JP2000249479A - Heat exchanger - Google Patents

Abstract

(57) [Summary] To provide a heat exchanger capable of improving heat exchange efficiency. SOLUTION: A plurality of flat fins 1a are stacked at a predetermined interval, and a heat transfer tube 2 through which a refrigerant passes along a stacking direction is inserted.
In a heat exchanger in which air is passed between the fin groups 1 and the heat transfer tubes 2 are arranged in a plurality of rows in the air passing direction A, a refrigerant gas and gas-liquid double layer flowing in the heat transfer tubes 2 The first heat transfer tube 2a, 2b having a two-pass configuration is divided into a portion having a large gas phase of the flow and a portion having a large liquid phase of the liquid and gas-liquid two-layer flow, and the former is provided with the latter. A second heat transfer tube 2c having a one-pass configuration is disposed in the portion, and the first and second heat transfer tubes 2c are provided.
a, 2b, 2c are connected to each other via a joint member 3, and each path of the first and second heat transfer tubes 2a, 2b, 2c is an inlet in a leeward row when acting as a condenser, The windward side row was an outlet, and at least a part of the path was of a counterflow type in which a plurality of rows overlapped in the air passing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat exchanger used for an air conditioner.

[0002]

2. Description of the Related Art In recent years, from the standpoint of protecting the global environment, there is an urgent need to save energy in equipment for preventing global warming and to substitute a refrigerant that does not destroy the ozone layer. In particular, increasing the efficiency of an air conditioner (air conditioner) that consumes high power in household electric appliance products and replacing it with a refrigerant is becoming the most important issue.

[0003] As a main technology for improving the efficiency of an air conditioner, there is optimization of a tube shape of a heat exchanger, a fin type, and a path type. As shown in FIG. 9, a general cross-fin tube type heat exchanger has a fin group 1 in which a plurality of flat fins are arranged in parallel at a predetermined interval, and It is composed of heat transfer tubes 2 (2i, 2j, 2k) inserted substantially orthogonally to the group 1, that is, along the fin stacking direction. Further, the heat transfer tubes 2 of this type of heat exchanger are arranged in a plurality of rows (two rows in FIG. 9) with respect to the air flow direction (lateral direction in FIG. 9) through which air passes.

When this type of heat exchanger is, for example, a condenser, two-pass heat transfer tubes 2i, 2j are connected in parallel to the refrigerant inlet side of the heat exchanger having a large amount of gas and gas phase components,
The pipe portion where the liquid and liquid phase components are increased is connected by a one-pass heat transfer pipe 2k. The refrigerant in each path pipe flows in a fixed direction (from top to bottom in FIG. 9) in each of the heat transfer tubes 2, and is called a two-pass cross-flow to a one-pass cross-flow system. Reference numeral 3c denotes a joint member that connects the two-pass heat transfer tubes 2i and 2j with the one-pass heat transfer tube 2k. In FIG. 9, the arrow indicating the refrigerant flow direction indicates the operation of the condenser.

[0005]

FIG. 10 is a schematic diagram showing the temperature of the refrigerant flowing in the heat exchanger, the air temperature at the inlet and the outlet of the heat exchanger, and the state of the refrigerant in the heat exchanger in FIG. It is a thing. When the heat exchanger of the two-pass cross-flow to one-pass cross-flow method is a condenser, the temperature of the refrigerant is changed at the inlet side by heat exchange with air in the state of superheated gas, and the superheat temperature T1 To the saturation temperature T2, and in this state of the saturation temperature T2, the refrigerant gas condenses with heat exchange,
Become liquid. Further, in the refrigerant, the ratio of the liquid component increases, and when the liquid reaches 100%, the temperature drops from the temperature T2 to the temperature T3.

