AIRCRAFT CABIN PNEUMATIC AIR CONDITIONING SYSTEM INCLUDING AN AMBIENT AIR COMPRESSOR

Abstract

TITLE OF THE INVENTION: PNEUMATIC AIR CONDITIONING SYSTEM FOR AN AIRCRAFT CABIN COMPRISING AN AMBIENT AIR COMPRESSOR. The invention relates to an air conditioning system for an aircraft cabin (10) comprising a pressurized air source (12), a fresh air source (14), a dynamic air circulation duct (16), a network of pipes (40, 41, 42, 43, 44, 45, 46, 47, 48, 49) and control valves (50, 51, 52, 53, 54, 55, 56, 57, 58, 59), a primary cooling exchanger (PHx), a main cooling exchanger (MHx), a turbomachine (20) comprising at least one first compressor (22) and an expansion unit. (24, 26).The air conditioning system is characterized in that: said first compressor (22) comprises an air inlet adapted to be connected, upon control of said valves, to said fresh air source (14) and / or said primary cooling exchanger (PHx), and an air outlet connected to said main cooling exchanger (MHx); said expansion unit (24, 26) comprises an air inlet adapted to be connected, upon control of said valves, either to said primary cooling exchanger (PHx) or to said main cooling exchanger (MHx) and an air outlet adapted to be connected to said cabin (10). Figure for the abbreviation: Figure 1.

Description

Title of the invention: PNEUMATIC AIR CONDITIONING SYSTEM FOR AN AIRCRAFT CABIN COMPRISING AN AMBIENT AIR COMPRESSOR Technical field of the invention

[0001] The invention relates to a pneumatic air conditioning system for an aircraft cabin. In particular, the invention relates to an air conditioning system comprising an ambient air compressor for increasing the air flow delivered to the cabin. Technological background

[0002] Throughout this text, the term "cabin" refers to any interior space in an aircraft where the air pressure and / or temperature must be controlled. This may include a passenger cabin, the cockpit, a cargo hold, and generally any area of ​​the aircraft that requires air at a controlled pressure and / or temperature. This air at a controlled pressure and / or temperature is supplied by an air conditioning system, which is the subject of this invention.

[0003] Throughout this text, the term "turbine" refers to a rotating device designed to use the kinetic energy of air to rotate a shaft supporting the turbine blades. The term "compressor" refers to a rotating device designed to increase the pressure of the air it receives at its inlet. Such a compressor typically comprises an air inlet, an air outlet, and an impeller adapted to allow the passage of a compressible fluid such as air, arranged between the inlet and outlet, and configured to draw in air at the compressor inlet, modify its pressure, temperature, and / or velocity, and deliver it at the air outlet.

[0004] There are a number of aircraft in which cabin environmental control is carried out entirely pneumatically, i.e. by systems operating from air taken from the compressors of the aircraft's propulsion engines and / or from outside air at dynamic pressure, more or less important depending on the type of outside air intake - scoop, wall inlet, etc. - and better known by the acronym RAM air or dynamic air, when the aircraft is in flight.

[0005] Throughout the following text, the concept of dynamic air refers to air taken from outside the aircraft by all types of known means, such as a scoop, a wall inlet better known by the English name of "flush / NACA" inlet, etc.

[0006] The general problem that has long existed with this type of air conditioning system is to minimize the air drawn from the engine compressors, so as to minimize the impact of this air withdrawal on fuel consumption of kerosene and on engine performance. Another problem is being able to ensure control of cabin temperature and pressure in all phases of aircraft operation, including takeoff, descent, and on the ground.

[0007] Also, the inventors sought to propose new architectures of a pneumatic air conditioning system which allow, at the same flow rate delivered to the aircraft cabin, to reduce the air withdrawal on the aircraft engines and in particular on the aircraft propulsion engines. Objectives of the invention

[0008] The invention aims to provide a pneumatic air conditioning system for an aircraft cabin.

[0009] The invention aims in particular to provide such an air conditioning system which optimizes the use of bleed air taken from the aircraft's propulsion engines to provide air conditioning to supply the cabin.

