Abstract:
An aircraft galley refrigeration system is provided which, in one embodiment, includes: first and second galleys; a first chiller for providing a first heat transfer fluid to the first galley; a second chiller for providing a second heat transfer fluid to the second galley; and a heat exchanger including a first circuit and a second circuit, the first circuit connecting the first galley with the first chiller, and the second circuit connecting the second galley with the second chiller. In another embodiment, the system includes a first cooling subsystem with a first heat transfer fluid, a second cooling subsystem with a second heat transfer fluid, and a heat exchanger that thermally couples the first and second cooling subsystems for distributing heat between the first and second heat transfer fluids.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application No. 60/902,421, filed Feb. 20, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention pertains generally to aircraft galley refrigeration systems. More particularly, this invention pertains to an aircraft galley refrigeration system with a multi-circuit liquid heat exchanger. 
       BACKGROUND OF THE INVENTION 
       [0003]    Aircraft galley refrigeration systems are used to refrigerate food carts, which are stored in at least one galley of the aircraft, to prevent spoilage of foodstuffs prior to providing the foodstuffs to onboard passengers. One conventional aircraft galley refrigeration system includes air chillers and cold air supply (or air ducting) systems in the galley that interface with the food carts to cool the interiors of the food carts. Another conventional aircraft galley refrigeration system includes at least one liquid chiller, a central or separate liquid recirculation unit, at least one galley air cooling unit, and a liquid plumbing system. Liquid chillers are remotely located from the galleys for chilling a heat transfer liquid that enters galley air cooling system devices. In such devices, heat is transferred from the interiors of the food carts to the liquid to keep the foodstuffs at proper storage temperature or temperatures (i.e., different galleys may store different foodstuffs, for example one galley may store a first type of foodstuff which requires one storage temperature and another galley may store another type of foodstuff or beverages which require another, different storage temperature) to prevent food spoilage. 
         [0004]    One conventional aircraft galley refrigeration system that includes liquid chillers is illustrated in  FIG. 1 . As shown in  FIG. 1 , the aircraft galley refrigeration system  10  includes at least one galley  20 , at least one remote chiller (RC)  30 , and a central liquid recirculation unit (RU)  40 . Although the at least one galley  20  includes three galley locations, namely Galley 1   22 , Galley 2   24 , and Galley 3   26  as shown, the at least one galley  20  may include fewer or additional galley locations. Similarly, although the at least one RC  30  includes three RC locations, namely RC 1   32 , RC 2   34 , and RC 3   36  as shown, the at least one RC  30  may include fewer or additional RC locations. However, the number of RCs generally corresponds with the number of galley locations in a one-to-one relationship. Each remote chiller, RC 1   32 , RC 2   34 , and RC 3   36  as shown, is a self-contained refrigeration unit with a refrigerant vapor cycle system that removes heat from a heat transfer fluid. As shown, the at least one galley  20  receives low temperature heat transfer fluid from the at least one RC  30  via line  32 . Also, the RU  40  receives high temperature heat transfer fluid from the at least one galley  20  via line  42 . Furthermore, the at least one RC  30  receives from RU  40  the high temperature heat transfer fluid output from the at least one galley  20 . 