Generally, the heat exchange amount Q is given by: Q = c · q · ΔT
It is represented by m. Here, c is the specific heat of air, q is the air flow rate, and ΔTm is the average temperature difference at the air outlet inlet of the heat exchanger. If the air specific heat c and the air flow rate q are constant, the heat exchange amount Q depends on the average temperature difference ΔTm at the air outlet inlet. Comparing the temperature of the refrigerant in the heat transfer tubes in the leeward row with that on the leeward side, the temperature is almost entirely the same except for the short portion of the inlet. Therefore, in the heat exchange by the heat exchanger of the two-pass cross-flow to one-pass cross-flow method, the temperature difference between the refrigerant and the airflow in the heat transfer tubes in the leeward row decreases with respect to that on the windward side. There is a loss in heat transmission. In general, in the case of a room air conditioner using HCFC-22, which is a type of chlorofluorocarbon, as a refrigerant, the increase in the number of one-pass units is as follows.
In practice, there is also a problem that since the pressure loss is increased due to the increase in the flow velocity of the refrigerant, the influence on the performance of the evaporator is particularly large.

[0007] The present invention has been made to solve the above problems, and has as its object to provide a heat exchanger capable of improving heat exchange efficiency.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of stacking a plurality of flat fins at predetermined intervals, inserting a heat transfer tube through which a refrigerant passes along the stacking direction, and forming each fin group. In a heat exchanger in which the heat transfer tubes are arranged in a plurality of rows in the air passing direction, a gas of a refrigerant flowing in the tubes of the heat transfer tubes and a gas phase of a gas-liquid two-layer flow The first heat transfer tube of the two-pass configuration is disposed in the former portion, and the first heat transfer tube of the one-pass configuration is disposed in the latter portion. Two heat transfer tubes are provided, the first and second heat transfer tubes are connected to each other via a joint member, and each path of the first and second heat transfer tubes serves as a condenser. When active, the leeward row is the inlet and the leeward row is the outlet, and at least part of the path is empty. It is obtained by a counter flow type overlapping across multiple columns passing direction.

According to this configuration, the heat exchange efficiency can be improved.

[0010]

In the heat exchanger according to the first aspect of the present invention, a plurality of flat fins are stacked at a predetermined interval, and a heat transfer tube through which a refrigerant passes along the stacking direction is inserted. In a heat exchanger in which the heat transfer tubes are arranged in a plurality of rows in the air passing direction, a gas of a refrigerant flowing in the tubes of the heat transfer tubes and a gas phase of a gas-liquid two-layer flow The first heat transfer tube of the two-pass configuration is disposed in the former portion, and the first heat transfer tube of the one-pass configuration is disposed in the latter portion. Two heat transfer tubes are provided, the first and second heat transfer tubes are connected to each other via a joint member, and each path of the first and second heat transfer tubes serves as a condenser. When operating, the leeward row is the inlet and the leeward row is the outlet, and at least part of the path is It is obtained by a counter flow type overlapping across multiple columns.

That is, a portion of the refrigerant gas and the gas-liquid two-layer flow having a large gas phase is constituted by a first heat transfer tube arranged in a two-pass configuration in a counterflow type, and a liquid and a gas-liquid two-layer flow are formed. A portion having many phases is constituted by a second heat transfer tube arranged in a counterflow type in a one-pass configuration. Here, the counter flow is
When the heat exchanger is a condenser, the refrigerant with more gas passes through the heat transfer tubes in the leeward row first, and then the heat transfer tubes in the leeward row that almost overlaps the heat transfer tubes in the leeward row. When the heat exchanger is an evaporator, the refrigerant passes first through the heat transfer tubes in the leeward row, and then through the heat transfer tubes in the leeward row.

According to this configuration, when the heat exchanger is a condenser, the superheated gas refrigerant flows in the leeward row of the first heat transfer tube of the two-pass configuration on the inlet side, and the refrigerant exchanges heat with the air. The temperature is slightly lowered, and the refrigerant in the gas-liquid two-layer flow, which has a large gas phase, flows to the windward side row in the first heat transfer tube and exchanges heat with air, so that the gas refrigerant gradually becomes liquid. Subsequently, the refrigerant having a large liquid phase component flows in the leeward row of the second heat transfer tube having a one-pass configuration, and the refrigerant whose temperature has further decreased due to heat exchange with air is moved to the leeward side of the second heat transfer tube. The heat is exchanged with the air flowing in the row, and the refrigerant is further cooled. As described above, the refrigerant temperatures in the first and second heat transfer tubes in the leeward row are higher in almost the entire region than the refrigerant temperatures in the corresponding first and second heat transfer tubes in the leeward row. Therefore, a large temperature difference between the refrigerant and the air can be obtained, and the heat exchange efficiency can be improved.

