JP2007212091A - Shell-and-tube type condenser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shell-and-tube type condenser being hardly influenced by the circulating composition of zeotropic refrigerant mixture. <P>SOLUTION: The shell-and-tube type condenser comprises a cylindrical shell part 1, first and second partition chambers 2, 3 provided at both ends of the shell part, and a plurality of heat transfer tubes 6 provided in the shell part for communicating the first and second partition chambers with each other. The zeotropic refrigerant mixture is distributed in the heat transfer tubes of small flow path cross section to increase the flow speed of the refrigerant so that the condensed liquid refrigerant entraps non-condensed refrigerant vapor and flows in the heat transfer tubes at a similar speed. Thus, the non-condensed refrigerant vapor is discharged from the condenser without being left, suppressing the deviation of the refrigerant composition from refrigerant composition when filled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shell-and-tube condenser, and more particularly to a shell-and-tube condenser used for a refrigerator or a condenser of an air conditioner using a non-azeotropic refrigerant mixture.

  In the refrigerant condensation process in the refrigerator or the condenser of the air conditioner, when a non-azeotropic refrigerant mixture is used, the temperature is highest on the saturated vapor line and lowest on the saturated liquid line in the two-phase region. Due to this temperature gradient, if a structure is adopted in which the refrigerant and the cooling water are opposed to each other, a temperature difference between the cooling water and the refrigerant can be secured, and heat exchange can be performed efficiently.

  For example, in Patent Document 1, a partition chamber partitioned by a partition plate (tube plate) is formed at both ends in a shell (body) of a cylindrical container, and the partition chambers at both ends are communicated by a plurality of heat transfer tubes, In the shell and tube type condenser in which the refrigerant is circulated in the shell and the cooling water is circulated in the heat transfer tube, the refrigerant flow in the shell and the cooling water flow in the heat transfer tube are configured to face each other. It has been proposed. In other words, a plurality of heat transfer tubes are divided into a plurality of heat transfer tube groups, and partition walls on both sides are provided so that the flow of cooling water for each heat transfer tube group is reversed, and the flow of refrigerant in the shell A baffle plate is arranged between each heat transfer tube group in the shell so as to be opposite to the flow of the cooling water in each heat transfer tube group, and is introduced into the heat transfer tube group at the inlet of the refrigerant flowing into the shell. The cooling water outlet portion is arranged, and the cooling water inlet portion flowing into the heat transfer tube group is arranged at the refrigerant outlet portion flowing out of the shell. According to this, since the flow of the refrigerant in the shell and the flow of the cooling water in the heat transfer tube are opposed, a temperature difference between the cooling water and the refrigerant can be secured and heat exchange can be performed efficiently.

Japanese Patent Laid-Open No. 11-325787 (FIG. 1)

  However, since the shell and tube type condenser of Patent Document 1 is configured to flow the refrigerant to the shell side where the channel cross-sectional area or channel space is large, when a non-azeotropic refrigerant mixture is used, the high boiling point refrigerant is Liquid refrigerant having a large specific gravity that has been condensed first accumulates at the bottom of the shell, the composition of the refrigerant discharged from the shell bottom becomes a high-boiling-point refrigerant, and the composition of the circulating refrigerant discharged from the condenser is the refrigerant composition at the time of sealing May cause refrigeration performance to be affected.

  An object of the present invention is to provide a shell-and-tube condenser that hardly affects the circulation composition of a non-azeotropic refrigerant mixture.

  In order to solve the above-described problems, the present invention communicates a cylindrical body, first and second partition chambers provided at both ends of the body, and the first and second partition chambers. In a shell and tube type condenser having a plurality of heat transfer tubes provided in the body portion, a non-azeotropic mixed refrigerant is circulated in the heat transfer tube, and a cooling fluid is circulated in the body portion. It is characterized by.