[0010] The invention also aims to provide, in at least one embodiment, such an air conditioning system which makes it possible to deliver a greater flow of conditioned air to the cabin with the same intake from the aircraft's propulsion engines.

[0011] The invention also aims to provide such a system which makes it possible to reduce the energy consumed by the aircraft.

[0012] The invention also aims to provide such an air conditioning system which benefits from optimized and compact integration, with a gain in mass and / or size.

[0013] The invention also aims to provide, in at least one embodiment, such a system which can adapt its mode of operation according to the flight conditions of the aircraft, and in particular according to its altitude.

[0014] The invention finally aims to provide a method for pneumatically conditioning an aircraft cabin. Description of the invention

[0015] To this end, the invention relates to an aircraft cabin air conditioning system comprising: - a source of pressurized air taken from an aircraft engine, known as air bleed, - a source of fresh air taken from outside the aircraft, known as ambient air, - a circulation channel for dynamically drawn air from outside the aircraft, - a network of pipes and control valves configured to regulate the airflow circulating through said pipes, between said source pressurized air, said fresh air source and said cabin, depending on the aircraft's flight conditions, - a heat exchanger, called the primary cooling exchanger (also referred to throughout the text by the acronym PHx), housed in said dynamic air circulation duct and fluidically connected to said bleed air source, - a heat exchanger, called the main cooling exchanger (also referred to throughout the text by the acronym MHx), housed in said dynamic air circulation duct, - an air cycle turbomachine comprising at least a first compressor and an expansion group mechanically coupled to each other by a mechanical shaft.

[0016] The air conditioning system according to the invention is characterized in that said first compressor includes an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said fresh air source and / or said primary cooling exchanger, and an air outlet fluidly connected to said main cooling exchanger.

[0017] The air conditioning system according to the invention is also characterized in that the expansion unit includes an air inlet adapted to be able to be fluidly connected, by said piping network, on control of said regulating valves, either to said primary cooling exchanger, or to said main cooling exchanger and an air outlet adapted to be able to be fluidly connected, by said piping network, on control of said regulating valves, to said cabin.

[0018] In other words and according to the invention, the air conditioning system has an architecture which allows it to be switched (by control of the system's regulating valves) from an operating mode, called ground mode, in which the air inlet of the first compressor is fluidly connected by said network of pipes to the bleed air source and an air inlet of the expansion group is connected to the main cooling exchanger, to a mode, called flight mode, in which the air inlet of the first compressor is fluidly connected by the network of pipes to the fresh air source and an air inlet of the expansion group is fluidly connected by the network of pipes to the primary cooling exchanger.

[0019] Thus, in ground mode, particularly on hot days, bleed air drawn from the propulsion engine supplies the compressor. The compressed air then passes through the MHx unit to supply the expansion unit where it is expanded to produce maximum cooling capacity (after, according to certain variants described later, passing through a water extraction loop). It is also possible, in a variant described later, to have a second compressor supplied by ambient air. and whose compressed air completes the bleed air flow that feeds the first compressor.

[0020] In flight mode, above a certain altitude, the compressor can compress an ambient airflow (resulting from the work done by the expansion unit, which is powered by bleed air taken from the engine to which the compressor is mechanically connected by the drive shaft), without compressing the bleed air. The total airflow (comprising the bleed airflow cooled by the PHx without passing through the compressor, and the additional airflow resulting from the compression of the ambient air) can then be conveyed to the cabin (after, according to certain variants described later, passing through a water extraction loop). Furthermore, and as described later, the expansion unit can consist of one or two turbines mounted on the drive shaft.

[0021] A system according to the invention is therefore configured to be able to present at least the flight mode and at least the ground mode described, each mode being the result of the control of the regulating valves associated with the network of pipes connecting the different organs of the system according to the invention.

[0022] Ground mode is activated for example when the aircraft is on the ground and at low altitude (for example below 15,000 feet altitude) and flight mode is activated for example at medium or high altitude (for example above 15,000 feet on a hot day or above 25,000 on a cold day).

[0023] Advantageously and according to a first embodiment of the invention, the expansion group of said turbomachine comprises a first turbine and a second turbine mechanically coupled to said first compressor by said mechanical shaft, said first turbine comprising an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said primary cooling exchanger and an air outlet fluidly connected to the cabin, said second turbine comprising an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said main cooling exchanger and an air outlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said cabin.