[0013] When the heat exchanger is an evaporator,
The flow of the above refrigerant is reversed, and similarly, the first
And the refrigerant temperature in the second heat transfer tube is higher in almost all areas than the refrigerant temperature in the corresponding first and second heat transfer tubes in the windward side row, so that the temperature difference between the refrigerant and the air is large. As a result, the heat exchange efficiency can be improved.
According to a second aspect of the present invention, in the heat exchanger according to the first aspect, the outlet of the windward row in the path of the second heat transfer tube is located at the lowermost end of the windward row. Things.

According to this configuration, when the heat exchanger is used as a condenser, the outlet of the second heat transfer tube having the lowest temperature of the liquid refrigerant can be arranged at the lower end of the heat exchanger.
The second heat transfer tubes on the leeward and leeward sides can be made to have a more complete counterflow, and the heat exchange efficiency can be further improved. A heat exchanger according to a third aspect is the heat exchanger according to the first or second aspect, wherein the joint member is a Y-branch type flow divider.

According to this configuration, when the heat exchanger functions as an evaporator, the refrigerant can be uniformly distributed to each row of the first heat transfer tubes, so that the performance of the evaporator can be improved. By using a versatile Y-branch type flow divider, significant cost reduction can be achieved. A heat exchanger according to a fourth aspect is the heat exchanger according to any one of the first to third aspects, wherein a part of the first heat transfer tube is located below the second heat transfer tube. .

According to a fifth aspect of the present invention, in the heat exchanger according to the fourth aspect, an inlet of one path of the first heat transfer tube is located near a lower end of a leeward row. According to the configuration of the heat exchanger according to claim 4 or claim 5, when the heat exchanger is used as a heat source side heat exchanger of a heat pump type air conditioner, the temperature of the heat exchanger is lower than that of the second heat transfer tube. Since the high first heat transfer tube is located below the heat exchanger, if this heat exchanger is located near the substrate of the outdoor unit,
It is possible to improve the defrosting performance during the heating defrosting operation and prevent the outdoor unit substrate from freezing (icing).

The heat exchanger according to claim 6 is a heat exchanger according to claims 1-5.
In the heat exchanger according to any one of the above, HF may be used as a refrigerant.
A mixed refrigerant containing C-32 or HFC-32, or a hydrocarbon refrigerant is used. According to this configuration,
HCFC-, a type of commonly used chlorofluorocarbon
HFC-32 or HFC which is a kind of alternative CFC whose pressure drop in the system is about 20-30% lower than that of HFC-22
By using a mixed refrigerant containing -32 or a hydrocarbon refrigerant, it is possible to improve condenser performance and prevent loss of evaporator performance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Those having the same functions as those of the conventional heat exchanger are denoted by the same reference numerals, and description thereof is omitted. FIG. 1 is a perspective view of a main part showing a first embodiment in which a heat exchanger according to the present invention is applied to a condenser, and FIG. 2 is a side view of the heat exchanger (the arrow indicating the direction of refrigerant flow indicates the condenser). During operation).

As shown in FIGS. 1 and 2, also in this heat exchanger, a plurality of flat fins 1a are stacked at predetermined intervals, and are substantially orthogonal to the fin group 1, that is, stacked fins. The heat transfer tube 2 of the refrigerant is inserted along the direction,
Air is allowed to pass between the fin groups 1. Further, the heat transfer tube 2 is divided into a portion having a large gas phase of a refrigerant gas and a gas-liquid two-layer flow flowing in the tube and a portion having a large liquid phase of a liquid and a gas-liquid two-layer flow. The first heat transfer tubes 2a and 2b having a two-pass configuration are provided, and the second heat transfer tubes 2c having a one-pass configuration are provided at the latter portion. The heat transfer tube 2c is a joint member 3
Are communicated with each other via

