Abstract:
A galley chiller system for an aircraft includes at least one condenser having a refrigerant fluid. The fluid within the condenser rejects heat to a first surrounding environment. To more efficiently use the condenser of the galley chiller system and reduce the requirement on other cooling systems within an aircraft, the condenser may reject its heat to a desired location using a heat exchanger. The galley chiller system includes at least one evaporator that receives fluid from the condenser. A first evaporator absorbs heat from a galley, which may include a bank of carts. The first evaporator is arranged in ducting that carries cooled air to the carts. A second evaporator may absorb heat from a cabin recirculation air duct of the aircraft cooling system. In this manner, the evaporators of the inventive galley chilling system cools not only the galley carts but also provides supplemental cooling to the aircraft cooling system thereby reducing its cooling requirements.

Description:
This application is a Continuation-In-Part of U.S. application Ser. No. 10/790,890 filed Mar. 2, 2004, now U.S. Pat. No. 7,024,874 which claimed priority to U.S. Provisional Patent Application Ser. No. 60/504,951 filed Sep. 22, 2003. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a galley chiller system for use in an aircraft, and more particularly, the invention relates to a more efficient galley chiller system having components shared with other cooling systems of the aircraft. 
   A typical commercial aircraft includes at least several nonintegrated cooling systems. For example, an aircraft cooling system primarily provides cooling for the aircraft cabin area. A power electronics cooling system cools the power electronics of various aircraft systems to maintain the electronics within a desired temperature range. A galley chiller system is dedicated to refrigerating the food carts in the galleys located throughout the aircraft. Each of these systems have a significant weight and power penalty associated to the aircraft. It is desirable to minimize the overall weight and power penalty to the aircraft to increase the overall efficiency of the aircraft. 
   Typically galley chiller systems are stand alone vapor cycle units. The galley chiller system includes a compressor pumping a refrigeration fluid to a condenser, which rejects heat from the compressed fluid within to the surrounding environment. The fluid from the condenser is regulated through an expansion valve to an evaporator where the refrigerant fluid expands to cool the fluid. The refrigerant fluid within the evaporator absorbs heat from the surrounding environment. The refrigerant fluid flows from the evaporator to the compressor where the cycle begins again. 
   The location of the galley chiller system condenser is such that typically a portion of the heat from the condenser is rejected to the cabin area, which increases the load on the aircraft cooling system. When the galleys are cooled within the desired temperature range, the galley chiller system may be unused or not operated to its full cooling capacity resulting in inefficiency in the context of aircraft&#39;s overall cooling systems. 
   Therefore, what is needed is a more efficient galley chiller system that more effectively uses the condenser and evaporator to reduce the requirements on the other cooling systems of the aircraft resulting in a reduction in weight and power penalty to the aircraft. 
   SUMMARY OF THE INVENTION 
   This invention provides a galley chiller system for an aircraft that includes at least one condenser having a refrigerant fluid. The fluid within the condenser rejects heat to a first surrounding environment. To more efficiently use the condenser of the galley chiller system and reduce the requirements on other cooling systems within an aircraft, the condenser may reject its heat to a power electronics cooling system. Heat from the condenser may be used to heat a cargo area, or may simply be rejected to ram air of an air conditioning pack of the aircraft cooling system or the exhaust air vent. 
   The galley chiller system also includes at least one evaporator that receives fluid from the condenser. In the embodiment shown, the inventive galley chiller system includes at least two evaporators. A first evaporator absorbs heat from a galley which may include a bank of carts. A second evaporator may absorb heat from a cabin upper recirculation air duct of the aircraft cooling system. In this manner, the evaporators of the inventive galley chilling system cool not only the galley carts but also provides supplemental cooling to the aircraft cooling system thereby reducing its cooling requirements. 
   The cooling systems of the aircraft may also share some controls to monitor and coordinate the operation of the cooling systems with one another. For example, a controller may be connected to a control valve of the recirculation evaporator to obtain a desirable proportion of refrigerant fluid through the evaporators to adjust the cooling capacity provided to each of the galley carts and upper recirculation air duct. Remotely located heat exchangers may be connected to the condenser or evaporator using air or liquid cooling and arranged throughout the aircraft enabling the condenser to be packaged compactly with the other galley chiller components while still providing heat to other aircraft areas. 
   Accordingly, this invention provides a more efficient galley chiller system that more effectively uses the condenser and evaporator reducing the requirements on the other cooling systems of the aircraft resulting in a reduction in weight and power penalty to the aircraft. 