  In other words, the flow rate of the refrigerant increases by flowing the non-azeotropic refrigerant mixture through the heat transfer tube having a small channel cross-sectional area, so that the condensed liquid refrigerant takes in the uncondensed refrigerant vapor and is equivalent in the heat transfer tube. Will flow at a speed of. As a result, uncondensed refrigerant vapor is not left behind, and the composition of the circulating refrigerant discharged from the condenser can be suppressed from deviating from the refrigerant composition at the time of sealing. That is, in a refrigeration cycle using a non-azeotropic refrigerant mixture, it is possible to prevent performance degradation due to refrigerant composition fluctuations. Moreover, since the flow velocity at which the refrigerant flows through the heat transfer tube is large, the heat transfer coefficient on the refrigerant side is improved, and the condensation performance can be improved.

  Moreover, since the volume of the heat transfer tube is smaller than the volume of the body portion, the refrigerant volume in the condenser is reduced, so that the amount of refrigerant enclosed can be reduced. Further, since the inside of the body portion is a cooling fluid chamber except for the area occupied by the heat transfer tube, even when a high-pressure non-azeotropic refrigerant mixture is used, the portion other than the portion constituting the heat transfer tube and the partition chamber corresponds to the refrigerant. There is no need for pressure resistance specifications. Therefore, compared with the prior art of Patent Document 1, it is not necessary to match the pressure resistance of the shell portion to the high pressure of the refrigerant, so that an increase in cost can be suppressed.

  In the above case, the plurality of heat transfer tubes are divided into a plurality of heat transfer tube groups, and the first and second partition chambers are staggered so that the flow of fluid flowing in the adjacent heat transfer tube groups is opposite to each other. In addition to providing an intermediate partition plate, a baffle plate is disposed between each heat transfer tube group in the body portion so that the fluid flow in the body portion is opposite to the fluid flow in each heat transfer tube group, and An inlet side of a fluid that is circulated through the heat transfer tube group is disposed on an inlet side of a fluid that is circulated in the body part, and an inlet of a fluid that is circulated through the heat transfer tube group on an outlet side of the fluid circulated within the body part Sides can be arranged and configured.

  According to this, since heat exchange can be performed between the refrigerant and the cooling fluid by the counter flow, heat exchange with the low-temperature cooling fluid can be performed on the downstream side of the refrigerant, the degree of supercooling of the refrigerant can be easily obtained, and the performance of the refrigeration cycle can be improved.

  Moreover, the baffle plate arrange | positioned between each heat exchanger tube group can be made into a flat plate, or can be formed with a cylindrical body. Furthermore, the flow path area of the heat transfer tube group can be formed smaller on the outlet side than on the inlet side of the non-azeotropic refrigerant mixture. That is, since the volume of the refrigerant decreases as the refrigerant condenses, the pressure loss of the heat transfer tube group from the inlet side to the outlet side can be equalized. It is desirable that the flow area of the cooling fluid is not so different from the upstream side to the downstream side of the cooling fluid.

  According to the present invention, it is possible to provide a shell and tube type condenser that hardly affects the circulation composition of the non-azeotropic refrigerant mixture.

  Hereinafter, the shell and tube type condenser of the present invention will be described with reference to the illustrated embodiments.

  FIG. 1 shows a cross-sectional view in the axial direction of the shell-and-tube condenser of Example 1 of the present invention, and FIG. 2 shows a cross-sectional view in the direction perpendicular to the axis. As shown in those figures, the shell and tube condenser of the present embodiment includes a cylindrical body 1, first and second partition chambers 2, 3 provided at both ends of the body 1, A plurality of heat transfer tubes 6 provided in the body 1 through the partition chambers 2 and 3 are configured. The partition chambers 2 and 3 are partitioned from the body portion 1 by tube plates 4 and 5, respectively.

  The plurality of heat transfer tubes 6 are divided into a plurality of heat transfer tube groups 7a to 7f. Each of the heat transfer tube groups 7a to 7f is composed of a plurality of heat transfer tubes 6, but in order to avoid complexity, FIG. 1 shows a single heat transfer tube as a representative. The partition plates 9 are alternately provided in the partition chambers 2 and 3 so that the flow of the fluid flowing through the adjacent heat transfer tube groups 7a to 7f is opposite to each other as indicated by the white arrows 8 in the figure. . By this middle partition plate 9, the partition chambers 2 and 3 are partitioned into small partition chambers 2a to 2d and 3a to 3c, respectively. Further, the baffle plates 10 are provided between the heat transfer tube groups 7a to 7f in the body portion 1 so that the fluid flow in the body portion 1 is opposite to the fluid flow in the heat transfer tube groups 7a to 7f. Is arranged. As a result, a meandering flow path indicated by an arrow 11 is formed in the body 1.