[0024] Thus, according to this variant, the expansion unit consists of two turbines. The first turbine is primarily used in flight mode to produce cooling power from the bleed air it receives at the inlet and to mechanically drive the compressor so that it can compress the ambient air it receives. The second turbine is primarily used in ground mode to produce cooling power from the air from the MHx heat exchanger. This second turbine can also be used in flight mode to produce additional cooling power.

[0025] Thus, according to this embodiment, on the ground in a hot day, the bleed air drawn from the propulsion engine passes through the primary cooling heat exchanger to be cooled. This air then flows to the compressor inlet to be compressed and exits through the main cooling heat exchanger. The cooled air can then be directed to a water extraction loop. The dried air is finally expanded through the second turbine to produce maximum cooling power.

[0026] In flight and above a certain altitude, the bleed air drawn from the propulsion engine passes through the PHx to be cooled. The air is then directed to the first turbine to produce cooling. The work created by this first turbine allows the compressor, which in this configuration is no longer compressing bleed air, to compress an additional flow of ambient air. This compressed ambient air flows through the MHx before supplementing the flow drawn from the engine. Depending on the requirements, this air can directly supply the cabin or be directed to a water extraction loop to be dried and / or to the second turbine.

[0027] Advantageously and according to this variant, the system further comprises a turbofan arranged in said air circulation channel and comprising an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said main cooling exchanger and an air outlet adapted to be able to be fluidly connected, on control of said regulating valves, to said air inlet of said second turbine.

[0028] According to this variant, the ventilation of the dynamic air circulation channel (corresponding to the cold pass of PHx and MHx) is ensured by means of the turbofan whose turbine is supplied by the air exiting the water extraction loop (and coming from the MHx heat exchanger). The air exiting the turbofan can supply the second turbine.

[0029] According to another variant, the air ventilation in the dynamic air circulation channel can be provided by an electric fan or by a fan wheel mounted on said mechanical shaft and arranged in said dynamic air circulation channel.

[0030] According to another embodiment, the turbomachine further comprises a second compressor mechanically coupled to said first compressor and the expansion unit comprises a single turbine mechanically connected to the first and second compressors by said mechanical shaft, said second compressor comprising an air inlet fluidly connected by said pipe network to said ambient air source, and an air outlet fluidly connected by said pipe network to said air inlet of said first compressor.

[0031] Thus, according to this embodiment, the ground operation on a hot day is as follows: bleed air drawn from the propulsion engine passes through the primary cooling heat exchanger to be cooled. This cooled air is then conveyed to the inlet of the first compressor, as is the ambient air flow, which is compressed by the second compressor. These two compressed air flows are mixed before being compressed by the first compressor. The compressed air is then conveyed to the main cooling heat exchanger (MHx). The air cooled by the MHx heat exchanger is conveyed to the expansion turbine, after possibly passing through a water extraction loop. The passage of air through the expansion turbine allows for maximum cooling capacity, which is then supplied to the cabin.

[0032] The operating mode in flight, above a certain altitude, is as follows: the bleed air drawn from the engine passes through the primary cooling heat exchanger to be cooled. The cooled air is then directed to the turbomachine turbine. The work created by this expansion turbine allows an additional flow of ambient air to be compressed by the second compressor, and also by the first compressor, which in this operating mode no longer compresses the bleed air drawn from the engine. This compressed ambient air mixes with the flow drawn from the engine, then is expanded by the turbine before passing through the main cooling heat exchanger. This cooled air is then directed to the cabin without passing through the water extraction loop by the control of an altitude valve, which may be a three-way valve.

[0033] Thus and according to the invention, the network of pipes and the associated control valves make it possible to switch from one operating mode to another depending on the needs.

[0034] Advantageously and according to this variant, the system further comprises a turbofan arranged in said air circulation channel and comprising an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said regulating valves, to said main cooling exchanger (MHx) and an air outlet adapted to be able to be fluidly connected, on control of said regulating valves, to said air inlet of said first turbine.

