Patent Publication Number: US-2023158861-A1

Title: Climate control system with a controlled ejector

Description:
This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. 10 2021 213 208.1, which was filed in Germany on Nov. 24, 2021, and which is herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a climate control system for heating or cooling a space, in particular a vehicle interior, having a compressor for conveying a refrigerant, and to a motor vehicle with a climate control system of this kind. 
     Description of the Background Art 
     Air conditioning systems are already known that operate with CO 2  as the refrigerant. Air conditioning systems of this kind are currently limited in their performance at high outdoor temperatures. In addition, alternative refrigerants with a better performance, such as R1234YF, are used in air conditioning systems. However, refrigerants of this kind are not environmentally neutral and, depending on the situation, can be flammable and compromise safety. Furthermore, refrigerants such as R1234YF have limited use in a heat pump mode. 
     U.S. Pat. No. 7,428,826 B2 describes an ejector device that controls a refrigerant inflow to a first and a second evaporator. U.S. Pat. No. 7,726,150 B2 also discloses an ejector device of this kind. 
     A refrigerant circuit with an ejector is known from U.S. Pat. No. 7,254,961 B2. The ejector is located downstream of a heat exchanger or condenser and serves as a decelerator for the refrigerant. 
     WO 2018/159322 A1 describes an ejector with an adjustable nozzle opening by means of a movable needle. 
     JP 2008-082614 A discloses an air conditioning system with an ejector. The air conditioning system has a plurality of compressors to increase the cooling capacity. 
     U.S. Pat. No. 7,707,849 B2 discloses a refrigerant circuit with an ejector. The ejector is formed integrally with a first evaporator, a second evaporator, and an adjusting mechanism. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a climate control system that can efficiently use the refrigerant CO 2  for heat pump applications as well. In particular, it is the object of the invention to provide a climate control system that can be reliably operated with CO 2  as the refrigerant even under extreme climatic conditions. 
     According to an exemplary embodiment of the invention, a climate control system is provided for heating or cooling a space, in particular a vehicle interior. The climate control system has a compressor for conveying a refrigerant. For example, the refrigerant can be CO 2 . However, the climate control system is not limited to CO 2  as a refrigerant. In particular, R1234yf, propane, butane, or mixtures of propane and butane, or mixtures of CO 2  and the like can be used as refrigerants by the climate control system. 
     The climate control system further comprises a high-pressure chiller, a low-pressure chiller, a liquid separator or economizer, and a controlled first ejector. 
     A high-pressure chiller for cooling the refrigerant is located downstream of the compressor and a low-pressure chiller for heating the refrigerant is located upstream of the compressor. Alternatively, a gas cooler and/or an interior condenser can be provided instead of the high-pressure chiller to implement the corresponding function. 
     A refrigerant exiting from the high-pressure chiller or the gas cooler and/or the interior condenser can be supplied to a motive mass inlet of a first controlled ejector, and a refrigerant exiting from the low-pressure chiller can be supplied to a suction mass inlet of the first ejector. Furthermore, an outlet of the first ejector is connected directly or indirectly to a liquid separator. 
     According to a further aspect of the invention, a motor vehicle is provided which has a climate control system of the invention. 
     For example, the climate control system can be operated as a CO 2  air conditioning system, which has increased efficiency. An electric vehicle equipped with such a climate control system can thus benefit from an increase in range. In this context, the climate control system enables the reliable use of CO 2  as a refrigerant even under extreme climatic conditions. 
     The first ejector can be designed as a controlled ejector. A motive mass flow, which has an increased pressure compared to a suction mass flow, can be provided at the motive mass inlet of the first ejector. The motive mass flow can thus be accelerated by the suction mass flow in an annular gap between a nozzle and a needle of the ejector. The momentum of the motive mass flow is transferred to the suction mass flow after passing the nozzle. Both mass flows mix in this case. The cross section increases in the downstream diffuser of the first ejector, as a result of which the velocity of the resulting total mass flow declines and the pressure increases above the level of the suction mass flow. The diffuser forms the outlet of the first ejector. 
     The size of the annular gap is adapted to requirements and boundary conditions by an axial displacement of the needle relative to the nozzle. Thus, a variable nozzle cross section can be realized. Proportional solenoids with a position sensor system, stepper motors with spindle gears, DC motors with spindle gears, or actuators based on shape-memory alloys can be used as actuators for controlling the first ejector. 