  Further, in the figure, a cooling water inlet pipe 12 is provided on the lower wall of the body 1, and a cooling water outlet pipe 13 is communicated with the upper wall. The refrigerant inlet pipe 14 for the non-azeotropic refrigerant mixture communicates with the small partition chamber 2 a near the cooling water outlet pipe 13, and the refrigerant outlet pipe 15 for the non-azeotropic refrigerant mixture communicates with the small compartment 2 d near the cooling water inlet pipe 12. Is communicated. Here, a known non-azeotropic mixed refrigerant can be used as the non-azeotropic mixed refrigerant. For example, R407C (HFC32-HFC125-HFC134a), carbon dioxide-hydrocarbon (for example, propane), hydrocarbon (for example, propane) -hydrocarbon (for example, isobutane), and the like are known.

  The operation of the condenser of this embodiment configured as described above will be described. The cooling water flows from the cooling water inlet pipe 12 into the cooling water chamber 16 in the body portion 1 and is discharged from the cooling water outlet pipe 13 through the zigzag flow path indicated by the arrow 11 shown in FIG. The On the other hand, the refrigerant vapor of the non-azeotropic refrigerant mixture compressed by a compressor (not shown) flows into the small partition chamber 2a from the refrigerant inlet pipe 14 and is installed in the cooling water chamber 16 in the body 1. It flows into the small compartment 3a through the group 7a. The non-azeotropic refrigerant mixture that has flowed into the small partition 3a changes the flow direction and flows into the small partition 2b through the heat transfer tube group 7b. In this way, the refrigerant vapor of the non-azeotropic refrigerant mixture is the small partition chamber 2b → the heat transfer tube group 7c → the small partition chamber 3b → the heat transfer tube group 7d → the small partition chamber 2c → the heat transfer tube group 7e → the small partition chamber 3c → The heat transfer tube group 7f flows into the small partition 2d, returns to the refrigeration cycle through the refrigerant outlet tube 15.

  The refrigerant vapor of the non-azeotropic refrigerant mixture is cooled by exchanging heat with the cooling water around each of the heat transfer tubes 6 constituting the heat transfer tube groups 7a to 7f in the process of flowing through the heat transfer tube groups 7a to 7f. Then, it is condensed and discharged from the refrigerant outlet pipe 15 as a liquid refrigerant. Moreover, in the shell and tube type condenser of the present embodiment, the non-azeotropic refrigerant mixture and the cooling water are heat-exchanged by counterflow.

  Here, the condensation characteristics of the non-azeotropic refrigerant mixture will be described with reference to FIG. FIG. 3 shows a vapor-liquid equilibrium diagram of a non-azeotropic refrigerant mixture of two types of refrigerants A and B having different boiling points. In the figure, the horizontal axis represents the A / B composition, and the vertical axis represents an arbitrary temperature. The liquid phase line and the gas phase line of such a non-azeotropic refrigerant mixture are shifted as shown in the figure, and when the refrigerant sealing composition is shown in the figure, the liquid composition and gas composition at an arbitrary temperature are different, and the saturation region Has a characteristic that the composition changes along the gas phase line and the liquid phase line. The temperature gradient is the temperature difference at the point where the encapsulated composition intersects the gas phase line and the liquid phase line.

  Since it has such characteristics, in the shell and tube type condenser of Patent Document 1, as shown in the schematic diagram shown in FIG. The refrigerant condenses first and liquid refrigerant with a large specific gravity accumulates at the bottom of the shell, the composition of the refrigerant discharged from the shell bottom becomes a high-boiling-point refrigerant, and the composition of the circulating refrigerant deviates from the refrigerant composition at the time of encapsulation. There is a problem.

