JPH09145076A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate instability in a circulation composition associated with a drop in the efficiency of heat transfer attributed to a temperature shift, the generation of icing and frosting attributed to a temperature shift in a mixed refrigerant during heating and a multiple pass designing in an heat exchanger used in a heat pump device using the nonazeotropic mixed refrigerant. SOLUTION: A multi-row/multi-stage heat exchanger having more than one row, heat exchanger tubes 2 are arranged with two kinds of tube diameter (small-diameter tubes < large-diameter tubes) and the small-diameter tubes 2a and the large-diameter tubes 2b of the heat exchanger tubes 2 are built divided in separate rows while a U bend 5a is arranged to link the small- diameter tubes 2a separately, a U bend 5b to link the large-diameter tubes 2b separately and a U bend 5ab to link the small-diameter tubes 2a and the large-diameter tubes 2b. Thus, a refrigerant pipeline is built to let a non- azeotropic mixed refrigerant flow in the direction of an inlet of an external fluid from the direction of an outlet thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used in a heat pump device using a non-azeotropic mixed refrigerant in which two or more kinds of refrigerants having different boiling points are mixed at a predetermined ratio.

[0002]

2. Description of the Related Art In recent years, from the standpoint of protecting the global environment, regulations on CFCs that destroy the ozone layer have been strengthened, and it has been decided to abolish CFC (chlorofluorocarbon), which has a particularly high destructive power, at the end of 1995. Also, the total amount of HCFC (hydrochloroful carbon), which has a relatively small destructive power, was regulated in 1996, and it has been decided that it will be completely abolished in the future. Therefore, for devices that use CFCs as refrigerants, alternative refrigerants are being developed, and HFCs (hydrofluorocarbons) that do not destroy the ozone layer are being studied, but HCFCs used in refrigerators and air conditioners are being investigated. No single refrigerant that can be used alone as an alternative refrigerant has been found in HFC, and therefore, a non-azeotropic mixed refrigerant obtained by mixing two or more kinds of HFC refrigerants is considered promising.

Conventionally, the evaporation temperature and the condensation temperature of a refrigerator or an air conditioner using a single refrigerant such as CFC or HCFC or an azeotropic mixed refrigerant are isothermal. However, when a non-azeotropic mixed refrigerant is used, the saturated refrigerant liquid temperature and the saturated refrigerant vapor temperature are different, and the saturated refrigerant liquid temperature is lower than the saturated refrigerant vapor temperature, which is non-isothermal.

A description will be given below with reference to the drawings. FIG.
FIG. 7 is a refrigeration cycle diagram of a conventional heat pump device.
In the figure, 9 is a compressor, 10 is a four-way valve, 11 is a heat source side heat exchanger (outdoor side), 12 is a throttle valve, 13 is a use side heat exchanger (inside room), and these are sequentially annularly formed. It is connected. Further, FIG. 10 is a side view of the outdoor heat exchanger used in the heat pump device using the single refrigerant (R22), and shows the refrigerant pipe shape. In the figure, 14 is a heat exchanger (2 rows and 24 stages), 2 is a heat transfer tube (all φ7.00 mm), 5 is a U-shaped tube, 14 is a T-shaped tube (refrigerant flow divider), and 15 is a multi-curved tube. Yes, and the flow direction (←) of the refrigerant is during heating operation.

Next, the specific operation of the heat exchanger will be described. From FIG. 9 and FIG. 10, when the heat exchanger 14 (outdoor side) is used as an evaporator during heating operation, the refrigerant decompressed and expanded by the throttle valve 12 of the heat pump device is:
After passing through each heat transfer tube from the heat transfer tube inlet 2 in by the U bend 5, the T-shaped tube 14 and the multi-curved tube 15, it is evaporated and vaporized, and exits the heat exchanger 8 from the heat transfer tube outlet 2out, and then the compressor 9
Is returned to.

[0006]

However, when the non-azeotropic mixed refrigerant is used in the heat pump device using the conventional heat exchanger, the performance of the heat exchanger 8 is not sufficiently exhibited, and the heat pump device as a whole is There was a problem that performance deteriorated.

When a non-azeotropic mixed refrigerant is evaporated at a constant pressure, the composition of the liquid refrigerant changes as it evaporates, unlike the case of a single refrigerant, and the evaporation temperature rises accordingly.
This non-isothermal property (temperature gradient) will be described with reference to the Mollier diagram of FIG.