   These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional schematic view of a commercial aircraft. 
       FIG. 2  is a Venn diagram of cooling systems of an aircraft having the inventive galley chiller system. 
       FIG. 3  is a schematic view of one example of a galley chiller system. 
       FIG. 4  is a schematic view of another example inventive galley chiller system. 
       FIG. 5  is a schematic view of a portion of the inventive galley chiller system utilizing a heat exchanger in conjunction with the condensers. 
       FIG. 6  is a schematic view of another example galley chiller system for the fore of the aircraft. 
       FIG. 7  is a schematic view of another example galley chiller system for the aft of the aircraft. 
       FIG. 8  is still another example galley chiller system for the fore of the aircraft. 
       FIG. 9  is a schematic view of still another example galley chiller system for the aft of the aircraft. 
       FIG. 10  is a schematic view of yet another example galley chiller system for both the fore and aft of the aircraft. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A high level schematic cross-sectional view of a commercial aircraft  10  is shown in  FIG. 1 . The aircraft  10  includes a cargo area  12  within the lower portion of the aircraft  10 . The cargo area  12  may include one or more power electronics power bays  14  housing various electronic components used in the control and operation of the aircraft  10 . An aircraft cooling system  16  includes one or more air conditioning packs typically located within the cargo area  12 . The aircraft cooling system  16  provides temperature conditioned air to a cabin area  22  to provide a comfortable climate for the passengers within the cabin area  22 . A power electronics cooling system  20  may also be located within the cargo area  12  to cool the power electronics equipment bay  14 . 
   Galleys  24  are positioned in various convenient locations within the cabin area  22 . The galleys  24  house multiple galley carts containing food and other perishable goods. The galleys  24  typically include ducting that delivers cooled air to the carts from a common air source. The galleys  24  and lavatories  26  vent odors to a vent system  30  located in an overhead area  28  located above the cabin area  22 . Air from the flight deck, lavatories, galleys and other areas of the aircraft are pumped out the vent system  30  by a fan  39  through an outflow valve  32  exhausting the air to the outside environment. 
   The inventive galley chiller system  36  is located in the overhead area  28  in the examples shown, although the galley chiller system  36  or components thereof may be located in any suitable area within the aircraft  10 . The aircraft cooling system  16  includes ducting  37  having an overhead recirculation air duct  38  located within the overhead area  28 , although the recirculation duct may be located elsewhere. The air is delivered from the recirculation air duct  38  by recirculation fans  34 . The aircraft cooling system  16  cools the air ducted to the cabin area  22 . To reduce the cooling requirement of the aircraft cooling system  16 , the inventive galley chiller system  36  provides supplemental cooling to the recirculation air when the cooling capacity of the galley chiller system is not fully needed to cool the galleys  24 . This improved efficiency, and other improved efficiency of the cooling systems of the aircraft, is realized by integrating some of the components of the galley chiller system with other aircraft cooling systems, which is represented by the Venn diagram of  FIG. 2 . 
   As very schematically depicted in  FIG. 2 , the galley chiller system  36  includes a condenser  42 , an evaporator  44 , and controls  46 . The galley chiller system  36  may also include ducting  37  for delivering the cooled air from the evaporator  44  or heated air from the condenser  42  to other aircraft cooling systems. These galley chiller system components  36  may be shared by other cooling systems of the aircraft, such as the aircraft cooling system  16  and the power electronics cooling system  20 , which will be discussed in more detail below. 
   One example inventive galley chiller system  36  is shown in  FIG. 3 . The schematic shown in  FIG. 3  may be well suited for a forward located galley cooler system, in addition to other galley locations within the aircraft  10 . The galley cooling system  36  includes compressors  48  that compress and pump a refrigerant fluid to condensers  42   a  and  42   b  (collectively referred to as “42”), where heat from the compressed fluid within the condensers  42  is rejected to the surrounding environment. The refrigerant fluid then flows to the evaporators  44   a  and  44   b  (collectively referred to as “44”) through expansion valves  50   a  and  50   b  (collectively referred to as “50”). As the fluid exits the expansion valves  50 , the fluid expands lowering the temperature of the fluid. The expansion valves  50  control automatically to a desired superheat setpoint. Preferably, the expansion valves  50  control to a superheat low setpoint of approximately between 5-10° F. to maximize cooling capacity from the evaporators  44  without liquid refrigerant slugging the compressors  48 . 