  In this regard, according to the present embodiment, the non-azeotropic refrigerant mixture is caused to flow through the heat transfer tube 6 having a relatively small cross-sectional area, and therefore, particularly, as shown in FIGS. The refrigerant condenses from the inner wall surface side of the heat transfer tube 6 as it goes from the upstream side to the downstream side of the heat transfer tube 6. At this time, since the flow velocity of the refrigerant flowing through the heat transfer tube 6 is large, the condensed liquid refrigerant takes in the refrigerant vapor and flows through the heat transfer tube at an equivalent speed. In addition, in a non-azeotropic refrigerant mixture, a high-boiling point refrigerant is more likely to condense than a low-boiling point refrigerant. However, after the high-boiling point refrigerant is condensed due to the refrigerant flowing in the heat transfer tube 6, a new high-boiling point refrigerant is supplied. As a result, condensation of the low boiling point refrigerant proceeds promptly. As a result, uncondensed refrigerant vapor is not left behind, and the composition of the circulating refrigerant discharged from the condenser due to the difference in the condensation temperature of the non-azeotropic refrigerant mixture can be prevented from deviating from the refrigerant composition at the time of filling. Moreover, since the flow velocity in the heat transfer tube 6 is increased, the heat transfer coefficient on the refrigerant side can be improved.

  Therefore, in a refrigeration cycle using a non-azeotropic refrigerant mixture, it is possible to prevent performance degradation due to refrigerant composition fluctuations. Moreover, it is possible to prevent an increase in the ratio of the high boiling point refrigerant in the final refrigerant liquid, and it is possible to prevent the heat exchange performance from being reduced and the high pressure side pressure from being increased to increase the energy consumed by the compressor. .

  Moreover, since the flow path cross-sectional area of the cooling water is reduced by the baffle plate 10, the flow rate is increased and the heat transfer performance on the cooling water side is improved as compared with the case without the baffle plate 10.

  Further, according to the present embodiment, the refrigerant inlet pipe 14 is provided at the upper part and the refrigerant outlet pipe 15 is provided at the lower part. Therefore, since the condensed refrigerant liquid is heavier than the refrigerant vapor, it easily flows downward. It has a structure that is easy to flow down from. On the other hand, the cooling water inlet pipe 12 is provided on the refrigerant outlet pipe 15 side, and the cooling water outlet pipe 13 is provided on the refrigerant inlet pipe 14 side. The refrigerant on the downstream side having a low temperature exchanges heat with the cooling water on the upstream side having a low temperature. Therefore, since the refrigerant and the cooling water flow are counterflows, it is possible to prevent performance degradation due to the temperature gradient in the two-phase region of the non-azeotropic refrigerant mixture. Thus, in order to increase the temperature difference between the refrigerant and the cooling water in order to ensure performance, it is not necessary to increase the inlet temperature of the evaporator provided on the downstream side of the condenser. Therefore, since it is not necessary to increase the discharge pressure of the compressor, an increase in power consumption of the compressor can be prevented.

  Furthermore, according to the present embodiment, since the volume of the heat transfer tube groups 7a to 7f is smaller than the volume of the body portion 1, the volume of the refrigerant in the condenser is reduced, and the amount of refrigerant enclosed can be reduced. As a result, the risk to the global environment when the refrigerant is discarded or leaked can be reduced.

  Further, since the inside of the body portion is a cooling fluid chamber except for the area occupied by the heat transfer tube, even when a high-pressure non-azeotropic refrigerant mixture is used, the portion other than the portion constituting the heat transfer tube and the partition chamber corresponds to the refrigerant. There is no need for pressure resistance specifications. Therefore, compared with the prior art of Patent Document 1, it is not necessary to match the pressure resistance of the shell portion to the high pressure of the refrigerant, so that an increase in cost can be suppressed.

  6 and 7 are sectional views of Embodiment 2 of the shell-and-tube condenser of the present invention. 6 is a sectional view in the axial direction of the present embodiment, and FIG. 7 is a sectional view in the direction perpendicular to the axis of the present embodiment. As shown in these figures, the difference between the present embodiment and the first embodiment is that the cross-sectional areas of the heat transfer tube groups 7a to 7e are increased toward the upstream side of the refrigerant and decreased toward the downstream side. Further, the positions of the cooling water outlet pipe 13 and the refrigerant inlet pipe 14 are changed to the opposite side because the number of passes of the heat transfer pipe groups 7a to 7e is an odd number. Since the other points are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

  That is, the cross-sectional area of the heat transfer tube group 7a on the most upstream side of the refrigerant is, for example, 2 to 10 times the cross-sectional area of the heat transfer tube group 7e on the most downstream side. The refrigerant flow rate can be made equivalent at the downstream side where there are many refrigerant liquids with a small amount of refrigerant, and the entire heat exchanger can be used effectively.