         [0005]    More particularly, Galley 1   22 , Galley 2   24 , and Galley 3   26 , which comprise the at least one galley  20 , include respective heat transfer fluid inlets and outlets  22   a ,  22   b ;  24   a ,  24   b ;  26   a ,  26   b . Similarly, RC 1   32 , RC 2   34 , and RC 3   36 , which comprise the at least one RC  30 , include respective heat transfer fluid inlets and outlets  32   a ,  32   b ;  34   a ,  34   b ;  36   a ,  36   b . Each heat transfer fluid inlet  22   a ,  24   a ,  26   a  of the galley locations  22 ,  24 ,  26  is fed low temperature heat transfer fluid by line  32 . Each heat transfer fluid outlet  22   b ,  24   b ,  26   b  of the galley locations  22 ,  24 ,  26  exhausts high temperature heat transfer fluid to line  42  after the heat transfer fluid has absorbed the heat from cooling foodstuffs stored in the galley locations  22 ,  24 ,  26 . RU  40  receives the high temperature heat transfer fluid exhausted to line  42  by the galley locations  22 ,  24 ,  26  (particularly the outlets  22   b ,  24   b ,  26   b  thereof) and pressurizes the heat transfer fluid. Additionally, each of the RC locations  32 ,  34 ,  36  (particularly the heat transfer fluid inlets  32   a ,  34   a ,  36   a  thereof) is fed high temperature, high pressure heat transfer fluid by RU  40 . Each heat transfer fluid outlet  32   b ,  34   b ,  36   b  of the RC locations  32 ,  34 ,  36  outputs low temperature, high pressure heat transfer fluid to line  32  to work on cooling foodstuffs stored in the galley locations  22 ,  24 ,  26 . 
         [0006]    According to the foregoing, it can be appreciated that RU  40  defines a single point of failure of the system  10 . That is, heat transfer fluid of the system  10  could not be sufficiently circulated between the at least one galley  20  and at least one remote chiller RC  30  if the RU  40  were to malfunction or fail. Furthermore, it can be appreciated that if heat transfer fluid were to leak from any one component of the system  10 , the entire system  10  would need to be turned off so that repairs could be made. In view of the foregoing, a new aircraft galley refrigeration system would be an important improvement in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    In an embodiment, an aircraft galley refrigeration system is provided that includes: a first galley; a first chiller for providing a first heat transfer fluid to the first galley; a second galley; a second chiller for providing a second heat transfer fluid to the second galley; and a heat exchanger including a first circuit and a second circuit, the first circuit connecting the first galley with the first chiller, and the second circuit connecting the second galley with the second chiller. The heat exchanger may be configured between inlets of the galleys and outlets of the chillers or, alternatively the heat exchanger may be configured between outlets of the galleys and inlets of the chillers. 
         [0008]    In another embodiment, the system includes a first liquid cooling subsystem with a first heat transfer fluid, a second liquid cooling subsystem with a second heat transfer fluid, and a heat exchanger that thermally couples the first and second liquid cooling subsystems for distributing heat between the first and second heat transfer fluids. Each liquid cooling subsystem may include a galley, a chiller, and a fluid path for fluidly communicating a heat transfer fluid between the galley and the chiller. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates a block diagram of a conventional aircraft galley refrigeration system; 
           [0010]      FIG. 2  illustrates a diagrammatic view of an example multi-circuit heat exchanger for an aircraft galley refrigeration system according to an embodiment of the present invention; 
           [0011]      FIG. 3  illustrates a diagrammatic view of another example multi-circuit heat exchanger for an aircraft galley refrigeration system according to an embodiment of the present invention; 
           [0012]      FIG. 4  illustrates a block diagram of one embodiment of an aircraft galley refrigeration system including the multi-circuit heat exchanger of  FIG. 2 ; and 
           [0013]      FIG. 5  illustrates a block diagram of another embodiment of an aircraft galley refrigeration system including the multi-circuit heat exchanger of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    Turning now to the Figures, an aircraft galley refrigeration system is described. Various embodiments of the aircraft galley refrigeration system are provided which include a multi-circuit heat exchanger and chillers that are refrigeration generation and recirculation units. That is, the chillers described hereinafter incorporate recirculation functionality of the RU  40  and refrigeration functionality of the RCs  32 ,  34 ,  36  which were described previously with respect to  FIG. 1 . One example multi-circuit heat exchanger is diagrammatically shown in  FIG. 2 . As shown in  FIG. 2 , the example multi-circuit heat exchanger is a liquid heat exchanger  50 . That is, the heat exchange fluid that is intended to be used with the heat exchanger  50  is a liquid. However, in some instances the heat exchange fluid used with the heat exchanger  50  may be a gas, a combination of a liquid and a gas, or a fluid that changes between liquid and gas phases. 
