Abstract:
Embodiments of the present invention provide improved space utilization concepts for aircraft, and particularly to using under floor space created by the envelope designed to house an airstair system. For example, this space may be used to house and integrate one or more fuel cell system(s) and/or components, such as hydrogen tanks and/or the fuel cell body, such that the fuel cell system can deliver useful byproducts to support various aircraft functions. Additionally or alternatively, the space may be used to store other components.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/682,936, filed Aug. 14, 2012, titled “Aircraft Equipment Concepts,” the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention relate generally to improved space utilization concepts for aircraft, and particularly to using under floor space created by the envelope designed to house an airstair system. For example, this space may be used to house and integrate one or more fuel cell system(s) and/or components, such as hydrogen tanks and/or the fuel cell body, such that the fuel cell system can deliver useful byproducts to support various aircraft functions. Additionally or alternatively, the space may be used to store other galley-related items, such as extra trash storage, trash compactor components, and/or chiller components, as well as heat management systems, fluid components (gas or liquid), or other power components, such as an inverter. It is also envisioned that this space may be used to integrate other components that would otherwise consume valuable space elsewhere in the aircraft. This space can also include components that assist with heat management. 
       BACKGROUND 
       [0003]    An airstair is a set of steps built into an airliner so that passengers (as well as aircraft crew and the maintenance team) may board the aircraft. Airstairs can be used on commercial, business, and freight aircraft. The airstairs are often built into a clamshell-style type door on the aircraft. They are commonly installed when an aircraft is intended to land on an airport tarmac, where there is limited ground infrastructure or service. The airstairs can be deployed in order to allow aircraft access without any external structures, thus eliminating the need for passengers to use a mobile stairway or jetway to board and exit the aircraft and providing the aircraft (and airline company) with more independence from ground services, even when they are available. As ground service costs increase, some airlines are choosing to integrate an airstair envelope into the aircraft in order to provide the option of limiting ground service cost. For example, in large airports, the cost of passenger ground service, parking, and time of ground handling can be important compared to the added weight and space of the air stair. More and more aircraft manufacturers are thus proposing to include an airstair envelope in aircraft, which can be optionally fitted with an airstair, in order to reduce time and the cost of ground operation. 
         [0004]    However, the weight of an airstair has an impact on fuel consumption during the aircraft operation. Each kilogram in an aircraft is taken into account, which is why some aircraft manufacturers decide to remove or to not install the airstair into the airstair envelope/space at all. In other words, because an aircraft is only cost competitive when it can fly with payload (i.e., passengers and/or freight) while reducing its other costs (i.e., fuel costs, etc.), if an aircraft has installed airstairs but is not currently using them because the aircraft boards and deplanes through a traditional jetway, then the airline may decide to remove the airstair from the aircraft. Thus, an aircraft may still have the airstair envelope/space, but the added weight of the airstair is removed. 
       BRIEF SUMMARY 
       [0005]    The present inventors have sought ways to make the airstair envelope space more valuable and useful, if an airstair is not installed in that space or has been removed. In one specific embodiment, the inventors have sought to use the airstair envelope to house various fuel cell system components and/or electronic items that use the fuel cell system power and other byproducts. Embodiments of the invention described herein thus provide unique ways to incorporate and integrate a fuel cell system into an airstair envelope. For example, embodiments include a fuel cell system (which can be divided in sub-system) integrated in the airstair space and that can deliver the generated electricity and other by-products (water, electricity, oxygen depleted air, and/or heat) for use by other aircraft applications and systems. Embodiments also relate to other uses for the airstair space, such as housing trash-related items, a trash compactor, a chiller, and/or an inverter for the fuel cell, all which may be powered via aircraft power, generator power (when on ground), or via a fuel cell system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  shows a top plan view of an airstair envelope on an aircraft. 
           [0007]      FIG. 2  shows a side perspective view of one potential configuration for aircraft components to be positioned in an airstair envelope. 
           [0008]      FIG. 3  shows a side perspective view of an aircraft through the boarding door, illustrating the airstair space below the passenger deck. 
           [0009]      FIG. 4  shows one embodiment of a location for an access panel to aces the airstair envelope. 
           [0010]      FIG. 5  shows an alternate embodiment for storage of aircraft components, such as fuel cell ancillaries or fuel cell system components. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    A number of components on-board an aircraft require electrical power for their activation. Many of these components are separate from the electrical components that are actually required to run the aircraft (i.e., the navigation system, fuel gauges, flight controls, and hydraulic systems). For example, aircraft also have catering equipment, heating/cooling systems, lavatories, power seats, water heaters, heater floor panels, and other components that require power as well. 
