JPH08100962A - Heat exchanger - Google Patents

Abstract

PURPOSE: To provide a heat exchanger excellent in heat exchange capacity even when a non-azeotrope refrigerant is used. CONSTITUTION: A corrugated fin 21 or a flat fin with its surface continued is used on the inlet side 17 of a heat exchanger 9. Water drops of moisture of outdoor air condensed on the fin 21 or the like drip smoothly running over the unbroken surface to prevent frosting on the surface of the fin thereby enhancing heat exchange capacity at the portion. On the other hand, on the outlet side 18 of the heat exchanger 9, as the moisture of the outdoor air condenses on the fin, water drops condensed are caught easily with a slit having a cut formed therein while are hard to freeze as the temperature of the refrigerant is higher than that on the inlet side 17. This achieves excellence in heat exchange capacity preventing frosting in the heat exchanger 9 as a whole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for a refrigerant circuit using a non-azeotropic mixed refrigerant as a refrigerant, and more particularly to a heat exchanger acting as an evaporator in the refrigerant circuit.

[0002]

2. Description of the Related Art For example, in a heat pump type air conditioner, during cooling operation, a refrigerant is circulated in the order of a compressor, a utilization side heat exchanger, a flow control valve, a heat source side heat exchanger, and a four-way valve to perform a heating operation. Although the refrigerant is sometimes circulated in the opposite direction to that during the cooling operation, the heat source side heat exchanger acts as an evaporator during this heating operation.

In such an air conditioner, when a single refrigerant (for example, R-22) is used as the refrigerant, the flow from the inlet side to the outlet side of the refrigerant flow path in the heat source side heat exchanger. The temperature in the pipe hardly changes.

On the other hand, in recent years, for the purpose of preventing ozone destruction, etc., as disclosed in JP-A-54-2561, a non-azeotropic refrigerant composed of a high boiling point refrigerant and a low boiling point refrigerant is used as the refrigerant. It is known to use a mixed refrigerant (hereinafter, also simply referred to as “mixed refrigerant”).

[0005]

However, when a non-azeotropic mixed refrigerant composed of a high-boiling point refrigerant and a low-boiling point refrigerant is used as the refrigerant in the refrigerant circuit, the low-boiling point refrigerant having a low boiling point is first put in the evaporator. Since the high-boiling-point refrigerant evaporates and evaporates later, temperature glide occurs at the inlet side and the outlet side of the refrigerant flow path of the evaporator.

[0006] In this temperature glide, the temperature is lowest on the inlet side of the evaporator having a throttle and highest on the outlet side, and a difference in temperature between the inlet and the outlet occurs. When such a temperature glide is used to lower the heat exchange temperature of the evaporator in order to improve the heat exchange capacity, the moisture in the outside air is condensed on the fins on the inlet side and then frozen, resulting in frost formation. There is.

Therefore, there is a limit to lowering the evaporation temperature in the evaporator, and there is a problem that a sufficient heat exchange capacity cannot be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat exchanger having excellent heat exchange capacity even when a non-azeotropic mixed refrigerant is used.

[0009]

According to a first aspect of the present invention, there is provided a heat exchanger for a refrigerant circuit, in which a non-azeotropic mixed refrigerant comprising a high boiling point refrigerant and a low boiling point refrigerant flows, wherein the heat exchanger is provided from an inlet of the refrigerant. A corrugated fin or a flat fin having a continuous surface is provided on the inlet side of the refrigerant flow path leading to the outlet, and a slit fin having a notch formed on the surface is provided on the outlet side.

A second invention is a heat exchanger of a refrigerant circuit in which a non-azeotropic mixed refrigerant composed of a high-boiling point refrigerant and a low-boiling point refrigerant flows, wherein the heat exchanger is a refrigerant flow path from an inlet to an outlet of the refrigerant. The fin provided on the outlet side is a fin having a higher heat exchange efficiency than the fin provided on the inlet side.