However, in this heat exchanger,
Each path of the first heat transfer tubes 2a and 2b and the second heat transfer tube 2c is such that when acting as a condenser, the leeward side row is the inlet and the leeward side row is the outlet, and at least a part of the path is air. It is a counter flow type that overlaps in a plurality of rows in the passing direction. Next, the operation of the heat exchanger will be described. FIG. 3 is a schematic diagram showing a change in temperature from the inlet to the outlet of the refrigerant, the air temperature of heat exchange, and the state of the refrigerant in the heat exchanger when the heat exchanger is a condenser. .

When this heat exchanger is a condenser, the superheated gas refrigerant flows in the leeward row in the first heat transfer tubes 2a and 2b at the inlet side, and the temperature of the refrigerant changes from T1 to T2 by heat exchange with air. Go down. In the state of the temperature T2, the refrigerant flows to the windward side rows of the first heat transfer tubes 2a and 2b to exchange heat with air, and the gas refrigerant gradually becomes liquid. Subsequently, the refrigerant having a large liquid phase component flows through the joint member 3 to the leeward side row of the second heat transfer tube 2c having the one-pass structure, and the temperature decreases from T2 to T3 due to heat exchange with air. I do. Further, in the state of the temperature T3, it flows to the windward side row in the second heat transfer tube 2c, and the temperature decreases from T3 to T4 due to heat exchange with air.

As described above, the refrigerant first flows in the leeward row,
After that, as shown in FIG. 3, the refrigerant temperature in the heat transfer tubes 2a, 2b, and 2c in the leeward row is substantially equal to that in the leeward row. Increases, the temperature difference between the refrigerant and the air can be increased, the average air temperature difference ΔTm before and after the heat exchange increases, and the heat exchange efficiency can be greatly improved. 5% improvement compared to the conventional path configuration.

In the above embodiment, the heat exchanger is used as the condenser. In the case of the evaporator, the flow of the refrigerant is reversed, but the operation can be applied in exactly the same manner. That is, in the case of the evaporator, the liquid and the refrigerant having a large liquid phase adiabatically expanded by the expansion device first flow into the second heat transfer tube 2 c having a one-pass configuration, and the heat flows through the joint member 3. Since the refrigerant having a large amount of gas and gaseous phase components flows into the first heat transfer tubes 2a and 2b of the two-pass configuration along with the exchange, the temperature difference between the leeward and the leeward is smaller than that in the case of the condenser (about 5 to 50K). Although the evaporator is low (about 1-2K), the first heat transfer tube 2a,
Each path of the second heat transfer tube 2c and the second heat transfer tube 2c is such that when acting as an evaporator, the upwind side row is an inlet and the leeward side row is an outlet,
Since at least a part of the path is of a counter-flow type in which a plurality of rows overlap in the air passing direction, a large temperature difference between the refrigerant and the air can be obtained, and the heat exchanger efficiency can be improved.

Next, a second embodiment will be described with reference to FIG. FIG. 4 is a side view showing a second embodiment in which the heat exchanger according to the present invention is applied to a condenser (arrows indicating the flow direction of the refrigerant indicate the operation of the condenser). First
The difference from the third embodiment is that the outlet of the windward row in the path of the second heat transfer tube 2c is located at the lowermost end of the windward row.

The operation of the heat exchanger according to the second embodiment will be described. Generally, the lowest end of the heat exchanger is
Low wind speed. The outlet 2f of the windward heat transfer tube in the second heat transfer tube 2c, which is a feature of the heat exchanger according to the second embodiment, has the lowest temperature when acting as a condenser. Is located at the lowermost end, the heat exchanger capacity of the second heat transfer tube 2c in the counterflow configuration in one pass is greater than the heat exchanger capacity of the first embodiment, It can be seen that the vessel performance can be improved. Further, according to the heat exchanger according to the second embodiment, the second heat transfer tube 2c does not have a concave path configuration unlike the heat exchanger according to the first embodiment, and the outlet 2
Since the path in the vicinity of f does not rise from the bottom to the top, it is also possible to prevent liquid sealing which occurs particularly at a low speed in the inverter type air conditioner, that is, when the flow rate of the refrigerant is low.

