KR20200093340A - Heat transfer pipe and Heat exchanger for chiller - Google Patents

Abstract

The present invention relates to a heat transfer tube and a chiller system in which efficiency is not reduced while using an eco-friendly refrigerant. The heat transfer pipe includes: a refrigerant tube having a space in which the refrigerant flows; a plurality of radiating fins protruding from an outer surface of the refrigerant tube and including an upper end surface having a step difference from the outer surface of the refrigerant tube; a main cavity formed between adjacent radiating fins and having an inlet formed between upper ends of the plurality of radiating fins; and a plurality of micro cavities formed on the upper surface of the radiating fins, having a height and a width smaller than those of the main cavity, and opened upward.

Description

Heat exchanger for heat exchanger and chiller {Heat transfer pipe and Heat exchanger for chiller}

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

In general, the chiller system is to supply cold water to a cold water demand destination, and is characterized in that cold water is cooled by heat exchange between a refrigerant circulating between the refrigeration system and cold water circulating between the cold water demand destination and the refrigeration system. Such a chiller system is a large-capacity facility, and can be installed in a large building.

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

In such a general heat pipe, there is a problem in that a fluid, which is a liquid or gas, passes through the inside surface of the heat pipe quickly and does not contact the inside surface of the heat pipe more than 100% when the fluid passes into the inside of the heat pipe, thereby deteriorating the transfer with the external second refrigerant.

In particular, there is a problem in that the performance of such a heat pipe is very deteriorated (40%) when the existing chiller R-134a is changed to an eco-friendly refrigerant (non-flammable, non-toxic) R1233zd.

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

Korean Registered Patent Publication No. 10-1084477

The problem to be solved by the present invention is to provide a heat transfer tube and a chiller system in which efficiency is not deteriorated 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 that are 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 the outer surface of the refrigerant tube includes a main cavity and a microcavity smaller in size than the main cavity.

Specifically, a refrigerant tube having a space through which a refrigerant flows; A plurality of heat dissipation fins protruding from the outer surface of the refrigerant tube and including a top surface having a step with the outer surface of the refrigerant tube; A main cavity formed between radiating fins adjacent to each other and an inlet formed between the upper ends of the radiating fins; And a plurality of microcavities formed on an upper surface of the heat dissipation fin, having a height and width smaller than the main cavity, and opening upward.

The heat sink fin includes a first portion having a lower end connected to an outer surface of the refrigerant tube, and a second portion connected to an upper end of the first portion and having an extended width than the first portion. It may be the top surface of the second portion.

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

The upper width of the microcavity may be smaller than the 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.

The depth of the microcavity may be greater than or equal to the inlet width of the microcavity.

The fine cavity inlet width may be 5% to 50% of the main cavity inlet width.

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

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

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

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

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

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

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

The inlet 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 pipes disposed in the heat exchange space of the case and through which the second refrigerant heat-exchanges with the first refrigerant flows, wherein the heat transfer pipes include: a refrigerant tube having a space in which a refrigerant flows; A plurality of radiating fins protruding from the outer surface of the refrigerant tube and including a top surface having a step with the outer surface of the refrigerant tube; A main cavity formed between radiating fins adjacent to each other and an inlet formed between the upper ends of the plurality of radiating fins; And a plurality of microcavities formed on an upper surface of the heat dissipation fin, having a height and width smaller than the main cavity, and opening upward.

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

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

First, the present invention has a structure in which the liquid refrigerant of the heat transfer pipe is difficult to penetrate into the microcavity and the main cavity due to the surface tension, so that the gaseous refrigerant is always present inside the microcavity, and the gaseous refrigerant inside the microcavity is liquid. There is an advantage of promoting the boiling of the liquid refrigerant by acting as a nucleus for phase change to change the phase of the refrigerant into a gaseous refrigerant.

Second, since the size of the main cavity and the microcavities are different from each other, there is an advantage that bubbles generated in the main cavity merge with bubbles generated in the microcavity 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 reduced while using an eco-friendly refrigerant.