         [0015]    As shown, the liquid heat exchanger  50  includes a first liquid inlet  52   a  (“Liquid inlet  1 ”), a second liquid inlet  54   a  (“Liquid inlet  2 ”), a third liquid inlet  56   a  (“Liquid inlet  3 ”), and a fourth liquid inlet  58   a  (“Liquid inlet  4 ”). Although the heat exchanger  50  is shown to include four liquid inlets  52   a ,  54   a ,  56   a ,  58   a , the heat exchanger  50  may be configured to include fewer or additional inlets. The liquid heat exchanger  50  also includes a first liquid outlet  52   b  (“Liquid outlet  1 ”), a second liquid outlet  54   b  (“Liquid outlet  2 ”), a third liquid outlet  56   b  (“Liquid outlet  3 ”), and a fourth liquid outlet  58   b  (“Liquid outlet  4 ”). Although the heat exchanger  50  is shown to include four liquid outlets  52   b ,  54   b ,  56   b ,  58   b , the heat exchanger  50  may be configured to include fewer or additional outlets. As shown, the number of outlets  52   b ,  54   b ,  56   b ,  58   b  generally corresponds with the number of inlets  52   a ,  54   a ,  56   a ,  58   a  in a one-to-one relationship so that distinct and separated channels, paths, conduits or circuits are defined through the heat exchanger  50 . That is, inlet  52   a  and outlet  52   b  are in fluid communication with each other to define a first circuit therebetween. Similarly, second, third and fourth circuits are defined between respective inlet/outlet pairs  54   a ,  54   b ;  56   a ,  56   b ; and  58   a ,  58   b . In this configuration each circuit is in thermal communication with an adjacent circuit or circuits. For example, a first heat transfer fluid flowing in the first circuit (i.e., between inlet  52   a  and outlet  52   b ) may exchange (i.e., accept or reject) heat with a second heat transfer fluid flowing the second circuit (i.e., between inlet  54   a  and outlet  54   b ) that is adjacent to the first circuit. Similarly, a second heat transfer fluid flowing in the second circuit (i.e., between inlet  54   a  and outlet  54   b ) may exchange (i.e., accept or reject) heat with a first heat transfer fluid flowing the first circuit and/or a third heat transfer fluid flowing in the third circuit (i.e., between inlet  56   a  and outlet  56   b ) since the second circuit is interposed between the first and third circuits. Accordingly, it can be appreciated that temperatures of the various heat transfer fluids flowing through the various circuits of the heat exchanger  50  may be substantially equalized in a passive manner. Although the heat exchanger  50  is illustrated as including distinct fluid circuits, channels, paths, conduits that are in at least partial physical contact with each other, alternatively the heat exchanger  50  may be configured as a manifold including a central chamber or reservoir in fluid communication with the inlets and outlets for mixing heat transfer fluid together and outputting various substantially equalized heat transfer fluid flows. Additionally, some embodiments of the heat exchanger  50  may include a fluid accumulator that is integral or unitary with the heat exchanger  50 . 