     More preferably, the climate control system can be used in combined air conditioning and heat pump systems in electric vehicles or BEVs. In this case, in particular, carbon dioxide or CO 2  can be used as a refrigerant, which is usable in the air conditioning mode and heat pump mode. 
     Due to the structure of the climate control system and the properties of CO 2 , different phase states and phase changes occur within the ejector. This can result in pressure surges or pulsations. Operating points with shock waves or pulsations in the 2-phase ejector can be avoided due to the variability of the nozzle cross section. 
     Furthermore, an increased temperature delta between the evaporator or the high-pressure chiller and the condenser or the low-pressure chiller can be utilized by means of the climate control system. 
     The efficiency of the climate control system can be increased if the outlet of the first ejector is indirectly connected to the liquid separator via an interior evaporator. For example, a cooling output can be supplied to the vehicle interior hereby before the refrigerant reaches the liquid separator. In the liquid separator, which is preferably designed as a so-called economizer, the refrigerant can be separated into its gaseous and liquid components. The gaseous components of the refrigerant are then conveyed or guided in the direction of the compressor and the liquid components of the refrigerant in the direction the low-pressure chiller. 
     According to a further exemplary embodiment, an interior evaporator can be connected in parallel to the low-pressure chiller, wherein an expansion valve can be connected upstream of the interior evaporator and/or low-pressure chiller. By connecting an expansion valve upstream, the inflow of the at least partially condensed refrigerant to the low-pressure chiller and/or the interior evaporator can be precisely controlled. In the interior evaporator in particular, the refrigerant, which is partially or completely in the liquid phase, can be evaporated again, as a result of which additional cooling output is generated. 
     The refrigerant inflow to the first ejector can be precooled if a refrigerant outlet of the high-pressure chiller or the gas cooler is thermally coupled to a refrigerant inlet of the compressor, in particular via an interior heat exchanger. An optional gas cooler in the front end can also be omitted due to this measure. 
     The low-pressure chiller and the high-pressure chiller are acted upon thermally by cooling water or heating water, respectively, in order to heat or cool the passing refrigerant. The corresponding heat transfer between the ambient air and refrigerant thus takes place via the cooling water. The efficiency losses due to the heat transfer via the cooling water are compensated by the efficiency increase of the climate control device. 
     The outlet of the first ejector can be indirectly connected to the liquid separator via a second ejector, wherein the outlet of the first ejector is connected to a suction mass inlet of the second ejector and the outlet of the second ejector is connected to the liquid separator. Further components, in particular interior evaporators or interior condensers, can be integrated into the climate control system due to this measure. The second ejector is preferably also designed as a controlled ejector analogous to the design of the first ejector. As a result, the refrigerant flow can be controlled independently of the first ejector by the additional integrated component. 
     The climate control system can be used in a particularly versatile manner if a branch arranged downstream of the compressor or a branch arranged upstream of the compressor, in particular downstream of the liquid separator, or a branch arranged downstream of the high-pressure chiller is connected directly or via an interior condenser or via an interior heat exchanger to a motive mass inlet of the first ejector or the second ejector. 
     The outlet of the first ejector can be connected to a motive mass inlet of the second ejector, wherein a refrigerant flows through an interior heat exchanger that is branched off upstream of the low-pressure chiller and is connected to the suction mass inlet of the first ejector; or wherein the interior heat exchanger is flowed through by a refrigerant branched off downstream of the high-pressure chiller and is connected to the suction mass inlet of the second ejector. As a result, the interior heat exchanger can be connected either to the high-pressure side or to the low-pressure side of the refrigerant in order to supply a heat output or a cooling output to the space, in particular the vehicle interior. 
     The climate control system can also be optimally used with CO 2  as the refrigerant for hot climate applications if a gas cooler can be connected between the refrigerant outlet of the high-pressure chiller and the motive mass inlet of the first ejector or between the refrigerant outlet of the liquid separator and the motive mass inlet of the first ejector. Moreover, increased comfort requirements, which have a higher demand for a cooling output, can also be reliably implemented by the additional gas cooler. 
