Patent Application
20170190430
This application claims priority to European Patent Application No. EP15382678.9 filed Dec. 30, 2015, the entirety of which is incorporated by reference.
The present invention is related to the field of aircraft engines and, in particular, relates to the field of cooling systems using bleed air from aircraft engines.
The cabin of a modern passenger aircraft is air-conditioned usually both when the aircraft is flying and is on the ground by means of the aircraft's air conditioning system. The aircraft air conditioning system is supplied with pressurized bleed air taken from a compressor of an aircraft engine, such as a turbofan, or the compressor in the aircraft's Auxiliary Power Unit.
Typically, the bleed air passes through an “air cycle machine” that comprises, among others, one or several heat exchangers, a compressor and one or several turbines that cool the bleed air to a desired lower temperature and pressure. In this type of air conditioning system, the air exiting the air cycle machine follows an inverse Brighton cycle and is usually mixed in a mixing chamber with air recirculated from the cabin. Pipes exiting the mixing chamber may receive air at different temperatures from a manifold, in such a way that they blow air into the cabin at different temperatures.
The present invention uses air from a ram air channel to cool the heat exchangers of the air cycle machine to be compressed and used later on to feed the cabin either via mixing chambers or via an air temperature manifold, since this temperature will be higher than the one selected for the cabin. In this manner the drag is reduced as well as the power needed in the overall cycle, which is improved and therefore achieving lower fuel consumption.
According to a first aspect, the invention provides an air conditioning system for a cabin of an aircraft, the air conditioning system comprising: i a pressurized air source which, when in an operative mode, provides work air with a pressure higher than 100 kPa; ii a cooling air source, suitable for providing cooling air; iii a main heat exchanger with a cold side and a hot side, the hot side comprising an inlet and an outlet and the cold side comprising an inlet and an outlet, in such a way that the inlet of the cold side of the main heat exchanger is in fluid communication with the cooling air source, and the inlet of the hot side of the main heat exchanger is in fluid communication with the pressurized air source; iv a secondary duct which bleeds part of the air from the outlet of the cold side of the main heat exchanger or from the inlet of the cold side of the main heat exchanger; v a first valve configured to allow or restrict the passage of air bled to the secondary duct; and vi a compressor with an inlet and an outlet, the inlet of the compressor being located in fluid communication with, the outlet of the cold side of the main heat exchanger or the inlet of the cold side of the main heat exchanger, a second valve being located in fluid communication with the outlet of the compressor; wherein the outlet of the compressor is in fluid communication with mixing means which in turn are in fluid communication with the cabin.
This air conditioning system allows using less air from the air pressurized source than the air conditioning systems known in the state of the art, since part of the air obtained from the atmosphere by the cooling air source is conveniently treated and added to the air to be introduced in the cabin.
The mixing device may comprise a manifold having at least one inlet and at least one outlet, wherein at least one inlet of the manifold is in fluid communication with the outlet of the compressor, each inlet of the manifold comprising a third valve; a mixing chamber comprising at least one inlet and at least one outlet, one of the inlets of the mixing chamber being fed by the outlet of the hot side of the main heat exchanger, and the at least one outlet of the mixing chamber being in fluid communication with the cabin; wherein at least an outlet of the manifold is in fluid communication with an outlet of the mixing chamber, this outlet of the manifold comprising a fourth valve; and wherein each outlet of the mixing chamber is in fluid communication with the cabin.
The mixing device may also comprise a manifold, comprising at least one inlet and at least one outlet, wherein at least one inlet of the manifold is in fluid communication with the outlet of the compressor, each inlet of the manifold comprising a third valve; a mixing chamber comprising at least two inlets and a plurality of outlets, one of the inlets of the mixing chamber being fed by the outlet of the hot side of the main heat exchanger, one of the inlets of the mixing chamber being fed by the and the plurality of outlets of the mixing chamber being in fluid communication with the cabin; wherein at least an outlet of the manifold is in fluid communication with an outlet of the mixing chamber, this outlet of the manifold comprising a fourth valve; and wherein each outlet of the mixing chamber is in fluid communication with the cabin.
The air conditioning system may further comprise a bypass channel which puts the pressurized air source in fluid communication with the manifold and a fifth valve configured to allow or restrict the pass of air bled to the bypass channel.
The mixing device may also comprise a mixing chamber comprising at least two inlets and a plurality of outlets, one of the inlets of the mixing chamber being fed by the outlet of the hot side of the main heat exchanger, one of the inlets of the mixing chamber being fed by the and the plurality of outlets of the mixing chamber being in fluid communication with the cabin.
These air conditioning systems have a better control of air temperature which is intended to be introduced in the cabin, as different temperatures may be obtained by the suitable setting of the outlets of the mixing chamber.
