DE102010034111A1 - Refrigerant circuit integrated air conditioner for cooling passenger cabin of hybrid vehicle, has expansion device with thermal energy exchanging cooling device on high pressure side of circuit for additional cooling of refrigerant - Google Patents

Abstract

The air conditioner (10) has a heat exchanger formed as an evaporator (22) and a condenser (14), a compressor device (12), and an expansion device (18) that are fluidly connected with each other for circulating a refrigerant. The expansion device is provided with a thermal energy exchanging cooling device (20) on a high pressure side of a refrigerant circuit for additional cooling of the refrigerant. The cooling device is arranged downstream of the condenser in the refrigerant circuit.

Description

Technical area

The present invention relates to a motor vehicle air conditioning system having a refrigerant circuit which has at least two heat exchangers configured as a condenser and as an evaporator and at least one compressor device and at least one expansion device and at least one further cooling device.

background

In the prior art, so-called internal-climate heat exchangers are known, which, for example, thermally couple a section of the low-pressure side of a refrigerant circuit located between evaporator and compressor with a section of the high-pressure side of the refrigerant circuit located between condenser and expander. In this way, for example, the comparatively cold refrigerant flowing from the evaporator to the compressor can be used for cooling the comparatively warm refrigerant supplied to the expansion device on the high-pressure side.

From the DE 16 13 684 A1 Furthermore, a refrigeration system for a motor vehicle is known, in which an additional heat transfer element is provided, with the flowing refrigerant from the formed and collected on an evaporator and the heat transfer element zugeleiteten, cold condensation water as needed, at least temporarily can be additionally cooled. The heat transfer element is designed here as an evaporation heat exchanger with an external evaporation structure.

This forms a common portion of the high-pressure liquid refrigerant flowing through high-pressure refrigerant line and the gaseous refrigerant flowing through low pressure suction gas line. The evaporation heat exchanger is used here to subcool the liquid refrigerant in the high pressure line by heat exchange with evaporating condensate on the one hand and the suction gas in the suction gas line on the other hand.

The known heat exchanger provides so far a two-fold thermal coupling, namely on the one hand between the suction gas line and the high pressure line and on the other hand between the high pressure line with evaporating condensation available.

In this case, it is inevitable that the evaporation structure is thermally coupled with the suction gas line. Consequently, not only the relatively warm high-pressure section but also the already relatively cold low-pressure section of the refrigerant circuit is further cooled by the condensate of the evaporator. Also, in the known embodiment, the comparatively warm or hot high-pressure line already at the beginning of the evaporation transmitter is subjected to condensation, which, however, depending on the operating condition of the vehicle may be limited.

It is accordingly an object of the present invention to provide an improved motor vehicle air-conditioning system which, during operation of the system, makes it possible, for example, to use condensate accumulating on an evaporator more efficiently for subcooling the refrigerant. Furthermore, it is an object of the invention to provide an optimized in terms of their required space motor vehicle air conditioning, which is also implemented with minimal installation effort and manufacturing costs.

invention

The object underlying the invention is achieved with a motor vehicle air conditioning system according to claim 1 and with a motor vehicle according to claim 14. Individual advantageous embodiments of the invention are the subject of each dependent claims.

The motor vehicle air conditioning system according to the invention has a refrigerant circuit in which at least two heat exchangers configured as a condenser and as an evaporator and at least one compressor device and at least one expansion device are provided. The refrigerant circuit has a high-pressure side located downstream of the compressor device and a low-pressure side located downstream of the expansion device. According to the thermodynamic properties of the refrigerant used and circulating in the refrigerant circuit, it has a higher temperature on the high pressure side than on the low pressure side.

Accordingly, thermal energy can be released to the environment via the condenser provided on the high pressure side and thermal energy can be absorbed via the low-pressure side evaporator typically associated with a passenger compartment of the vehicle. In this way, z. B. the passenger compartment of the motor vehicle cooled.

To improve the efficiency and cooling performance of the motor vehicle air conditioning system, a further cooling device is provided for additional cooling of the refrigerant, which in the Refrigerant circuit of the expansion device upstream in thermal energy exchange manner is thermally coupled exclusively to the high pressure side of the refrigerant circuit.

That is, the cooling device has no influence on the low-pressure side of the refrigerant circuit. In this case, it can preferably be provided that the cooling device is actively cooled by supplying a coolant located outside the refrigerant circuit.

By virtue of the fact that the cooling device is thermally coupled exclusively to the high pressure side of the refrigerant circuit, the entire "cooling capacity" of the cooling device can be used for "subcooling" the refrigerant to be supplied to the expansion device.