[0035] Thus, according to this embodiment, air ventilation in the dynamic air circulation duct is ensured by the turbofan driven by air from the main cooling heat exchanger. According to another embodiment, air ventilation in the dynamic air circulation duct can be ensured by an electric fan or by a fan wheel mounted on said mechanical shaft and arranged in said dynamic air circulation duct.

[0036] Advantageously and according to the invention, the system further comprises a water extraction loop fluidly connected to said main cooling exchanger (MHX) and to an air inlet of the expansion group of said turbomachine, said water extraction loop comprising at least a condenser, a water separator and optionally a heater.

[0037] Advantageously, the water extraction loop is adapted to be able to be fluidly connected by said pipe network, on the control of an altitude valve, to said main cooling exchanger and to at least one turbine of said air cycle turbomachine, so as to be able to extract the water present in the air delivered by said main cooling exchanger before being delivered to this expansion turbine.

[0038] The system according to this variant therefore allows, when flight conditions so require, below a predetermined altitude, the air to be dried by the water extraction loop before being supplied to the turbomachine's expansion unit. A system according to the invention also allows, above this predetermined altitude, the water extraction loop to be bypassed when the air is sufficiently dry and cool to supply the aircraft cabin.

[0039] A system according to the invention also allows for optimized and compact integration, in particular a reduction in mass and size, by performing air conditioning functions with a limited number of equipment while maintaining high flexibility.

[0040] In addition, the invention makes it possible to obtain a reliable, flexible air conditioning system that can adapt to the different flight conditions of the aircraft, and in particular according to its altitude.

[0041] Advantageously and according to the invention, said fresh air source comprises a dynamic air intake device on an aircraft scoop or in the dynamic air circulation channel.

[0042] The invention also relates to an aircraft comprising a cabin and an air conditioning system for this cabin, characterized in that said cabin air conditioning system is a system according to the invention.

[0043] The advantages and technical effects of an air conditioning system according to the invention apply mutatis mutandis to an aircraft according to the invention.

[0044] The invention also relates to a method for air conditioning an aircraft cabin comprising a pressurized air source, referred to as air bleed; a fresh air source, referred to as ambient air; a dynamic air circulation duct drawn from outside the aircraft; a network of ducts and control valves configured to regulate the airflow through said ducts, between said pressurized air source, said fresh air source and said cabin, according to the aircraft's flight conditions; a heat exchanger, referred to as the primary cooling exchanger (PHx), housed in said dynamic air circulation duct; a heat exchanger, said main cooling exchanger (MHx), housed in said dynamic air circulation channel; an air cycle turbomachine comprising at least a first compressor and an expansion group mechanically coupled to each other by a mechanical shaft.

[0045] The method according to the invention is characterized in that it comprises the following steps: - the bleed air is taken from an aircraft engine; - ambient air is taken from outside the aircraft; - the bleed air is conveyed by the said network of pipes, towards the primary cooling exchanger; - an air inlet of said first compressor is made in fluidic communication, by said network of pipes, on control of said regulating valves, to said fresh air source and / or said primary cooling exchanger (PHx), - an air outlet of said first compressor is put into fluidic communication with said main cooling exchanger (MHx), - an air inlet of said expansion group is made in fluidic communication, by said piping network, on control of said regulating valves, said primary cooling exchanger (PHx), and / or said main cooling exchanger (MHx), - an air outlet of the expansion group is put into fluidic communication, by the said piping network, on control of the said regulating valves, to the said cabin.

[0046] An air conditioning method according to the invention is advantageously implemented by an air conditioning system according to the invention and an air conditioning system according to the invention advantageously implements a method according to the invention.

[0047] Thus, the advantages and technical effects of an air conditioning system according to the invention apply mutatis mutandis to a process according to the invention.

[0048] Note that it is possible to provide an additional heat exchanger arranged between the outlet of the expansion unit and the cabin. Such an exchanger is, for example, a condenser in a water extraction loop.

