Abstract: An air-conditioning system operated with CO2 for a vehicle has a high-pressure section that is connected to the output of a compressor and includes a gas cooler, a low-pressure section that is connected to the suction side of the compressor and includes an evaporator, and an expansion member connecting the high-pressure section and the low-pressure section. The expansion member has a fixed restrictor with a throttle opening of predetermined length and diameter connected between an inlet from the high-pressure section and an outlet to the low-pressure section whereby under all operating conditions of the system, a pressure of refrigerant in the high-pressure section of the system is limited to values of less than 14 MPa. The restrictor can be connected in parallel with a pressure limiting valve and can include two or more different throttle openings that can be selectively connected for refrigerant flow.

Abstract: An optimized CO2 air-conditioning system for a vehicle has individual components designed and/or matched to one another in such a way that if the high pressures in the high-pressure section deviate by up to ±30% from the optimum high pressures, the associated optimum performance figures are reduced by no more than 20%. The individual components include a controllable compressor, a gas cooler, an internal heat exchanger, an evaporator and an accumulator. As a result, a fixed throttle expansion member can be used between the high-pressure and low-pressure sections of the system.

Abstract: A heat-exchanger tube block is disclosed having at least two header tubes (6, 7), which are C-shaped in cross section and each of which has a continuous longitudinal slot (10, 11). Flat tubes (2a, 2b) are inserted into the header-tube longitudinal slots. A cover-plate element (12) is provided which has a plurality of C-shaped openings and is fitted over one end of the at least two header tubes, so that the header tubes respectively fit into one of the openings and are secured in a fluid-tight manner. The tube-block can be used, for example, in an evaporator of CO2 air-conditioning installations for a motor vehicle.

Abstract: A heat-exchanger tube block is disclosed having at least two header tubes (6, 7), which are C-shaped in cross section and each of which has a continuous longitudinal slot (10, 11). Flat tubes (2a, 2b) are inserted into the header-tube longitudinal slots. A cover-plate element (12) is provided which has a plurality of C-shaped openings and is fitted over one end of the at least two header tubes, so that the header tubes respectively fit into one of the openings and are secured in a fluid-tight manner. The tube-block can be used, for example, in an evaporator of CO2 air-conditioning installations for a motor vehicle.

Abstract: The invention relates to an air conditioner with a refrigerant loop containing a compressor, an evaporator, an accumulator positioned on the low-pressure side between the evaporator and the compressor, and an internal heat exchanger with a high-pressure side heat transfer channel and a low-pressure side heat transfer channel. According to the invention, the internal heat exchanger has a multichannel tube wound into a radial spiral or a meander shape. In addition or alternatively, the internal heat exchanger contains a multichannel tube which is positioned in the air current path of a cool air current of a high-pressure side condenser/gas cooler. Utilization, for example as a CO2 air conditioner in motor vehicles.

Abstract: An expansion element for a CO2 motor vehicle air conditioner includes a valve unit which can be used particularly for such an expansion element and which has a fixed throttle between an upstream valve high-pressure side and a downstream valve low-pressure side. The expansion element contains a control valve which is acted upon by the low-pressure-side refrigerant pressure or a physical quantity connected therewith as the correcting variable, or valve unit. The valve unit contains a fixed throttle and at least one additional valve component in the form of a pressure control valve which is arranged in a bypass line bypassing the fixed throttle, or in the form of a control vale influencing the passage cross-section of the fixed throttle.

Abstract: In a condenser for an air-conditioning system, in particular for an air-conditioning system of a motor vehicle, there is provision for a collector (15) to be formed from a plurality of series-connected tubes (18) which extend between header tubes (10, 11) and the cross section of which is a multiple of the cross section of the flat tubes (13).

Abstract: The invention relates to a method for forming at least one flat-tube insertion slot in a header tube. A sawcut is introduced into the header tube during a sawing step, and the slot is configured, during a subsequent punching step, by means of a slot punch, which punches into the region of the sawcut. A rimmed opening can be configured during the punching step by using a slot punch with a larger width and/or length relative to the sawcut. The sawcut is preferably introduced to a depth less that the wall thickness of the header tube. The respective web region(s) between chamber of a multi-chamber header tube can be compressed during the punching operation to a level lower than that of a header-tube wall region functioning as a flat-tube insertion stop, in order to form a chamber-connecting duct.