         [0012]    However, one concern with these components is their energy consumption. It may be desirable to power these systems separately, rather than relying on the aircraft engines&#39; drive generators or additional power sources, such as a kerosene-burning auxiliary power unit (APU) (or by a ground power unit if the aircraft is not yet in flight). Additionally, use of aircraft power produces noise and CO 2  emissions, both of which are desirably reduced. Accordingly, it is desirable to identify ways to improve fuel efficiency and power management by providing innovative ways to power these components. There are new ways being developed to generate power to run on-board components, as well as to harness beneficial by-products of that power generation for other uses on-board aircraft. 
         [0013]    The relatively new technology of fuel cells provides a promising cleaner and quieter way to supplement energy sources already aboard aircrafts. A fuel cell has several outputs in addition to electrical power, and these other outputs often are not utilized, but can be used to avoid loss of other usable energy sources (such as thermal, electric and/or pneumatic power) generated by the fuel cell system. Fuel cell systems combine a fuel source of compressed hydrogen with oxygen in the air to produce electrical and thermal power as a main product. Water, heat, and Oxygen Depleted Air (ODA) are produced as by-products, which are far less harmful than CO 2  emissions from current aircraft power generation processes. Because the proposed use of fuel cell systems on-board aircraft and other vehicles is relatively new, there are not always appropriate storage systems in place for the fuel cell systems. 
         [0014]    Embodiments of the present invention thus provide unique storage locations for fuel cell components and identify ways to use previously unused space on-board an aircraft. In one specific embodiment, the airstair space  10  is used to house a fuel cell system  12 .  FIG. 1  shows a top plan view of an airstair envelope  10 , positioned in the lower fuselage of an aircraft  14 , which is also shown in  FIG. 3 . This location may be in the front, aft, or any other allowed location in the aircraft.  FIG. 1  also shows the location of galleys  16  and a lavatory  18  on the main level of the aircraft. The airstair space  10  is a free envelope of space below the main level, in the belly of the aircraft, and is present if the airstairs are not installed or if they have been removed. 
         [0015]      FIG. 2  illustrates a side perspective view of the airstair envelope  10  that has additional components positioned therein. Fuel cell system  12  components are provided, such as compressed hydrogen tanks  20  and a fuel cell body  22 , which form a fuel cell system  12 .  FIG. 2  also shows an alternate embodiment, which uses the airstair space  10  to contain a trash compactor  24  or trash compactor components, a chiller  26  or chiller components, and/or an inverter  28  or inverter components, and/or any other common components used inside a private or commercial airplane. For example, this space may also be used to store extra pillows and blankets, extra water or soda bottles, extra cups or other service items, compacted trash, or any other items that can be stored and do not need to accessed immediately. 
         [0016]    Referring now to the fuel cell system  12  storage embodiment, the fuel cell system  12  can have an integrated hydrogen storage or it may have a decentralized hydrogen storage, as described in co-pending Application No. PCT/IB2013/051984, titled “Removable Storage for Hydrogen On-board Passenger Transport Vehicles Such as Aircraft,” filed Mar. 13, 2013, the entire contents of which are incorporated herein. The hydrogen storage could be located in unpressurized area as well as the pressurized area of the airstairs. Because this is free space, it provides a good location for hydrogen tank storage. 
         [0017]    The hydrogen storage can be liquid, gaseous or solid. As shown, the hydrogen tanks  20  may be directly connected to a fuel cell  22 . Alternatively, the fuel cell body  22  may be located in the airstair space  10  and connected to the hydrogen tanks (stored elsewhere located in an area remote from the airstair space  10 , perhaps in an unpressurized area if desired or required) via tubing or other conduit. This allows the hydrogen tanks to deliver hydrogen to fuel cell (as well as to any other fuel cell bodies that may be located elsewhere on the aircraft). (For example, in one embodiment, the hydrogen tanks may deliver hydrogen to fuel cells positioned on individual seats, as described in co-pending Application No. PCT/IB2013/051979, titled “Vehicle Seat Powered by Fuel Cell,” filed Mar. 13, 2013, the entire contents of which are incorporated herein.) 
         [0018]    The use of an inverter  28  to convert fuel cell power is also an option, depending on VDC or VAC consumers. The fuel cell system  12  produces Direct Current. If Alternating Current consumers are installed on the aircraft, then an inverter  28  may be installed in the fuel cell system  12 . The fuel cell system  12  may be interconnected to the onboard electrical grid of the aircraft, such that it can deliver general power that can be distributed as needed. Alternatively, it may be autonomous and supply power directly to the electrical consumers plugged into the fuel cell system  12 . The concept is not restricted to an existing fuel cell technology and can be used by any future technology. 