[0049] The invention also relates to an air conditioning system, an air conditioning method, and an aircraft comprising such an air conditioning system, characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0050] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, and which refers to the accompanying figures in which:

[0051] [Fig-1] is a schematic view of an air conditioning system according to a first embodiment of the invention,

[0052] [Fig.2] is a schematic view of the air conditioning system of [Fig.1] in ground mode,

[0053] [Fig.3] is a schematic view of the air conditioning system of [Fig.1] in flight mode.

[0054] [Fig.4] is a schematic view of an air conditioning system according to a second embodiment of the invention,

[0055] [Fig.5] is a schematic view of the air conditioning system of the [Fig.4] in ground mode,

[0056] [Fig.6] is a schematic view of the air conditioning system of the [Fig.4] in flight mode,

[0057] [Fig.7] is a schematic view of the air conditioning system according to another embodiment of the invention, in flight mode,

[0058] [Fig.8] is a schematic view of the air conditioning system of the [Fig.7] in ground mode.

[0059] Detailed description of an embodiment of the invention

[0060] In the figures, the scales and proportions are not strictly respected for the purposes of illustration and clarity.

[0061] In addition, identical, similar or analogous elements are designated by the same references in all figures.

[0062] Figures 1, 2, and 3 illustrate a first embodiment of the system according to the invention, and Figures 4, 5, and 6 illustrate a second embodiment of the system according to the invention. Figures 7 and 8 illustrate a variant of the second embodiment. Figures 2 and 3 illustrate the system of [Fig. 1] in ground and flight modes, respectively. In these figures, bold lines represent the conduits that fluidly connect the system equipment in the corresponding operating mode by controlling the corresponding regulating valves, and thin lines represent the conduits not used in that operating mode.

[0063] The same principle is used for figures 4, 5, 6, 7 and 8 on which the lines in bold are those used for the corresponding operating mode.

[0064] In other words, in operation, the pipes shown in bold are those which carry air from one piece of equipment to another, this movement of air being obtained by piloting the system's regulating valves arranged on the system's pipes.

[0065] The principle underlying the invention is to have an architecture that, by controlling regulating valves and a network of pipes, allows the system to be switched from a ground mode to a flight mode (and vice versa) as needed. These flight and ground modes are characterized in particular by the type of air (bleed or ambient) that supplies the compressor 22 and by the air that is conveyed to the expansion unit. This expansion unit is formed by the turbines 24 and 26 in the embodiment shown in Figures 1, 2 and 3, and by the single turbine 24 in the embodiment shown in Figures 4, 5, 6, 7 and 8.

[0066] Thus, [Fig.1] describes a pneumatic air conditioning system for a cabin 10 of an aircraft comprising a fresh air source 14, a bleed air source 12, a channel 16 for circulating dynamic air taken from outside the aircraft, and a network of pipes 41, 42, 43, 44, 45, 46, 47, 48, 49 and control valves 51, 52, 53, 54, 55, 56, 57, 58 configured to be able to regulate the flow of air circulating through the pipes according to the flight conditions of the aircraft.

[0067] The bleed air source 12 is, for example, air taken from a propulsion engine of the aircraft and the fresh air source 14 (also referred to by the terminology of ambient air source) is, for example, air taken from an aircraft scoop outside the aircraft.

[0068] An air conditioning system according to the embodiment of [Fig.1] also includes a turbomachine comprising a compressor 22, a first turbine 24 mechanically connected to the compressor 22 by a mechanical shaft 18 and a second turbine 26 mechanically connected to the first turbine 24 by the same mechanical shaft 18.

[0069] The system of [Fig.1] also includes a turbofan 32 connected by the pipe 45 of the pipe network to an inlet of the turbine 26 and to a water extraction loop comprising a heater 33 and a condenser 34. The outlet of the heater 33 is connected to the inlet of the turbofan 32 by the pipe 44 of the pipe network.

[0070] The system also includes a primary cooling exchanger (hereinafter referred to as PHx), housed in said dynamic air circulation channel 16 and fluidically connected to the bleed air source 12.

[0071] The system also includes a main cooling exchanger (hereinafter referred to as MHx), housed in said dynamic air circulation channel 16, upstream of the exchanger PHx.