     A refrigerant outlet of a gas cooler can be connected to the motive mass inlet of the second ejector. Depending on the design of the climate control system, the gas cooler can basically be used for heat transfer in any direction. Thus, the gas cooler can be used to remove heat from the refrigerant or to supply heat to the refrigerant. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes, combinations, and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG.  1    shows a schematic representation of a climate control device according to a first exemplary embodiment; 
         FIG.  2    shows a schematic representation of a climate control device according to a second exemplary embodiment; 
         FIG.  3    shows a schematic representation of a climate control device according to a third exemplary embodiment; 
         FIG.  4    shows a schematic representation of a climate control device according to a fourth exemplary embodiment; 
         FIG.  5    shows a schematic representation of a climate control device according to a fifth exemplary embodiment; 
         FIGS.  6   a  and  6   b    show schematic representations of a climate control device according to a sixth exemplary embodiment in a cooling mode and in a heating mode; 
         FIGS.  7   a  and  7   b    shows schematic representations of a climate control device according to a seventh exemplary embodiment in a cooling mode and in a heating mode; 
         FIGS.  8   a  and  8   b    show schematic representations of a climate control device according to an eighth exemplary embodiment in an air conditioning mode and in a heat pump mode; 
         FIGS.  9   a  and  9   b    show schematic representations of a climate control device according to a ninth exemplary embodiment in an air conditioning mode and in a heat pump mode; 
         FIGS.  10   a  to  10   c    show schematic representations of a climate control device according to a tenth exemplary embodiment in an air conditioning mode, in a heat pump mode, and in a reheating mode; 
         FIGS.  11   a  and  11   b    show schematic representations of a climate control device according to an eleventh exemplary embodiment in an air conditioning mode and in a heating mode; 
         FIGS.  12   a  and  12   b    show schematic representations of a climate control device according to a twelfth exemplary embodiment in an air conditioning mode and in a heating mode; and 
         FIG.  13    shows a side view of a motor vehicle of the invention according to an exemplary embodiment with a climate control device. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a schematic representation of a climate control device  10  according to a first exemplary embodiment. Climate control system  10  is used to heat or cool an exemplary vehicle interior  110 , which is illustrated in  FIG.  13   . 
     Climate control system  10  has a compressor  11  for conveying a refrigerant. For example, CO 2  can be used as the refrigerant. In the illustrated exemplary embodiment, compressor  11  is designed as an electrically driven compressor. 
     Downstream of compressor  11 , a high-pressure chiller  12  is provided for cooling the refrigerant or removing heat from the refrigerant to a water cooling circuit. 
     Analogous to high-pressure chiller  12 , a low-pressure chiller  13  is provided upstream of compressor  11  for heating the refrigerant or for removing heat output from the thermally coupled water cooling circuit. 
     A refrigerant exiting high-pressure chiller  12  is supplied to a motive mass inlet  22  of a first ejector  21 , and a refrigerant exiting from low-pressure chiller  13  is supplied to a suction mass inlet  23  of first ejector  21 . 
     In the illustrated exemplary embodiment, an outlet  24  of first ejector  21  is indirectly connected to a liquid separator  14  via an interior evaporator  15 . Interior evaporator  15  is preferably thermally coupled to vehicle interior  110  and can, for example, have air flowing therethrough from an interior fan. 
     Liquid separator  14  is designed as an economizer and can separate the liquid phase from the gaseous phase of the refrigerant. Accordingly, the gaseous phase can be guided in the direction of compressor  11  and the liquid phase to low-pressure chiller  13 . 
     First ejector  21  is designed as a controlled ejector and has an electric drive  25 . Electric actuator  25  is used to adjust a cross section of an annular gap, with which the velocity or a volumetric flow rate of the motive mass flow supplied through motive mass inlet  22  is adjusted. 
     Furthermore, an expansion valve  16  is arranged between liquid separator  14  and low-pressure chiller  13  in order to evaporate and thus to cool the refrigerant supplied in the liquid phase to low-pressure chiller  13 . 
     A schematic representation of a climate control device  10  according to a second exemplary embodiment is illustrated in  FIG.  2   . In contrast to the first exemplary embodiment, an interior heat exchanger  17  is provided here, which thermally couples a refrigerant outlet of high-pressure chiller  12  to a refrigerant inlet of compressor  11 . 
       FIG.  3    shows a schematic representation of a climate control device  10  according to a third exemplary embodiment. Climate control device  10  according to a third exemplary embodiment is based on the exemplary embodiments already described, but interior evaporator  15  is arranged in parallel to low-pressure chiller  13 . In this case, an expansion valve  18  is connected upstream of interior evaporator  15 , analogous to low-pressure chiller  13 . 
     Because interior evaporator  15  is arranged at a new position, first ejector  21 , in particular outlet  24  of first ejector  21 , can be connected proximately or directly to liquid separator  14 . 