[0011]

According to the first invention, on the inlet side of the heat exchanger,
Since a corrugated fin or a flat fin with a continuous surface is used, when the humidity of the outside air condenses on the fin due to heat exchange between the outside air and the refrigerant, the condensed water droplets are smoothly dropped along the continuous surface of the fin, Prevents frost formation on the fin surface. Therefore, the heat exchange capacity in this portion can be enhanced.

On the other hand, on the outlet side of the heat exchanger, since the temperature of the refrigerant is higher than that on the inlet side, when the humidity of the outside air condenses on the fins, the condensed water droplets are likely to be trapped in the slit with the notch, but on the outlet side. Since the temperature of the refrigerant is higher than that on the inlet side, it is hard to freeze and frost formation on the fin surface is prevented. Moreover, since the slit fin having excellent heat exchange capacity is used on the outlet side, the refrigerant temperature at this portion is higher than that at the inlet, but the heat exchange capacity is excellent.

Therefore, in the first aspect of the invention, the heat exchanger as a whole is prevented from frosting and is excellent in heat exchange capacity.

According to the second aspect of the invention, the outlet side of the heat exchanger having a high refrigerant temperature is provided with the fins having a high heat exchange capacity, so that the refrigerant temperature at the outlet side is high but the outside air and the heat are sufficiently heated. On the inlet side of the heat exchanger with a low refrigerant temperature, while the fins with a low heat exchange rate are used, the refrigerant temperature is low enough that frost formation on the inlet side is prevented, while heat exchange is possible as a whole. You can improve your ability.

[0015]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 6 is a refrigerant circuit diagram of the air conditioner according to the embodiment of the present invention. This air conditioner uses a non-azeotropic mixed refrigerant composed of a high boiling point refrigerant and a low boiling point refrigerant as the refrigerant circulating in the refrigerant circuit.

In the refrigerant circuit 1 of FIG. 6, a compressor 3, a use side heat exchanger 5, a pressure reducing device 7, a heat source side heat exchanger (heat exchanger) 9, a four-way valve 11 as a flow path switching valve, and an accumulator 13. Are connected by a refrigerant pipe.

The heat source side heat exchanger 9 and the use side heat exchanger 5 are
The fans 5a and 9a are provided to exchange heat between the outdoor air or the indoor air and the refrigerant.

The four-way valve 11 constitutes a flow passage so that the refrigerant flows in the direction indicated by the broken line arrow during the cooling operation, and constitutes a flow passage such that the refrigerant flows in the direction indicated by the solid line arrow during the heating operation. By switching the four-way valve 11 in this manner, the refrigerant flow paths are switched between the cooling and heating.

As the non-azeotropic mixed refrigerant, for example, R13
4a 52 Wt%, R125 25 Wt%, R32 2
A mixed refrigerant mixed at 3 wt% is used. Generally, R
The boiling point of 134a is -26 degrees Celsius, the boiling point of R125 is -48 degrees Celsius, and the boiling point of R32 is -52 degrees Celsius. In the mixed refrigerant having such a composition, R3 having a low boiling point is vaporized at the time of evaporation.
2 and R125 tend to evaporate first, and the composition changes in the heat exchanger, so that a temperature glide in which the temperature increases as the distance from the decompression device 7 increases is likely to occur. That is, the refrigerant temperature tends to be lowest on the inlet side of the heat exchanger and higher on the outlet side.

The heat source side heat exchanger 9 functions as an evaporator during the heating operation, and the refrigerant flow path 15 in which the refrigerant whose pressure has been reduced by the pressure reducing device 7 is introduced to exchange heat is arranged in a meandering manner.

As shown in FIG. 1, the heat source side heat exchanger 9 has an inlet side 17 and an outlet side 18 into which the refrigerant flows during heating.
And the vertical half of the heat exchanger is the inlet side 17 and the other half is the outlet side 18.

On the inlet side 17, a large number of corrugated fins 21 or flat fins 23 having continuous surfaces are laminated, and a refrigerant pipe (refrigerant flow path) is formed on these numerous fins.
15 is inserted.