The 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 according to an embodiment of the present invention
Figure 2 shows the structure of a compressor according to an embodiment of the present invention.
3 is a view illustrating a case in which a compressor does not generate surge in accordance with an embodiment of the present invention.
4 is a view showing a case in which a compressor generates a surge according to an embodiment of the present invention.
5 is a perspective view of a heat transfer pipe according to an embodiment of the present invention.
FIG. 6 is an enlarged view of the entrance of the main cavity of FIG. 5.
7 is a cross-sectional view of the heat transfer pipe of FIG. 5.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together 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 the person having the scope of the invention, and the present invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

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

The terminology used herein is for describing the embodiments and is not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless otherwise specified in the phrase. As used herein, "comprises" and/or "comprising" refers to the components, steps and/or actions mentioned, excluding 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 in the present specification may be used as meanings commonly understood by those skilled in the art to which the present invention pertains. In addition, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively, unless specifically defined.

In the drawings, the thickness or size of each component is exaggerated, omitted, or schematically illustrated for convenience and clarity. In addition, the size and area of each component does not entirely 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 drawings for describing a chiller system according to embodiments of the present invention.

1 shows the chiller system of the present invention. On the other hand, 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 anywhere that compresses gaseous substances.

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

In addition, the chiller system 1 according to an embodiment of the present invention is a cooling water unit 600 for heating the cooling water through heat exchange between the refrigerant compressed in the condenser 200 and the cooling water, and expanded in the evaporator 400 Further comprising 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 by the compressor 100 with the cooling water flowing from the cooling water unit 600. The high pressure refrigerant condenses 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 flows into the condensation space 230 corresponding to the interior space of the condenser 200 through the condenser connection flow path 150. In addition, the condensation space 230 includes a cooling water flow path 210 through which cooling water flowing 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 is composed of a cooling water flow path 211 through which cooling water flows from the cooling water unit 600 and a cooling water discharge flow path 212 through which cooling water is discharged to the cooling water unit 600. The cooling water flowing into the cooling water inflow passage 211 is exchanged with the refrigerant in the condensation space 230 and then passes through the cooling water connecting passage 240 provided inside or outside the condenser 200 to the cooling water discharge passage 212. Inflow.

The cooling water unit 600 and the condenser 200 are connected via the cooling water tube 220. The cooling water tube 220 may not only be a passage for cooling water between the cooling water unit 600 and the condenser 200 but also may be made of a material such as rubber so as not to leak out.

The cooling water tube 220 is composed of a cooling water inflow tube 221 connected to the cooling water inflow 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 flows into the condenser 200 through the cooling water inlet tube 221. The cooling water introduced into the condenser 200 flows into the condenser 200 while sequentially passing through the cooling water inflow passage 211, the cooling water connection passage 240, and the cooling water discharge passage 212 provided in the condenser 200. After heat exchange with the refrigerant, it passes through the cooling water discharge tube 222 again and flows into the cooling water unit 600.

Meanwhile, the cooling water absorbing 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 is cooled in the cooling water inlet pipe 610 and the cooling water unit 600, which are inlets to which cooling water absorbing heat is introduced through the main body 630 and the cooling water discharge tube 222, and then 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 flowing into the body portion 630. Specifically, the body portion 630 is provided with a fan that generates a flow of air and is composed of 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 body (630). do.

The air discharged after the heat exchange at the air outlet 631 may be used for heating. The refrigerant that has been heat-exchanged in the condenser 200 is condensed to accumulate under the condensation space 230. The depleted refrigerant flows into the refrigerant box 250 provided inside the condensation space 230 and then flows to the expander 300.

The refrigerant box 250 is introduced into the refrigerant inlet 251, and the introduced refrigerant is discharged into the evaporator connecting passage 260. The evaporator connecting passage 260 includes an evaporator connecting passage inlet 261, and the evaporator connecting passage inlet 261 may be located under the refrigerant box 250.

The evaporator 400 includes an evaporation chamber 401 having an evaporation space 430 where heat exchange occurs between the refrigerant expanded in the expander 300 and 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 inside the evaporator 400, and the refrigerant injection hole 451 provided in the refrigerant injection device 450 is connected. Afterwards, it spreads evenly inside the evaporator 400.

In addition, the inside of the evaporator 400 is provided with a cold water flow path 410 including a cold water inflow path 411 through which cold water flows into the evaporator 400 and a cold water discharge flow path 412 through which cold water is discharged outside the evaporator 400. do.