         [0016]    An example liquid heat exchanger including a fluid accumulator is illustrated in  FIG. 3 . As shown, liquid heat exchanger  50 ′ includes a first liquid inlet  52   a ′ (“Liquid inlet  1 ”), a second liquid inlet  54   a ′ (“Liquid inlet  2 ”), a third liquid inlet  56   a ′ (“Liquid inlet  3 ”), and a fourth liquid inlet  58   a ′ (“Liquid inlet  4 ”). Although the heat exchanger  50 ′ is shown to include four liquid inlets  52   a ′,  54   a ′,  56   a ′,  58   a ′, the heat exchanger  50 ′ may be configured to include fewer or additional inlets. The liquid heat exchanger  50 ′ also includes a first liquid outlet  52   b ′ (“Liquid outlet  1 ”), a second liquid outlet  54   b ′ (“Liquid outlet  2 ”), a third liquid outlet  56   b ′ (“Liquid outlet  3 ”), and a fourth liquid outlet  58   b ′ (“Liquid outlet  4 ”). Although the heat exchanger  50 ′ is shown to include four liquid outlets  52   b ′,  54   b ′,  56   b ′,  58   b ′, the heat exchanger  50 ′ may be configured to include fewer or additional outlets. As shown, the number of outlets  52   b ′,  54   b ′,  56   b ′,  58   b ′ generally corresponds with the number of inlets  52   a ′,  54   a ′,  56   a ′,  58   a ′ in a one-to-one relationship so that distinct and separated channels, paths, conduits or circuits are defined through the heat exchanger  50 ′. That is, inlet  52   a ′ and outlet  52   b ′ are in fluid communication with each other to define a first circuit therebetween. Similarly, second, third and fourth circuits are defined between respective inlet/outlet pairs  54   a ′,  54   b ′;  56   a ′,  56   b ′; and  58   a ′,  58   b ′. As was explained previously with respect to example heat exchanger  50  ( FIG. 2 ), each circuit of the heat exchanger  50 ′ is in thermal communication with an adjacent circuit or circuits (e.g., by being in physical contact with a one or more circuit or circuits). Furthermore, since heat exchanger  50 ′ includes a liquid accumulator, the four circuits are immersed in the heat transfer fluid as shown. By immersing the circuits in the heat transfer fluid, the transfer of heat may be facilitated or enhanced from each circuit as well as between circuits. Accordingly, it can be appreciated that temperatures of the various heat transfer fluids flowing through the various circuits of the heat exchanger  50 ′ may be substantially equalized by the heat exchanger  50 ′ in a passive manner. Although the heat exchanger  50 ′ is illustrated as including distinct fluid circuits that pass through the accumulated heat transfer fluid, alternatively the heat exchanger  50 ′ may be configured as a manifold including a central chamber or reservoir in fluid communication with the inlets and outlets for mixing heat transfer fluid together (e.g., accumulating heat transfer fluid from all or some of the circuits) and outputting various substantially equalized heat transfer fluid flows. 
         [0017]    Turning now to  FIGS. 4 and 5 , first and second embodiments are diagrammatically illustrated of an aircraft galley refrigeration system that includes a multi-circuit heat exchanger. Although the embodiments of the system  100 ,  100 ′ are illustrated as including the example heat exchanger  50  ( FIG. 2 ) interposed between a number of galleys and a number of chillers, it should be appreciated that the illustrated embodiments of the system  100 ,  100 ′ may alternatively include the other example heat exchanger  50 ′ ( FIG. 3 ). The heat exchanger  50  is configured to interconnect galley/chiller pairs to define galley cooling subsystems. As shown in  FIG. 4 , the heat exchanger  50  of system  100  is configured in between the outlets of chillers and the inlets of galleys. However, as will be described hereafter with reference to  FIG. 5 , the heat exchanger  50  may be configured otherwise in relation to the inlets and outlets of the chillers and galleys. 
         [0018]    As shown in  FIG. 4 , the first embodiment of the system  100  includes galleys (namely Galley 1   72 , Galley 2   74 , Galley 3   76  and Galley 4   78 ), chillers (namely Chiller 1   92 , Chiller 2   94 , Chiller 3   96  and Chiller 4   98 ), and heat exchanger  50 . Although four galleys and four chillers are shown as being interconnected by heat exchanger  50  in the first embodiment of system  100 , the system  100  may include fewer or additional galleys and heat exchangers (e.g., in a one-to-one relationship). As shown, each galley includes a heat transfer fluid inlet and outlet. That is, Galley 1   72  includes inlet  72   a  and outlet  72   b ; Galley 2   74  includes inlet  74   a  and outlet  74   b ; Galley 3   76  includes inlet  76   a  and outlet  76   b ; and Galley  4   78  includes inlet  78   a  and outlet  78   b . Heat transfer fluid flows in each galley from the galley&#39;s inlet to its outlet. As further shown, each chiller includes a heat transfer fluid inlet and outlet. That is, Chiller  1   92  includes inlet  92   a  and outlet  92   b ; Chiller 2   94  includes inlet  94   a  and outlet  94   b ; Chiller 3   96  includes inlet  96   a  and outlet  96   b ; and Chiller 4   98  includes inlet  98   a  and outlet  98   b . Heat transfer fluid flows in each chiller from the chiller&#39;s inlet to its outlet through an internal recirculation device. 
