube 21 has a flow space 29 therein and extends in the first direction. Here, the first direction is the X-axis direction, and the second refrigerant flows. The refrigerant tube 21 is made of a metal material having high thermal conductivity. The refrigerant tube 21 helps heat exchange between the second refrigerant flowing inside and the first refrigerant flowing outside.

The cross-sectional shape of the refrigerant tube 21 (based on FIG. 5 , hereinafter the cross-sectional shape is based on the Y-Z axis cross-section) may be a circular or elliptical polygon having a refrigerant flow space 22 therein. Preferably, the refrigerant tube 21 is circular with a large outer surface area.

The diameter of the refrigerant tube 21 is not limited. However, when the refrigerant tube 21 is too large, heat exchange efficiency is reduced, and when it is too small, the heat exchange time takes a long time, so the diameter of the refrigerant tube 21 may be 17 mm to 25 mm. The diameter of the refrigerant tube 21 is preferably 19-21 mm.

The refrigerant tube 21 may have a plurality of grooves or protrusions to increase the surface area. For example, a plurality of guide grooves (not shown) may be formed on the inner surface of the refrigerant tube 21 . The guide groove is formed by recessing the inner surface of the refrigerant tube 21 to the outside.

The plurality of guide grooves 21a may be regularly or irregularly formed on the inner surface of the refrigerant tube 21 . The plurality of guide grooves 21a improve the contact area between the second refrigerant and the inner surface of the refrigerant tube 21 .

The outer surface of the refrigerant tube 21 may include a main cavity 30 having a step difference from each other and a microcavity 40 . The main cavity 30 may have a larger size than the microcavity 40 , and may be disposed below the microcavity 40 . Here, being disposed below means that the lower end of the main cavity 30 is positioned below the lower end of the microcavity 40 .

The bubbles generated in the main cavity 30 and the bubbles generated in the microcavities 40 merge with each other due to the size difference between the main cavity 30 and the microcavity 40 so that the bubbles are separated from the refrigerant tube 21 This facilitates the conversion of the liquid refrigerant into the gaseous refrigerant, and the bubbles thus escaped are promoted.

The main cavity 30 and the microcavity 40 may be created in various ways. For example, the outer surface of the refrigerant tube 21 is pressed by a roller in the circumferential direction intersecting the first direction and the first direction to form a plurality of grooves 31 and 32 and a plurality of heat dissipation fins 23, and a heat dissipation fin 23 is pressed from the top to the bottom so that the heat dissipation fin 23 is bent or the upper portion of the heat dissipation fin 23 is expanded to form a main cavity 30, and the microcavity 40 is formed by punching, wet etching, or dry etching can be formed.

The plurality of heat dissipation fins 23 are formed to protrude from the outer surface of the refrigerant tube 21 . The plurality of heat dissipation fins 23 may be respectively adhered to the outer surface of the refrigerant tube 21 or may be formed integrally, but it is easy to manufacture by the above-described method.

The heat dissipation fin 23 has a first portion 23a having a lower end connected to the outer surface of the refrigerant tube 21, and a second portion connected to the upper end of the first portion 23a and having a wider width than the first portion 23a. part 23b.

The lower end of the first portion 23a is connected to the outer surface of the refrigerant tube 21 , and the upper end of the first portion 23a is connected to the second portion 23b. The first portions 23a adjacent to each other are spaced apart from each other to form the interior of the main cavity 30 . The first portions 23a adjacent to each other are spaced apart by a sufficient distance so that the main cavity 30 maintains a certain width even when the second portion 23b is expanded.

The second part 23b is connected to the end of the first part 23a and is connected to the upper part. The second portion 23b has a greater width than the first portion 23a. The second part 23b may be manufactured by pressing the upper end of the heat dissipation fin 23 . The second portions 23b adjacent to each other may be partially in contact with each other or may be spaced apart from each other by a distance smaller than the width of the main cavity 30 . The space between adjacent second portions 23b will define the entrance 38 of the main cavity 30 .

Each heat dissipation fin 23 may include an upper surface 23c having a step difference from the outer surface of the refrigerant tube 21 . Here, the outer surface of the refrigerant tube 21 will mean the bottom surface of the main cavity (30). Specifically, the upper surface 23c may be the upper surface of the second part 23b.

The area of the top surface 23c may be larger than the area of the inlet 38 of the main cavity 30 and the width of the inlet of the microcavity 40 . Preferably, the largest width of the top surface 23c is greater than the largest width of the main cavity 30 . The second portion 23b of each heat dissipation fin 23 preferably has a sufficient area so that the microcavity 40 is formed.

