Jet pump unit and refrigerant circuit

Abstract

The invention relates to a jet pump unit (300, 400) having at least two jet pumps (100), which are connected in parallel with one another, for conveying a suction fluid (242) in a refrigerant circuit (200) of a temperature-control system by means of a propellant fluid (231) using the Bernoulli effect, wherein each of the at least two jet pumps has a primary nozzle (103) for accelerating the propellant fluid, a secondary connection interface (102) for supplying the suction fluid, a mixing tube (104) downstream of the primary nozzle (103) and downstream of the secondary connection interface (102), and a diffuser (105) downstream of the mixing tube (104); the jet pump unit has a common pressure line (310) for supplying the propellant fluid to the jet pumps (100, 150, 152) connected in parallel; and the at least two jet pumps are positioned geometrically parallel to each other and so as to lie on a common plane. The invention further relates to a refrigerant circuit (200) comprising such a jet pump unit (300, 400).

Description

[0001] R.415442-IP2

[0002] - 1 -

[0003] Description

[0004] title

[0005] Jet pump unit and refrigerant circuit

[0006] The present invention relates to a jet pump for conveying a suction fluid in a refrigerant circuit of a temperature control system and to a refrigerant circuit with such a jet pump.

[0007] Background of the invention

[0008] Jet pumps (also known as ejectors) can be used, for example, in refrigeration circuits of temperature control systems (e.g., to regulate the temperature of one or more components of a vehicle). An ejector has a primary flow and a secondary flow that mix within the ejector. The primary flow (propellant fluid) is forced through a nozzle at high pressure and exits at high velocity and therefore low pressure. The secondary flow (suction fluid) starts at a significantly lower pressure than the primary flow but is also accelerated in a nozzle. The two flows mix, and the secondary flow is accelerated because the primary flow exits the nozzle at very high velocity and carries the secondary flow along with it (momentum is transferred from the primary to the secondary flow).In the case of a supersonic ejector, a compression pulse occurs at the end of the mixing tube, causing the pressure to rise again. In a subsequent diffuser, additional kinetic energy can be converted into pressure. In summary, the expansion of a high-pressure flow (primary flow) in an ejector can draw in a secondary flow at a lower pressure. With a correct design, the pressure exiting the ejector is higher than at the secondary inlet. R.415442-IP2.

[0009] - 2 -

[0010] Disclosure of the invention

[0011] According to the invention, a jet pump unit and a refrigerant circuit with the features of the independent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

[0012] The invention utilizes the measure of connecting several jet pumps (also referred to as ejectors or injectors, depending on their operating point – primarily evacuating or primarily compressing) in parallel within a jet pump unit. This measure serves in particular to ensure that the jet pumps can be operated at their respective optimal operating points. Especially in vehicle temperature control systems, the performance requirements of a jet pump can fluctuate considerably. However, due to the rigid geometry of the jet pump, it can typically only be operated efficiently within a relatively narrow ratio between primary and secondary pressure. A jet pump with a rigid geometry can only be operated at a defined operating point (fixed mass flow rate, pressure ratio).The jet pumps of the jet pump unit according to the invention are therefore designed to be individually activated and deactivated, so that optionally no, one, or several jet pumps are active simultaneously and compress the suction fluid. The parallel arrangement of several jet pumps accordingly allows a larger operating range to be covered than would be possible with a single jet pump. This prevents, for example, the compression pulse from shifting further downstream of the mixing tube into a diffuser in jet pumps operating with supersonic flow, thus reducing the efficiency of the jet pump. The diffuser serves to convert the kinetic energy of the mixing fluid into pressure (i.e., potential energy).The diffuser can only perform this task efficiently if the fluid flowing through it moves at a speed below the speed of sound, since the diverging wall of the diffuser acts as a nozzle on a supersonic flow. Activating a number of jet pumps adapted to the current performance requirements ensures that the compression shock (and thus also the deceleration of the R.415442-IP2) is minimized.

[0013] - 3 -

[0014] Flow below the speed of sound) occurs within the mixing tube (ideally in an end region of the mixing tube), resulting in a subsonic inlet flow into the diffuser.