  Here, the cross-sectional areas of the heat transfer tube groups 7a to 7e are changed between the upstream side and the downstream side, but the cross-sectional area of the cooling water flow path changes from the upstream side to the downstream side in order to make the cooling water flow rate constant. It is better not to. That is, although the number of pipes in the heat transfer tube group on the upstream side of the refrigerant is increased, it is necessary to set the position of the baffle plate 10 so that the cross-sectional areas of the cooling water flow paths are at the same level. Since there is no change in the cross-sectional area of the cooling water flow path, an increase in cooling water pressure loss can be prevented.

  8 and 9 are sectional views of Embodiment 3 of the shell-and-tube condenser of the present invention. FIG. 8 is a sectional view in the axial direction of the present embodiment, and FIG. 9 is a sectional view in the direction perpendicular to the axis of the present embodiment. As shown in these figures, this embodiment is different from the first embodiment in that the number of passes of the heat transfer tube group is 2 and that the baffle plate 10 is a cylindrical body.

  That is, the heat transfer tube groups 7a and 7b are divided into two inside and outside the cylindrical baffle plate 10. The structure can be simplified by making the baffle plate 10 a cylindrical type that is more resistant to deformation than a flat plate.

  10 and 11 are sectional views of a shell-and-tube condenser according to a fourth embodiment of the present invention. FIG. 10 is a cross-sectional view of the present embodiment in the direction perpendicular to the axis. As shown in the figure, the cooling fluid flow path is divided into four by the baffle plate 10. FIG. 11 shows a perspective view of a portion of the baffle plate 10. As shown in FIG. 11, the baffle plate 10 is formed so that a flow 18 of cooling water flows in series in four cooling fluid flow paths. Moreover, the direction of the flow of the refrigerant in the heat transfer tube group is opposite to the flow of the cooling water, and has a counter flow arrangement.

  According to this embodiment, since the cross-sectional area of the heat transfer tube group on the downstream side of the refrigerant is smaller than that on the upstream side of the refrigerant, the flow rate of the refrigerant can be made equal from upstream to downstream. Moreover, there exists an advantage which the intensity | strength of the baffle plate 10 increases by making the baffle plate 10 into the structure which combined the flat plate.

  FIG. 12 is a sectional view in the axial direction of Example 5 of the shell and tube type condenser of the present invention. This embodiment is different from the second embodiment of FIG. 6 in that the baffle plate 10 is arranged in a direction orthogonal to the axial direction of the trunk portion 1 and the cooling water flow path is formed in a zigzag in the axial direction. is there. As a result, the relationship between the cooling water outlet pipe 13 and the refrigerant inlet pipe 14 and the relationship between the cooling water inlet pipe 12 and the refrigerant outlet pipe 15 are opposed to each other. The relationship with the heat pipe 6 is a cross flow.

  Also in this embodiment, since the non-azeotropic refrigerant mixture flows in the heat transfer tube 6 having a relatively small cross-sectional area, the flow velocity in the heat transfer tube 6 increases, The heat transfer rate can be improved. In particular, the condensation of the refrigerant proceeds from the inner wall surface side of the heat transfer tube 6 as it goes from the upstream side to the downstream side of the heat transfer tube 6. However, since the flow velocity of the refrigerant flowing in the heat transfer tube 6 is large, the condensed refrigerant liquid Takes in the refrigerant vapor and flows in the heat transfer tube at the same level. In addition, in a non-azeotropic refrigerant mixture, a high-boiling point refrigerant is more likely to condense than a low-boiling point refrigerant. However, after the high-boiling point refrigerant is condensed due to the refrigerant flowing in the heat transfer tube 6, a new high-boiling point refrigerant is supplied. As a result, condensation of the low boiling point refrigerant proceeds promptly. As a result, the refrigerant vapor that has not been condensed is not left behind, and the composition of the circulating refrigerant discharged from the condenser can be prevented from deviating from the refrigerant composition at the time of encapsulation due to the difference in the condensation temperature of the non-azeotropic refrigerant mixture. . Therefore, in a refrigeration cycle using a non-azeotropic refrigerant mixture, it is possible to prevent performance degradation due to refrigerant composition fluctuations. Moreover, it is possible to prevent an increase in the ratio of the high boiling point refrigerant in the final refrigerant liquid, and it is possible to prevent the heat exchange performance from being reduced and the high pressure side pressure from being increased to increase the energy consumed by the compressor. .