         [0019]      FIG. 2  also shows a trash compactor  24  positioned in the airstair space  10 . This may be an actual trash compactor or one or more electrical or mechanical components of the compactor.  FIG. 2  further shows a chiller  26  positioned in the airstair space  10 . The chiller  26  can supply cold air to one or more galleys  16  or any other product which requires cold air. Other galley components may have one or more components positioned in this space  10  as well. By integrating one or more of these galley components in the space  10 , additional floor space in the galley or for adding more passenger seats can be created and/or more food and drink products can be stored in the saved space. 
         [0020]    As discussed, by-products generated by the fuel cell system  12  are electricity, heat, water (H 2 O) and Oxygen Depleted Air. At least one (and preferably more than one) of the fuel cell by-products can be used by aircraft components. For example, the by-products may be used in the galley (e.g., by ovens, chillers, trash compactors, beverage makers, etc.), in the lavatory (e.g., to power the flush, heat water, provide electricity for lights, etc.), and the seat level (e.g., for seat controls, charger systems, heated seats, etc.) and/or any other products which can used at least one of the product generated by the fuel cell. The configuration may be optimized as shown in  FIG. 2 . 
         [0021]    One specific use of a by-product at the floor level is to deliver the heat from the fuel cell activity to alleviate the need for a floor warmer. Currently, heated floor panels are used to avoid a cold feeling near the aircraft door. In the embodiment shown in  FIG. 2 , both the chiller  26  and the fuel cell system  12  produce heat. Accordingly, heat generated by one or more of these system can be used to heat the floor.  FIG. 3  shows a perspective view through a boarding door of an aircraft, with the boarding door removed. This figure illustrates how the floor-based components may be positioned to take advantage of heat generated. 
         [0022]    In a specific embodiment, the floor heating can be achieved with heat generated by the fuel cell systems, such as hot air (gas) and/or liquid. The heat may be delivered upwards, in order to heat the floor and general doorway area, in lieu of using heated floor panels. This heat rise is illustrated by the arrows marked “H.” In addition or alternatively, the heat (via air or liquid) may be routed to the galley or lavatory sections of the aircraft, or optionally to other areas of the cabin for use. In addition or alternatively, the heat (via air or liquid) may be routed to the cargo bay or other areas where the gathered heat may be useful. 
         [0023]      FIG. 3  also shows a service panel  30  that may be integrated into the passenger deck floor  36  in order to refill the hydrogen tank(s)  20  or other items in airstair space  10 . An overboard discharge indicator can also be located in the service panel  30 . (It is also possible for the burst disc or overboard discharge to be located in another location in accordance with various safety rules, regulations, guidelines and/or airframer requirements.) Another use for the service panel  30  is that is the airstair space  10  is used as a trash compartment and/or for trash compaction, then the trash areas can be easily accessed for insertion and removal of trash. Additionally, the space  10  may be used to store other items that are useful in-flight, but that may not need to be accessed immediately. For example, pillows and blankets, extra cups or plates, extra drinks (water bottles, sodas, coffee grounds, and other beverages), may be stored in this otherwise unused space as well. 
         [0024]    Additionally, the service panel facilitates fuel cell system maintenance or maintenance of the trash compactor, chiller, inverter, or any other components located in space  10 .  FIG. 4  shows an example of where the access panel  30  may be located on/under the passenger deck. The access panel  30  may have an open and closure mechanism that is similar to a upper head cabin luggage storage compartment. Alternatively, any other securing system for panel  30  may be used. 
         [0025]    An alternate embodiment provides a fuel cell system positioned above the galley  16 , as shown in  FIG. 5 . (Although  FIG. 5  shows a galley, it should be understood that space in the lavatory ceiling may also be used.) Hydrogen is lighter than air, and it is preferable to avoid hydrogen accumulation and create an explosive atmosphere. Accordingly, there may also be provided a hydrogen sensor for safety purposes and regulations. By locating one or more components of a fuel cell system  12  between the cabin roof  32  and aircraft skin  34 , space can also be saved. In one embodiment, all of the hydrogen tank components  20  can be installed in the location of  FIG. 5 , and the electrical or other sub-systems of the fuel cell can be installed under the floor. In another embodiment, all components are located above the galley (or the lavatory). In a further embodiment, all components are located in the airstair space  10 , or a combination of these options may be used. 
         [0026]    Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.