       FIG.  4    shows a schematic representation of a climate control device  10  according to a fourth exemplary embodiment, which is based on the second exemplary embodiment. In this case, in the fourth exemplary embodiment, analogous to the third exemplary embodiment, interior evaporator  15  has been moved downstream of liquid separator  14  and in parallel to low-pressure chiller  13 . There is also an interior heat exchanger  17 , which thermally couples the refrigerant outlet of high-pressure chiller  12  to the refrigerant inlet of compressor  11 . 
       FIG.  5    illustrates in a schematic representation a climate control device  10  according to a fifth exemplary embodiment. Climate control device  10  according to the fifth exemplary embodiment is based on the third exemplary embodiment and has an interior condenser  19 . 
     Interior condenser  19  is placed downstream of compressor  11 , in parallel to high-pressure chiller  12 . 
     Furthermore, outlet  24  of first ejector  21  opens into a suction mass inlet  33  of a second ejector  31 . Interior condenser  19  is connected to a motive mass inlet  32  of second ejector  31 . Finally, an outlet  34  of second ejector  31  opens into liquid separator  14 . Thus, first ejector  21  is indirectly connected to liquid separator  14  via second ejector  31 . 
     Second ejector  31  is designed as a controlled ejector, analogous to first ejector  21 . 
     In the fifth exemplary embodiment, a branch A 1  arranged downstream of the compressor is indirectly connected to motive mass inlet  23  of second ejector  31  via interior condenser  19 . 
     Thus, an interior condenser  19  is arranged in parallel to high-pressure chiller  12  and is set up to heat a supply air of vehicle interior  110 . The second jet pump or second ejector  31  is used to control the application and utilization of the expansion work. 
     In the fifth exemplary embodiment, heating as well as cooling and reheating are realized by direct heat transfer from the climate control circuit to the interior air. 
       FIG.  6   a    and  FIG.  6   b    show schematic representations of a climate control device  10  according to a sixth exemplary embodiment in a cooling mode and in a heating mode. Here,  FIG.  6   a    shows climate control device  10  in a cooling mode or air conditioning mode, and  FIG.  6   b    shows the climate control device in a heating mode. 
     The sixth exemplary embodiment is based on the first exemplary embodiment and was expanded by second ejector  31  and an interior heat exchanger  40 . Interior heat exchanger  40  is arranged in parallel to second ejector  31  and is connected to motive mass inlet  32  of second ejector  31 . In the cooling mode, interior heat exchanger  40  is coupled to second ejector  31  via liquid separator  14 . 
     To realize the heating mode, it is necessary to connect interior heat exchanger  40  via a branch A 1  located downstream of the compressor. In both operating modes, interior heat exchanger  40  opens into motive mass inlet  32  of second ejector  31 . An expansion valve  18  is positioned in branch A 1 . 
     The switching of the operating modes occurs via two valves  51 ,  52 . 
     Optionally, a water heat exchanger or an air heater for the interior air can be provided to ensure the reheating mode for drying air in vehicle interior  110 . 
     The exemplary embodiments shown in the figures explain the principle, for the sake of simplicity, using a motor vehicle  100  (see  FIG.  13   ). However, climate control system  10  is not limited to use in motor vehicles  100 . 
     Schematic representations of a climate control device according to a seventh exemplary embodiment in a cooling mode and in a heating mode are shown in  FIG.  7   a    and  FIG.  7   b   . The seventh exemplary embodiment substantially corresponds to the sixth exemplary embodiment. In particular, the operating mode shown in  FIG.  7   a    for cooling the vehicle interior  110  by means of interior heat exchanger  40  corresponds to  FIG.  6     a.    
       FIG.  7   b    differs in that a branch A 2  downstream of high-pressure chiller  12  is used to provide refrigerant to interior heat exchanger  40  and to supply it to motive mass inlet  32  of second ejector  31 . 
       FIG.  8   a    and  FIG.  8   b    are schematic representations of a climate control device  10  according to an eighth exemplary embodiment in an air conditioning mode and in a heat pump mode. The eighth exemplary embodiment is based on the second exemplary embodiment and has been supplemented by second ejector  31 , which is arranged in parallel to an interior heat exchanger  40 . Interior heat exchanger  40  replaces interior evaporator  15  in this case. 
     In the cooling mode, interior heat exchanger  40  is supplied with refrigerant via a third branch A 3 , which is located between low-pressure chiller  13  and liquid separator  14 . Interior heat exchanger  40  opens into suction mass port  23  of first ejector  21 . 
