Method for operating a stationary air conditioning system in a vehicle and vehicle stationary air conditioning system

Abstract

Method for operating a stationary air conditioning system in a vehicle using two coolant circuits (1, 2) connected by heat exchangers and at least one cold storage unit (12) that can be charged and discharged, at least during vehicle standstill phases, wherein a first coolant circuit (1) comprises at least one refrigerant compressor (3), one condenser (4), one expansion valve (5) and one evaporator (6) and a second coolant circuit (2) comprises at least one heat exchanger (8) containing the evaporator (6) of the first coolant circuit (1) for absorbing cold and a liquid / air heat exchanger (9') for releasing air conditioning cooling, characterized by that the refrigerant compressor (3) is driven electrically by means of low voltage independently of the vehicle drive motor in order to charge the cold storage unit (12) when sufficient electrical energy is available and to provide air conditioning cooling at the liquid / air heat exchanger (9') when the cold storage unit (12) is discharged during standstill phases of the vehicle drive, wherein the second coolant circuit (2) is part of the cold storage unit (12) and is supplied by a second coolant medium (2A) independent of a first coolant medium (1A) of the first coolant circuit (1) and that both coolant circuits (1, 2) in the area of ​​the evaporator (6) of the first coolant circuit (1) and the heat exchanger (8) of the second coolant circuit (2) containing it, directly deliver cold to the liquid / air heat exchanger (9').

Description

[0001] The invention relates to a method for operating a stationary air conditioning system in a vehicle according to the preamble of claim 1 and to a vehicle stationary air conditioning system according to the preamble of claim 7. Accordingly, the invention is based on a known operating mode of stationary air conditioning systems in which two coolant circuits connected by heat exchangers and at least one cold storage device that can be charged and discharged during vehicle standstill phases are used, and in which a first coolant circuit comprises at least a coolant compressor, a condenser, an expansion valve and an evaporator, and a second coolant circuit comprises at least a heat exchanger containing the evaporator of the first coolant circuit for absorbing cold, as well as a liquid / air heat exchanger for delivering air conditioning cooling and, optionally, a coolant pump.

[0002] The challenge with stationary vehicle air conditioning systems is to provide sufficiently cool air (air conditioning air) during breaks, such as rest stops, even in relatively warm and / or humid conditions. The energy required to operate such stationary vehicle air conditioning systems is considerable, typically ranging from 1 to 5 kWh.

[0003] Commercially available vehicle air conditioning systems are typically designed to function as well as for maintaining a comfortable climate in the driver's cabin while driving. This involves combining both systems and providing the energy required to drive the refrigeration compressor of a refrigerant circuit through mechanical coupling to the vehicle engine. When the engine is running, the refrigeration compressor is mechanically driven by the engine. To bridge longer periods of inactivity, the cooling generated during driving is stored and can be used during these periods. This is achieved as follows: A well-known integrated vehicle and stationary air conditioning system consists of two circuits: a conventional refrigeration circuit for generating the cooling and a refrigeration transfer circuit for distributing the cooling. The conventional refrigeration circuit is designed for refrigerant R134a, for example; its components are a refrigerant compressor, a refrigerant condenser, a refrigerant expansion valve, and an evaporator. However, unlike a typical vehicle air conditioning system, this evaporator does not cool air, but rather a refrigerant, such as a water-antifreeze mixture. The evaporator serves as the interface between the two refrigerant circuits. The second refrigerant circuit comprises the aforementioned evaporator interface, a cold storage unit, an air conditioning unit, and a distribution and control unit for the refrigerant.The so-called air conditioning unit is positioned at any point remote from the evaporator to transfer cooling power from the circulating secondary refrigerant circuit to the air being cooled. A liquid-to-air heat exchanger is used for this purpose. The distribution and control unit for the refrigerant in the secondary circuit can be connected either to the liquid-to-air heat exchanger or to a cold storage unit. The cold storage unit consists of an insulated housing and several storage elements with intervening flow channels for the refrigerant. The refrigerant can be a mixture of water and, for example, antifreeze. Due to the efficient heat transfer properties between the cold storage unit (consisting of storage elements and intervening flow channels for the refrigerant) and the evaporator of the first refrigerant circuit, a cooling capacity of 5 kWh can be charged into the cold storage unit in a relatively short time. If cabin air conditioning is running or continues during such a charging process, the cold storage unit charging takes correspondingly longer, e.g., three times as long. In this known stationary vehicle air conditioning system, when air conditioning is being used while driving, the refrigerant of the second refrigerant circuit circulates between the evaporator and the air conditioning unit. In the liquid-to-air heat exchanger of the air conditioning unit, the cabin air (fresh air or recirculated air) is cooled and dehumidified.In this operating mode, also known as maintenance air conditioning (without "cooling down" the cab), the continuously operating evaporator typically delivers more cooling energy than is required for climate control. The unused portion of the cooling capacity is used to charge the cold storage unit. In cases of extreme air conditioning demands, the cold storage unit can also be used to increase cooling capacity. The refrigerant is then further cooled in the cold storage unit after passing through the evaporator, and only then is it directed to the air conditioning unit in the vehicle cabin. Such a combined driving and stationary air conditioning system for vehicles is exceptionally complex, particularly with regard to its control system and refrigerant distribution.