[0072] The exchangers are represented in series so that the air flowing in the channel 16 (from top to bottom in the figures) first passes through the MHx, then the PHx, but it is also possible, in another embodiment, to provide exchangers in parallel so that the air passes simultaneously through both exchangers in the channel 16.

[0073] Fig. 2 illustrates the principle of air circulation in the ground mode of the system of Fig. 1.

[0074] The bleed air source 12, taken from the propulsion engine, passes through the PHx heat exchanger to be cooled by the air circulating in channel 16. This cooled air is conveyed by line 41 of the piping network to the inlet of the compressor 22 to be compressed. This circulation is made possible by the control valve 51 located on line 4L. The air compressed by the compressor 22 is then conveyed to the MHx heat exchanger by line 42. This air is cooled again by the MHx heat exchanger. This cooled air is then conveyed by line 43 of the piping network to the heater 33 and the condenser 34 of the water extraction loop. This is made possible by the control of the regulating valves 52 and 56. The water extraction loop also includes a water separator 36. The recovered water can be reinjected into the dynamic air circulation channel upstream of the MHX exchanger via a pipe not shown in the figures.

[0075] The air dried by the water extraction loop can then supply the turbofan 32 via the duct 44 and the control of the regulating valves 54 and 53. The turbofan 32 housed in the channel 16 thus ensures the dynamic air circulation in the channel 16.

[0076] Furthermore, the air exiting the turbofan 32 feeds the turbine 26 to expand the air and produce maximum cooling power. This supply is provided via the duct 45 which, according to the embodiment shown in the figures, includes an additional water separator 37.

[0077] The air exiting the turbine 26 passes through the condenser 34 and supplies the cabin 10 via the pipe 49 of the pipe network.

[0078] Alternatively, the dried air at the outlet of the water extraction loop can directly supply the turbine 26 by the simultaneous control of the regulating valves 53 and 54. This variant is implemented when the turbofan 32 is replaced by an electric fan or by a fan wheel directly mounted on the mechanical shaft to ensure air circulation in the channel 16.

[0079] In flight and above a certain altitude, the system can switch to the operating mode represented by [Fig.3].

[0080] In this operating mode, the bleed air 12 drawn from the propulsion engine passes through the PHX to be cooled. The air is then conveyed to the first turbine 24 via the conduit 41 to produce cooling. This is made possible by the control of the regulating valves 55 and 51. The work created by this first turbine 24 compresses an additional flow of ambient air 14, which supplies the compressor 22 via the conduit 46. In this configuration, the compressor 22 is no longer supplied by the bleed air 12.

[0081] The ambient air flow 14 compressed by the compressor 22 is conveyed to the MHX via the pipe 42. The air exiting the MHX is mixed with the air from the turbine 24 and conveyed via the pipe 48 to the pipe 43. Depending on the requirements, this air can directly supply the cabin 10 via the pipe 47 and the pilot valve 56, or be conveyed to the water extraction loop to be dried and / or to the second turbine 26. The control valve 56 is preferably an altitude valve which allows air to flow through the pipe 47 when a predetermined altitude is reached by the aircraft.

[0082] Figures 4, 5 and 6 illustrate another embodiment in which the turbomachine comprises two compressors 22, 23 and a single turbine 24.

[0083] The same references are used on these figures for elements identical or substantially identical to the embodiment of figures 1, 2 and 3.

[0084] Thus, according to this embodiment and as shown in [Fig. 5], the ground operation on a hot day is as follows: the bleed air 12 drawn from the propulsion engine passes through the PHx heat exchanger to be cooled. This cooled air is then conveyed to the inlet of the first compressor 22 via the piping 41 of the piping network and by the control of the regulating valve 51. In parallel, the second compressor 23 is supplied with ambient air 14 conveyed via the piping 46. The air compressed by the second compressor 23 joins the bleed air flow at the inlet of the first compressor 22 via the piping 40. These two air flows are thus mixed before being compressed by the first compressor 22. The compressed air is conveyed to the main cooling heat exchanger MHx via the piping 42 of the piping network.The air cooled by the MHx heat exchanger is conveyed to the water extraction loop via pipe 43, then to the turbofan 32 and to the expansion turbine 24, following the same principle as in the first embodiment. The passage of air through the expansion turbine allows for the production of maximum cooling capacity, which is then supplied to the cabin 10 via pipe 49.