[0015] A jet pump usable within the scope of the invention comprises a primary nozzle for accelerating the motive fluid and a secondary connection interface for supplying the suction fluid, as well as a mixing tube downstream of the primary nozzle and downstream of the secondary connection interface, and a diffuser downstream of the mixing tube. Jet pumps can generally be operated transonically or subsonically. In a transonically operated jet pump, the motive fluid exceeds the speed of sound on its way through the primary nozzle. This has an impact on the nozzle design, since a convergent flow path has an accelerating effect for subsonic flows, while a divergent flow path has an accelerating effect for supersonic flows. At least the design of the primary nozzle is therefore dependent on the desired flow velocity. In the case of a subsonically operated jet pump, the speed of sound is not exceeded at any point.

[0016] In the jet pump unit according to the invention, as already mentioned, at least two jet pumps are connected in parallel. The jet pumps connected in parallel are geometrically parallel to each other and lie in a common plane. Within the scope of this invention, jet pumps are described as lying within a plane if the gross flow directions (the line connecting the center of the primary nozzle to the center of the outlet port or the diffuser) of the parallel jet pumps form an angle of max. 5° with the common plane. The common plane is defined as the plane that yields the smallest sum of squared angles for the angles enclosed between the gross flow directions and the plane. Within the scope of this invention, jet pumps are described as geometrically parallel if the gross flow directions of the parallel jet pumps differ from each other by max. 10°.The jet pump unit according to the invention has a common pressure line for supplying the motive fluid to the jet pumps connected in parallel. For example, the at least two jet pumps can each be designed as pipe-type R.415442-IP2.

[0017] - 4 -

[0018] Ejectors are provided that can be mechanically connected to one another, for example by welding, or soldered into a common connection block, which also houses the common pressure line. Within the scope of this invention, pipe ejectors are understood to be jet pumps whose flow-shaping components (also referred to as the "core") are installed in a pipe section as a housing or jacket. For example, the flow-shaping components can be made, at least partially, of a plastic and / or a metal that melts at a comparatively low temperature, e.g., by injection molding, and pressed into the pipe section. This enables cost-effective mass production of the jet pumps.

[0019] According to at least one embodiment, all jet pumps connected in parallel within the jet pump unit can be identical, which has a positive effect on manufacturing complexity. Alternatively, however, at least one of the at least two jet pumps can differ in its design from the other two. For example, one of the jet pumps can be smaller to allow for finer gradation of the operating intervals.

[0020] According to at least one embodiment, a common actuating mechanism, for example an actuator, is provided for the selective opening and closing of the common pressure line for individual or all of the parallel-connected jet pumps. The common actuating mechanism (e.g., a piston that successively opens or closes several openings, each connected to a terminal interface of the parallel-connected jet pumps) enables control with particularly low mechanical and regulatory complexity. Conventionally, each of the parallel-connected jet pumps could be controlled by separate (e.g., electromechanical) valves. In contrast, this embodiment allows for common control with only a single actuating mechanism. For the actuating mechanism, in addition to active control (e.g.,Electromechanical actuators can also be controlled passively, for example using a thermomechanical element (e.g., thermal wax, bimetal, etc.), thus completely eliminating the control effort. R.415442-IP2.

[0021] - 5 -

[0022] According to at least one embodiment, a common suction line is provided for supplying the suction fluid to the parallel-connected jet pumps, and optionally a common control mechanism, e.g., an actuator, is provided for selectively opening and closing the common suction line for individual or all of the parallel-connected jet pumps. Alternatively or additionally, a common outlet line can be provided for discharging the motive fluid and the suction fluid (i.e., the mixed fluid) from the parallel-connected jet pumps, and optionally a common control mechanism, e.g., an actuator, is provided for selectively opening and closing the common outlet line for individual or all of the parallel-connected jet pumps. Selective activation or deactivation of the secondary interface or...The outlet offers the additional advantage of preventing backflow of the mixed fluid to the common suction line through jet pumps that are not currently being supplied with motive fluid. The secondary-side actuating mechanism (i.e., the mechanism that opens and closes the common suction line or the outlet line) can be connected to the primary-side common actuating mechanism, allowing a single control element (e.g., actuator) to perform all actuation tasks. In particular, for the actuating mechanism used to open and close the outlet line, a flat locking element (e.g., a sliding partition or similar) can be used instead of the piston already described. However, depending on the specific common pressure or suction line used, this design with a flat locking element can also be used to open and close that line as well.