[0004] Examples of stationary air conditioning systems are known from DE 10 2004 002 715 A1 and DE 198 60 057 A1.

[0005] Based on this, the invention aims to simplify the design of stationary vehicle air conditioning systems and to improve the energy resources for cabin air conditioning when the vehicle's engine is not running. Such stationary vehicle air conditioning systems can, of course, cool various areas of a vehicle, not just the passenger compartment.

[0006] To solve this problem, a method with the features of claim 1 and a device with the feature of claim 7 are proposed. Accordingly, it is provided that the refrigerant compressor of the first coolant circuit is driven independently of the vehicle's drive motor, namely electrically by means of low voltage, in order to charge the cold storage unit when sufficient electrical energy is available and to provide air conditioning cooling at the liquid / air exchanger when the cold storage unit is discharged during periods of vehicle inactivity.Furthermore, it can be provided that a refrigerant pump used in the second coolant circuit is electrically operated via low voltage, particularly when the refrigerant compressor is stationary, in order to discharge the cold storage unit via the liquid / air heat exchanger and – if desired – to supply air conditioning cooling from the first coolant circuit to the liquid / air heat exchanger. The invention is therefore based on the fundamental concept of providing two energy reservoirs for cooling when the vehicle is stationary: the rechargeable cold storage unit on the one hand, and the vehicle's on-board battery for electrical voltage on the other. This battery then continues to supply electrical energy for air conditioning cooling via the refrigerant compressor even when the cold storage unit is discharged and the vehicle is stationary.

[0007] The invention allows the cold storage unit to be significantly smaller compared to known vehicle stationary air conditioning systems, without compromising cooling performance during the occasional extended cooling phases. This reduction in size also decreases the weight of the cold storage unit and allows it to be positioned directly at the point of air conditioning delivery, thus improving compactness, particularly as described below. Cold storage capacities of approximately 2 kWh are sufficient for a large number of applications. The accumulator batteries are protected against deep discharge by suitable, known battery monitors, as is generally the case. While the use of purely electrical drive energy for refrigerant compressors is known in principle from WO 85 / 03603, this invention presents a different approach.The solution used there, however, is designed for cooling coolers with eutectic storage plates, which, after the cold storage is discharged, continue to operate at a significantly higher temperature level than when the cold storage is fully charged. Such temperature differences are fundamentally unacceptable for air conditioning. Furthermore, eutectic storage plates are unsuitable for transferring the cooling effect to the air conditioning system via liquid / air heat exchangers in a vehicle's stationary air conditioning system.