         [0019]    As described previously, the heat exchanger  50  includes first, second, third and fourth circuits defined between respective inlet/outlet pairs  52   a ,  52   b ;  54   a ,  54   b ;  56   a ,  56   b ; and  58   a ,  58   b . As shown, inlet  52   a  of heat exchanger  50  is in fluid communication with outlet  92   b  of chiller  92  while outlet  52   b  of heat exchanger  50  is in fluid communication with inlet  72   a  of galley  72 . Furthermore, outlet  72   b  of galley  72  is in fluid communication with inlet  92   a  of chiller  92 . As such, a first galley cooling subsystem is defined by galley  72 , chiller  92  and the first circuit (i.e., the channel, path, conduit, etc. between inlet  52   a  and outlet  52   b ) of heat exchanger  50 . Similarly, inlet  54   a  of heat exchanger  50  is in fluid communication with outlet  94   b  of chiller  94  while outlet  54   b  of heat exchanger  50  is in fluid communication with inlet  74   a  of galley  74 . Furthermore, outlet  74   b  of galley  74  is in fluid communication with inlet  94   a  of chiller  94 . As such, a second galley cooling subsystem is defined by galley  74 , chiller  94  and the second circuit (i.e., the channel, path, conduit, etc. between inlet  54   a  and outlet  54   b ) of heat exchanger  50 . Additionally, inlet  56   a  of heat exchanger  50  is in fluid communication with outlet  96   b  of chiller  96  while outlet  56   b  of heat exchanger  50  is in fluid communication with inlet  76   a  of galley  76 . Furthermore, outlet  76   b  of galley  76  is in fluid communication with inlet  96   a  of chiller  96 . As such, a third galley cooling subsystem is defined by galley  76 , chiller  96  and the third circuit (i.e., the channel, path, conduit, etc. between inlet  56   a  and outlet  56   b ) of heat exchanger  50 . Finally, inlet  58   a  of heat exchanger  50  is in fluid communication with outlet  98   b  of chiller  98  while outlet  58   b  of heat exchanger  50  is in fluid communication with inlet  78   a  of galley  78 . Furthermore, outlet  78   b  of galley  78  is in fluid communication with inlet  98   a  of chiller  98 . As such, a fourth galley cooling subsystem is defined by galley  78 , chiller  98  and the fourth circuit (i.e., the channel, path, conduit, etc. between inlet  58   a  and outlet  58   b ) of heat exchanger  50 . Since all of the galley cooling subsystems circulate their respective heat transfer fluid though loops which pass through the adjacent circuits of heat exchanger  50 , if one or more of the chillers were to malfunction or fail, the system  100  can continue to provide sufficiently cooled fluid to each galley. 