     In the heat pump mode, which is illustrated in  FIG.  8   b   , interior heat exchanger  40  is connected to suction mass port  33  of second ejector  31  in parallel to motive mass port  22  of first ejector  21 . In the heat pump mode, interior heat exchanger  40  can be connected in parallel to high-pressure chiller  12  via branch A 2  and used to heat vehicle interior  110 . 
     In the cooling mode of climate control device  10 , an expansion valve  18  is connected upstream of interior heat exchanger  40 . 
     Additional gas coolers  41  are used in the following exemplary embodiments shown in  FIGS.  9  to  12   . These additional gas coolers  41  can be positioned in a front end of motor vehicle  100 , for example. In this regard, a direct heat transfer between the refrigerant and an environment is possible. In this regard, depending on the design, an optional interior heat exchanger  17  can also be used. 
     In  FIG.  9   a    and  FIG.  9   b   , schematic representations of a climate control device  10  according to a ninth exemplary embodiment are shown in an air conditioning mode and in a heat pump mode. The ninth exemplary embodiment is substantially based on the first exemplary embodiment and has been expanded by gas cooler  41 , which is integrated into the refrigerant circuit in series with the refrigerant outlet of high-pressure chiller  12 . 
     A refrigerant outlet of gas cooler  41  is connected both to motive mass inlet  22  of first ejector  21  and to the refrigerant outlet, for liquid refrigerant, of liquid separator  14 . 
     Preferably, a water heat exchanger or an air heater for the interior air of vehicle interior  110  can be provided to ensure the heating and reheating mode for air drying. 
     In the illustrated exemplary embodiment, three valves or shut-off valves  51 ,  52 ,  53  are required to selectively drive first ejector  21  with the refrigerant exiting gas cooler  41  or exiting high-pressure chiller  12 . 
       FIG.  10   a   ,  FIG.  10   b   , and  FIG.  10   c    show schematic representations of a climate control device  10  according to a tenth exemplary embodiment in an air conditioning mode, a heat pump mode, and a reheating mode. Climate control device  10  according to the eighth exemplary embodiment is based on the third exemplary embodiment and, analogous to the tenth exemplary embodiment, has three shut-off valves  51 ,  52 ,  53  to control the connection between high-pressure chiller  12  or gas cooler  41  with first ejector  21 . 
     Preferably, the respective shut-off valves  51 ,  52 ,  53  can be controlled by a control unit  54  which, for example, can also control expansion valves  16 ,  18 . 
     In the tenth exemplary embodiment, heating as well as cooling and reheating are realized by direct heat transfer from the refrigerant circuit to vehicle interior  110 . 
     A further expansion valve  18 , which is used in the heat pump mode, is connected downstream of gas cooler  41 . Refrigerant flows through interior condenser  19  via shut-off valves  51 ,  52 ,  53  in the heat pump mode and in the reheating mode in order to provide a heat output for vehicle interior  110 . 
     In the air conditioning mode of climate control device  10 , interior condenser  19  is decoupled from the refrigerant circuit, and only interior evaporator  15  is used to generate a cooling output. 
       FIG.  11   a    and  FIG.  11   b    show schematic representations of a climate control device  10  according to an eleventh exemplary embodiment in an air conditioning mode and in a heating mode. The eleventh exemplary embodiment of climate control device  10  is based on the sixth exemplary embodiment. Analogous to this, depending on whether interior heat exchanger  40  is supplied with refrigerant via branch A 1  downstream of compressor  11  or via liquid separator  14 , a heat output or a cooling output can be generated in interior heat exchanger  40  and discharged to vehicle interior  110 . 
     Due to the additional gas cooler  41 , three further shut-off valves  53 ,  55 ,  56  are required in addition to the already present two shut-off valves  51 ,  52  to control the refrigerant flow. 
       FIG.  12   a    and  FIG.  12   b    show schematic representations of a climate control device  10  according to a twelfth exemplary embodiment in an air conditioning mode and in a heating mode. The twelfth exemplary embodiment is based on the seventh exemplary embodiment and is also supplemented by gas cooler  41 . 
     Interior heat exchanger  40  can optionally be connected in series to high-pressure chiller  12  in order to heat vehicle interior  110  in the heat pump mode. 
     An optional water heat exchanger or an air heater for the interior air is provided to ensure the reheating mode for air drying. 
       FIG.  13    shows a side view of a motor vehicle  100  of the invention according to an exemplary embodiment with a climate control device  10  of the invention. Motor vehicle  100  is preferably designed as an electric vehicle or BEV and has a vehicle interior  110  which can be heated, cooled, or dehumidified by climate control device  10 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.