The main cavity 30 is formed between the heat dissipation fins 23 adjacent to each other, and an inlet may be formed between the upper ends of the plurality of heat dissipation fins 23 . The size of the main cavity 30 may be larger than that of the microcavity 40 .

If the inlet 38 of the main cavity 30 is too small, the bubbles inside the main cavity 30 cannot escape to the outside, and if the inlet 38 of the main cavity 30 is too large, the inside of the main cavity 30 is The amount of liquid refrigerant that penetrates into the

Specifically, the lower width W3 of the main cavity 30 may be greater than the width W1 of the inlet 38 of the main cavity 30 . Here, the lower width W3 of the main cavity 30 increases from the bottom to the upper side, and then decreases again or may be constant. The lower width W3 of the main cavity 30 may be 2 to 4 times the width W1 of the inlet 38 of the main cavity 30 . Preferably, the lower width W3 of the main cavity 30 may be 3 to 4 times the width W1 of the inlet 38 of the main cavity 30 .

The lower width W3 of the main cavity 30 may be 300 μm to 400 μm. The entrance 38 width W1 of the main cavity 30 may be between 10 μm and 50 μm.

If the depth H2 of the main cavity 30 is too small, large bubbles cannot be formed, and if the depth H2 of the main cavity 30 is too deep, the bubbles generated inside the main cavity 30 are not released. It is difficult. Accordingly, the depth H2 of the main cavity 30 may have a sufficient depth to trap air bubbles.

The depth H2 of the main cavity 30 may be 5 to 10 times the width W1 of the entrance 38 of the main cavity 30 . Preferably, the depth H2 of the main cavity 30 may be 7 to 8 times the width W1 of the entrance 38 of the main cavity 30 . The depth H2 of the main cavity 30 may be 0.9 mm to 1.2 mm.

The microcavity 40 may be formed on the upper surface of the heat dissipation fin 23 . Specifically, the microcavity 40 may be located on one side of the heat dissipation fin 23 defining the perimeter (perimeter) of the inlet 38 of the main cavity 30 . More specifically, the microcavity 40 may be located on the upper surface 23c of the second portion 23b.

When the microcavity 40 is located on the upper surface of the second part 23b, the upper surface of the second part 23b corresponds to the outermost side of the heat dissipation fin 23, so that when the bubbles grown in the main cavity 30 rise, It is advantageous to merge with the bubbles formed in the microcavities 40 .

Preferably, in order to improve the probability that the bubbles of the microcavity 40 and the bubbles of the main cavity 30 merge with each other, the microcavities 40 are formed along the edge of the top surface 23c of the heat dissipation fin 23 in multiple numbers. Dogs may be placed.

If the separation distance between the microcavities 40 adjacent to each other is too large, the amount of air bubbles generated in the microcavities 40 is small, so that the bubbles generated in the main cavity 30 cannot be smoothly separated, and the separation distance is too large. If it is small, there is a risk that the liquid refrigerant flows into the microcavity 40 due to the pressure of the bubbles generated in the adjacent microcavities 40 . Accordingly, the spacing between the microcavities 40 adjacent to each other may be 2 to 5 times the width of the entrance to the microcavities 40 . The distance between the adjacent microcavities 40 is preferably 3 to 3 times the width of the entrance to the microcavities 40 .

The microcavity 40 is formed by being depressed from the top surface 23c of the heat dissipation fin 23 to the bottom, and the top is opened. The microcavity 40 may have various shapes. Preferably, in order to prevent the external refrigerant from completely flowing into the microcavity 40 , the upper width of the microcavity 40 may be smaller than the lower width of the microcavity 40 . More preferably, the width of the microcavity 40 may become smaller as it progresses from the top to the bottom.

The size of the microcavity 40 may be smaller than that of the microcavity 40 . The width of the microcavity 40 may be smaller than the width of the main cavity 30 , and the depth H1 of the microcavity 40 may be smaller than the depth H2 of the main cavity 30 . Also, the entrance width of the microcavity 40 may be smaller than the entrance 38 width W1 of the main cavity 30 .

If the inlet of the microcavity 40 is too small, the bubbles inside the microcavity 40 cannot escape to the outside, and if the inlet of the microcavity 40 is too large, the liquid refrigerant penetrating into the microcavity 40 quantity will increase.

The entrance width of the microcavity 40 may be smaller than the depth of the main cavity 30 or the width of the main cavity 30 . The entrance width of the microcavity 40 may be 5% to 50% of the entrance 38 width W1 of the main cavity 30 . Preferably, the entrance width of the microcavity 40 may be 10% to 20% of the entrance 38 width W1 of the main cavity 30 . The entrance width of the microcavity 40 is usually between 10 μm and 50 μm.