[0023] Alternatively, a separate check valve can be provided at the end of each diffuser to block backflow. In this design variant, backflow prevention is proposed using individual check valves installed at the outlet of the jet pump unit (in the medium-pressure channel). These valves can then be mounted together on a common plate outside the housing of the respective jet pump or in the respective connection interfaces of the common outlet line. Thus, the R.415442-IP2

[0024] - 6 -

[0025] Check valves are easier to install, which can reduce production costs and also increases accessibility for repair and maintenance work.

[0026] According to at least one embodiment, the actuating mechanism comprises a piston that is rotatable and / or linearly displaceable within a tube and / or bore, wherein the piston is configured to selectively open and / or selectively close openings within a wall of the tube or bore, with each of the primary nozzles of the jet pumps being connected to one of the openings in the wall of the tube or bore. In particular, the piston can be designed as a hollow cylinder and have at least one recess in a shell wall of the hollow cylinder, wherein the at least one recess is configured to at least partially coincide with the openings in the wall of the tube or bore, depending on a position of the piston. According to at least one embodiment, the at least one recess is configured to close one or more of the openings in the wall of the tube or bore.to simultaneously release the bore. For example, the recess can have an extension along the cylinder axis that exceeds the distance between two adjacent openings within the wall of the tube or bore, so that one and the same recess can simultaneously release none, one, or several of the openings, depending on the relative (rotational and / or translational) position of the piston to the tube or bore. The supply of suction fluid or propellant fluid, or the discharge of the mixing fluid, can occur via the cavity inside the hollow cylinder (e.g., via an axial opening in one of the end faces of the piston or via one or more radial recesses).

[0027] Alternatively, the piston can also comprise a solid cylinder in whose outer surface at least one recess is provided, the design of which corresponds to the at least one recess described here. In such a case, the at least one recess can, in particular, comprise a channel for supplying the suction or propellant fluid or for discharging the mixing fluid. R.415442-IP2

[0028] - 7 -

[0029] For example, at least one recess or depression can be circular bores that can be aligned with the (e.g., also circular) openings by discrete movements of the piston. Further options include recesses or depressions extended circumferentially and / or axially along the piston, which can align with several of the openings simultaneously or remain aligned with the respective opening over a larger range of motion, thus enabling continuous piston movements (e.g., to slowly start up a jet pump and not supply it abruptly with motive or suction fluid). Furthermore, there is the possibility of using essentially triangular recesses or depressions.Recesses are used, which allows for a selection of the number and identity of the activated jet pumps by means of both a rotational movement and a translational movement of the piston.

[0030] A refrigerant circuit according to the invention for a temperature control system comprises at least one jet pump according to the invention, a compressor for compressing a refrigerant, a refrigerant condenser for at least partially condensing the refrigerant downstream of the compressor, and a refrigerant evaporator for at least partially evaporating the refrigerant, wherein the jet pump is arranged such that the at least partially condensed refrigerant is supplied to it downstream of the refrigerant condenser as motive fluid and the at least partially evaporated refrigerant is supplied downstream of the refrigerant evaporator as suction fluid, and wherein an outlet of the jet pump opens into a liquid phase separator, which is configured to separate a liquid fraction from a gas fraction of the refrigerant, wherein the gas fraction is fed to the compressor on the suction side and the liquid fraction is fed to the refrigerant evaporator.

[0031] In particular, the jet pump or the refrigerant circuit according to the invention can be used in a temperature control system of a vehicle, for example, a vehicle that is at least partially electrically powered. The temperature control system can be used, in particular, for temperature control of the vehicle interior and / or the traction battery and / or the traction motor R.415442-IP2

[0032] - 8 -

[0033] and / or other components of the vehicle. However, it should be expressly noted that embodiments of the jet pump unit or the refrigerant circuit according to the invention can also be used in other mobile and / or stationary application scenarios, for example, for cooling and / or heating and / or dehumidifying buildings (e.g., air conditioning, heat pump, etc.). In particular, the heating and / or cooling and / or dehumidification of the building is preferably carried out by a device, especially an HVAC system (Heating, Ventilation and Air Conditioning system), preferably an air conditioner or a heat pump, which includes a jet pump unit or a refrigerant circuit according to the invention. The use of the jet pump unit or the refrigerant circuit according to the invention for heating drinking water, especially in a hot water heat pump, is also conceivable.

