DE102009019759A1 - Air conditioning unit, particularly for vehicle, has compressor for compressing working medium, and has heat sink that is arranged downstream compressor - Google Patents

Abstract

The air conditioning unit (12) has a compressor (16) for compressing a working medium, and has a heat sink (18) that is arranged downstream the compressor. A heat source (28) is arranged between a heat exchanger (32) and the compressor for conveying heat on the working medium that is supplied to the compressor. An independent claim is also included for a method for operating an air conditioning unit, particularly for a vehicle.

Description

The The invention relates to an air conditioning device, in particular for a vehicle, with a compressor for compressing a Working medium and with a downstream of the compressor arranged heat sink, wherein downstream of the heat sink arranged an expansion device for relaxing the working medium and wherein downstream of the expansion device is a heat exchanger for transferring heat to the relaxed working medium is arranged. Furthermore, the invention relates to a method for operating such an air conditioning device.

The DE 102 10 354 B4 describes an air conditioning system for a motor vehicle, which is switchable from a refrigeration system operation in a heat pump operation. In refrigeration plant operation, a heat exchanger serves as an evaporator. A working medium evaporating in the evaporator removes heat from the supply air supplied to the vehicle interior and thus ensures cooling of the supply air. In heat pump operation of the heat exchanger is flowed through in the opposite direction of the working fluid, and the working fluid condenses in the then operated as a condenser heat exchanger. An expansion device arranged downstream of the heat exchanger in heat pump operation ensures a subsequent expansion of the working medium, which then flows through an engine coolant heat exchanger. The vaporized by means of the engine coolant heat exchanger working fluid is then returned to the compressor in heat pump operation.

When disadvantageous in such an air conditioner is the fact that that in heat pump operation comparatively low efficiencies occur can.

task It is therefore an air conditioning device of the present invention to create the type mentioned, which with an improved Efficiency is operable.

These Task is by an air conditioning device with the features of claim 1 and a method for operating a Air conditioning device with the features of the claim 13 solved. Advantageous embodiments with appropriate Further developments of the invention are dependent on the respective Claims specified.

The Air conditioning device according to the invention comprises a compressor for compressing a working fluid and a downstream the heat sink arranged in the compressor. Another heat sink downstream is directly or indirectly with a heat source connected in front of the compressor. Downstream of the heat sink is an expansion device for relaxing the working medium arranged. Downstream of the expansion device is a heat exchanger for transmitting Heat is arranged on the relaxed working medium. Between the heat exchanger and the compressor is a provided further heat source, by means of which heat transferred to the compressor feedable working fluid is. When using a collector, a dryer, an internal heat exchanger Before the compressor, the position of the heat sink is inevitable between first heat source and compressor. That is in heat pump operation of the air conditioning device the Working medium already on the input side of the compressor already comparatively warm before. By operating the compressor, the heat content of the working medium further increased. This then on the output side the compressor particularly strong heated working fluid can so at the downstream of the compressor arranged heat sink Heat to a heat sink supplied Transfer cooling medium, even if the cooling medium already has a relatively high temperature.

Is it, as in the prior art according to the DE 102 10 354 B4 , In the cooling medium to air of the vehicle interior, then only a comparatively low heat extraction through the cooling medium is possible without the provision of the further heat source when the cooling medium itself is already comparatively strongly heated. This can be done with the air conditioner DE 102 10 354 B4 lead to the fact that at the provided in heat pump mode as a heat sink capacitor no condensation of the working medium takes place more. In such an operation of the heat pump in which compressed only gaseous working fluid, cooled and then expanded, there is a particularly low efficiency. Such a mode of operation of the heat pump, which with the very low. Efficiency is also referred to as hot gas operation, in which the working fluid undergoes a triangular process.

present On the other hand, the additional heat source ensures that that even with a comparatively warm cooling medium at the heat sink a comparatively high temperature difference exists between the working medium and the cooling medium. The heat sink is thus able to the working medium especially largely to remove heat. This is an improved Efficiency of the air conditioning device, especially in unfavorable Operating conditions, namely at already comparatively warm cooling medium at the heat sink, reachable.

