KR20120089907A - Air conditioning system for automotive vehicles - Google Patents

Abstract

PURPOSE: An air conditioning device for vehicles is provided to remarkably increase cooling performance even though using new refrigerant by having a structure for using an internal heat exchanger when the new refrigerant is used. CONSTITUTION: An air conditioning device for vehicles comprises a condenser(20), an evaporator(40), a compressor(10), and an internal double-pipe heat exchanger(50). The internal double-pipe heat exchanger is arranged in a pipe path between the condenser and the evaporator and the evaporator and the compressor. The internal double-pipe heat exchange comprises an internal path(52a) and an external path(54a). High temperature refrigerant supplied from the condenser to the evaporator and low temperature refrigerant supplied from the evaporator to the compressor are heat-exchanged each other through the internal path and the external path. The effective rectilinear length(l) of the internal path and the external path is at least over 200mm.

Description

Air Conditioning System for Vehicles {AIR CONDITIONING SYSTEM FOR AUTOMOTIVE VEHICLES}

The present invention relates to a vehicle air conditioner, and more particularly, to a vehicle air conditioner that can maintain the same cooling performance or higher cooling performance than when using the R134a old refrigerant despite the use of R1234yf new refrigerant.

If the refrigerant in the vehicle air conditioner leaks into the atmosphere, it may cause global warming. Therefore, in recent years, there is a trend to use a refrigerant with less concern about global warming.

As a refrigerant with little fear of global warming, there is R1234yf new refrigerant (hereinafter referred to as "new refrigerant").

The new refrigerant has a significantly lower Global Warming Potential (GWP) than the conventional R134a refrigerant (hereinafter referred to as "old refrigerant"). Therefore, it is possible to reduce global warming, and thus, it is recently used in vehicle air conditioners.

By the way, the new refrigerant has the advantage of reducing the concern of global warming, but has the disadvantage of lower heat dissipation characteristics than the old refrigerant, and because of this disadvantage, when applied to the air conditioner of the old refrigerant, the performance of the air conditioner is remarkable There is a problem that is lowered.

That is, as shown in FIG. 1, the new refrigerant A has an enthalpy (Δh) of 0.81 times smaller and a specific gravity (m) of 1.18 times higher than that of the old refrigerant (B). In particular, in the new refrigerant A, the enthalpy width E1 in the two-phase region of the PH diagram is smaller than the enthalpy width E2 of the old refrigerant B.

Therefore, due to the refrigerant characteristics of the new refrigerant, the heat dissipation amount of the new refrigerant was shown to be about 5% inferior to the old refrigerant as shown in Equation 1 below.

[Formula 1]

Q _{_1234yf} = 1.18 (m _{_R134a} ) × 0.81 (△ h _{_R134a} ) = 0.95.6 Qe _{_R134a}

Thus, when the new refrigerant is used in the air conditioner of the old refrigerant as it is, there is a disadvantage that the performance of the air conditioner is significantly reduced, there is a problem that the cooling efficiency of the air conditioner is lowered due to this disadvantage. In particular, since the cooling efficiency of the air conditioning apparatus is lowered, a drawback is pointed out that the temperature in the vehicle interior cannot be maintained comfortably.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a vehicle air conditioner capable of maintaining cooling performance equivalent to that of using an old refrigerant even when using a new refrigerant.

Another object of the present invention is to provide an air conditioner for a vehicle that can reduce the risk of global warming while improving cooling efficiency in a cabin by using a new refrigerant so as to maintain cooling performance equivalent to that of using an old refrigerant. To provide.

In order to achieve the above object, the vehicle air conditioner of the present invention, a vehicle air conditioner having a compressor, a condenser, an expansion valve and an evaporator and a pipe connecting the same, in the vehicle air conditioner so that the refrigerant is circulated, In the two phase region, the refrigerant having a enthalpy width smaller than the enthalpy width of the R134a refrigerant is circulated, and in the evaporator and the hot refrigerant supplied to the evaporator from the condenser on the pipe path between the condenser and the evaporator and between the evaporator and the compressor. And a double tube internal heat exchanger having an internal flow path and an external flow path such that the low temperature refrigerants supplied to the compressor exchange with each other. The double pipe internal heat exchanger includes the internal heat exchanger between the high temperature refrigerant and the low temperature refrigerant. The effective linear length (L) of the external flow path is characterized by being at least 200 mm or more.

Preferably, the effective linear length of the inner and outer flow paths is characterized in that the 200 ~ 400mm range. In some cases, the effective linear length of the inner and outer flow paths is in the range of 200 to 289 mm.

The refrigerant is characterized by being an R1234yf refrigerant having an enthalpy width in the two-phase region of the PH diagram smaller than the enthalpy width of the R134a refrigerant.