[0034] Regardless of the overall design of the jet pump, it can be provided that the jet pump has a casing and a core arranged within the casing, wherein the core defines an internal geometry of the jet pump and wherein the casing defines an external geometry of the jet pump and is configured to mechanically support the core. In particular, the core can be made of a first material and the casing of a second material that differs from the first material, wherein the second material has higher mechanical strength and / or higher hardness than the first material and / or wherein, at a predetermined temperature, the first material exhibits higher deformability than the second material. The higher deformability of the first material allows for the manufacture of an internal contour of the jet pump with particularly high precision (for example, using an injection molding process, etc.).The inner contour is particularly relevant for the design, as it controls the flow of the motive and suction fluids. Therefore, the precision of the inner contour is also crucial for the efficiency of the jet pump. Despite this, the core is supported by the casing, which comprises the mechanically more robust secondary material, ensuring high pressure resistance for the entire jet pump, for example, with a significantly higher resistance than R.415442-IP2.

[0035] - 9 -

[0036] Less material is used for the core. Details of possible embodiments of such a jet pump with different materials in the casing and core are disclosed in the parallel patent application DE 102025145870.7, in particular in Figure 1 and the associated description.

[0037] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0038] The invention is schematically illustrated in the drawing using exemplary embodiments and is described below with reference to the drawing.

[0039] Brief description of the drawings

[0040] Figure 1 shows a jet pump as it can be used according to at least one embodiment of the invention.

[0041] Figure 2 shows a refrigerant circuit according to one embodiment of the invention.

[0042] Figure 3 shows a first embodiment of a jet pump unit according to the invention.

[0043] Figures 4A and 4B show further variants, in particular of the actuating mechanism, of the first embodiment of a jet pump unit according to the invention shown in Figure 3.

[0044] Figure 5 shows a second embodiment of an invention

[0045] Jet pump unit. R.415442-IP2

[0046] - 10 -

[0047] Figure 6 shows a further embodiment of an adjusting mechanism as it can be used in embodiments of the invention.

[0048] embodiment(s) of the invention

[0049] Figure 1 shows a jet pump, as it can be used according to at least one embodiment of the invention, schematically shown by means of a longitudinal section drawing and labelled overall with 100.

[0050] The jet pump comprises a first connection interface 101 for supplying a propellant fluid to a primary nozzle 103 of the jet pump 100 and a second connection interface 102 for supplying a suction fluid to a mixing tube 104 of the jet pump 100, which is located downstream of the primary nozzle 103. In the example shown here, the primary nozzle 103 is designed as a supersonic nozzle, which accelerates the propellant fluid (given a suitable inlet pressure of the propellant fluid and a suitable pressure drop across the jet pump 100) to a velocity exceeding the relevant speed of sound. A region within the primary nozzle where the speed of sound is exceeded is marked with a dashed ellipse. This acceleration significantly reduces the pressure of the propellant fluid on its way through the primary nozzle 103 to the inlet of the mixing tube 104 (e.g., from approximately 30 bar to 2 bar).

[0051] If a suction fluid with a suitable inlet pressure, which is typically significantly lower than the inlet pressure of the propellant fluid (e.g., 2 bar), is present at the second connection interface 102, the suction fluid is accelerated by momentum transfer from the propellant fluid in the mixing tube 104 downstream of the primary nozzle 103 to the suction fluid. The propellant fluid is decelerated accordingly. Under optimal operating conditions, the propellant fluid thus falls below the speed of sound again in a final section 140 at an end of the mixing tube 104 furthest from the primary nozzle. R.415442-IP2

[0052] - 11 -

[0053] Downstream of the mixing tube 104, a diffuser 105 is connected in the form of a section widening in its cross-section, which serves to further decelerate and increase the pressure in the mixed fluid (also referred to as mixing fluid). For example, under the operating conditions mentioned above, an outlet pressure of 3 to 4 bar can be achieved at the outlet of the diffuser.