In the figure, T ₁ is an isotherm showing the frost formation limit temperature (provisionally -3 ° C.) and T ₂ is the outside air temperature (provisionally 7 ° C.).

Since the heat exchanger 14 (evaporator) has multiple passes to reduce the pressure loss, the pressure of the mixed refrigerant in the heat exchanger 14 is substantially constant, and the temperature at the inlet is T. ₁ , the temperature at the outlet becomes T _{2 which} is higher than T ₁ , and a large temperature difference occurs between the inlet and the outlet (temperature slip). Thus, when a mixed refrigerant having a large temperature gradient is used, the optimum evaporation temperature range in the heat exchanger is narrowly limited by the outside air temperature (7 ° C) and the frosting limit temperature (-3 ° C), and (1) When the evaporation pressure is increased to avoid frost formation, the evaporation temperature becomes higher than the outside air temperature on the evaporator outlet side, and the evaporator cannot be used effectively. (2) If the evaporation pressure is set low, the evaporator inlet The evaporation temperature on the side becomes lower than the frost limit temperature, and icing or frost occurs. Therefore, there has been a problem in that the thermal efficiency is reduced due to the temperature slippage and the formation of ice and frost causes the capacity of the heat exchanger to be deteriorated and the capacity of the entire apparatus to be deteriorated. Further, in the case of using a mixed refrigerant, the multi-pass construction requires a sophisticated technique for stabilizing the path balance and composition at the time of diversion.

In view of the above-mentioned problems, the heat exchanger of the present invention reduces the thermal efficiency due to the temperature slip of the mixed refrigerant in the refrigeration cycle using the non-azeotropic mixed refrigerant, the occurrence of icing and frost formation during heating, and the multi-passage. It aims to improve the performance of the heat exchanger by improving the problems of unstable path balance and circulation composition due to the increase in temperature.

[0011]

In order to solve the above problems, the heat exchanger of the present invention is a multi-row multi-stage heat exchanger having two or more rows, and a heat transfer tube having two kinds of tube diameters (narrow tube <thick tube). Have
And, the thin tubes and the thick tubes of the heat transfer tubes are arranged in rows, and the first tube has a first U bend for connecting the thin tubes, and the second tube has a second U bend for connecting the thick tubes, and the thin tube and the thick tube are connected to each other. By having the third U bend, the non-azeotropic mixed refrigerant constitutes a refrigerant pipe line for flowing the external fluid from the outlet row direction to the inlet row direction.

Further, another heat exchanger of the present invention is such that the thin tubes and the thick tubes of the heat transfer tubes of the heat exchanger described above are arranged in the same row.

Further, another heat exchanger of the present invention has heat transfer tubes of three kinds of tube diameters (thin tube <medium tube <thick tube), and the heat transfer tube of the above heat exchanger has a thin tube and a thick tube. The middle pipe is provided between the and.

Further, another heat exchanger of the present invention is a one-row multistage heat exchanger which constitutes a heat transfer tube having two or more kinds of tube diameters.

[0015]

The operation of the heat exchanger of the present invention is shown in FIG.
A case where the heat pump is used as a heat source side heat exchanger (during heating, an evaporator) using the non-azeotropic mixed refrigerant will be described.

The heat exchanger of the present invention is a multi-row multi-stage heat exchanger having two or more rows, wherein thin tubes and large tubes of heat transfer tubes are installed in each row, and U-bends and large tubes for connecting the thin tubes are respectively connected. From the inlet of the heat exchanger to the U bend (narrow tube portion) by having a U bend to be connected, and further by providing a U bend (intermediate) in the conduit between the thin tube portion and the thick tube portion in the heat exchanger. ) Has a large pressure loss, and the pressure loss can be reduced from the U bend to the outlet (thick pipe portion). Therefore, the thin tube part changes isothermally by decompressing in accordance with the temperature gradient of the mixed refrigerant, and the thick tube part changes non-isothermally, increasing the evaporator inlet temperature during heating operation and close to the azeotropic refrigerant. Since the temperature change can be obtained, it is possible to prevent the formation of ice and frost. As a result, in the heat exchanger, the heat exchanger capacity can be increased by avoiding frost formation, and the performance of the entire device can be improved. Further, the U-bend configures a refrigerant pipe line that allows the non-azeotropic mixed refrigerant to flow from the outlet row direction of the external fluid to the inlet row direction, whereby a counterflow element is added to the heat exchanger, and a further heat exchanger The ability can be increased. Moreover, since the thick tube portion reduces the pressure loss, it is not necessary to provide multiple passes.