Specifically, as shown in FIG. 3, the corrugated fins 21 are formed by being bent or have irregularities formed on the surface to improve the heat exchange area. On the other hand, since the surface is a continuous surface, even if moisture in the outside air condenses on the surface to cause dew condensation, the dew condensation is transmitted along the surface and drops smoothly. Therefore, frost formation in this portion is prevented, and the heat exchange capacity is improved. As shown in FIG. 4, the flat fin 23 has a continuous surface and is formed flat. By using this flat fin 23, the corrugated fin 2
As in the case of 1, the heat exchange capacity can be improved while preventing frost formation.

A slit fin 25 is laminated on the outlet side 18 which is the other half of the heat source side heat exchanger 9. As shown in FIG. 2, the slit fin 25 has a large number of notches formed on the surface thereof, thereby improving the heat exchange efficiency. The shape of the slit 27 is not particularly limited and various commonly used shapes are possible. The slit fin 25 is generally excellent in heat exchange efficiency, but has a characteristic that condensed water is easily trapped in the slit portion. For this reason, dew condensation is likely to occur, but since it is used on the outlet side of the heat exchanger whose temperature is higher than the inlet side, dew condensation is unlikely to form frost, and there is almost no risk of frost formation.

As described above, in this embodiment, in the heat source side heat exchanger 9, the corrugated fins 21 or the flat fins 23 are used on the inlet side and the slit fins 25 on the outlet side.
Since it uses, it has excellent heat exchange capability as a whole while preventing frost formation.

Next, the operation of this embodiment will be described.

In the refrigerant circuit 1 shown in FIG. 6, during cooling operation, the four-way valve 11 of FIG. 1 is positioned as indicated by the broken line, and the compressor 3, the heat source side heat exchanger 9, the pressure reducing device 7, and the use side heat are used. The refrigerant is circulated in the order of the exchanger 5, the four-way valve 11, and the accumulator 13. On the other hand, during the heating operation, the four-way valve 11 is located as shown by the solid line in FIG. 1, and the compressor 3, the use side heat exchanger 5, the pressure reducing device 7, the heat source side heat exchanger 9, and the four way valve 1 are placed.
First, the refrigerant is circulated in the order of the accumulator 13.

During the heating operation, the heat source side heat exchanger 9 functions as an evaporator. In this case, the refrigerant compressed by the decompression device 7 is introduced from the inlet side of the heat exchanger 9 and led out from the outlet side thereof, as shown in FIG.

On the inlet side 17 of the heat source side heat exchanger 9, corrugated fins 21 or flat fins 23 having continuous surfaces are used as fins, and when moisture of the outside air is condensed on the fins, condensed water droplets form a continuous surface. As it drips smoothly, it prevents frost formation on the fin surface. Therefore, the heat exchange capacity in this portion can be enhanced. In other words, since a fin whose heat exchange efficiency is inferior to that of the slit fin 25 on the outlet side 18 is used on the inlet side 17, frost formation is prevented although the refrigerant temperature is low.

On the other hand, on the outlet side 18 of the heat source side heat exchanger 9, when the moisture of the outside air is condensed on the fins, the condensed water droplets are
Although it is captured by the slit 27 formed with the notch, the refrigerant temperature at the outlet side of the heat exchanger is higher than that at the inlet side due to the temperature glide, so that it is less likely to freeze. Therefore, frost formation on the fin surface is prevented. Moreover, since the slit fin 23 having excellent heat exchange capacity is used on the outlet side 18,
Although the refrigerant temperature is higher than that on the inlet side 17, the heat exchange capacity is excellent.

That is, as shown in FIG. 5, the relationship between the refrigerant flow path and the refrigerant temperature in the heat source side heat exchanger 9 is shown in FIG.
Has a temperature glide that the refrigerant temperature of the refrigerant is lower than the refrigerant temperature of the outlet side 18, but the refrigerant temperature of the inlet side 12 is low.
The corrugated fins 21 or the flat fins 23 are used as the slit fins 25 and the slit fins 25 are used on the outlet side 18 where the refrigerant temperature is high. In other words, the fins corresponding to the refrigerant temperature are used, so that frost formation is prevented and heat exchange is performed. The entire vessel has excellent heat exchange capacity.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the scope of the present invention.