   Heat from the environment surrounding the evaporators  44  is absorbed into the fluid prior to returning to the compressors  48 . It may be desirable to provide at least two condensers  42 , evaporators  44  and compressors  48  to provide redundancy within the galley chiller system  36 . Moreover, as will be appreciated from the discussion below, having multiple condensers  42  and evaporators  44  may better enable the galley chiller system  36  to be more efficiently integrated with other cooling systems of the aircraft  10 . Alternatively, it may be desirable to separate the condensers  42  and evaporators  44  ( FIGS. 8 and 9 ) to provide a more manageable size and weight unit. 
   One evaporator  44   a  may be arranged within the airflow path of the ducting  37  of the galleys  24 , which includes multiple galley carts  53 . The air within the ducting  37  is moved through the galleys  24  by a fan  52 . The ducting  37  carries the air to one or more galleys  24 , where it is distributed to each of the galley carts  53  by a manifold. At least a portion of the ducting  37  is preferably located in the area in which the rest of the galley chiller system  36  is located, such as the overhead area  28 . Prior art arrangements require multiple heat exchanges to be connected in a liquid cooling loop with the evaporator. Those heat exchangers are, in turn, arranged within separate ducting for each galley. One inventive arrangement enables a centrally located, common evaporator to be used for multiple galleys and/or carts by placing the evaporator  44   a  in the ducting  37 . Of course, liquid loops may be used to cool the galleys  24  ( FIGS. 6 and 7 ). Furthermore, the liquid loops may be configured with the evaporators  44   b  from the first and second galley chiller systems, shown at  100  and  102  in  FIG. 10 , in series. 
   The evaporator  44   a  used to cool the galleys  24  may require a cooling capacity sufficient to lower the temperature within the galley carts  53  from approximately 40° F. to approximately 30° F. A second evaporator  44   b  may be arranged in the flow path of an upper recirculation air duct  38 . A fan  34  moves the air within the duct  38  across the evaporator  44   b . The evaporator  44   b  within the upper recirculation air duct  38  may require a cooling capacity sufficient to cool the air from approximately 100° F. to approximately 50° F. 
   The cooling system controls  46  includes a controller  56  that is directed to a recirculation evaporator control valve  51 . The control valve  51  meters the flow of refrigerant fluid into the evaporators. The amount of fluid entering the evaporators corresponds with the cooling capacity for the evaporator. That is, generally, the more refrigerant fluid entering evaporator, the more cooling capacity that is provided by that evaporator. The valve  51  maintains to a minimum pressure to preclude air-side freezing. 
   The controller  56  coordinates the operation of the control valve  51  based upon, for example, a temperature sensor  54  associated within the galleys  24 . The speed of the galley fan  52  is controlled to obtain the required temperature at the galley outlet temperature sensor  54 . The temperature sensor  59  measures the temperature at the inlet of the galley  24  or galley carts  53 , and the controller  56  determines the amount of refrigerant fluid necessary to flow into the evaporator  44   a  associated with the galley  24  to ensure that the air is cooled to the desired temperature. 
   When the air in the galleys  24  is cooled to the desired temperature, the controller  56  may open the control valve  51  associated with the recirculation air evaporator  44   b  and supplement the cooling of the upper recirculation air provided by the aircraft cooling system  16 . Additionally, the valve  55  is used to provide defrost capability for the evaporators  44   a  and  44   b.    
   With continuing reference to  FIG. 3 , the condensers  42  reject heat to desired areas of the aircraft  10  to reduce the requirements on other cooling systems of the aircraft. To obtain a more compact galley chiller system  36  and keep the condensers  42  in close proximity to the other galley chiller system components, one or more heat exchangers may be located remotely from the galley chiller system and connected to the condensers by a liquid cooling passage extending in a loop between the heat exchanger and condensers  42 . 
   In one example shown in  FIG. 3 , a pump  58  pumps a cooling liquid from the condenser  42   a  to a cargo heat exchanger  60  located within the cargo area  12 . Another heat exchanger  62  may be located within the same loop and integrated as part of the power electronics cooling system  20  to reject heat to the aircraft exterior through the RAM system. In another example shown in  FIG. 3 , another pump  58  may pump a cooling liquid from the condenser  42   b  to another cargo heat exchanger  60 . Another heat exchanger  64  within the same loop may be located within a ram airflow path of an air conditioning pack  18  to reject the hot air to the aircraft exterior. 