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 is a passage through which cold water in the cold water inlet tube 421 and the evaporator 400, which are the passages of the cold water inside the air conditioning unit 500 to the evaporator 400, goes to the air conditioning unit 500. It is composed of a phosphorus cold water discharge tube (422). That is, the cold water inflow tube 421 communicates with the cold water inflow passage 411 and the cold water discharge tube 422 communicates with the cold water discharge passage 412.

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

The air conditioning unit 500 cools cold water through a refrigerant. The cooled cold water absorbs heat of the air in the air conditioning unit 500 to enable indoor cooling. The air conditioning unit 500 includes a cold water discharge pipe 520 in communication with the cold water inflow tube 421 and a cold water inflow pipe 510 in communication with the cold water discharge tube 422. The refrigerant after heat exchange in the evaporator 400 flows back into the compressor 100 through the compressor connection channel 460.

2 shows a centrifugal compressor 100 (aka turbo compressor) according to an embodiment of the present invention.

The compressor 100 according to FIG. 2 is connected to at least one impeller 120 for compressing the refrigerant in the axial direction (Ax) in the centrifugal direction, the impeller 120 and the motor 130 for rotating the impeller 120 A rotating shaft 110, a bearing unit 140 including a plurality of magnetic bearings 141 supporting 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 a distance from the thrust bearing and a thrust bearing 160 that restricts the rotation shaft 110 from vibrating in the axial direction Ax.

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

The motor 130 may have a structure having a rotating shaft 110 and a separate rotating shaft 110 and transmitting rotational force to the rotating shaft 110 by a belt (not shown), but in an embodiment of the present invention, the motor ( 13) is composed of a stator (not shown) and the 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 rotating shaft 110 means a left-right direction. The rotating shaft 110 preferably includes a metal so that it can be moved by the magnetic force of the magnetic bearing 141 and the thrust bearing.

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

The magnetic bearing 141 and the thrust bearing 160 are composed of a conductor, and the coil 143 is wound. It acts like a magnet by the current flowing through the coiled coil 143.

The magnetic bearing 141 is provided with a plurality to surround the rotating shaft 110 around the rotating shaft 110, and the thrust bearing 160 extends in the rotational radial direction of the rotating shaft 110 to provide a rotating shaft blade 111 It is provided to be adjacent to.

The magnetic bearing 141 allows the rotating shaft 110 to rotate without friction while in the air. To this end, at least three or more magnetic bearings 141 should be provided around the rotating shaft 110, and each magnetic bearing 141 should be installed in a balance around the rotating shaft 110.

In the case of an embodiment of the present invention, four magnetic bearings 141 are provided to be symmetric about the rotating shaft 110, and the rotating shaft 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 floated and rotated in the air, energy lost due to friction is reduced unlike the conventional invention provided with a bearing.

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 rotating shaft 110.

The plurality of magnetic bearings 141 are installed at least at two points of the rotating shaft 110. The two points correspond to different points along the longitudinal direction of the rotating shaft 110. Since the rotating shaft 110 corresponds to a straight line, it is necessary to support the rotating shaft 110 at at least two points to prevent vibration in the circumferential direction.

Looking at the flow of the refrigerant, the refrigerant flowing into the compressor 100 through the compressor 100 connecting passage 460 is compressed into the circumferential direction by the action of the impeller 120 and then discharged to the condenser connecting 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 rotational direction of the impeller 120.

The thrust bearing 160 limits the movement of the rotating shaft 110 by vibration in the axial direction (Ax), and when the surge occurs, the rotating shaft 110 moves in the direction of the impeller 120, with other configurations of the compressor 100 The rotation shaft 110 is prevented from being dispatched.

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 rotation shaft blade 111 in the axial direction (Ax) of the rotation shaft 110. That is, in the axial direction (Ax) of the rotating shaft 110, the first thrust bearing 161, the rotating shaft blade 111, and the second thrust bearing 162 are arranged in this order.

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 further away from the impeller 120 than the second thrust bearing. Located, 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 can minimize the vibration of the rotating shaft 110 in the direction of the rotating shaft 110 by the operation of the rotating shaft blade 111 and the magnetic force having a large area. It works.