[0054] In particular, the jet pump 100 can be designed as a pipe ejector, the flow-shaping components 120 (also referred to as core 120) of which are installed in a pipe section as a housing or jacket 110.

[0055] Figure 2 shows a refrigerant circuit according to an embodiment of the invention schematically using a functional diagram and is labelled overall with 200.

[0056] The refrigerant circuit 200 comprises a compressor 210 for compressing a refrigerant, for example propane, CO2, or another suitable gas that can be at least partially condensed under the selected operating conditions, a refrigerant condenser 220, a jet pump unit 300 comprising several jet pumps 100 connected in parallel, which may be configured in particular as described with reference to Figure 1, a liquid phase separator 250, and a refrigerant evaporator 240 for transferring heat to the refrigerant. An expansion valve 245 for expanding the refrigerant is arranged upstream of the refrigerant evaporator 240.

[0057] The jet pump unit 300 can be designed in particular as shown in Figure 3 or 4.

[0058] As can be seen in Figure 2, the jet pump unit 300 is used in the refrigerant circuit 200 for pre-compression of the expanded refrigerant 242 exiting the refrigerant evaporator 240. The liquid phase of the compressed refrigerant 231 after exiting the refrigerant condenser 220 (and in the example shown, a further heat exchanger 230, which is provided for transferring heat between the compressed refrigerant on the pressure side of the compressor and the refrigerant 253 supplied to the compressor on the suction side) is R.415442-IP2

[0059] - 12 -

[0060] The refrigerant is pressurized and, for acceleration and expansion, is directed as a propellant fluid into the primary nozzle(s) 103 of the jet pump(s) 100. On the secondary side (connection interface 102), the expanded refrigerant 242 is drawn in as a suction fluid at evaporator pressure level. The mixture 251 of propellant fluid and suction fluid, pre-compressed by the jet pump unit 300, is directed into the liquid phase separator 250, where the separated liquid phase 252 is then directed through the expansion valve 245 to the refrigerant evaporator 240. The vapor component 253 of the refrigerant, separated in the liquid phase separator 250, is returned to the compressor 210 via the heat exchanger 230. The pre-compression by the jet pump unit 300 reduces the compression work required in the compressor 210.

[0061] Figures 3 to 6 show different versions of the actuating mechanisms for controlling the jet pump unit. Several positions of the same actuating mechanism are shown in each figure to illustrate the function of the different versions.

[0062] Figure 3 schematically illustrates a first embodiment of a jet pump unit according to the invention in a sectional drawing, and is designated as 300. A first jet pump 100, which can be configured as explained with reference to Figure 1, is connected in parallel with, in the example shown, two further jet pumps 150, 152, which can be configured identically to the first jet pump 100. The jet pumps 100, 150, 152 are also arranged geometrically parallel to each other and lying in a common plane.

[0063] The jet pump unit 300 has a common pressure line 310 for supplying the motive fluid to the parallel-connected jet pumps 100, 150, 152 and a common actuating mechanism 320 for selectively opening and closing the common pressure line 310 for individual or all of the parallel-connected jet pumps 100, 150, 152. The common pressure line 310 can, for example, be housed in a terminal block into which the tube ejectors 100, 150, 152 can be soldered (R.415442-IP2).

[0064] - 13 -

[0065] In the example shown here, the actuating mechanism 320 has a (hollow cylindrical) piston with an axial bore, which, in the closed position, blocks the inlet on the primary side to the jet pumps 100, 150, and 152. The further the piston is pulled outwards, the more of the jet pumps 100, 150, and 152 are released and supplied with motive fluid on the primary side. The motive fluid can be supplied, for example, through the bore. However, a solid piston can also be used, with the supply line connected laterally to the tube in which the piston is guided.