Next, a heat exchanger according to a third embodiment will be described with reference to FIG. FIG. 5 is a side view showing a third embodiment in which the heat exchanger according to the present invention is applied to an evaporator (an arrow indicating a refrigerant flow direction indicates an evaporator operation). The difference from the heat exchanger of the second embodiment is that the joint member 3 connecting the first and second heat transfer tubes 2a, 2b, 2c is a Y-branch type flow divider 3a.

When the heat exchanger is operated as an evaporator, when the refrigerant 5c of the gas-liquid two-phase flow from the second heat transfer tube 2c is divided into the first heat transfer tubes 2a and 2b, the joint member 3 is used. By adopting the Y-branch type flow divider 3a and installing it horizontally or vertically, the refrigerants 5a and 5b flowing into the first heat transfer tubes 2a and 2b can be distributed substantially evenly, and the evaporator performance is greatly improved. Improvement can be achieved. Further, in order to use the versatile Y-branch type flow divider 3a,
The cost can be reduced as compared with the case where non-versatile parts are used.

Next, a fourth embodiment will be described with reference to FIG. FIG. 6 is a side view showing a fourth embodiment in which the heat exchanger according to the present invention is applied to a condenser (the arrow indicating the refrigerant flow direction indicates the operation of the condenser). The difference from the third embodiment is that one heat transfer tube 2b of the first heat transfer tubes 2a and 2b of the two-pass configuration is placed below the other first heat transfer tube 2a and the second heat transfer tube 2c. It is the point of arrangement.

The operation of the heat exchanger according to the fourth embodiment will be described with reference to FIGS. FIG.
Shows a general refrigeration cycle of a heat pump type air conditioner, and includes a compressor 11, a four-way valve 12, a use side heat exchanger 13, a heat source side heat exchanger (outdoor unit) 14, and a throttle device 15. Each pipe is connected in a ring shape. When using the heat exchanger according to the fourth embodiment, the heat source side heat exchanger 14 operates as a condenser during the cooling operation and as an evaporator during the heating operation. Here, in the case of low heating temperature (for example, outdoor temperature 2 ° C / wet bulb temperature 1 ° C),
Since the heat source side heat exchanger 14 acts as an evaporator, the fins become frosted, and if continuous operation is continued, defrosting is necessary to recover the heating capacity. During the defrosting operation, the heat source side heat exchanger 14 is operated as a condenser, defrosts the frost and flows down from the upper part of the heat exchanger 14 to the lower part.

Here, in the case of the heat exchanger according to the third embodiment shown in FIG. 5, since the lower part of the heat exchanger has a heat transfer tube corresponding to the outlet of the condenser having the lowest temperature, the outdoor unit Water accumulated on a substrate provided in the machine grows as ice, which may cause a decrease in heating capacity or growth of substrate icing due to continuous operation. On the other hand, in the case of the heat exchanger according to the fourth embodiment, as shown in FIG.
Is disposed below the heat transfer tube 2a and the second heat transfer tube 2c, the relatively high-temperature refrigerant flowing through the first heat transfer tube 2b during the defrosting operation is supplied to the heat source side heat exchanger (outdoor unit) 14. Since it can be arranged at the position closest to the substrate 6, the temperature of the substrate 6
The temperature can be raised as compared with the heat exchanger according to the third embodiment, and it is possible to prevent the icing on the substrate 5 after the defrosting operation and the icing to grow. Further, since the first heat transfer tubes 2a and 2b and the second heat transfer tube 2c maintain the two-pass counterflow to the one-pass counterflow, respectively, the heat exchangers up to the third embodiment are used. It is possible to obtain performance equivalent to efficiency.