         [0020]    As shown in  FIG. 5 , the heat exchanger  50  of a second embodiment of system  100 ′ is configured in between the outlets of galleys and the inlets of chillers. The second embodiment of system  100 ′ includes galleys (namely Galley 1   72 , Galley 2   74 , Galley 3   76  and Galley  4   78 ), chillers (namely Chiller 1   92 , Chiller 2   94 , Chiller 3   96  and Chiller 4   98 ), and heat exchanger  50 . Although four galleys and four chillers are shown as being interconnected by heat exchanger  50  in the second embodiment of system  100  shown in  FIG. 5 , the system  100 ′ may include fewer or additional galleys and heat exchangers (e.g., in a one-to-one relationship). As shown, each galley includes a heat transfer fluid inlet and outlet. That is, Galley 1   72  includes inlet  72   a  and outlet  72   b ; Galley 2   74  includes inlet  74   a  and outlet  74   b ; Galley 3   76  includes inlet  76   a  and outlet  76   b ; and Galley 4   78  includes inlet  78   a  and outlet  78   b . Heat transfer fluid flows in each galley from the galley&#39;s inlet to its outlet. As further shown, each chiller includes a heat transfer fluid inlet and outlet. That is, Chiller 1   92  includes inlet  92   a  and outlet  92   b ; Chiller 2   94  includes inlet  94   a  and outlet  94   b ; Chiller 3   96  includes inlet  96   a  and outlet  96   b ; and Chiller 4   98  includes inlet  98   a  and outlet  98   b . Heat transfer fluid flows in each chiller from the chiller&#39;s inlet to its outlet through an internal recirculation device. 
         [0021]    As described previously, the heat exchanger  50  includes first, second, third and fourth circuits defined between respective inlet/outlet pairs  52   a ,  52   b ;  54   a ,  54   b ;  56   a ,  56   b ; and  58   a ,  58   b . As shown, inlet  52   a  of heat exchanger  50  is in fluid communication with outlet  72   b  of galley  72  while outlet  52   b  of heat exchanger  50  is in fluid communication with inlet  92   a  of chiller  92 . Furthermore, outlet  92   b  of chiller  92  is in fluid communication with inlet  72   a  of galley  72 . As such, a first galley cooling subsystem is defined by galley  72 , chiller  92  and the first circuit (i.e., the channel, path, conduit, etc. between inlet  52   a  and outlet  52   b ) of heat exchanger  50 . Similarly, inlet  54   a  of heat exchanger  50  is in fluid communication with outlet  74   b  of galley  74  while outlet  54   b  of heat exchanger  50  is in fluid communication with inlet  94   a  of chiller  94 . Furthermore, outlet  94   b  of chiller  94  is in fluid communication with inlet  74   a  of galley  74 . As such, a second galley cooling subsystem is defined by galley  74 , chiller  94  and the second circuit (i.e., the channel, path, conduit, etc. between inlet  54   a  and outlet  54   b ) of heat exchanger  50 . Additionally, inlet  56   a  of heat exchanger  50  is in fluid communication with outlet  76   b  of galley  76  while outlet  56   b  of heat exchanger  50  is in fluid communication with inlet  96   a  of chiller  96 . Furthermore, outlet  96   b  of chiller  96  is in fluid communication with inlet  76   a  of galley  76 . As such, a third galley cooling subsystem is defined by galley  76 , chiller  96  and the third circuit (i.e., the channel, path, conduit, etc. between inlet  56   a  and outlet  56   b ) of heat exchanger  50 . Finally, inlet  58   a  of heat exchanger  50  is in fluid communication with outlet  78   b  of galley  78  while outlet  58   b  of heat exchanger  50  is in fluid communication with inlet  98   a  of chiller  98 . Furthermore, outlet  98   b  of chiller  98  is in fluid communication with inlet  78   a  of galley  78 . As such, a fourth galley cooling subsystem is defined by galley  78 , chiller  98  and the fourth circuit (i.e., the channel, path, conduit, etc. between inlet  58   a  and outlet  58   b ) of heat exchanger  50 . Since all of the galley cooling subsystems circulate their respective heat transfer fluids though loops which pass through the adjacent circuits of heat exchanger  50 , if one or more of the chillers were to malfunction or fail, the system  100 ′ can continue to provide sufficiently cooled fluid to each galley. 
         [0022]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0023]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
         [0024]    Various embodiments of this invention are described herein. However, it should be understood that the illustrated and described embodiments are exemplary only, and should not be taken as limiting the scope of the invention.