The gap sensor 70 measures the axial (Ax) (left and right) movement of the rotating shaft 110. Of course, the gap sensor 70 can measure the movement of the rotating shaft 110 in the vertical direction (direction perpendicular 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 is composed of a first gap sensor 710 that measures the vertical movement of the rotating shaft 110 and a second gap sensor 720 that measures the horizontal movement of the rotating shaft 110. . The second gap sensor 720 may be disposed spaced apart from one end of 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 on the rotating shaft 110, thrust is generated in the direction of the impeller 120 (right direction). The force generated in the right direction should be pulled with the maximum force using the magnetic force of the thrust bearing 160, but the position of the rotating shaft 110 is located in the middle of two thrust bearings 160 (reference position C0). If it is, it is difficult to quickly move the rotating shaft 110 to the reference position C0 in response to the rapid axis movement.

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

Accordingly, the present invention is to cause the rotation shaft 110 to be positioned by eccentrically opposite the direction in which the thrust is generated when surge generation is expected.

Specifically, the control unit 700 determines a surge generation condition based on the information received from the gap sensor 70. The control unit 700 may determine the surge occurrence condition when the position of the rotation shaft 110 measured by the gap sensor 70 is outside 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 is not generated.

Here, the normal position range (-C1 to +C1) of the rotation shaft 110 refers to an area within a certain distance in the left and right directions based on the reference position C0 of the rotation shaft 110. The normal position range (-C1 to +C1) of the rotating shaft 110 causes the rotating shaft 110 to vibrate in the axial direction (Ax) due to various environmental and peripheral factors when the rotating shaft 110 rotates. This is the range where vibration is considered to be normal. The normal position range (-C1 to +C1) is an experimental value, and the normal position range (-C1 to +C1) is calculated based on the kurtosis or skewness of the position of the rotating shaft 110. You can decide. The method of determining the normal position range (-C1 to +C1) is not limited.

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 in the opposite direction of the impeller 120 from the reference position C0. Can be placed. The position in which the rotation shaft 110 is eccentric means that the rotation shaft blade 111 is located between the first thrust bearing 160 and the reference position C0.

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

Specifically, when the surge generation condition is satisfied, the control unit 700 may supply current only to the first thrust bearing 161 of the first and second thrust bearings 162. As another example, when the surge generation condition is satisfied, the controller 700 may adjust 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.

After the surge generation condition is satisfied, the control unit 700 may eccentrically rotate the rotation shaft 110 in the opposite direction of the impeller 120, and then control the position of the rotation shaft 110 to be fixed to the eccentric position for a predetermined time. That is, the control unit 700 may increase the amount of current supplied to the first thrust bearing 161 when a surge occurs after the rotating shaft 110 is eccentric in the opposite direction to the impeller 120. 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 predetermined reference based on the eccentric position. You can also

When the non-surge condition is satisfied, the controller 700 may equally adjust the amount of current supplied to the first thrust bearing 161 and the amount of current supplied to the second thrust bearing 162. Alternatively, the control unit 700 adjusts the amount of current supplied to the first thrust bearing 161 and the second thrust bearing 162 when the non-surge condition is satisfied, so that the rotating shaft 110 is positioned at the reference position ( C0).

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

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

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

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

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

In the general heat pipe, there is a problem in that the fluid, which is a liquid or gas, passes through the inside surface of the heat pipe more than 100% and does not evenly contact the inside surface of the heat pipe, and the external second refrigerant and the delivery are deteriorated.

In addition, since the fluid is moved at a constant speed without obstruction of obstacles when passing through the inside of the heat transfer pipe, the heat transfer of the fluid is not completely accomplished with the surface, so that not only sufficient heat exchange has not been achieved, but also some flow when the fluid moves ( Since almost no flow occurs, it passes through the inside of the heat transfer pipe as it is, so heat transfer inside the fluid cannot be effectively achieved.

In particular, there is a problem in that the performance of the heat pipe 20 is very deteriorated (40%) when the existing chiller refrigerant R-134a is changed to an eco-friendly refrigerant (non-flammable, non-toxic) R1233zd.

Therefore, the heat exchanger tube 20 of the present invention solves the above-described problems, has excellent efficiency, and has a configuration capable of using an eco-friendly refrigerant.