Abstract: The invention relates to a method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range. The method includes standstill level monitoring with the compressor switched off and/or in-operation level monitoring with the compressor switched on. In the case of in-operation level monitoring, the refrigerant overheat (dTü) at the evaporator is registered and, in the event of excessive overheat, it is concluded that there is underfilling. At a standstill, the pressure and temperature of the refrigerant are registered, and it is concluded that there is an improper refrigerant filling level if the pressure (pKM) lies below a minimum pressure value (pmin) or the temperature (TKM) lies above a maximum saturation temperature value (TS) with the pressure being outside a predefinable intended pressure range ([pu,po]).

Abstract: A multichannel flat tube for a heat exchanger has a plurality of parallel flow channels aligned in a row, side by side, along a transverse axis of the tube. At least the inner flow channels have oval cross-sections, and major semiaxes of the inner flow channels are inclined relative to the transverse axis of the tube at an acute angle. The flat tube can be designed for high operating pressures with relatively low weight and relatively high heat exchange capability. The construction may be used, for example, in CO2 air conditioners in motor vehicles.

Abstract: In a condenser for an air-conditioning system, in particular for an air-conditioning system of a motor vehicle, there is provision for a collector (15) to be formed from a plurality of series-connected tubes (18) which extend between header tubes (10, 11) and the cross section of which is a multiple of the cross section of the flat tubes (13).

Abstract: An integrated modular collector—heat exchanger unit for motor vehicle air conditioners and the like has a collector housing in which a collecting space and a heat exchanger unit are disposed. The heat exchanger unit includes two separate heat exchanger ducts which are in a thermal contact. One heat exchanger duct has a helical course and is part of a first flow duct which extends from a housing inlet to a housing outlet in the collector housing. The other heat exchanger duct is part of a second flow duct extending between the collecting space and a housing connection. This other heat exchanger duct also has a helical course, its coils in each case being in a thermal contact with at least one adjoining coil of the first of the first heat exchanger duct.

Abstract: An air conditioning system has a refrigerant cycle, a coolant cycle, a refrigerant/coolant heat exchanger, coupling these cycles so as to transfer heat, and valve for operating mode-dependent control of the refrigerant flow, whereby the air conditioning system can be operated not only in air conditioning mode but at least also in a heat pump or reheat mode. An internal combustion engine exhaust gas/coolant heat exchanger is connected upstream in series to the refrigerant/coolant heat exchanger in the coolant cycle at least in the heat pump mode; and/or in the reheat operating mode the refrigerant/coolant heat exchanger functions as a condenser/gas cooler, connected upstream in series on the coolant side to the supply air/coolant heat exchanger. In addition or as an alternative, a drying operating mode can be provided for drying the supply air/refrigerant heat exchanger with reversed air conveying direction.

Abstract: In an air conditioner for a motor vehicle, an internal heat exchanger is combined with a condenser and a collector.

Abstract: An intake plenum unit is provided for a heat exchanger with a tube block made of a plurality of heat exchanger tubes. The heat exchanger incorporates an intake plenum with a tube wall in which a lengthwise slot is provided for receiving ends of the heat exchanger tubes. The intake plenum is made of one or more individual tubes inserted into one another endwise or fitted together. Each intake plenum has, at least at one individual tube end, a lengthwise slot that is open and made before or after the construction of the intake plenum. This allows problem-free compensation for manufacturing tolerances of the tube ends to be fitted into the lengthwise slot regarding their length in the direction of the lengthwise slot. The intake plenum unit is suitable for use, for example, for gas coolers and evaporators of carbon-dioxide air conditioners.

Abstract: In known collectors for condensers of motor vehicle air conditioners, the dryer cartridge is inserted from an upper end into the collector via a spacing rod. According to the invention, the dryer cartridge can be secured by releasable connecting means to the sealing lid, and the sealing lid can be mounted on the end associated with the flow segment of the collector profile.