In another heat exchanger according to the present invention, the number of stages of the thin tubes can be arbitrarily changed by arranging the thin tubes and the thick tubes in the heat transfer tubes of the above heat exchanger in the same row, so that the pressure loss in the thin tube portion can be changed. Is easily set, and decompression corresponding to various heat pump devices and mixed refrigerants can be obtained. Therefore, the temperature rise of the evaporator inlet portion and the temperature distribution close to azeotrope can be obtained during the heating operation, so that the formation of ice and frost can be prevented. The other operations are similar to those of the above heat exchanger, and the description thereof will be omitted.

In another heat exchanger of the present invention, when the pressure reduction corresponding to the temperature gradient of the mixed refrigerant cannot be obtained only by the combination of the thin tube and the thick tube, the thin tube and the thick tube in the heat transfer tube of the heat exchanger described above are used. By providing an intermediate tube between the and, the pressure reduction can be performed in stages. Therefore, the temperature at the inlet of the evaporator and the temperature change close to that of the azeotropic refrigerant can be obtained during the heating operation, so that the formation of ice and frost can be prevented. The other operations are similar to those of the above heat exchanger, and the description thereof will be omitted.

Another heat exchanger of the present invention is a one-row multi-stage heat exchanger in which heat transfer tubes having two or more kinds of tube diameters are arranged in the same row, and the inlet (narrow tube portion) and the outlet in the heat exchanger are arranged. By providing a U bend (intermediate) in the pipe line between the (thick pipe portions), the pressure loss is large from the inlet of the heat exchanger to the U bend (narrow pipe portion), and the U bend is the outlet (thick pipe portion). Up to can reduce pressure loss. Therefore, by changing the temperature of the heat exchanger (evaporator) from the inlet to the U bend by reducing the pressure (capillary tube portion) corresponding to the temperature gradient of the mixed refrigerant, and by changing the non-isothermal change from the U bend to the outlet, Since a rise in the temperature at the inlet of the evaporator and a temperature distribution close to azeotrope are obtained during the heating operation, it is possible to prevent the formation of ice and frost.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat exchanger according to an embodiment of the present invention will be described below with reference to the drawings. Components having the same functions as those described in the section of the related art are denoted by the same reference numerals, and detailed description will be omitted.

1 and 2 are a side view and a vertical cross-sectional view of a multi-row multi-stage heat exchanger 1 (here, a two-row multi-stage heat exchanger) according to the first embodiment of the present invention. The heat exchanger 1 is The thin tubes 2a and the thick tubes 2b in the heat transfer tube 2 are arranged in rows, and each of the thin tubes 2a has a U bend 5a and each of the thick tubes 2b has a U bend 5b. By having the U-bends 5ab connected to each other, a refrigerant pipeline for flowing the non-azeotropic mixed refrigerant from the outlet row direction of the external fluid to the inlet row direction is formed. FIG. 6 is a Mollier diagram (heating operation) when the heat exchanger of the present invention is used as an evaporator in a heat pump device.