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

5 is a perspective view of the heat transfer tube 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 transfer tube 20 of FIG. 5 It is a cross section.

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

The refrigerant tube 21 has a flow space 29 therein and extends in the first direction. Here, the first direction is a direction in which the second refrigerant flows in the X-axis direction. The refrigerant tube 21 is a metal material having a 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, the following cross-sectional shape is based on the Y-Z axis cross-section) may be a circular, 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, if the refrigerant tube 21 is too large, the heat exchange efficiency is lowered, and if it is too small, the heat exchange time is long, so the diameter of the refrigerant tube 21 may be 17 mm to 25 mm. The diameter of the refrigerant tube 21 is preferably 19-21mm.

The refrigerant tube 21 may have a number of grooves or protrusions for expanding the surface area. For example, a plurality of induction grooves (not shown) may be formed on the inner surface of the refrigerant tube 21. The induction groove is formed by recessing the inner surface of the refrigerant tube 21 outward.

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 improves 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 with each other, and a fine cavity 40. The main cavity 30 has a larger size than the microcavity 40 and may be disposed below the microcavity 40. Here, the arrangement below means that the lower end of the main cavity 30 is located below the lower end of the microcavity 40.

Due to the difference in size between the main cavity 30 and the fine cavity 40, bubbles generated in the main cavity 30 and bubbles generated in the fine cavity 40 merge with each other so that the bubbles are separated from the refrigerant tube 21 To promote this, the separated bubbles promote liquid refrigeration into gaseous refrigerant.

The main cavity 30 and the fine cavity 40 can be created in a variety of ways. For example, the outer surface of the refrigerant tube 21 is pressurized by a roller in a circumferential direction crossing the first direction and the first direction, thereby forming a plurality of grooves 31 and 32 and a plurality of radiating fins 23, and radiating fins (23) is pressed from the top to the bottom of the heat dissipation fin 23 is bent or the top of the heat dissipation fin 23 is expanded to form the main cavity 30, the fine cavity 40 is punch, wet etching, dry etching Can be formed.

The plurality of heat sink 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 integrally formed, but it is easy to manufacture by being formed 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 an extended width than the first portion 23a. Includes portion 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, thereby forming the interior of the main cavity 30. The first portions 23a adjacent to each other are spaced at a sufficient distance so that the main cavity 30 maintains a certain width even when the second portion 23b is expanded.

The second portion 23b is connected to the upper end of the first portion 23a and connected to the upper portion. The second portion 23b has a larger width than the first portion 23a. The second portion 23b may be manufactured by pressing the top 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 at a distance smaller than the width of the main cavity 30. The space between adjacent second portions 23b defines the inlet 38 of the main cavity 30.

Each heat dissipation fin 23 may include an upper surface 23c having a step with 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 an upper surface of the second portion 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. It is preferable that the largest width of the top surface 23c is larger than the largest width of the main cavity 30. It is preferable that the second portion 23b of each heat dissipation fin 23 has a sufficient area so that the microcavity 40 is formed.

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

If the inlet 38 of the main cavity 30 is too small, 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 The amount of liquid refrigerant penetrating into becomes large.

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 may increase or decrease again as it progresses from the bottom to the top, 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 width W1 of the inlet 38 of the main cavity 30 may be 10 μm to 50 μm.

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

The depth H2 of the main cavity 30 may be 5 to 10 times compared to the width W1 of the inlet 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 inlet 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 top surface of the heat dissipation fin 23. Specifically, the microcavity 40 may be located on one surface of the heat dissipation fin 23 that defines the periphery (border) of the entrance 38 of the main cavity 30. More specifically, the microcavity 40 may be located on the upper surface 23c, which is the upper surface of the second portion 23b.

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

Preferably, in order to improve the probability that the air bubbles of the microcavity 40 and the air bubbles of the main cavity 30 merge with each other, the microcavities 40 are provided along a rim of the top surface 23c of the heat sink fin 23. Dogs can be placed.

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

The microcavity 40 is formed by being recessed 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 be 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. In addition, the inlet width of the microcavity 40 may be smaller than the inlet 38 width W1 of the main cavity 30.