According to a first advantageous embodiment, it is provided that the cooling device is designed as a heat exchanger, which is fed with condensate, which accumulates in the operation of the air conditioner at its at least one evaporator. In that regard, a condensate collection device is provided on the evaporator, from which a relatively cold condensation water can be fed to the cooling device via a separate supply line.

It is further provided that the cooling device is designed for a purely convective and / or based on heat transfer heat exchange between refrigerant and condensate. That is, the additional cooling device for the refrigerant is self-contained and has in each case an inlet and a drain both for the condensed water and for the expansion device to be supplied to the refrigerant. The refrigerant to be cooled and the condensate do not mix in this case but are connected via a conduit or container wall of the cooling device in thermally conductive thermal contact with each other.

Unlike an evaporative cooler, such. B. in the DE 196 13 684 A1 described, the cooling device can thus be arranged much more flexible and universal at different locations in the motor vehicle, since possibly excess condensation leaves the cooling device exclusively via a condensate drain provided for this purpose. Any moisture-sensitive components of the motor vehicle can therefore be easily positioned in the vicinity of the additional cooling device according to the inventive solution.

According to a further preferred embodiment, it is provided that the cooling device is arranged downstream of a condenser and thus also downstream of the compressor device in the refrigerant circuit. According to a further advantageous refinement, the motor vehicle air conditioning system is provided with a third heat exchanger which thermally couples a region of the high-pressure side of the refrigerant circuit located between the condenser and expansion device with a region of the low-pressure side of the refrigerant circuit lying between evaporator and compressor. In this way, for example, the comparatively cold refrigerant flowing from the evaporator to the compressor can be used for subcooling or cooling the refrigerant flowing from the condenser to the expansion valve and having a comparatively hot or warm refrigerant.

It proves to be advantageous if according to a further embodiment, the additional cooling device downstream of the third heat exchanger with the high pressure side of the refrigerant circuit is thermally coupled and downstream of the third heat exchanger in the refrigerant circuit is arranged. The use of the third heat exchanger as well as the additional condensing device to be acted upon cooling device can improve the overall efficiency of the automotive air conditioning. Namely, the third heat exchanger cools the refrigerant flowing out of the condenser to the expansion device to, for example, a first temperature level, which is usually higher than the temperature of the condensed water.

With the aid of the additional cooling device arranged downstream of the third heat exchanger, the refrigerant, which has already been cooled via the third heat exchanger, can be cooled further below the first temperature level on the high pressure side. In this respect, a serial and stepwise cooling of the high-pressure side of the refrigerant circuit, namely first with a third heat exchanger and downstream of the same by means of the cooling device, is realized.

The comparatively cold condensate occurring at the evaporator during operation of the air conditioning system is thus used exclusively to cool or cool the refrigerant which has already been cooled to a first temperature level by means of the third heat exchanger.

According to a further preferred embodiment, it is further provided that the third heat exchanger and / or that the cooling device as a tubular heat exchanger, each with an inner tube and a, the inner tube to form a permeable space radially enclosing outer tube are formed. The third heat exchanger and / or the cooling device can be designed in this respect as so-called coaxial tube heat exchangers, which in each case with each other thermal energy-exchanging media flow through the respective heat exchanger in the opposite direction.

For the third heat exchanger can be provided, for example, that the inner tube of the low pressure side of the refrigerant circuit and the space formed between the inner and outer tube of the high pressure side of the refrigerant circuit are assigned.

For an embodiment of the cooling device in the form of a coaxial tube heat exchanger, however, a configuration may prove advantageous in which the inner tube is assigned to the high pressure side of the refrigerant circuit and the intermediate space formed between the inner and outer tube is applied to the condensate accumulating on at least one evaporator ,

Alternatively, however, a reverse configuration is conceivable in which the radially outer intermediate space with the refrigerant and the inner tube is subjected to condensation.

According to a further preferred embodiment of the air conditioner, at least two evaporators connected in parallel with each other in terms of flow technology are provided, each with an upstream expansion device. In this case, the cooling device is disposed upstream of at least one of the expansion devices. It is also fluidically connected to at least one of the evaporator for receiving evaporator-side condensate. Likewise, it can be provided that each of the expansion devices is provided with a cooling device specially provided for this purpose.

It is also conceivable to arrange the cooling device upstream of a branch of the refrigerant line leading to the two evaporators. It is also possible for one or more cooling devices to be fluidly connected to one or more evaporators for supplying condensate water accumulating at the respective evaporator, respectively.

According to a further embodiment, it is further provided that the at least one cooling device is permanently connected to the at least one evaporator via a line leading to condensation. In this case, it is possible to dispense with a device controlling the condensation water supply, since the temperature of the accumulating condensation water is always lower than the temperature of the coolant supplied to the cooling device.

In that regard, an improvement in the efficiency and an increase in the performance of the air conditioning system can always be achieved via the condensate connection of the refrigerant circuit.