And the inner heat exchanger includes an inner tube having the inner passage and an outer tube mounted at an outer side of the inner tube so as to form the outer passage between the inner tube and the inner tube. Silver, a spiral groove is formed on the outer circumferential surface in the longitudinal direction to form the outer flow path in a spiral shape, the outer tube is formed with expansion pipes at each end, one of them is a high temperature refrigerant passing through the condenser Refrigerant inlet for introducing is formed, the other is characterized in that the refrigerant outlet for discharging the introduced refrigerant is formed.

And the effective straight length of the flow path is characterized in that the linear distance between the refrigerant inlet and the refrigerant outlet.

The internal heat exchanger is characterized by having at least two bending portions.

According to the vehicle air conditioner according to the present invention, since the internal heat exchanger is used when using the new refrigerant, there is an effect that the cooling performance can be significantly improved despite the use of the new refrigerant.

In addition, since the cooling performance is remarkably improved in spite of the use of the new refrigerant, there is an effect of securing the same cooling performance or higher cooling performance when using the old refrigerant despite the use of the new refrigerant.

In addition, despite the use of a new refrigerant structure that can significantly improve the cooling performance, even if the new refrigerant is applied to the air conditioner of the old refrigerant as it is capable of maintaining the cooling performance or more than the same cooling performance when using the old refrigerant It works.

In addition, despite the use of new refrigerants can ensure the same cooling performance or more cooling performance than when using the old refrigerant, there is an effect that can satisfy the environmentally friendly requirements and at the same time secure excellent cooling performance.

In addition, since the internal heat exchanger can be adjusted to an optimal state to prevent overheating of the refrigerant, it can prevent damage to the compressor due to the overheating of the refrigerant and at the same time compensate for the performance degradation caused by the use of a new refrigerant. It works.

1 is a PH diagram showing the heat dissipation characteristics of R1234yf new refrigerant and R134a old refrigerant.
2 is a view showing the vehicle air conditioner according to the present invention,
3 is a cross-sectional view showing in detail the internal heat exchanger constituting the vehicle air conditioner of the present invention;
4 is a view showing a modification of the internal heat exchanger constituting the present invention.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the vehicle air conditioner according to the present invention will be described in detail.

First, before looking at the features of the vehicle air conditioner according to the present invention, a brief description of the vehicle air conditioner with reference to FIG.

The vehicle air conditioner includes a compressor 10, a condenser 20, an expansion valve 30, an evaporator 40, and a pipe B connecting them to each other.

The compressor 10 compresses the vaporized refrigerant into a gas of high temperature and high pressure, and the condenser 20 liquefies the refrigerant of high temperature and high pressure.

The expansion valve 30 expands the liquefied refrigerant at low temperature and low pressure, and the evaporator 40 introduces the expanded low temperature and low pressure refrigerant and heat-exchanges with the surrounding air to generate cold air.

Next, the features of the vehicle air conditioner according to the present invention will be described in detail with reference to FIGS. 2 and 3.

First, the air conditioner of the present invention further includes an internal heat exchanger 50 having a double pipe structure.

The internal heat exchanger 50 exchanges heat between the outlet refrigerant of the condenser 20 and the outlet refrigerant of the evaporator 40, and includes an inner tube 52 and an outer tube 54.

The inner tube 52 has an inner flow passage 52a formed therein, and a low-temperature refrigerant supplied from the evaporator 40 to the compressor 10 flows through the inner flow passage 52a.

The outer tube 54 is provided around the outer surface of the inner tube 52. In particular, the outer passage 54a is provided between the inner tube 52 and the high temperature refrigerant supplied from the condenser 20 to the evaporator 40 flows through the outer passage 54a.

Here, a spiral groove 54b is formed on an outer circumferential surface of the inner tube 52, and the spiral groove 54b cooperates with an inner circumferential surface of the outer tube 54 to form an outer flow path 54a, and thus the outer flow path formed therein. 54a is configured in a spiral shape.

At one end and the other end of the outer tube 54, expansion pipe parts 56 and 58 are formed, respectively. One end of the expansion tube 56 is a portion for introducing a high temperature refrigerant passing through the condenser 20, and a refrigerant inlet 56a is formed. The expansion pipe 58 at the other end is a portion for discharging the introduced refrigerant, and a refrigerant discharge port 58a is formed.

According to such an internal heat exchanger 50, the high temperature refrigerant flowing along the external passage 54a and the low temperature refrigerant flowing along the internal passage 52a are mutually heat exchanged.

Therefore, the temperature of the refrigerant flowing along the external flow path 54a is lowered. As a result, the temperature of the refrigerant introduced from the condenser 20 to the evaporator 40 is further lowered to supercool. As a result, the cooling efficiency of the evaporator 40 is improved.