If the inlet of the microcavity 40 is too small, bubbles inside the microcavity 40 may not escape to the outside, and if the inlet of the microcavity 40 is too large, the liquid refrigerant penetrating into the interior of the microcavity 40 The amount will increase.

The microcavity 40 inlet width may be such that the main cavity 30 is less than the depth or the width of the main cavity 30. The microcavity 40 inlet width may be 5% to 50% compared to the inlet 38 width W1 of the main cavity 30. Preferably, the microcavity 40 inlet width may be 10% to 20% compared to the inlet 38 width W1 of the main cavity 30. The microcavity 40 inlet width is usually 10 μm to 50 μm.

If the depth H1 of the microcavity 40 is too small, bubbles of an appropriate size cannot be produced, and if the depth H1 of the microcavity 40 is too deep, bubbles generated inside the microcavity 40 are It is difficult to escape. Therefore, the depth H1 of the microcavity 40 may have a sufficient depth to confine appropriate bubbles.

The depth H1 of the microcavity 40 may be 0.01% to 10% compared to the depth H2 of the main cavity 30. Preferably, the depth H1 of the microcavity 40 may be 4% to 7% compared to 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 inlet width of the microcavity 40. The depth H1 of the microcavity 40 is usually 10 μm to 100 μm.

In the above, although the preferred embodiments of the present invention have been illustrated and described, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or prospect 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 through which refrigerant flows;
A plurality of radiating fins protruding from the outer surface of the refrigerant tube and including a top surface having a step with the outer surface of the refrigerant tube;
A main cavity formed between radiating fins adjacent to each other and an inlet formed between the upper ends of the plurality of radiating fins; And
A heat transfer tube formed on the upper surface of the heat dissipation fin, having a depth and width smaller than the main cavity, and including a plurality of microcavities opened upward. According to claim 1,
The heat sink fin,
A first portion having a lower end connected to an outer surface of the refrigerant tube,
It is connected to the upper end of the first portion, and includes a second portion having an expanded width than the first portion,
The upper surface is a heat transfer pipe that is an upper surface of the second portion. According to claim 1,
The plurality of micro-cavities are heat transfer tubes disposed along the rim of the upper surface. According to claim 1,
The upper width of the microcavity is smaller than the lower width of the microcavity. According to claim 1,
The width of the microcavity is a heat transfer tube that becomes smaller as it progresses from the top to the bottom. According to claim 1,
The depth of the micro-cavity is a heat transfer tube that 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 a heat transfer tube that is equal to or greater than the inlet width of the microcavity. According to claim 1,
The microcavity inlet width is 5% to 50% of the inlet 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 microcavity inlet width. According to claim 2,
The heat pipe is formed between the inlets of the main cavity and the second portions adjacent to each other. According to claim 1,
The heat transfer pipe having a lower width of the main cavity is larger than an inlet width of the main cavity. According to claim 1,
The heat transfer pipe having a 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 heat transfer pipe compared to the inlet width of the main cavity. According to claim 1,
The lower width of the main cavity is 300㎛ 400㎛ heat pipe. According to claim 1,
The main cavity has a depth of 0.9mm to 1.2mm heat transfer tube. According to claim 1,
The heat transfer tube having an inlet 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
It is disposed in the heat exchange space of the case, and includes a plurality of heat transfer tubes through which the second refrigerant to heat exchange with the first refrigerant flows
The heat transfer tube,
A refrigerant tube having a space through which refrigerant flows;
A plurality of radiating fins protruding from the outer surface of the refrigerant tube and including a top surface having a step with the outer surface of the refrigerant tube;
A main cavity formed between radiating fins adjacent to each other and an inlet formed between the upper ends of the plurality of radiating fins; And
A heat exchanger for a chiller formed on an upper surface of the heat dissipation fin, having a height and width smaller than the main cavity, and including a plurality of microcavities opened upward. The method of claim 18,
The heat sink fin,
A first portion having a lower end connected to an outer surface of the refrigerant tube,
It is connected to the upper end of the first portion, and includes a second portion having an expanded width than the first portion,
The upper surface is a heat exchanger for a chiller which is an upper surface of the second part. The method of claim 18,
The plurality of micro-cavities are heat exchangers for chillers which are disposed along the rim of the upper surface.

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