[0085] The system according to this embodiment can also switch to flight mode above a certain altitude. In this operating mode illustrated by [Fig. 6], the bleed air flow 12 taken from the engine passes through the heat exchanger PHx to be cooled. The cooled air is conveyed to the turbine 24 via the conduit 41 of the piping network. The work created by the expansion turbine 24 allows an additional flow of ambient air to be compressed by the second compressor 23, and also by the first compressor 22, which in this operating mode no longer compresses the bleed air taken from the engine. This compressed ambient air flow mixes with the flow taken from the engine and expanded by the turbine 24 to reach the heat exchanger MHx. This is made possible by the control of the regulating valve 50. This air flow cooled by the MHx is then routed to the cabin without going through the water extraction loop by the control of the altitude valve 52.

[0086] Figure 7 illustrates an alternative embodiment shown in flight mode. In this embodiment, the turbofan is replaced by a fan wheel mounted on shaft 18 such that the rotation of shaft 18 (resulting from the work done by the turbine 24) drives the fan wheel and thus the movement of air in the dynamic air circulation channel. The same embodiment can be used for the first embodiment.

[0087] It is also possible to replace the fan wheel with an electric fan independent of the mechanical shaft 18 to ensure air ventilation in the dynamic air circulation channel 16.

[0088] Figure 8 illustrates the system of Figure 7, switched to ground mode. The operating principle is the same as that of Figure 5, except that the system includes a 4-wheel turbomachine so that the fan 32 is directly supported by the shaft 18 of the turbomachine and its rotation depends on the work produced by the turbine 24.

[0089] It should also be noted that the system described in connection with Figures 1, 2 and 3 can also be implemented with a four-wheeled turbomachine, in which case the turbofan 32 is replaced by a wheel of the four-wheeled turbomachine. The operating principle remains identical to that described in connection with Figures 1, 2 and 3, with the exception, of course, of the rotation of the fan 32, which then results from the work produced by the turbines of the expansion unit.

[0090] Regardless of the embodiment, the opening / closing control of the various regulating valves is, for example, provided by a control unit of the air conditioning system. The control unit is therefore configured to determine the opening / closing position of all the system's regulating valves according to the aircraft's flight conditions (altitude, outside temperature, flight state (ground, climb, cruise, descent), etc.) and to switch the system from a ground mode to a flight mode and vice versa.

[0091] The control may also depend on information provided by computers on board the aircraft such as the integrated air system computer (better known by the acronym IASC for Integrated Air System Controller), the bleed management system computer (better known by the acronym BMC for Bleed Management Controller), and generally any computer on board the aircraft capable of providing data related to a cabin air requirement.

Claims

1. Demands Aircraft cabin air conditioning system (10) comprising - a pressurized air source (12) taken from an aircraft engine, known as air bleed, - a source of fresh air (14) taken from outside the aircraft, called ambient air, - a channel (16) for the circulation of dynamic air taken from outside the aircraft, - a network of pipes (40, 41, 42, 43, 44, 45, 46, 47, 48, 49) and control valves (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) configured to regulate the flow of air circulating through said pipes, between said pressurized air source (12), said fresh air source (14) and said cabin (10), according to the aircraft's flight conditions, - a heat exchanger, called the primary cooling exchanger (PHx), housed in said dynamic air circulation channel (16) and fluidically connected to said bleed air source (12), - a heat exchanger, referred to as the main cooling exchanger (MHx), housed in said dynamic air circulation channel (16), - an air-cycle turbomachine (20) comprising at least a first compressor (22) and an expansion unit (24, 26) mechanically coupled to each other by a mechanical shaft (18), said air conditioning system being characterized in that: - said first compressor (22) comprises an air inlet adapted to be fluidly connected by said pipe network, on control of said regulating valves, to said fresh air source (14) and / or said primary cooling exchanger (PHx), and an air outlet fluidly connected to said main cooling exchanger (MHx), - said expansion group (24, 26) includes an air inlet adapted to be able to be fluidly connected, by said piping network, on control of said regulating valves, either to said primary cooling exchanger (PHx), or to said main cooling exchanger (MHx) and an air outlet adapted to be able to be fluidly connected, by said piping network, on control of said regulating valves, to said cabin (10).