In addition, since the internal heat exchanger 50 having such a configuration can improve the cooling efficiency of the evaporator 40, when the refrigerant of the air conditioner is replaced with new refrigerant, that is, "R1234yf new refrigerant", It compensates for the deterioration of the air conditioning system.

Therefore, even if the refrigerant of the air conditioner is replaced with a new refrigerant, the same cooling performance or higher cooling performance as in the case of using the old refrigerant, that is, the "R134a refrigerant" can be maintained. As a result, it is possible to satisfy environmentally friendly demands and at the same time ensure excellent cooling performance.

On the other hand, the internal heat exchanger 50, it is important to heat-exchange the refrigerant on the outlet side of the condenser 20 and the refrigerant on the outlet side of the evaporator 40, so that the refrigerant on the outlet side of the evaporator 40 does not overheat.

This is because, when the outlet refrigerant of the evaporator 40 is overheated, the overheated refrigerant is introduced into the compressor 10 and deteriorates the internal parts of the compressor 10 and the outlet pipes, thereby providing durability of the compressor 10. Because it weakens and shortens the life.

As a method of heat exchanging the refrigerant on the outlet side of the evaporator 40 so as not to overheat, there is a method of appropriately adjusting the length of the internal heat exchanger 50.

In this method, by appropriately adjusting the length of the internal heat exchanger (50), the mutual heat exchange time between the outlet refrigerant of the condenser 20 and the outlet refrigerant of the evaporator 40 is adjusted to an optimum state, whereby the evaporator ( The refrigerant introduced into the 40) is supercooled, but the refrigerant introduced into the compressor 10 is not overheated. Therefore, the cooling performance of the evaporator 40 can be improved, and the damage of the compressor 10 can be prevented.

On the other hand, the optimum length of the internal heat exchanger 50 to prevent the refrigerant overheating while being able to compensate for the performance degradation of the air conditioner according to the use of the new refrigerant appeared to be in the range of about 200 ~ 400mm.

As a result of the test using the internal heat exchanger 50 having a diameter of 19 mm, the performance improvement of about 2.5% per 100 mm length of the internal heat exchanger 50 was observed as compared to the air conditioner using the old refrigerant. At this time, since the air conditioner using the new refrigerant exhibits about 5% performance degradation compared to the air conditioner using the old refrigerant, the length of the internal heat exchanger 50 is increased to compensate for the 5% performance degradation. This should be at least 200 mm.

In addition, as a result of the test, when the length of the internal heat exchanger 50 is 400 mm or more, the temperature of the refrigerant at the outlet side of the compressor 10 is overheated to 130 ° C. or more causing damage to the compressor 10. Therefore, in order not to cause damage to the internal heat exchanger 50, the length of the internal heat exchanger 50 should not exceed a maximum of 400 mm.

As a result, the optimum length of the internal heat exchanger 50 which can compensate for the performance degradation caused by the use of the new refrigerant and prevent the damage of the compressor 10 due to the overtemperature of the refrigerant is at least 200 mm, the maximum It is preferable that it is 400 mm.

More preferably, the length of the internal heat exchanger 50 is most preferably in the range of 200 to 289 mm.

Because, as a result of the test, when the internal heat exchanger 50 is used, the temperature rise of the refrigerant passing through the internal heat exchanger 50 is about 4.5 ° C. per 100 mm of the length of the internal heat exchanger 50. When the outlet 50a refrigerant passing through the exchanger 50 is raised to a temperature of about 13 ° C., the performance degradation caused by the use of the new refrigerant can be most stably compensated, and at the same time, the outlet of the compressor 10 This is because it has been shown to maintain the refrigerant temperature on the side.

Therefore, based on the heat exchange performance of the internal heat exchanger 50 providing a temperature increase effect of about 4.5 ° C. per 100 mm in length, the temperature rise of the refrigerant at the outlet side 50a of the internal heat exchanger 50 is " 13 ° C. " It was shown that the length of the internal heat exchanger 50 corresponding to "was about 289 mm.

As a result, the performance degradation phenomenon caused by the use of the new refrigerant can be most stably compensated, and the optimum length of the internal heat exchanger 50 capable of maintaining the compressor 10 in an optimal state without overheating of the refrigerant is 200 to 289. Most preferably, it is in the mm range.

On the other hand, the length of the internal heat exchanger 50 means the effective straight length (L) in which the high temperature refrigerant introduced into the external flow path 54a and the low temperature refrigerant introduced into the internal flow path 52a are mutually heat exchanged.

Specifically, it means the effective straight length l of the outer flow path 54a formed between the inner pipe 52 and the outer pipe 54. More specifically, it means a straight line distance l1 between the refrigerant introduction port 56a on one side and the refrigerant discharge port 58a on the other side formed in the expansion pipes 56 and 58 at both ends of the outer tube 54.