   Another example galley chiller system  36  is shown in  FIG. 4 , which may be suitable for an aft galley chiller system  36  or any other suitable galley location. The operation of the galley chiller system  36  as shown in  FIG. 4  is similar to that shown in  FIG. 3 . However, the condensers  42   a  and  42   b  are positioned within the vent system  30  to reject heat to the exhaust air within the vent, which exits the aircraft  10  through the outflow valve  32 . To obtain a more compact galley chiller system  36  and keep the condensers  42  in close proximity to the other galley chiller system components, an exhaust air heat exchanger may be located remotely from the galley chiller system and connected to the condensers by a liquid cooling passage  71  extending in a loop between the heat exchanger and condensers  42 . For example,  FIG. 5  illustrates a heat exchanger  70 , which carries liquid heated by the condensers  42 , arranged in the vent system  30  to reject heat to the air driven by the fan  39  out the outflow valve  32 . 
     FIGS. 6 and 7  are similar to  FIGS. 3 and 4 , however,  FIGS. 6 and 7  utilize a liquid loop  80  to cool the galleys  24 . 
   Referring to  FIG. 6 , a liquid condenser loop  71  is used to cool components remote from the condensers  42 , such as power electronics. A similar loop is shown in  FIGS. 4 and 5 . 
   A flash tank  76  is used to increase the cycle efficiency and reduce the compressor power requirement by up to 20%. The flash tank  76  receives slightly subcooled liquid exiting the condenser  42  through a fixed orifice to throttle the fluid from the condenser  42  to an interstage pressure or midlevel stage of the scroll-type compressor. The throttled liquid from the flash tank  76  flows through a pressure regulator  78  to the compressor  48 . Liquid from the flash tank  76  flows through the thermostatic expansion valve  50  to the evaporator  44 . 
   A liquid loop  80  is used in connection with the evaporators  44  to cool the galleys  24 . A liquid heat exchangers  86  may be associated with each of the galleys and arranged within the galley ducting  37 . A fan  52  blows air through the liquid heat exchanger  86  to cool the galleys  24 . Diverter valves  84  may be arranged in the liquid loop  80  to direct the flow of fluid through the liquid loop  80  to as desired based upon the cooling needs of each of the galleys  24 . 
   An aft galley chiller system is shown in  FIG. 7 . The aft galley chiller system of  FIG. 7  is similar to that shown in  FIG. 4 , however, the galley chiller system  36  includes the liquid loop  80  shown in  FIG. 6 . 
   Referring to  FIGS. 8 and 9 , the galley chiller systems  36  shown are similar to those depicted in  FIGS. 3 and 4 , however, the systems  36  can be divided to provide first and second galley refrigeration units  90  and  92 . 
   The galley chiller systems  36  depicted an  FIGS. 3 and 4  include condensers  42   a  and  42   b  and evaporators  44   a  and  44   b  that are physically combined with one another in one location. The systems shown in  FIGS. 3 and 4  provide redundancy within the galley chiller system  36 , but results in a bulky, heavy package. As an alternate approach, the galley chiller system  36  may be split into the first and second galley refrigeration units  90  and  92 , as schematically depicted by the partition line  94 . As a result, each galley refrigeration unit  90  and  92  is approximately half the weight of the system shown in  FIGS. 3 and 4 , which makes installation and removal of the systems easier. Accordingly, each of the evaporators  44   a  and  44   b  are arranged within separate recirculation air ducting  38   a  and  38   b . The evaporators  44   a  and  44   b  are also associated with separate galley ducting  37   a  and  37   b.    
   Referring to  FIG. 10 , first and second galley chiller systems  100  and  102  are shown. For the example shown, the first and second galley chiller systems  100  and  102  are located in the aft of the aircraft, although they serve both fore and aft galleys. The systems  100  and  102  each include an air cooling galley circuit  104  for cooling first galley  106 . The liquid galley cooling circuit  108  cools second galleys  110 . However, the liquid heat exchanger  86  of the first and second galley chiller systems  100  and  102  form a series connection providing a liquid galley cooling circuit  108 . Controls (not shown) cooperate with the series, liquid galley cooling circuit  108  to regulate the flow of liquid to the heat exchangers  86  since there is a heat build-up within the series circuit  108  as the fluid progresses through the circuit  108 . Aside from the series liquid galley cooling circuit  108 , the liquid cooling circuit  108  is arranged similarly to that shown in  FIGS. 6 and 7 . 
   Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.