[0008] The invention can now be implemented in various ways. According to a first preferred operating mode, the second coolant circuit, driven by a refrigerant pump, transfers stored and / or in-situ generated cooling for immediate use to the liquid / air heat exchanger via a second circuit medium that is independent of the first circuit medium of the first coolant circuit and of the cold storage unit. Unlike the aforementioned vehicle stationary air conditioning systems, the cold storage unit's contents are thus kept separate from the circuit medium of the second coolant circuit. This makes it possible to keep the operating volume of the second coolant circuit extremely small and to optimally adapt the (second) circuit medium to the specific characteristics of this circuit and, in particular, to favorable material pairings in the area of ​​the liquid / air heat exchanger.Therefore, any cold storage medium, including solids, can be used, and in particular, the quantity and weight of the storage medium can be optimized. Furthermore, a distribution and control unit for the second circuit medium can be omitted or significantly simplified. Such a method for operating a vehicle stationary air conditioning system and a corresponding vehicle stationary air conditioning system is of independent inventive significance even without the characterizing features of claim 1. Nevertheless, a separate heat exchanger, namely for charging and discharging the cold storage unit, can be omitted if the cold storage unit is combined with the evaporator of the first coolant circuit and with the heat exchanger of the second coolant circuit, which contains the evaporator for cold absorption, to form a heat exchange unit, which will be described in more detail below.

[0009] Furthermore, it is provided that the second coolant circuit is part of the cold storage system and is traversed by a second circuit medium independent of the cooling medium of the first coolant circuit, and that in the area of ​​the evaporator of the first coolant circuit and the heat exchanger of the cold storage system containing it, cold is transferred directly to the liquid / air heat exchanger.

[0010] The cold storage substance can alternatively remain stationary within the cold storage unit. This eliminates the need for a dedicated refrigerant circuit for transporting the cold to the liquid-to-air heat exchanger used for air conditioning. The entire heat exchanger assembly can be installed directly at the point of use for cooling, similar to a conventional air conditioner. The cold storage unit adds a comparatively small amount of weight to the heat exchanger, as portions of the circulating cold storage medium can be stored in a thermally insulated auxiliary storage tank located away from the cooling point. Connecting lines between the auxiliary storage tank and the cold storage unit can be easily installed and thermally insulated. This results in a triple heat exchange process, and a refrigerant distribution and control unit, as described in the aforementioned prior art, is completely unnecessary.During operating phases without charging or discharging the cold storage unit, the refrigerant pump of this circuit, if present, simply needs to be switched off. The amount of cold storage medium contained in the combined liquid / air heat exchanger acts as a buffer, which evens out the cold absorption of the integrated heat exchanger, and especially its cold emission, in a manner that is comfortable for the vehicle user. The second embodiment is of independent inventive significance, even apart from the characterizing features of claim 1.

[0011] If the cold storage unit is combined with the evaporator of the first coolant circuit and with the heat exchanger containing the evaporator for cold absorption, this is, as already explained, particularly advantageous from a thermal engineering and circuit engineering perspective and also allows for a reduction in the number of components as well as comparatively flexible placement in the vehicle and a compact design. This method and a corresponding integrated heat exchanger are also of independent inventive significance even without the characterizing features of claim 1.

[0012] If a tube-in-tube system is used for the evaporator and the heat exchanger containing it, a highly efficient heat exchange between the first refrigerant circuit, the second refrigerant circuit, and / or the cold storage unit and the liquid / air heat exchanger can be achieved in a particularly simple manner. This is because one of the heat exchange media is inserted between the other two heat exchange media, allowing for the selective exchange of cooling energy between the media via the shortest possible path. Relatively small quantities of cooling media may be sufficient for effective heat exchange. Such an integrated heat exchanger is of independent inventive significance, even without the characterizing features of claim 1.

[0013] The aforementioned components, as well as those claimed and described in the exemplary embodiments, to be used according to the invention, are not subject to any special exceptional conditions with regard to their size, shape, material selection, and technical design, so that the selection criteria known in the field of application can be applied without restriction. Further details, features, and advantages of the subject matter of the invention will become apparent from the dependent claims and from the following description of the associated drawing and table, in which—by way of example—an exemplary embodiment of a vehicle stationary air conditioning system is shown.