For example, the arrangement of fins having continuous surfaces (corrugated fins 21 or flat fins 23) and fins having notches formed in the surface (slit fins) is the same in the heat exchanger as shown in FIG. As shown in FIG. 7, the number of divisions is not limited to four, and the inlet side 17
The flat fin 23, the corrugated fin 21, the flat fin 23, and the slit fin 25 may be arranged in this order from the outlet side 18 to the outlet side 18, and at least the inlet side 17 is the corrugated fin or the flat fin 21,
If the outlet side 18 is the slit fin 25, the same effect can be obtained.

Further, as shown in FIG. 8, the same effect can be obtained even if the fins of the heat exchanger are divided into two and the refrigerant passages are divided into a large number.

Further, as shown in FIG. 9, the same effect can be obtained even if the refrigerant passages are arranged above and below the inlet side 17 and the outlet side 18, respectively.

[0037]

According to the first aspect of the present invention, since corrugated fins or flat fins having a continuous surface are used on the inlet side of the heat exchanger, the water droplets condensed by the humidity of the outside air on the fins have a continuous surface. Smoothly dripping,
While preventing frost formation on the fin surface, heat exchange capacity in this part is enhanced. On the other hand, on the outlet side of the heat exchanger,
When the humidity of the outside air condenses on the fins, the condensed water droplets are likely to be captured by the slit having the notch, but since the refrigerant temperature here is higher than the inlet side, the captured water droplets are less likely to freeze. Therefore, the heat exchanger as a whole has excellent heat exchange capability while preventing frost formation.

According to the second aspect of the present invention, the outlet side of the heat exchanger having a high refrigerant temperature is provided with the fins having an excellent heat exchange capacity, so that the refrigerant temperature is high but the heat can be sufficiently exchanged with the outside air. On the inlet side of the heat exchanger with a low temperature, although a fin with a low heat exchange rate is used, the refrigerant temperature is sufficiently low to prevent frost formation on the inlet side, while averaging the heat exchange capacity as a whole, A heat exchanger with good cost balance can be constructed.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a slit fin used at an outlet of the heat source side heat exchanger shown in FIG.

3 is a perspective view of a corrugated fin used at an inlet of the heat source side heat exchanger shown in FIG.

FIG. 4 is a perspective view of a flat fin used at an inlet portion of the heat source side heat exchanger shown in FIG.

5 is a graph showing the relationship between the refrigerant flow path and the temperature of the heat exchanger of the heat source side heat exchanger shown in FIG.

FIG. 6 is a refrigerant circuit diagram of the air conditioner according to the embodiment of the present invention.

FIG. 7 is a perspective view of a heat exchanger showing another embodiment of the invention.

FIG. 8 is a perspective view of a heat exchanger showing another embodiment of the invention.

FIG. 9 is a perspective view of a heat exchanger showing another embodiment of the invention.

[Explanation of symbols]

 1 Refrigerant Circuit 9 Heat Source Side Heat Exchanger (Heat Exchanger) 15 Refrigerant Flow Path 17 Inlet Side 18 Outlet Side 21 Corrugated Fin 23 Flat Fin 25 Slit Fin

Front Page Continuation (72) Inventor Hideaki Mukata 2-5-5 Keihan Hon-dori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A heat exchanger of a refrigerant circuit in which a non-azeotropic mixed refrigerant composed of a high-boiling point refrigerant and a low-boiling point refrigerant flows, wherein the heat exchanger is provided on an inlet side of a refrigerant passage extending from an inlet of the refrigerant to an outlet thereof. A heat exchanger comprising a corrugated fin or a flat fin having a continuous surface, and a slit fin having a notch formed on the surface on the outlet side. 2. A heat exchanger of a refrigerant circuit in which a non-azeotropic mixed refrigerant composed of a high-boiling-point refrigerant and a low-boiling-point refrigerant flows, wherein the heat exchanger is provided on an outlet side of a refrigerant passage extending from an inlet to an outlet of the refrigerant. A heat exchanger characterized in that the fins provided are fins having a higher heat exchange efficiency than the fins provided on the inlet side.