In an advantageous embodiment of the invention is between the Heat sink and the expansion device another heat sink for reducing a temperature of the expansion device arranged to relaxing medium. This can be the working medium even before reaching the expansion device heat be withdrawn. For a given reduction in pressure the expansion device is then the working fluid downstream the expansion device cooler than this without the Provision of the further heat sink would be the case. It must therefore be the same conditions of entry to the heat exchanger to reach the working medium at the expansion device less be greatly relaxed. This is the air conditioning device operated more efficiently. For a given reduction in pressure at the expander is provided by the provision of the additional heat sink upstream of the expansion device a larger Heat input into the working fluid at the heat exchanger reachable. This increased efficiency of the heat exchanger also leads to an improvement in the efficiency of the Air conditioning unit.

Especially advantageous are the further heat source and the others Heat sink through an internal heat exchanger provided. This is a high-pressure side line area the air conditioning device as the further heat source and a low-pressure side line region of the air conditioning device as the heat sink. Such an internal heat exchanger is compact and highly efficient as there are no external heat sources or heat sinks are provided.

The Another heat source can be the output side of the heat exchanger be arranged. Here is space to accommodate the further heat source, in particular for housing the internal heat exchanger, comparatively easily available. The internal heat exchanger can be interpreted as comparatively large.

In addition, but preferably, alternatively, the further heat source Be arranged on the input side of the compressor. Here is one particularly low heat loss before the entry of the working medium placed in the compressor. Is the further heat source provided by the internal heat exchanger, so has the heat sink serving, low-pressure side Line area of the air conditioning device in this case due the comparatively long conduction path until reaching the heat sink a comparatively low temperature. This is for transferring heat favorably.

In a further advantageous embodiment of the invention is the Heat exchanger for transferring ambient heat trained on the working medium. Is the air conditioning device housed in a vehicle, so the heat exchanger be located in a front area of the vehicle, where an efficient Absorption of ambient heat by the heat exchanger is possible. By using the ambient heat is a particularly large heat reservoir for Available.

When Furthermore, it has been shown to be advantageous if the air-conditioning device comprises a collection container. Such, in the heat pump cycle integrated collecting tank serves as a compensating vessel and as a reservoir for the working medium. Prefers the collecting container has a dryer, by means of which Water is removable from the working medium. About the collection container are also preferred other impurities from the working medium Deposable, which otherwise leads to damage to the compressor could lead.

Advantageous the collecting tank is also in a refrigeration system the air conditioning device involved, the refrigeration system a further expansion device and one of the further expansion device includes after switched evaporator. So serves the same collection container for Storage of the working medium when operating the air conditioning device as a heat pump and when operating the air conditioning device as a refrigeration system.

At the Operating the air conditioning device as a heat pump is the part of the refrigeration system, which the further expansion device and the further expansion device according to switched evaporator comprises, preferably not from the working medium flows through, though filled.

Of the Evaporator is in arrangement of the air conditioning in one Vehicle preferably arranged in a climate box of the vehicle. In the refrigeration system operation of the air conditioning device is the air box flowing through the supply air by means of the evaporator cooled, and the cooled supply air flows in the interior of the vehicle.

To improve the efficiency of the air conditioning device may be arranged in the refrigeration system in the inner heat exchanger. A particularly compact integration of the internal heat exchanger into the refrigeration system can be achieved if the collecting container comprises the internal heat exchanger. The collecting tank with the inner heat exchanger is the low pressure side between the evaporator and the compressor and high pressure side between the heat exchanger for cooling the working medium and the evaporator upstream, further expansion device arranged. By means of the internal heat exchanger, heat can be transferred from the high-pressure side working medium to the low-pressure side working medium.

in this connection it has been shown to be advantageous if an environmental line is provided, by means of which the internal heat exchanger or a side of which is bypassable. As the flow through the internal heat exchanger with a pressure loss the working medium is connected, by bypassing the inner Heat exchanger, the air conditioning device operated with a particularly low pressure loss and therefore particularly fuel-efficient be when the air conditioning device as a heat pump is operated. Here are still the collection and / or drying and / or Cleaning functions of the collection container used. Prefers a shut-off device is provided, by means of which the bypass line lockable is when the air conditioning device as a refrigeration system should be operated.