Preferably, the condensed water leading line is formed thermally insulated and z. B. provided with a thermal insulation. As a result, the condensate occurring at the evaporator can be supplied as cold as possible to the cooling device. Thermal losses in the course of condensed water transport can thus be reduced.

Furthermore, it is provided in a preferred embodiment that the cooling device has a condensate discharge, via which the condensation water supplied from the evaporator can be removed in a controlled manner.

It is also advantageous if between the at least one cooling device and the at least one evaporator, a pump for supplying condensate to the cooling device is provided. Such a design proves to be advantageous in such installation conditions in the motor vehicle when the cooling device can not be arranged below the height level of the evaporator or its condensate outlet. The pump allows this a height compensation and a highly flexible and variable arrangement of cooling device and evaporator to each other, at least as far as their arrangement in the vehicle vertical direction.

The pump is preferably provided with a control which regulates the supply of condensate to the cooling device in dependence on the temperature and / or the condensate level in an evaporator-side collecting container.

In embodiments of the air conditioner, in which the cooling device is below the evaporation level, the transport of condensate water arising at the evaporator to the cooling device can be effected purely by gravity.

According to a further preferred embodiment of the air conditioning system with at least two evaporators is further provided that at least one of the evaporator is designed for cooling a vehicle battery. Such, multiple evaporator having air conditioning or refrigeration system can be used in particular in hybrid vehicles, one of the evaporator, for example, for cooling the passenger compartment and the other evaporator designed for cooling the vehicle battery and distributed accordingly in the motor vehicle.

Depending on the required cooling capacity and the condensate water accumulating in the operation of the air conditioning system at the individual evaporators, a plurality of cooling devices, each cooling separate branches of the refrigerant circuit, can be coupled either with one or even with several evaporators for the supply of condensate.

The invention makes it possible to increase the efficiency and performance of a motor vehicle air conditioning system by utilizing the "stored refrigeration energy" in the condensed water and to use it for subcooling the refrigerant upstream of an expansion device.

In a further independent aspect, the invention further relates to a motor vehicle which is equipped with an air conditioning system described above.

Brief description of the figures

Other objects, features and advantageous applications of the invention will become apparent in the following description of exemplary embodiments with reference to the drawings. It show here:

1 a schematic representation of the motor vehicle air conditioning system according to the invention with a single evaporator and

2 another embodiment with two evaporators.

Detailed description

In the 1 schematically illustrated motor vehicle air conditioning 10 has a refrigerant circuit with a high-pressure side 24 and a low pressure side 26 on. Considered in the flow direction of the circulating refrigerant, first is a compressor device designed as a compressor 12 and this downstream a capacitor 14 intended. That from the condenser 14 flowing, relatively warm or hot refrigerant flows through an internal heat exchanger below 16 and then a cooling device 20 before it, for example, designed as an expansion valve expansion device 18 arrives.

By the at the expansion device 18 taking place spatial expansion and pressure reduction of the refrigerant undergoes this a cooling, before the further downstream evaporator 22 is supplied. By means of the cooled over the refrigerant evaporator 22 For example, the passenger cell not explicitly shown here can be deprived of thermal energy and thus be cooled.

Downstream of the evaporator 22 Although the refrigerant may have a higher temperature than between expansion device 18 and evaporator 22 on. However, it is typically still colder than that between the condenser 14 and expander 18 flowing refrigerant, so by means of the third heat exchanger 16 which thermally couples the low-pressure region of the refrigerant circuit downstream of the evaporator with the high-pressure region of the refrigerant circuit downstream of the condenser, a cooling or undercooling of the high-pressure side 24 flowing refrigerant can be achieved.

Downstream of the third, internal heat exchanger 16 the high-pressure side refrigerant flows back into the compressor 12 ,

The additional cooling device 20 is in this case downstream of the third heat exchanger 16 arranged in the refrigerant circuit. This is via a supply line 21 in the operation of the air conditioning 10 on the evaporator 22 accumulating and comparatively cold condensation water can be supplied. Because the condensate is usually colder than the downstream of the evaporator 22 flowing refrigerant is already on the high pressure side 24 of the third heat exchanger 16 previously cooled to a first temperature level refrigerant further subcooled and thus the cooling capacity and the efficiency of the air conditioner 10 be further improved.

By the cooling device 20 Only with the high pressure side of the refrigerant circuit exchanges thermal energy, the enthalpy of the accumulating condensate can finally for further cooling of the expansion valve 18 supplied refrigerant can be used.