[0014] The drawing shows Fig. Figure 1 shows, as a block diagram, the essential elements of a first embodiment of a vehicle stationary air conditioning system; Fig. Figure 2 shows a block diagram of the essential elements of a second embodiment of a vehicle stationary air conditioning system; Fig. Figure 3 shows a schematic representation of an integrated heat exchanger and cold storage unit for the embodiment according to [reference to figure]. Fig. 1 as well as Fig. Figure 4 shows a schematic representation of an integrated heat exchanger and cold storage unit for the embodiment according to [reference missing]. Fig. 2

[0015] The in Fig. Figure 1, a vehicle stationary air conditioning system 10 shown in excerpts as a schematic diagram, has a first refrigerant circuit 1 and a second refrigerant circuit 2 connected to it. The first refrigerant circuit 1, filled, for example, with refrigerant R134a, comprises at least one (preferably controllable) refrigerant compressor 3, a condenser 4, an expansion valve 5, and an evaporator 6, as well as conventional piping that completes the circuit. The second refrigerant circuit 2, filled with water and optionally a known agent that lowers the freezing temperature, comprises at least one refrigerant pump 7, a heat exchanger 8 containing the evaporator 6 of the first refrigerant circuit 1 for absorbing the cooling, and a liquid-to-air heat exchanger 9 for transferring cooling to the room air by means of an evaporator fan 11.The arrows within the two coolant circuits 1 and 2 indicate the flow direction of the first circuit medium (R134a) and the second circuit medium (water). The refrigerant compressor 3 is operated exclusively electrically with 24 volts direct current, thus being mechanically independent of the vehicle's drive motor. The electrical drive voltage can also be 12, 36, or even 48 volts. In this context, "low voltage" as used in the invention refers to an electrical voltage, particularly a direct current voltage, between approximately 10 and 50 volts.

[0016] In the first coolant circuit 1, the cooling required for the air conditioning system is generated, along with a surplus of cooling energy. This allows not only for maintenance air conditioning and cooling of at least one compartment in the vehicle, even under strong solar radiation, but also provides sufficient cooling energy to charge a cold storage unit. A corresponding cold storage unit 12 is also located in the unit, which also houses the evaporator 6 and heat exchanger 8. A corresponding integrated arrangement is described in connection with Fig. 3 will be explained.

[0017] In the second refrigerant circuit 2, a fluid refrigerant, such as water, is circulated between the unit consisting of evaporator 6, heat exchanger 8, and cold storage tank 12, and the liquid-to-air heat exchanger 9 by means of a refrigerant pump 7 designed as a water pump. With sufficient thermal insulation of the circuit lines and the two other components, the cooling loss due to the recirculation is minimal. By switching off the electrically driven water pump, the cooling loss in the second refrigerant circuit can be reduced to almost zero if required. If, with the water pump running, room air is then passed through the liquid-to-air heat exchanger 9 by means of a conventional evaporator fan 11, the cooling required for room air conditioning is extracted from the second refrigerant circuit 2.Suitable piping, in particular air distribution means 13 for air conditioning air, which may already be present in the vehicle, transports the air conditioning cooling to the preferred outlet locations. However, the air conditioning air can also exit directly from an air conditioning unit known per se, consisting of a liquid / air heat exchanger 9, an evaporator fan 11, and an air distribution means 13, at the preferred central location for air conditioning air.