According to one Another advantageous embodiment of the invention is between the heat sink and the heat exchanger the heat pump circuit a bypass line with a Shut-off arranged, wherein by opening the shut-off device the heat exchanger with the working medium below Bypassing of at least the expansion device can be acted upon. After opening the shut-off device flows so the compressed working medium without first being relaxed, to the heat exchanger. In this case, the serves Heat exchanger then as a gas cooler, where the cooled by the gas cooler working medium in refrigeration system operation of the air conditioning device that expansion device is supplied, which is connected upstream of the evaporator. Preferably, the bypass line also serves to bypass the inner heat exchanger of the heat pump circuit.

After all it has proven to be advantageous if the heat sink in a coolant circuit for cooling an aggregate the drive, such as the drive unit itself involved is. The heat release from the compressed working fluid ensures the coolant of the coolant circuit in this case, that in the coolant circuit injected heat for heating an air stream, in particular one that can be fed to the interior of the vehicle Supply air flow is available. Especially in warm-up mode of the drive unit can be the feeding of heat in the coolant circuit complementary or alternative be used to ensure that the drive unit particularly quickly the consumption favorably influencing the operating temperature reached. In contrast to the benefit of an evaporator of the air conditioning device as a heater, the evaporator in heat pump mode is used as a condenser and for heating the supply air is, by using the coolant circuit as a heat source for the interior an undesirable admission the supply air flow with too much moisture avoidable.

• a) ein Verdichter ein Arbeitsmedium verdichtet,
• b) dem verdichteten Arbeitsmedium an einer stromabwärts des Verdichters angeordneten Wärmesenke Wärme entzogen wird,
• c) das Arbeitsmittel stromabwärts der Wärmesenke mittels einer Expansionseinrichtung entspannt wird, und
• d) stromabwärts der Expansionseinrichtung mittels eines Wärmeübertrages Wärme auf das entspannte Arbeitsmedium übertragen wird, wobei

mittels einer weiteren, zwischen dem Wärmeübertrager und dem Verdichter angeordneten Wärmequelle Wärme auf das dem Verdichter zugeführte Arbeitsmedium zugetragen wird.According to another aspect of the invention, the air conditioning device is operated with improved efficiency when

• a) a compressor compresses a working medium,
• b) heat is removed from the compressed working medium at a heat sink arranged downstream of the compressor,
• c) the working fluid downstream of the heat sink is expanded by means of an expansion device, and
• d) heat is transferred to the relaxed working medium downstream of the expansion device by means of a heat transfer, wherein

Heat is applied to the working medium supplied to the compressor by means of a further heat source arranged between the heat exchanger and the compressor.

The for the air conditioning device according to the invention described preferred embodiments and advantages also apply to the invention Method for operating an air conditioning device.

The features and feature combinations mentioned above in the description as well as the below mentioned in the figure description and / or in the figures alone shown features and feature combinations are not only in the specified combination, but also usable in other combinations or in isolation, without to leave the scope of the invention.

Further Advantages, features and details of the invention will become apparent the claims, the following description is more preferred Embodiments and with reference to the drawings, in which identical or functionally identical elements with identical reference numerals are provided. Showing:

1 schematically a first embodiment of an arranged in a motor vehicle air conditioning device which is operable as a heat pump and as a refrigeration system; and

2 a further embodiment of the air conditioning device.

From a motor vehicle 10 with an air conditioning device 12 are in 1 and 2 schematically shown individual components. The air conditioning device 12 is used to air-condition an interior 14 of the motor vehicle 10 , In a heat pump operation of the air conditioning device 12 becomes the interior 14 supplied heated air. To provide heat in heat pump operation, the air conditioning device 12 a compressor 16 in which a working medium, for example carbon dioxide or 2,3,3,3-tetrafluoroprop-1-ene (HFO 1234 yf) is compressed. Downstream of the compressor 16 is a heat sink 18 arranged, which in a coolant only partially shown 20 for cooling an aggregate of the drive, such as the drive unit 22 , the battery, the fuel cell of the vehicle 10 is involved. At the heat sink 18 Heat is transferred from the compressed, heated working fluid to the engine coolant. In the coolant circuit 20 then the heat is to support a warm up of the drive motor so 22 available and in particular for applying to the interior 14 of the vehicle 10 with heated supply air.