The sectional view of the axial direction of the shell and tube type condenser of Example 1 of the present invention is shown. Sectional drawing of the axis orthogonal direction of Example 1 is shown. It is an example of the vapor-liquid equilibrium diagram of the non-azeotropic refrigerant mixture of two types of refrigerants A and B having different boiling points. It is a schematic diagram explaining a problem when a non-azeotropic refrigerant mixture is used for the shell and tube type condenser of patent document 1. It is a figure explaining the effect of Example 1 of this invention. Sectional drawing of the axial direction of the shell and tube type | mold condenser of Example 2 of this invention is shown. Sectional drawing of the axis orthogonal direction of Example 2 is shown. Sectional drawing of the axial direction of the shell and tube type | mold condenser of Example 3 of this invention is shown. Sectional drawing of the axis orthogonal direction of Example 3 is shown. Sectional drawing of the axis orthogonal direction of the shell and tube type | mold condenser of Example 4 of this invention is shown. It is a perspective view explaining the flow of the cooling water of Example 4. Sectional drawing of the axis orthogonal direction of the shell and tube type condenser of Example 5 of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body part 2, 3 Partition chamber 4, 5 Tube plate 6 Heat transfer tube 7a-7f Heat transfer tube group 9 Middle partition plate 10 Baffle plate 12 Cooling water inlet pipe 13 Cooling water outlet pipe 14 Refrigerant inlet pipe 15 Refrigerant outlet pipe

Claims (6)

A cylindrical body, first and second partition chambers provided at both ends of the body, and a plurality of heat transfer tubes provided in the body through the first and second partition chambers In a shell-and-tube condenser comprising
A shell-and-tube condenser, wherein a non-azeotropic refrigerant mixture is circulated in the heat transfer tube, and a cooling fluid is circulated in the body portion. The shell and tube condenser according to claim 1,
Dividing the plurality of heat transfer tubes into a plurality of heat transfer tube groups, and alternately providing intermediate partition plates in the first and second partition chambers so that the flow of fluid flowing in the adjacent heat transfer tube groups is opposite to each other In addition, a baffle plate is arranged between each heat transfer tube group in the body portion so that the fluid flow in the body portion is opposite to the fluid flow in each heat transfer tube group, and is distributed in the body portion. An outlet side of the fluid that is passed through the heat transfer tube group is disposed on the inlet side of the fluid to be disposed, and an inlet side of the fluid that is circulated through the heat transfer tube group is disposed on the outlet side of the fluid that is circulated in the body portion. A shell and tube type condenser characterized by comprising: The shell and tube condenser according to claim 2,
A shell-and-tube condenser, wherein the baffle plate disposed between the heat transfer tube groups is a flat plate. The shell and tube condenser according to claim 2,
A shell-and-tube condenser, wherein a baffle plate disposed between the heat transfer tube groups is a cylindrical body. In the shell and tube type condenser according to any one of claims 2 to 4,
A shell-and-tube condenser having a flow passage area of the heat transfer tube group formed smaller on the outlet side than the inlet side of the non-azeotropic refrigerant mixture. The shell and tube condenser according to claim 1,
Dividing the plurality of heat transfer tubes into a plurality of heat transfer tube groups, and alternately providing intermediate partition plates in the first and second partition chambers so that the flow of fluid flowing in the adjacent heat transfer tube groups is opposite to each other And a shell-and-tube type wherein a plurality of baffle plates in which the heat transfer tubes are orthogonal to each other are arranged in the body portion, and a fluid flow path circulating in the body portion is meandered by the plurality of baffle plates. Condenser.

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