[0066] The common actuating mechanism 320, which can be actuated, for example, by means of an electromechanical actuator (not shown separately) or passively controlled (e.g., using a thermal wax that changes its spatial expansion with temperature, or a bimetallic strip), selectively activates the respective jet pumps 100, 150, 152, which then pump suction fluid from the second connection interface. In the example shown, this second interface is permanently supplied with suction fluid from a common suction line 330, for example, from the refrigerant evaporator 240 shown in Figure 2. The pre-compressed mixed flow at the outlet of the jet pumps 100, 150, 152 then mixes from all jet pumps 100, 150, 152.

[0067] The number of active jet pumps 100, 150, 152 is determined by the insertion depth of the piston of the actuating mechanism 320 into the common pressure line 310.

[0068] In a further variant 300A of the first embodiment of the jet pump unit, shown in Figure 4A, the actuating mechanism 320A comprises a hollow cylindrical piston instead of the end-open piston. This piston has radial recesses 322 through which the motive fluid can exit the piston when these recesses 322 overlap or coincide with corresponding openings 312 to which the respective jet pumps 100, 150, 152 are connected. In this variant 300A as well, the piston must be moved translationally into the desired position to activate or deactivate jet pumps 100, 150, 152. R.415442-IP2

[0069] - 14 -

[0070] Figure 4B also shows a third variant 320B for the actuating mechanism 320 of the first embodiment 300 of the jet pump unit. In this third variant, compared to the second variant 320A, the piston of the actuating mechanism 320B is not provided with circular recesses 322 to supply the openings 312 with the motive fluid, but with recesses (in the form of elongated holes) 324 oriented axially along the piston. These elongated holes or recesses 324 have, for example, a length that allows at least two of the openings 312 to be aligned simultaneously with the same elongated hole or recess 324, so that one recess 324 can supply several jet pumps 100, 150, 152 simultaneously. In this third variant as well, the piston of the actuating mechanism 320B is moved translationally in the axial direction in order to activate or deactivate the desired jet pumps 100, 150, 152.However, in contrast to the second variant, the elongated slots 324 in this variant allow for continuous adjustment of the piston, whereas in the second variant 300A, activation of the jet pumps 100, 150, 152 only occurs in discrete piston positions, namely precisely when the respective slots 322 exactly align with the openings 312. In particular, the elongated slots 324 therefore also allow for greater tolerances with regard to the piston position.

[0071] Figure 5 shows a second embodiment of a jet pump unit according to the invention with jet pumps 100, 150, 152 connected in parallel, and is collectively designated 400. The second jet pump unit 400 is essentially identical to the first jet pump unit 300, 300A, which was explained with reference to Figure 3, but differs from this first jet pump unit 300 in particular in that the actuating mechanism 420 of this second embodiment 400 has a piston with the axial bore that is not moved translationally to select the various actuating options, but by a rotation about the piston axis. Analogous to the second and third variants of the first embodiment 300, 300A, the rotation of the piston creates recesses 422, 424 in the wall of the hollow cylinder forming the piston with openings 312 in the wall of the R.415442-IP2

[0072] - 15 -

[0073] common pressure line 310 was brought into alignment, thus activating the jet pumps 100, 150, 152 connected to the openings 312.

[0074] The recesses 422, 424 can, for example, be designed as substantially circular bores 422 or as elongated holes 424 oriented in the circumferential direction of the piston, as shown in Fig. 5, whereby in the case of the elongated holes 424 a continuous adjustment is possible (which also allows a greater tolerance with regard to the angular position of the piston), while in the case of individual bores 422 only discrete rotation angles lead to a coverage between the respective recess 422 and the associated opening 312.

[0075] Figure 6 shows a further embodiment of the actuating mechanism, designated 520. The actuating mechanism 520 conceptually combines aspects of the actuating mechanism of the first embodiment 300A and the second embodiment 400 of the jet pump unit, since it can be actuated to activate or deactivate the jet pumps by means of both translational and rotational movement. In the example shown, only a triangular recess 524 is provided, which extends axially and circumferentially over the wall of the piston such that, depending on the axial and / or rotational position of the piston, it supplies any one of the openings, several adjacent openings, or all openings simultaneously with the motive fluid, as shown schematically in Figure 6.This design of the actuating mechanism 520 is particularly advantageous in cases where not all jet pumps in the jet pump unit have the same capacity, since the individual control of each jet pump allows the most suitable combination of jet pumps for the current power requirement to be specifically activated. For this purpose, recess shapes other than the triangular shape shown here can also be used to increase the number of possible combinations, for example, to activate jet pumps that are not adjacent to each other simultaneously without the jet pumps in between.