Via a high pressure line 24 becomes in the heat pump operation of the air conditioning 12 the working fluid an internal heat exchanger 26 fed, in which by the high pressure line 24 a heat source 28 is provided. After flowing through the internal heat exchanger 26 The working fluid is connected to an expansion valve 30 relaxed. The at the expansion valve 30 Relaxed working medium then takes in a heat exchanger 32 Heat from the environment of the motor vehicle 10 on. For efficient and large-scale heat input from the ambient air into the working medium of the heat exchanger 32 in a front area 34 of the motor vehicle 10 , or arranged near the exhaust line. For the operation of the heat pump, a warm area on the vehicle is advantageous. Thus, the outside air in the front area is rather colder than air near the vehicle in a badly flow around place.

The heated, relaxed working medium is passed through a low-pressure line 36 back to the compressor 16 fed, taking it before reaching the compressor 16 a collection container 38 can flow through.

In the area of the internal heat exchanger 26 , which in the embodiment of the 1 on the output side of the heat exchanger 32 in the front area 34 of the motor vehicle 10 is arranged through the low pressure line 36 a heat sink 40 provided. Here is the fact that in the high pressure line 24 flowing working fluid before reaching the expansion valve 30 cooled and at the same time the heat exchanger 32 leaving, heated working fluid further heated. This is already the input side of the compressor 16 the working fluid with increased temperature available, which by the compression work of the compressor 16 is further increased. Even with comparatively warm engine coolant so allows the heat sink 18 such an efficient lowering of the temperature of the compressed working medium, that a particularly high efficiency of the air conditioning device 12 is reachable.

In refrigeration system operation of the air conditioning device 12 is a shut-off device 42 which is in a bypass line 44 to bypass the expansion valve 30 is arranged, opened. About the bypass 44 The compressed, high pressure working medium then flows to the heat exchanger 32 to which in refrigeration system operation of the air conditioning device 12 then acts as a gas cooler.

The cooled and under a still high pressure working medium then flows to the inner heat exchanger 46 to which in the sump 38 is arranged. The internal heat exchanger 46 may comprise a wound tube, which in a space between an outer wall of the collecting container 38 and an inner container. Here, the inner container is used for collecting and separating liquid working medium. The tube winding surrounds the inner container and heat can be drawn from the high pressure working medium flowing through the tube winding to the relaxed and in an evaporator 48 the refrigerant circuit evaporated working fluid to be transmitted. This is in the inner heat exchanger 46 the working medium under high pressure is further cooled and that of the evaporator 48 coming, relaxed working fluid continues to heat before returning to the compressor 16 is supplied.

In refrigeration plant operation, therefore, the internal heat exchanger 46 of the collection container 38 flows through the high pressure working fluid, and the working fluid under high pressure leaves the reservoir 38 via an outlet line 50 , The outlet line 50 leads to an expansion valve 52 the refrigeration circuit, which is the evaporator 48 is downstream. At the evaporator 48 , which present in one with the interior 14 of the vehicle 10 communicating air conditioning box 54 can be arranged, a temperature sensor 56 be arranged.

An entrance line 58 leads from the evaporator 48 to the collection container 38 , There, in the refrigeration system operation, the relaxed and vaporized working medium flows through the internal heat carrier 46 before putting it over a sump 38 with the compressor 16 connecting connection line 60 back to the compressor 16 is supplied. For applying the compressor 16 with a lubricant which is in the sump 38 is deposited from the working fluid, at a low point of a U-tube 62 be arranged through a passage bore through which the lubricant in the flowed through by the working medium U-tube 62 can occur. With the working fluid then the lubricant is the compressor 16 fed.

In heat pump mode, this flows into the sump 38 over the low pressure line 36 entering working fluid through a bypass line 64 , which is the high pressure side of the internal heat exchanger 46 bypasses. As a result, the working fluid can collect the container 38 with a particularly low pressure loss and then through the connecting line 60 back to the compressor 16 be supplied. In refrigeration system operation of the air conditioning device 12 is the bypass line 64 by means of a shut-off device 66 locked, so that the working medium is forced to the internal heat exchanger 46 to flow through. With the refrigerant HFO 1234 yf the collector is not urgently required. The collector can also be integrated in the condenser here.