Therefore, the optimum length "200-289 mm" of the internal heat exchanger 50 described above means the straight line distance l1 between the refrigerant inlet 56a of the outer tube 54 and the refrigerant outlet 58a.

On the other hand, the optimum length of the internal heat exchanger 50, as shown in Figure 4, even if the internal heat exchanger 50 is bent to have at least two or more bends 59, as described above, the outer tube 54 Means a total linear distance (l1 + l2 + l3) between the refrigerant introduction port 56a and the refrigerant discharge port 58a.

As described above, the air conditioner of the present invention has a structure in which the internal heat exchanger 50 is used when using the new refrigerant, so that the cooling performance of the apparatus can be remarkably improved despite the use of the new refrigerant.

In addition, since the cooling performance is remarkably improved despite the use of the new refrigerant, it is possible to ensure the same cooling performance or higher cooling performance than the use of the old refrigerant despite the use of the new refrigerant.

In addition, despite the use of the new refrigerant structure, which can significantly improve the cooling performance, even if the new refrigerant is applied to the air conditioning system of the old refrigerant can maintain the cooling performance or higher cooling performance equivalent to the use of the old refrigerant. .

In addition, despite the use of new refrigerants can ensure the same cooling performance or more cooling performance than when using the old refrigerant, it is possible to satisfy the environmentally friendly requirements and at the same time ensure excellent cooling performance.

In addition, since the structure of the internal heat exchanger 50 can be adjusted to an optimal state to prevent overheating of the refrigerant, it is possible to prevent damage to the compressor 10 due to the overtemperature of the refrigerant, and at the same time, to reduce the performance of the use of the new refrigerant. The phenomenon can be compensated for.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

10: compressor 10a: outlet side of the compressor
20: condenser 30: expansion valve
40: evaporator 50: internal heat exchanger
52: inner tube 52a: inner channel
54: outer tube 54a: outer channel
56, 58: Expansion part 56a: refrigerant inlet
58a: refrigerant outlet l: effective straight length
59: bending part
E1: R1234yf refrigerant enthalpy width in two phase region
E2: R134a refrigerant enthalpy width in two phase region

Claims (7)

In a vehicle air conditioner having a compressor (10), a condenser (20), an expansion valve (30), an evaporator (40) and a pipe (B) connecting them, the refrigerant is circulated.
In the air conditioner, a refrigerant whose enthalpy width in the two-phase region of the PH diagram is smaller than the enthalpy width of the R134a refrigerant is circulated, between the condenser 20 and the evaporator 40, and between the evaporator 40 and the compressor 10. On the pipe path between the inner flow path (52a) so that the high-temperature refrigerant supplied to the evaporator 40 from the condenser 20 and the low-temperature refrigerant supplied to the compressor 10 from the evaporator 40 and the heat exchange with each other; It further comprises a double tube internal heat exchanger (50) having an external flow path (54a),
The double-pipe internal heat exchanger (50), the vehicle air conditioner, characterized in that the effective straight length (L) of the inner and outer flow paths (52a, 54a) for the heat exchange between the high temperature refrigerant and the low temperature refrigerant is at least 200 mm or more. . The method of claim 1,
The effective straight length (l) of the inner and outer flow paths 52a and 54a is
Vehicle air conditioning apparatus, characterized in that the range of 200 ~ 400㎜. The method of claim 1,
The effective straight length (l) of the inner and outer flow paths 52a and 54a is
Vehicle air conditioner, characterized in that the range of 200 ~ 289mm. The method of claim 1,
The refrigerant is
A vehicle air conditioner, wherein the enthalpy width in the two-phase region of the PH diagram is R1234yf refrigerant, which is smaller than the enthalpy width of the R134a refrigerant. The method according to any one of claims 1 to 4,
The internal heat exchanger 50,
The inner tube 52 having the inner passage 52a and the outer tube 54a are spaced apart from the inner tube 52 so as to be formed between the inner tube 52 and the inner tube 52. An outer tube (54),
The inner tube 52, the spiral groove 54b is formed on the outer peripheral surface along the longitudinal direction to form the outer passage 54a in a spiral,
The outer tube 54 has expansion pipes 56 and 58 formed at both ends thereof, and one of them has a refrigerant inlet 56a for introducing a high-temperature refrigerant passing through the condenser 10. And a coolant discharge port (58a) for discharging the introduced coolant in the other. 6. The method of claim 5,
The effective linear length (l) of the flow paths 52a and 54a is
Vehicle air conditioning apparatus, characterized in that the linear distance between the refrigerant introduction port (56a) and the refrigerant discharge port (58a). The method according to claim 6,
The internal heat exchanger 50,
A vehicle air conditioner having at least two bending portions (59).

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