If the depth H1 of the microcavity 40 is too small, it is not possible to create a bubble of an appropriate size, and if the depth H1 of the microcavity 40 is too deep, the bubbles generated inside the microcavity 40 are hard to get out of Accordingly, the depth H1 of the microcavity 40 may have a sufficient depth to trap appropriate air bubbles.

The depth H1 of the microcavity 40 may be 0.01% to 10% of the depth H2 of the main cavity 30 . Preferably, the depth H1 of the microcavity 40 may be 4% to 7% of the depth H2 of the main cavity 30 .

The depth H1 of the microcavity 40 may be smaller than the width of the main cavity 30 . The depth H1 of the microcavity 40 may be 5% to 90% of the width of the main cavity 30 . Preferably, the depth H1 of the microcavity 40 may be 10% to 20% of the width of the main cavity 30 .

The depth H1 of the microcavity 40 may be greater than or equal to the entrance width of the microcavity 40 . The depth H1 of the microcavity 40 is usually 10 μm to 100 μm.

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications may be made by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

20: heat transfer tube 21: refrigerant tube
23: heat sink 30: main cavity
40: auxiliary cavity 100: compressor

Claims (20)

a refrigerant tube having a space in which the refrigerant flows;
a plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including an upper surface having a step difference from the outer surface of the refrigerant tube;
a main cavity formed between adjacent heat dissipation fins and having an inlet formed between upper ends of the plurality of heat dissipation fins; and
It is formed on the upper surface of the heat dissipation fin, has a smaller depth and width than the main cavity, and includes a plurality of microcavities open upward,
The plurality of microcavities are arranged along the edge of the top surface,
An upper width of the microcavity is smaller than a lower width of the microcavity. According to claim 1,
The heat dissipation fin is
a first portion having a lower end connected to the outer surface of the refrigerant tube;
It is connected to the upper end of the first part and includes a second part having a width that is wider than that of the first part,
The upper surface of the heat transfer tube is an upper surface of the second part. delete delete According to claim 1,
The width of the microcavity becomes smaller as it progresses from the top to the bottom. According to claim 1,
The depth of the microcavity is 0.01% to 10% of the depth of the main cavity. According to claim 1,
The depth of the microcavity is 5% to 90% of the width of the main cavity. According to claim 1,
The depth of the microcavity is greater than or equal to the entrance width of the microcavity. According to claim 1,
The entrance width of the microcavity is 5% to 50% of the entrance width of the main cavity. According to claim 1,
The distance between the microcavities adjacent to each other is 2 to 5 times the width of the entrance to the microcavity. 3. The method of claim 2,
The inlet of the main cavity is formed between the second portions adjacent to each other. According to claim 1,
a lower width of the main cavity is greater than an inlet width of the main cavity. According to claim 1,
The lower width of the main cavity is 2 to 4 times the inlet width of the main cavity. According to claim 1,
The depth of the main cavity is 5 to 10 times the inlet width of the main cavity. According to claim 1,
A lower width of the main cavity is 300 μm to 400 μm. According to claim 1,
The depth of the main cavity is 0.9mm to 1.2mm. According to claim 1,
The entrance width of the microcavity is 10 μm to 50 μm. a case having a heat exchange space;
a first refrigerant supply pipe connected to the case to supply a first refrigerant to the heat exchange space;
a first refrigerant discharge pipe connected to the case to discharge the first refrigerant in the heat exchange space; and
and a plurality of heat transfer tubes disposed in the heat exchange space of the case and through which a second refrigerant exchanging heat with the first refrigerant flows;
The heat pipe is
a refrigerant tube having a space in which the refrigerant flows;
a plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including an upper surface having a step difference from the outer surface of the refrigerant tube;
a main cavity formed between adjacent heat dissipation fins and having an inlet formed between upper ends of the plurality of heat dissipation fins; and
It is formed on the upper surface of the heat dissipation fin, has a height and a width smaller than that of the main cavity, and includes a plurality of microcavities open upwards,
The plurality of microcavities are arranged along the edge of the top surface,
An upper width of the microcavity is smaller than a lower width of the microcavity. 19. The method of claim 18,
The heat dissipation fin is
a first part having a lower end connected to the outer surface of the refrigerant tube;
It is connected to the upper end of the first part and includes a second part having a width that is wider than that of the first part,
The upper surface is a heat exchanger for a chiller that is an upper surface of the second part. 19. The method of claim 18,
The plurality of microcavities are heat exchangers for chillers that are disposed along the edge of the upper surface.

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