At the in 2 shown embodiment of the air conditioning device 12 is the internal heat exchanger 26 the heat pump circuit input side of the compressor 16 arranged. Here, the forms of the sump 38 to the compressor 16 leading connection line 60 the heat sink 40 and those of the heat sink 18 to the expansion valve 30 leading high pressure line 24 the heat source 28 ,

By opening the shut-off device 42 In refrigeration plant operation, the compressed working medium can be in the front area 34 of the motor vehicle 10 arranged heat exchanger 32 bypassing the expansion valve 30 and the heat source 28 the internal heat exchanger 32 be supplied.

In heat pump operation of the air conditioning device 12 on the other hand, the internal heat exchanger ensures 26 for a heat input into the compressor 16 inflowing working medium, and for heat dissipation in the high pressure line 24 flowing working fluid, so that at the expansion valve 30 a less strong expansion of the working medium is necessary.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10210354 B4 [0002, 0007, 0007]

Claims (14)

Air conditioning device, in particular for a vehicle ( 10 ), with a compressor ( 16 ) for compressing a working medium, and with a downstream of the compressor ( 16 ) arranged heat sink ( 18 ), downstream of the heat sink ( 18 ) an expansion device ( 30 ) is arranged to relax the working medium, and wherein downstream of the expansion device ( 30 ) a heat exchanger ( 32 ) is arranged for transferring heat to the expanded working medium, characterized in that between the heat exchanger ( 32 ) and the compressor ( 16 ) another heat source ( 28 ) for transferring heat to the compressor ( 16 ) is arranged feedable working medium. Air-conditioning device according to claim 1, characterized in that between the heat sink ( 18 ) and the expansion device ( 30 ) another heat sink ( 40 ) for reducing a temperature of the at the expansion device ( 30 ) is arranged to relaxing working medium. Air conditioning device according to claim 1 and 2, characterized in that the further heat source ( 28 ) and the further heat sink ( 40 ) by an internal heat exchanger ( 26 ) are provided. Air conditioning device according to one of claims 1 to 3, characterized in that the further heat source ( 28 ) on the output side of the heat exchanger ( 32 ) is arranged. Air conditioning device according to one of claims 1 to 4, characterized in that the further heat source ( 28 ) on the input side of the compressor ( 16 ) is arranged. Air conditioning device according to one of claims 1 to 5, characterized in that the heat exchanger ( 32 ) is formed for transmitting ambient heat to the working medium. Air conditioning device according to one of claims 1 to 6, characterized in that the air conditioning device ( 12 ) a collecting container ( 38 ). Air conditioning device according to claim 7, characterized in that the collecting container ( 38 ) is integrated in a refrigeration system, which comprises a further expansion device ( 52 ) and one of the further expansion device ( 52 ) downstream evaporator ( 48 ). Air conditioning device according to claim 7 or 8, characterized in that the collecting container ( 38 ) an internal heat exchanger ( 46 ). Air-conditioning device according to claim 9, characterized in that one, in particular by means of a shut-off device ( 66 ) lockable, bypass ( 64 ) is provided, by means of which the internal heat exchanger wholly or partially ( 46 ) is bypassable. Air conditioning device according to one of claims 1 to 10, characterized in that between the heat sink ( 18 ) and the heat exchanger ( 32 ) a bypass ( 44 ) with a shut-off device ( 42 ), wherein by opening the shut-off device ( 42 ) of the heat exchanger ( 32 ) with the working medium, bypassing at least the expansion device ( 30 ) can be acted upon. Air conditioning device according to one of claims 1 to 11, characterized in that the heat sink ( 18 ) in a coolant circuit ( 20 ) for cooling a drive unit ( 22 ) is involved. Method for operating an air-conditioning device ( 12 ), in particular for a vehicle ( 10 ), in which a) a compressor ( 16 ) compresses a working medium, b) the compressed working medium at a downstream of the compressor ( 16 ) arranged heat sink ( 18 ) Heat is removed, c) the working fluid downstream of the heat sink ( 18 ) by means of an expansion device ( 30 ) and d) downstream of the expansion device ( 30 ) by means of a heat exchanger ( 32 ) Heat is transferred to the relaxed working medium, characterized in that by means of another, between the heat exchanger ( 32 ) and the compressor ( 16 ) arranged heat source ( 28 ) Heat to the compressor ( 16 ) supplied working medium is transferred. A method according to claim 13, characterized in that the method by means of an air conditioning device ( 12 ) is carried out according to one of claims 1 to 12.