The further, in 2 illustrated embodiment of a motor vehicle air conditioning 30 looks in addition to in 1 illustrated configuration a total of two fluidically connected in parallel to each other evaporator 22 . 32 of which, for example, one for cooling the passenger compartment and another for cooling a vehicle battery, in particular that of a hybrid vehicle, is used. Downstream of the third heat exchanger 16 branches the high pressure line, with an upper branch to the expansion valve 18 and to the evaporator 22 and the other branch to the expansion valve 28 and subsequently to the evaporator 32 leads.

As in 2 shown here is only an expansion valve 28 the cooling device 20 upstream of the accumulating condensation of both evaporators 22 . 32 by means of appropriate supply lines 21 . 23 is fed.

In a modification of this is conceivable, including the expansion device 18 a separate cooling device 20 assigned. It is also within the scope of the invention if a cooling device 20 is arranged upstream of the branch of the high-pressure side refrigerant pipe.

The illustrated embodiments show only possible embodiment of the invention to which further numerous variants are conceivable and within the scope of the invention. The exemplary embodiments shown are in no way to be construed as limiting the scope, applicability or configuration possibilities of the invention. The present description merely shows the person skilled in the art a possible implementation of an exemplary embodiment according to the invention. Thus, the most varied modifications can be made to the function and arrangement of elements described without thereby abandoning the scope of protection or its equivalents as defined by the following claims.

LIST OF REFERENCE NUMBERS

10

air conditioning

12

compressor

14

capacitor

16

heat exchangers

18

expander

20

cooling device

21

Condensate supply line

22

Evaporator

23

Condensate supply line

24

High-pressure line

26

Low-pressure line

28

expander

30

air conditioning

32

Evaporator

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1613684 A1 [0003]
• DE 19613684 A1 [0016]

Claims (14)

Automotive air conditioning system with a refrigerant circuit, which at least two, as a capacitor ( 14 ) and as an evaporator ( 22 . 32 ) formed heat exchanger and at least one compressor device ( 12 ) and at least one expansion device ( 18 . 28 ), which are fluidically interconnected for the circulation of a refrigerant, wherein for additional cooling of the refrigerant of the expansion device ( 18 . 28 ) at least one, exclusively with a high-pressure side ( 24 ) of the refrigerant circuit thermal energy exchanging cooling device ( 20 ) is provided. Automotive air conditioning system according to claim 1, wherein the cooling device is used as a heat exchanger ( 20 ), which is fed with condensate, which in the operation of the air conditioner on the evaporator ( 22 . 32 ) accumulates. Automotive air conditioning system according to one of the preceding claims, wherein the cooling device ( 20 ) is designed for a purely convection and / or heat conduction based heat exchange between refrigerant and condensed water. Automotive air conditioning system according to one of the preceding claims, wherein the cooling device ( 20 ) downstream of the capacitor ( 14 ) is arranged in the refrigerant circuit. Automotive air conditioning system according to one of the preceding claims, further comprising a third heat exchanger ( 16 ), one between capacitor ( 14 ) and expander ( 18 . 28 ) lying area of the high pressure side ( 24 ) of the refrigerant circuit thermally with a between evaporator ( 22 . 32 ) and compressors ( 12 ) lying region of the low pressure side ( 26 ) of the refrigerant circuit couples. An automotive air conditioning system according to claim 5, wherein the cooling device ( 20 ) downstream of the third heat exchanger ( 16 ) is arranged in the refrigerant circuit. Automotive air conditioning system according to one of the preceding claims 5 or 6, wherein the third heat exchanger ( 16 ) and / or the cooling device ( 20 ) are formed as a tubular heat exchanger with an inner tube and a, the inner tube to form a permeable space radially enclosing the outer tube. Motor vehicle air conditioning system according to one of the preceding claims, which at least two fluidically connected in parallel with each other evaporator ( 22 . 32 ), each with an upstream expansion device ( 18 . 28 ) and wherein the cooling device ( 20 ) at least one of the expansion devices ( 18 . 28 ) is upstream. Automotive air conditioning system according to one of the preceding claims, wherein the cooling device ( 20 ) via a condensed water leading line ( 21 . 23 ) permanently with the at least one evaporator ( 22 . 32 ) connected is. Automotive air conditioning system according to claim 9, wherein the condensed water leading line ( 21 . 23 ) is provided with a thermal insulation. Motor vehicle air conditioning system according to one of the preceding claims 2 to 10, wherein the cooling device ( 20 ) a process for dispensing of the evaporator ( 22 . 32 ) has supplied condensed water. Automotive air conditioning system according to one of the preceding claims, wherein between the at least one cooling device ( 20 ) and the at least one evaporator ( 22 . 32 ) a pump for supplying condensed water to the cooling device ( 20 ) is provided. Motor vehicle air conditioning system according to one of the preceding claims 8 to 12, wherein at least one of the evaporators ( 22 . 32 ) is designed for cooling a vehicle battery. Motor vehicle with an air conditioner according to one of the preceding claims.

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