[0018] A preferred operating mode of this embodiment is as follows: With sufficient electrical voltage supply in the vehicle, i.e., preferably with the vehicle's drive engine running, an alternator (not shown in the drawing) generates sufficient direct current (DC) by means of the running vehicle drive engine to drive the refrigerant compressor 3, which in the illustrated and thus preferred embodiment is designed as a controllable 24V DC compressor. This occurs completely independently of any vehicle air conditioning system installed in the vehicle and also independently of the mechanical vehicle drive, i.e., purely electrically. The compressor runs while the vehicle, particularly a commercial vehicle, is in motion and uses the energy supplied by the alternator to supply the refrigerant in the evaporator 6 and the cold storage unit 12 preferably integrated therein.During this phase of the cooling process, various operating modes are possible. Firstly, the cooling can be immediately transferred via the second refrigerant circuit to the consumer, the air conditioning unit, consisting of a liquid / air heat exchanger 9, an evaporator fan 11, and an air distribution unit 13. If there is a particularly high demand for cooling, it is possible, in extreme cases, that not only is the cold storage unit not charged, but any residual cooling stored within it is also consumed. Alternatively, the second refrigerant circuit can be switched off, so that all the cooling is supplied to the cold storage unit 12. The stored cooling energy is then available to the vehicle's stationary air conditioning system. If this system is then switched on to cool the cab during a break in driving or to keep it cool, the stored cooling energy is first drawn from the cold storage unit. Only the second refrigerant circuit is active during this process.The first refrigerant circuit is not in use. Electrical power consumption is limited to the operation of the refrigerant pump 7 and the evaporator fan 11. If the cooling energy from the cold storage unit is depleted and the vehicle's drive engine is still off, the refrigerant compressor 3 switches on to meet the current cooling demand. The compressor draws the required energy from the vehicle battery. The cold storage unit is not recharged during this time, as the cooling energy supplied is transferred directly to the secondary circuit (second refrigerant circuit) via the primary circuit (first refrigerant circuit) within the unit consisting of the evaporator 6, heat exchanger 8, and cold storage unit 12.

[0019] The vehicle's stationary air conditioning system utilizes two energy storage devices when stationary: firstly, the cold storage unit 12, provided it is charged; and secondly, the vehicle battery, which powers the electrically driven refrigerant compressor. The cooling time can therefore easily last at least six to eight hours.

[0020] Out of Fig. 3 is for the embodiment according to Fig. Figure 1 shows a particularly suitable integrated heat exchanger schematically. It comprises, firstly, a tube-in-tube cooling coil arrangement 14 and, secondly, a storage container 15 filled with a cold-storing substance 16 and preferably thermally insulated on the outside, into which the tube-in-tube cooling coil arrangement 14 is immersed. The circulating medium (R134a) of the primary circuit (first refrigerant circuit) flows through an outer tube 14A. The outer tube 14A contains the evaporator 6. The circulating medium of the secondary circuit (second refrigerant circuit), consisting, for example, of water and anti-caking agents, flows through an inner tube 14B. The cold-storing substance 16 in the storage container 15 can, for example, contain a water / anti-caking agent mixture, which is generally not circulated and is in liquid form in the preferred temperature range between +1° and -5°. Semi-solid and solid cold-storing substances can also be used.Outside the storage tank 15, the inner tube 14B extends from the outer tube 14A and is arranged separately. Inside the storage tank 15, the inner tube 14B serves as the heat exchanger 8, containing the evaporator 6 (on its outer surface), between the primary and secondary circuits.

[0021] The cooling medium 1A of the primary circuit transfers its cooling energy via indirect heat transfer not only to the cooling medium 2A of the secondary circuit, but also to the cold storage substance 16. It utilizes the outer tube 14A as a heat exchanger. In this way, cooling can be efficiently transferred to both the secondary circuit and the cold storage unit for charging.

[0022] When the cold storage unit is discharged, the pipe wall of the outer pipe 14A, which is inserted between the cold-storing substance 16 and the secondary circuit, together with the quantity of first cooling medium 1A enclosed by the outer pipe 14A, has a compensating effect on the cooling output to the cooling medium 2A of the second coolant circuit, without, however, hindering the discharge of the cold storage unit.

[0023] According to the in Fig. 2 second embodiment shown and the special embodiment according to Fig. 4, the first coolant circuit 1 is essentially identical to the first embodiment.