2. System according to claim 1, characterized in that said expansion group comprises a first turbine (24) and a second turbine (26) mechanically coupled to said first compressor (22) by said mechanical shaft (18), said first turbine (24) comprising an air inlet adapted to be able to be fluidly connected by said piping network, on control of said regulating valves, to said primary cooling exchanger (PHx) and an air outlet fluidly connected to the cabin (10), said second turbine (26) comprising an air inlet adapted to be able to be fluidly connected by said piping network, on control of said regulating valves, to said main cooling exchanger (MHx) and an air outlet adapted to be able to be fluidly connected by said piping network, on control of said regulating valves, to said cabin (10).

3. System according to claim 2, characterized in that it further comprises a turbofan (32) arranged in said air circulation channel (16) and comprising an air inlet adapted to be able to be fluidly connected by said network of pipes, on control of said control valves, to said main cooling exchanger (MHx) and an air outlet adapted to be able to be fluidly connected, on control of said control valves, to said air inlet of said second turbine (26).

4. System according to claim 1, characterized in that the turbomachine further comprises a second compressor (23) mechanically coupled to said first compressor (22) and the expansion group comprises a single turbine (24) mechanically connected to the compressors by said mechanical shaft (18), said second compressor (23) comprising an air inlet fluidly connected by said pipe network to said ambient air source (14), and an air outlet fluidly connected by said pipe network to said air inlet of said first compressor (22).

5. System according to claim 4, characterized in that it further comprises a turbofan (32) arranged in said air circulation channel (16) and comprising an air inlet adapted to be fluidly connected, via said ductwork, by control of said regulating valves, to said main cooling exchanger (MHx) and an air outlet adapted for to be able to be fluidly connected, on control of said regulating valves, to said air inlet of said turbine (24).

6. System according to any one of claims 1, 2 or 4 characterized in that it further comprises a fan wheel mounted on said mechanical shaft (18) and arranged in said channel (16) for the circulation of dynamic air.

7. System according to any one of claims 1 to 6, characterized in that it further comprises a water extraction loop fluidly connected to said main cooling exchanger (MHx) and to an air inlet of a turbine of said turbomachine, said water extraction loop comprising at least one condenser (34) and a water separator (36).

8. System according to claim 7 characterized in that said water extraction loop further comprises a heater (33).

9. A method for air conditioning a cabin (10) of an aircraft comprising a pressurized air source (12), referred to as air bleed; a fresh air source (14), referred to as ambient air; a channel (16) for circulating dynamic air taken from outside the aircraft; a network of pipes (40, 41, 42, 43, 44, 45, 46, 47, 48, 49) and control valves (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) configured to be able to regulate the flow of air circulating through said pipes, between said pressurized air source (12), said fresh air source (14) and said cabin (10), according to the flight conditions of the aircraft; a heat exchanger, called primary cooling exchanger (PHx), housed in said dynamic air circulation channel (16); a heat exchanger, called main cooling exchanger (MHx), housed in said dynamic air circulation channel (16);an air-cycle turbomachine (20) comprising at least a first compressor (22) and an expansion group (24, 26) mechanically coupled to each other by a mechanical shaft (18), characterized in that it comprises the following steps: - bleed air (12) is taken from an engine of the aircraft; - ambient air (14) is taken from outside the aircraft; - the bleed air (12) is conveyed by said piping system to the primary cooling exchanger (PHx); - an air inlet (22a) of said first compressor is made fluidic, by said piping system, to; control of said regulating valves, to said fresh air source (14) and / or said primary cooling exchanger (PHx), - an air outlet of said first compressor is put into fluidic communication with said main cooling exchanger (MHx), - an air inlet of said expansion group is made in fluidic communication, by said piping network, on control of said regulating valves, to said primary cooling exchanger (PHx), and / or to said main cooling exchanger (MHx), - an air outlet of the expansion group is made in fluidic communication, by said piping network, on control of said regulating valves, to said cabin (10).

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