Next, a heat exchanger according to a fifth embodiment will be described with reference to FIG. FIG. 8 is a side view showing a fifth embodiment in which the heat exchanger according to the present invention is applied to a condenser (the arrow indicating the refrigerant flow direction indicates the operation of the condenser). The difference from the fourth embodiment is that the second embodiment
The heat source side heat exchanger 14 is disposed with the inlet heat transfer tube portion 2h of the first heat transfer tube 2b located at the lower part of the heat transfer tube 2c located between the lower stage of the heat exchanger and the two tubes. Is located near the substrate 6 of the outdoor unit.

When this heat exchanger is used in a refrigeration cycle similar to that of the fourth embodiment, the heat transfer tube portion 2h to the condenser having the highest temperature during the defrosting operation is located closest to the substrate 6 of the outdoor unit. Since it can be disposed at the position, the temperature of the substrate 6 can be further increased as compared with the heat exchanger according to the fourth embodiment, and the growth of icing on the substrate 6 after the defrosting operation can be prevented. It becomes possible. In particular, it is effective for a heat pump type air conditioner using a constant speed compressor with weak defrosting performance. Furthermore, since the first heat transfer tubes 2a and 2b and the second heat transfer tube 2c maintain the two-pass counterflow to the one-pass counterflow, respectively, the heat exchangers up to the fourth embodiment are used. It is possible to obtain performance equivalent to efficiency.

The refrigerant used in the heat exchanger according to each of the above embodiments is HCFC-
Alternatively, HFC-32 or a mixed refrigerant containing HFC-32, which is a type of alternative chlorofluorocarbon, or a hydrocarbon refrigerant may be used instead. In the case of a heat pump type room air conditioner using HCFC-22 refrigerant, a type of chlorofluorocarbon, a decrease in the number of passes and the addition of valves have a practical effect on performance degradation due to an increase in flow velocity and an increase in pressure loss due to the addition of valves. As mentioned above, the effect is generally large. Here, [Table 1] below shows the ratio of pressure loss reduction of each refrigerant to the refrigeration cycle system using HCFC-22. is there.

[0034]

[Table 1] HFC-407C and HFC-410 in [Table 1]
A is a mixed refrigerant containing HFC-32, which is a type of alternative Freon, and HC-290 is a hydrocarbon refrigerant. HFC-32 or a portion of a mixed refrigerant containing HFC-32 (HFC-410A), or a hydrocarbon refrigerant (H
C-290) is HCFC-2 which is a type of chlorofluorocarbon refrigerant.
It can be seen that the pressure loss is reduced by about 20 to 30% with respect to 2. Therefore, by using HFC-32 or a mixed refrigerant or a hydrocarbon refrigerant refrigerant containing HFC-32 as described above in the heat exchanger of each of the above-described embodiments, the pressure loss of the evaporator is significantly reduced, It is also possible to improve the heat exchanger efficiency in both the evaporator and the condenser as compared with the case where the conventional HCFC-22 is used.

In the above embodiment, the case where the heat exchangers 2a, 2b, and 2c are arranged in two rows in the air passing direction has been described, but the present invention is not limited to this. However, it is needless to say that the present invention can be applied to a heat exchanger in which the heat transfer tubes 2 are arranged in three or more rows in the air passing direction.

[0036]

As is clear from the above embodiment,
According to the present invention, in the heat exchanger in which the heat transfer tubes are arranged in a plurality of rows in the air passing direction, a portion of the refrigerant gas flowing in the tubes of the heat transfer tubes and the gas-phase portion of the gas-liquid two-layer flow are large. A first heat transfer tube having a two-pass structure, and a second heat transfer tube having a one-pass structure provided in a portion of the liquid and gas-liquid two-layer flow having a large liquid phase. Each path of the heat transfer tubes 2 is a counter-flow type in which the leeward row is an inlet and the leeward row is an outlet when acting as a condenser, and at least a part of the path overlaps between a plurality of rows in the air passing direction. As a result, 1) the performance of the condenser and the evaporator can be improved, and 2) the outlet of the windward side row in the path of the second heat transfer tube is located at the lowermost end of the windward side row. It is possible to improve the condensation performance and prevent liquid sealing in the air conditioner of the inverter type. By making the joint member connecting the heat pipes into a Y-branch flow splitter, the flow splitting in the evaporator can be improved and the performance can be improved. 4) By disposing the first heat transfer pipe below the second heat transfer pipe, Icing can be prevented from occurring on the outdoor unit substrate at the time of heating and low temperature. 5) The inlet of the first heat transfer tube is placed near the substrate, such as between the bottom two stages of the heat exchanger. Thereby, it is possible to improve the heating defrosting performance and prevent the occurrence of icing generated on the outdoor unit substrate. 6) The pressure loss in the system with respect to HCFC-22 is reduced by 20%.
By using HFC-32, a mixed refrigerant containing HFC-32, or a hydrocarbon refrigerant, which is 30% lower, system performance (condenser / evaporator) can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a heat exchanger according to a first embodiment of the present invention.