[0024] The only difference is that the integrated heat exchanger unit, consisting of evaporator 6, heat exchanger 8, and liquid / air heat exchanger 9', is constructed differently, as explained below. In the second embodiment, the cooling is transferred directly to a liquid / air heat exchanger 9' integrated into the evaporator and heat exchanger 8, as described below. Therefore, a simple transport circuit, as in the first embodiment, is not used. However, a cold storage circuit may be provided, as described below. An integrated heat exchanger preferred for use with the second embodiment is now described in connection with Fig. 4 explained. Its structure corresponds insofar as it does not correspond to the structure according to Fig. 3 agree that an outer tube 14A of a tube-in-tube cooling coil arrangement 14 carries the cooling medium 1A of the primary circuit, e.g. R134a, wherein an inner tube 14B, in particular coaxially extending, is arranged inside it, within which the second cooling medium 2A, e.g. water, is optionally provided with an additive to lower the freezing temperature, such as anti-caking agents.

[0025] In contrast to the integrated heat exchanger according to Fig. 3. A storage tank accommodating the pipe-in-pipe cooling coil arrangement 14 is not provided. Instead, a cold-storing substance 16 circulates in the inner pipe 14B by gravity flow or, as not shown, with the assistance of a fluid pump. Outside the actual heat storage unit is an additional storage tank 12', which receives the inlet and outlet openings of the inner pipe 14B at spaced-apart ends. The second "coolant circuit 2" thus comprises, in addition to the inner pipe 14B, any connecting lines and the preferably externally located additional storage tank 12', as well as optionally a circulation pump. The inner pipe 14B is therefore simultaneously part of a storage tank 15 for a cold-storing, preferably, but not necessarily, fluid cold-storing substance 16. However, solid cold-storing substances can also be provided in the inner pipe 14B.

[0026] The tube-in-tube cooling coil arrangement 14 is provided, in a manner known per se, with a plurality of closely spaced fins 17 for heat exchange with the air conditioning air. The fins 17 are part of the liquid / air heat exchanger 9' for cooling the air conditioning air and allow the passage of air conditioning air.

[0027] The operating mode of the integrated heat exchanger according to Fig. The following is now stated: the outer pipe 14A encompasses the evaporator of the primary circuit and transfers cold to the fins 17 on its outer surface for transport by the air conditioning air. Likewise, cold is transferred to the inner pipe 14B, which is part of the cold storage unit 12 and releases cold to the cold storage substance 16 when sufficient cooling energy is available or when there is no demand for cold at the fins 17 (an evaporator fan is switched on).

[0028] When the vehicle's drive motor is not running, cooling can now be drawn from the storage tank 15 until it is completely discharged. If cooling is still required afterwards, the refrigerant compressor can be powered by electricity from the vehicle's battery, as also explained in the first embodiment. REFERENCE MARK 1. First coolant circuit 1A Cooling medium 2. Second coolant circuit 2A Cooling medium 3 Refrigerant compressor 4 Capacitor 5 Expansion valve 6 evaporators 7 Refrigerant pump 8 heat exchangers 9 Liquid / air heat exchangers 9' Liquid / Air Heat Exchanger 10 Vehicle stationary air conditioning 11 evaporator blowers 12 cold storage units 12' Additional storage 13 Air distribution devices 14 pipe-in-pipe cooling coil arrangement 14A Outer pipe 14B inner tube 15 storage containers 16 Cold-storing substance 17 slats