Next, the operation will be described. 1 and 6, the heat exchanger 1 of the present invention is provided for each row of the thin tubes 2a and the thick tubes 2b of the heat transfer tube 2 in the multi-row multi-stage heat exchanger 1, and the inner diameter and the number of steps of each tube are arbitrary. (For example, thin tube diameter da = 7.00 mm, number of stages sa = 24 steps, thick tube diameter db = 9.52 mm, sb = 20 steps), and further the inlet (narrow tube portion) and outlet in the heat exchanger 1 By providing the U bend (intermediate) 5ab in the conduit between the (thick pipe portions), the pressure loss from the inlet of the heat exchanger 1 to the U bend 5ab (narrow pipe portion) is large, and from the U bend 5ab to the outlet ( It is possible to reduce the pressure loss up to the thick tube portion. Here, from FIG. 6, T1 is the frost formation limit temperature (provisionally −3 ° C.), T1
Considering that 2 is an isotherm indicating the outside air temperature (tentatively 7 ° C.), the mixed refrigerant has a temperature gradient of the mixed refrigerant in the thin tube portion from the inlet to the U bend 5ab in the heat exchanger 1 (evaporator). Since it has a corresponding pressure loss, an isothermal change is made, and a non-isothermal change is made in the thick pipe portion from the U bend 5ab to the outlet. Therefore, during the heating operation, in the heat exchanger 1 (evaporator), the rise in the evaporator inlet temperature and the temperature change close to that of the azeotropic refrigerant are obtained, so that the formation of ice and frost can be prevented. In addition, U bend 5a,
By constructing a refrigerant pipe through which the non-azeotropic mixed refrigerant flows from the outlet row direction of the external fluid to the inlet row direction by 5b and 5ab, a counterflow element is added to the heat exchanger, and the capacity of the further heat exchanger is increased. Can be increased. Further, in the heat exchanger 1 of the present invention, the pressure loss of each of the thin tubes 2a and the thick tubes 2b can be adjusted by the combination of the inner diameter and the number of stages. It has an effective characteristic that it does not require a refrigerant split flow (path balance) and does not cause a composition change when the mixed refrigerant is split. Further, the type of the inner diameter of the heat transfer tube 2 can be used without changing manufacturing equipment such as the bending process of the conventional heat exchanger, because the heat exchanger tubes 2 are installed in each row. It is also beneficial in terms of manufacturing cost.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a side view of the multi-row multi-stage heat exchanger 6 (here, two-row multi-stage) in the second embodiment. The difference from the first embodiment is that the thin tubes in the heat transfer tubes 2 are in the same row (front row). 2a and a thick tube 2b. Other configurations are the same as those shown in the first embodiment, and therefore the description thereof is omitted. FIG. 7 is a Mollier diagram (heating operation) when the heat exchanger of the present invention is used as an evaporator in a heat hoop device. Yes, the heat exchangers of the first and second embodiments are shown in dashed and solid lines, respectively.

Next, the operation of the second embodiment will be described with reference to FIGS. Since the inner diameter and the number of stages of the heat transfer tubes are limited depending on the type of capability to be used, when the heat exchanger of the first embodiment (broken line), that is, the thin tubes 2a and the thick tubes 2b of the heat transfer tubes are combined in each row, they are mixed. In some cases, the pressure reduction corresponding to the temperature gradient of the refrigerant cannot be obtained. Therefore, in the heat exchanger 6 in the second embodiment (solid line), the thin tubes 2a and the thick tubes 2b of the heat transfer tubes 2 are installed in the same row (front row) to arbitrarily determine the number of stages of the thin tubes 2a (the rest are Thick tube),
It is possible to set the pressure loss of the thin tube portion so as to reach the frost formation limit temperature T1 (for example, -3 ° C). That is, the heat exchanger 6 is
It is possible to easily obtain a desired pressure loss corresponding to various heat pump devices and mixed refrigerants. Therefore, since the temperature at the inlet of the evaporator rises and the temperature distribution close to that of the azeotropic refrigerant is obtained during the heating operation, the formation of icing and frost in the heat exchanger 6 is prevented and the capacity of the heat exchanger is increased. Therefore, the performance of the entire device can be improved. Since other effects are equivalent to those of the heat exchanger 1,
Description is omitted.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a side view of the multi-row multi-stage heat exchanger 7 (here, three-row multi-stage) in the third embodiment. The difference from the first and second embodiments is that the thin tubes 2a in the heat transfer tube 2 The point is that the middle tube 2c is provided between the tube 2b and the tube 2b. Other configurations are the same as those shown in the first and second embodiments, and therefore description thereof will be omitted. FIG. 8 is a Mollier diagram (heating operation when the heat exchanger of the present invention is used in a heat pump device as an evaporator). ) And the heat exchangers of the first and third embodiments are shown in broken and solid lines, respectively.

Next, the operation of the third embodiment will be described with reference to FIGS. 4 and 8. Since the inner diameter of the heat transfer tube and the number of stages are limited depending on the type of capability to be used, the heat exchanger of the first embodiment (broken line), that is, the thin tubes 2a and the thick tubes 2b of the heat transfer tube are combined only in each row to form a mixed refrigerant. In some cases, the reduced pressure corresponding to the temperature gradient of 1 cannot be obtained. Therefore,
The heat exchanger 7 in the third embodiment (solid line) is a thin tube and a middle tube portion by providing the middle tube 2c between the thin tube 2a and the thick tube 2b in the heat transfer tube 2 of the heat exchanger 1 described above. In, since the pressure loss corresponding to the inner diameters and the number of stages of the thin tube 2a and the middle tube 2c is obtained stepwise, it is possible to change the mixed refrigerant isothermally so as not to fall below the frosting limit temperature T1 (for example, -3 ° C). . That is, the heat exchanger 7
Can easily obtain a desired pressure loss corresponding to various heat pump devices and mixed refrigerants. Therefore, since the temperature rise of the evaporator inlet and the temperature distribution close to that of the azeotropic refrigerant during the heating operation can be obtained, the occurrence of icing and frost is prevented and the capacity of the heat exchanger is increased.
The performance of the entire device can be improved.

Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a side view of the one-row multi-stage heat exchanger 8 in the fourth embodiment, in which the heat transfer tubes 2 having two or more tube diameters are arranged in the same row. Thin tube 2
a (φ7.00 mm) and large tube 2b (φ9.52 m)
If two types of heat transfer tubes 2 of m) are used, the first, second,
The third embodiment is different from the third embodiment in that it is a one-row type heat exchanger, and therefore it is not possible to form a refrigerant pipe line for flowing the non-azeotropic mixed refrigerant from the outlet row direction of the external fluid to the inlet row direction. The Mollier diagram (heating operation) when the heat exchanger of the present invention is used as an evaporator in a heat pump device is the same as in FIG.

Next, the operation of the fourth embodiment will be described. In the heat exchanger 8 of the present invention, the thin tubes 2a and the thick tubes 2b of the heat transfer tubes 2 in the one-row multi-stage heat exchanger are provided in the same row, and the inner diameter and the number of stages of each tube are arbitrarily set (for example, the thin tube diameter). da = 7.00 mm, number of steps sa = 6 steps, large pipe diameter d
b = 9.52 mm, sb = 4 steps), and further U in the pipe between the inlet (thin pipe part) and the outlet (thick pipe part) in the heat exchanger 1.
By providing the bend (medium tube) 5ab, the pressure loss from the inlet of the heat exchanger 1 to the U bend 5ab (narrow tube portion) is large, and the pressure loss from the U bend 5ab to the outlet (thick tube portion) is small. be able to. Therefore, FIG.
Therefore, the mixed refrigerant has the pressure loss corresponding to the temperature gradient of the mixed refrigerant in the thin tube portion from the inlet to the U-bend 5ab in the heat exchanger 1 (evaporator), so that the mixed refrigerant is isothermalized.
A non-isothermal change is performed in the thick pipe portion from the U bend 5ab to the outlet. Therefore, the temperature rise at the inlet of the heat exchanger 8 (evaporator) and the temperature change close to that of the azeotropic refrigerant can be obtained during the heating operation, so that the formation of ice and frost can be prevented. Therefore, increasing the capacity of the heat exchanger,
The performance of the entire device can be improved.

[0029]

As is clear from the above description, the heat exchanger of the present invention is a multi-row multi-stage heat exchanger having two or more rows,
Between the thin tubes and the thick tubes in the heat exchanger, there are U-bends that connect the thin tubes and the thick tubes of the heat transfer tubes in rows, and that connect the thin tubes and U-bends that connect the thick tubes. By providing a U-bend (intermediate) in the pipe, the pressure loss from the inlet to the U-bend (narrow pipe part) of the heat exchanger is large, and the pressure loss from the U-bend to the outlet (thick pipe part) is small. be able to. Therefore, the thin tube section changes the temperature isothermally by reducing the pressure corresponding to the temperature gradient of the mixed refrigerant, and the thick tube section changes the temperature non-isothermally to raise the temperature of the evaporator inlet during the heating operation and make it an azeotropic refrigerant. Since a close temperature change can be obtained, it is possible to prevent the formation of ice and frost. As a result, in the heat exchanger, the heat exchanger capacity can be increased by avoiding frost formation, and the performance of the entire device can be improved. Further, the U-bend configures a refrigerant pipe line that allows the non-azeotropic mixed refrigerant to flow from the outlet row direction of the external fluid to the inlet row direction, whereby a counterflow element is added to the heat exchanger, and a further heat exchanger The ability can be increased. Also, depending on the combination of the inner diameter and the number of steps
Since each pressure loss can be adjusted, refrigerant splitting (path balance) associated with multiple passes, which was a problem of conventional heat exchangers
It has an effective feature that does not require the above, and does not cause a composition change when the mixed refrigerant is split. Furthermore, since the type of the inner diameter of the heat transfer tube is installed in each row, the heat exchanger of the present invention can be used in that it can be used with almost no change in the manufacturing equipment such as the bending process of the conventional heat exchanger. It is also beneficial in terms of cost.