Claims

R.415442-IP2 - 16 - Claims 1. Jet pump unit (300, 400) with at least two jet pumps (100) connected in parallel for pumping a suction fluid (242) in a refrigerant circuit (200) of a temperature control system using a propellant fluid (231) utilizing the Bernoulli effect, wherein each of the at least two jet pumps has a primary nozzle (103) for accelerating the propellant fluid, a secondary connection interface (102) for supplying the suction fluid, a mixing tube (104) downstream of the primary nozzle (103) and downstream of the secondary connection interface (102), and a diffuser (105) downstream of the mixing tube (104), wherein the jet pump unit has a common pressure line (310) for supplying the propellant fluid to the jet pumps (100, 150, 152) connected in parallel, wherein the at least two jet pumps are geometrically parallel to each other and are arranged lying in a common plane.

2. Jet pump unit (300, 400) according to claim 1, wherein the jet pump unit has a common actuating mechanism (320, 420, 520) for selectively opening and closing the common pressure line (310) for one, several or all of the parallel-connected jet pumps (100, 150, 152).

3. Jet pump unit according to claim 2, wherein the actuating mechanism (320, 420, 520) comprises a piston rotatable and / or linearly displaceable within a tube and / or bore, which is configured to selectively release and / or selectively close openings (312) within a wall of the tube or bore, wherein each primary nozzle (103) of the jet pumps is connected to at least one of the openings (312) in the wall of the tube or bore. R.415442-IP2 - 17 - 4. Jet pump unit according to claim 3, wherein the piston is designed in a hollow cylindrical shape and has at least one recess (322, 324, 422, 424, 524) in a shell wall of the hollow cylinder, wherein the at least one recess is arranged to at least partially coincide with the openings (312) in the wall of the tube or bore, depending on a position of the piston.

5. Jet pump unit according to claim 3, wherein the piston is cylindrical and has at least one recess in a cylindrical surface of the cylinder, wherein the at least one recess is arranged to at least partially coincide with the openings (312) in the wall of the tube or bore depending on a position of the piston.

6. Jet pump unit according to claim 4 or 5, wherein the at least one recess (322, 324, 422, 424, 524) or the at least one depression is configured to simultaneously release one or more of the openings (312) in the wall of the tube or bore.

7. Jet pump unit according to one of the preceding claims, wherein the at least two jet pumps (100) are provided as pipe ejectors, comprising a jacket (110) in the form of a pipe section and a core (120) arranged within the jacket, where the core (120) defines an internal geometry of the jet pump (100), wherein the jacket (110) defines an outer geometry of the jet pump (100) and is designed to mechanically support the core (120).

8. Jet pump unit according to claim 7, wherein the core (120) comprises a first material and the shell (110) comprises a second material which differs from the first material, wherein the second material has a higher mechanical strength and / or a higher hardness than the first material and / or R.415442-IP2 - 18 - where, at a predetermined temperature, the first material exhibits a higher deformability than the second material.

9. Refrigerant circuit (200) for a temperature control system comprising a jet pump unit according to one of the preceding claims, a compressor (210) for compressing a refrigerant (253), a refrigerant condenser (220) for at least partially condensing the refrigerant downstream of the compressor (210), and a refrigerant evaporator (240) for at least partially evaporating the refrigerant, wherein the jet pump unit is arranged such that the at least partially condensed refrigerant (231) is supplied to it downstream of the refrigerant condenser (220) to the common pressure line as motive fluid and the at least partially evaporated refrigerant (242) is supplied downstream of the refrigerant evaporator (240) as suction fluid, and wherein downstream of an outlet of the jet pump unit a gaseous fraction (253) of the refrigerant is supplied to the compressor (210) on the suction side and a liquid fraction (252) of the refrigerant is supplied to the Refrigerant evaporator (240) is used.

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