Claims

[1] Method for operating a stationary air conditioning system in a vehicle using two coolant circuits (1, 2) connected by heat exchangers and at least one cold storage device (12) that can be charged and discharged, at least during vehicle standstill phases, wherein a first coolant circuit (1) comprises at least one refrigerant compressor (3), a condenser (4), an expansion valve (5) and an evaporator (6) and a second coolant circuit (2) comprises at least one heat exchanger (8) containing the evaporator (6) of the first coolant circuit (1) for absorbing cold and a liquid / air heat exchanger (9') for delivering air conditioning cooling, characterized by , that the refrigerant compressor (3) is driven electrically by means of low voltage independently of the vehicle drive motor in order to charge the cold storage unit (12) when sufficient electrical energy is available and to provide air conditioning cooling at the liquid / air heat exchanger (9') when the cold storage unit (12) is discharged during standstill phases of the vehicle drive, wherein the second coolant circuit (2) is part of the cold storage unit (12) and is supplied by a second coolant medium (2A) independent of a first coolant medium (1A) of the first coolant circuit (1) and that both coolant circuits (1, 2) in the area of ​​the evaporator (6) of the first coolant circuit (1) and the heat exchanger (8) of the second coolant circuit (2) containing it, directly deliver cold to the liquid / air heat exchanger (9'). [2] Method according to claim 1, wherein the cold storage unit (12) is not permeated by the second cooling medium (2A), but the second cooling medium (2A) remains stationary. [3] Method according to one of claims 1 or 2, characterized by , that the cold storage unit (12) is combined with the evaporator (6) of the first coolant circuit (1) and with the heat exchanger (8) of the second coolant circuit (2) which contains the evaporator (6) for the purpose of cold absorption to form a heat exchanger unit. [4] Method according to any one of claims 1 to 3, characterized by the use of a tube-in-tube system for the evaporator (6) and the heat exchanger (8) containing it. [5] Vehicle stationary air conditioning system with two coolant circuits (1, 2) connected by a heat exchanger and with at least one rechargeable and dischargeable cold storage unit (12), wherein a first coolant circuit (1) comprises at least a refrigerant compressor (3), a condenser (4), an expansion valve (5) and an evaporator (6), and wherein a second coolant circuit (2) comprises at least a heat exchanger (8) containing the evaporator (6) of the first coolant circuit (1) for absorbing cold and a liquid / air heat exchanger (9') for releasing air conditioning cooling, characterized by , that the refrigerant compressor (3) is mechanically independent of the vehicle drive motor and can be electrically operated by means of low voltage in order to charge the cold storage unit (12) when sufficient electrical energy is available and to provide air conditioning cooling at the liquid / air heat exchanger (9') when the cold storage unit (12) is discharged during standstill phases of the vehicle drive, wherein the second coolant circuit (2) is part of the cold storage unit (12) and incorporates a second coolant medium (2A) independent of a first coolant medium (1A) of the first coolant circuit (1), and that both coolant circuits (1, 2) in the area of ​​the evaporator (6) of the first coolant circuit (1) and the heat exchanger (8) of the second coolant circuit (2) containing it have heat exchange media, such as fins (17), for the direct transfer of cold to an air conditioning airflow. [6] Vehicle stationary air conditioning system according to claim 5, characterized by a pipe-in-pipe system in which one pipe comprises the evaporator (6) of the first coolant circuit (1) and in which the other pipe receives the second cooling medium (2A) of the second coolant circuit (2) in the area of ​​the heat exchanger (8) of the second coolant circuit (2). [7] Vehicle stationary air conditioning system according to claim 5 or 6, characterized by an additional storage unit (12') which can be circulated through by the second cooling medium (2A) or a cold-storing substance (16) in conjunction with the cold storage unit (12). [8] Vehicle stationary air conditioning system according to one of claims 5 to 7, characterized by , that the cold storage unit (12) is combined with the evaporator (6) of the first coolant circuit (1) and with the heat exchanger (8) of the second coolant circuit (2) which contains the evaporator (6) for the purpose of cold absorption to form a heat exchanger unit. [9] Vehicle stationary air conditioning system according to one of claims 5 to 8, characterized by , that the evaporator (6) and the cold storage unit (12) in the area of ​​the liquid / air heat exchanger (9') are designed as a pipe-in-pipe system. [10] Vehicle stationary air conditioning system according to one of claims 5 to 9, characterized by , that the cold storage unit (12) is not flowed through by the second cooling medium (2A), but the second cooling medium (2A) is at rest.

Images