FIG. 2 is a side view of the heat exchanger according to the embodiment;

FIG. 3 is a schematic diagram showing a change in refrigerant temperature when the heat exchanger according to the embodiment is a condenser, an air temperature of heat exchange, and a state of the refrigerant in the heat exchanger.

FIG. 4 is a side view of a heat exchanger according to a second embodiment of the present invention.

FIG. 5 is a side view of a heat exchanger according to a third embodiment of the present invention.

FIG. 6 is a side view of a heat exchanger according to a fourth embodiment of the present invention.

FIG. 7 is a diagram schematically showing a refrigeration cycle in an air conditioner provided with the heat exchanger.

FIG. 8 is a side view of a heat exchanger according to a fifth embodiment of the present invention.

FIG. 9 is a side view of a conventional heat exchanger.

FIG. 10 is a schematic diagram of a change in refrigerant temperature when a conventional heat exchanger is used as a condenser, an air temperature of heat exchange, and a state of the refrigerant in the heat exchanger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fin group 1a Fin 2a, 2b 1st heat transfer tube 2c 2nd heat transfer tube 2d Heat transfer tube part at the leeward lowermost end 2e Heat transfer tube part at the leeward uppermost end 2g Pipe joint part 2f Outlet part of windward heat transfer tube 2h Inlet heat transfer tube part 3 Joint member 3a Y-branch type flow divider 6 Substrate 11 Compressor 12 Four-way valve 13 User side heat exchanger 14 Heat source side heat exchanger 15 Throttle device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Yasuda 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 3L103 AA20 AA22 AA35 BB42 CC18 CC22 CC30 DD06 DD33 DD69

Claims (6)

[Claims] 1. A plurality of flat fins are stacked at a predetermined interval, a heat transfer tube through which a refrigerant passes is inserted along the stacking direction, air is passed between each fin group, and In the heat exchanger in which the heat transfer tubes are arranged in a plurality of rows, a portion of the gas and gas-liquid two-layer flow of the refrigerant flowing in the tubes of the heat transfer tube and a portion of the liquid and gas-liquid two-layer flows The first heat transfer tube having a two-pass configuration is disposed in the former portion, and the second heat transfer tube having a one-pass configuration is disposed in the latter portion. The two heat transfer tubes are communicated with each other via a joint member, and each path of the first and second heat transfer tubes has an inlet on the leeward side row and an upwind side row on the windward side when acting as a condenser. It is a counterflow type that becomes an outlet and at least a part of the path overlaps in multiple rows in the air passage direction. Heat exchanger. 2. The heat exchanger according to claim 1, wherein the outlet of the windward row in the path of the second heat transfer tube is located at the lowermost end of the windward row. 3. The heat exchanger according to claim 1, wherein the joint member is a Y-branch type flow divider. 4. The heat exchanger according to claim 1, wherein a part of the first heat transfer tube is located below the second heat transfer tube. 5. The heat exchanger according to claim 4, wherein an inlet of one path of the first heat transfer tube is located near a lower end of the leeward row. 6. A refrigerant comprising HFC-32 or HF
The heat exchanger according to any one of claims 1 to 5, wherein a mixed refrigerant containing C-32 or a hydrocarbon refrigerant is used.