In another heat exchanger of the present invention, by configuring the thin tubes and the thick tubes in the heat transfer tubes of the above-mentioned heat exchanger in the same row, the pressure loss of the thin tubes can be arbitrarily changed, and thus various heat exchangers can be used. A reduced pressure corresponding to the heat pump device and the mixed refrigerant can be obtained. Therefore, the temperature rise of the evaporator inlet portion and the temperature distribution close to azeotrope can be obtained during the heating operation, so that the formation of ice and frost can be prevented. Other effects are the same as those of the above heat exchanger,
Description is omitted.

In another heat exchanger of the present invention, when the pressure reduction corresponding to the temperature gradient of the mixed refrigerant cannot be obtained only by the combination of the thin tube and the thick tube, the thin tube and the thick tube in the heat transfer tube of the heat exchanger described above are used. By providing an intermediate tube between the and, the pressure reduction can be performed in stages. Therefore, the temperature at the inlet of the evaporator and the temperature change close to that of the azeotropic refrigerant can be obtained during the heating operation, so that the formation of ice and frost can be prevented. Since other effects are the same as those of the above heat exchanger, description thereof will be omitted.

Another heat exchanger of the present invention is a one-row multi-stage heat exchanger in which heat transfer tubes having two or more kinds of tube diameters are arranged in the same row, and an inlet (narrow tube portion) and an outlet in the heat exchanger are provided. By providing a U bend (intermediate) in the pipe line between the (thick pipe portions), the pressure loss is large from the inlet of the heat exchanger to the U bend (narrow pipe portion), and the U bend is the outlet (thick pipe portion). Up to can reduce pressure loss. Therefore, by changing the temperature of the heat exchanger (evaporator) from the inlet to the U bend by reducing the pressure (capillary tube portion) corresponding to the temperature gradient of the mixed refrigerant, and by changing the non-isothermal change from the U bend to the outlet, It is possible to raise the temperature at the inlet of the evaporator during the heating operation, prevent the formation of ice and frost, increase the capacity of the heat exchanger, and improve the performance of the entire apparatus.

[Brief description of the drawings]

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

FIG. 2 is a diagram of a heat exchanger according to a first embodiment of the present invention.
Middle II-II vertical sectional view

FIG. 3 is a side view of the heat exchanger according to the second embodiment of the present invention.

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

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

FIG. 6 is a Mollier diagram of the heat pump device according to the first and fourth embodiments of the present invention.

FIG. 7 is a Mollier diagram of the heat pump device according to the second embodiment of the present invention.

FIG. 8 is a Mollier diagram of the heat pump device according to the third embodiment of the present invention.

FIG. 9 is a refrigeration cycle diagram of a heat pump device in a conventional example.

FIG. 10 is a side view of a conventional heat exchanger.

FIG. 11 is a Mollier diagram when a non-azeotropic mixed refrigerant is used in a conventional heat pump device.

[Explanation of symbols]

1 heat exchanger (2 rows multi-stage) 2, 2a, 2b heat transfer tube (a: thin tube, b: thick tube) 3 fins 4 side plate 5, 5a, 5b, 5ab U-shaped tube (a: thin tube, b: thick tube, ab: Different diameter pipe 6 Heat exchanger (2 rows multi-stage) 7 Heat exchanger (3 rows multi-stage) 8 Heat exchanger (1 row multi-stage) 9 Compressor 10 Four-way valve 11 Heat source side heat exchanger (outside) 12 Throttle valve 13 Use side heat exchanger (indoor side) 14 Heat exchanger (2 rows, 24 stages) 15 T-shaped tube 16 Multi-curved tube

Claims (4)

[Claims] 1. In a multi-row multi-stage heat exchanger having two or more rows, 2
Having a heat transfer tube of different tube diameters (thin tube <thick tube), and configuring the thin tubes and the thick tubes of the heat transfer tube in rows, and connecting the first U-bend and the thick tube respectively connecting the thin tubes Heat having a second U bend for connecting the thin pipe and the thick pipe and having a third U bend for connecting the thin pipe and the thick pipe with a refrigerant pipe for flowing the non-azeotropic mixed refrigerant from the outlet row direction of the external fluid to the inlet row direction. Exchanger. 2. The heat exchanger according to claim 1, wherein the thin tubes and the thick tubes of the heat transfer tubes are arranged in the same row. 3. A heat transfer tube having three kinds of tube diameters (narrow tube <middle tube <thick tube), and a middle tube is provided between the thin tube and the thick tube of the heat transfer tube. The heat exchanger according to 2. 4. A heat exchanger in a single-row multi-stage heat exchanger, characterized by comprising heat transfer tubes having two or more kinds of tube diameters.