The air conditioning system may further comprise a secondary heat exchanger by means of which heat is transferred from the outlet of the compressor to the air in the secondary duct.
The air conditioning system may further comprise a turbine with an inlet and an outlet, the inlet of the turbine being in fluid communication with an outlet of the cabin, wherein the compressor is driven by energy produced in the turbine.
This air conditioning system demands lower energy consumption, as the compressor does not need an external energy source to be moved.
The air conditioning system may further comprise a secondary heat exchanger by means of which heat is transferred from the outlet of the cabin to the air in the secondary duct.
At least a second outlet of the manifold may be in fluid connection with a second outlet of the mixing chamber.
The main heat exchanger may be comprised in an air cycling machine.
These and other characteristics and advantages of the invention will be clearly understood in view of the detailed description of the invention and further in view of the preferred embodiments of the invention, with reference to the drawings. Preferred embodiments are given just as examples and are not intended to limit the scope of the present invention.
Having outlined the object of the invention, specific non-limitative embodiments are described hereinafter.
The inlet 43 of the cold side of the main heat exchanger 4 is in fluid communication with the cooling air source 3, and the inlet 41 of the hot side of the main heat exchanger 4 is in fluid communication with the pressurized air source 2. The main heat exchanger 4 thus allow a heat exchanging between the cooling air obtained in the cooling air source 3 and the work air obtained in the pressurized air source 2.
The inlet 51 of the compressor is in fluid communication with the outlet 44 of the cold side of the main heat exchanger 4, so that the cooling air exiting the main heat exchanger 4 enters the compressor 5.
The compressor 5 may be driven by the energy provided by an electric motor 99. The compressor 5 may also or alternatively drive energy provided by the air cycling machine 15.
The air conditioning system 1 may comprise a secondary duct 13 which bleeds part of the air from the outlet 44 of the cold side of the main heat exchanger 4. Further, the air conditioning system 1 may comprise a first valve 11 configured to allow or restrict the pass of air bled to the secondary duct 13.
The air conditioning system 1 may further comprise a secondary heat exchanger 8. The secondary heat exchanger 8 transfers heat from the outlet 52 of the compressor 5 to the air exiting the cold side of the main heat exchanger 4.
The air conditioning system 1 may further comprise a bypass channel 14 which puts the pressurized air source 2 in fluid communication with the manifold 6 and a fifth valve 12 configured to allow or restrict the pass of air bled to the bypass channel 14.
The air conditioning system 1 may further comprise a manifold 6, comprising two inlets 61, 62 and two outlets 63, 64, wherein the two inlets 61, 62 of the manifold 6 are in fluid communication with the outlet 52 of the compressor, the second valve 31 being located between the two inlets 61, 62 of the manifold 6 and the outlet 52 of the compressor. Each inlet 61, 62 of the manifold 6 comprises a third valve 32, 33 and each outlet 63, 64 of the manifold 6 comprises a fourth valve 34, 35.
Each outlet 63, 64 of the manifold 6 may be in fluid communication with an outlet 72, 73 of the mixing chamber 7. Each outlet 72, 73 of the mixing chamber 7 may be in fluid communication with the cabin 10. Outlets 63, 64 of the manifold are used to control a final temperature obtained in the different outlets 72, 73 of the mixing chamber 7. By feeding each outlet 72, 73 of the mixing chamber 7 with one outlet 63, 64 of the manifold 6 which is at different temperature, different temperatures are obtained in each of the outlets 72, 73 of the mixing chamber 7. In other embodiments, the manifold 6 comprises more outlets.
The compressor 5 is drive by a turbine 9. This turbine 9 comprises an inlet 91 and an outlet 92. The inlet 91 of the turbine is in fluid communication with the outlet 101 of the cabin 10, so it is fed by air exiting the cabin 10. Energy contained in the air exiting the cabin and being evacuated to atmospheric air drives the turbine 9. By using energy in the air exiting the cabin to drive the turbine, energy need to be taken from other sources and thus there is an energy savings with respect to the energy generators in the aircraft. Alternatively or in addition, the turbine 9 may be driven by air exiting the main heat exchanger 4 or by another source of energy in the aircraft.
A third heat exchanger 81 may be placed such that heat is transferred between the inlet of the turbine 91 and the exit of the compressor 52. A one way valve 36 is placed in the inlet of the turbine 91.
The outlet 52 of the compressor is in fluid communication with an inlet 74 of the mixing chamber. The other inlet 71 of the mixing chamber 7 is fed by the outlet 42 of the hot side of the main heat exchanger 4, and the outlets 72, 73 of the mixing chamber are in fluid communication with the cabin 10.
Because of this arrangement, fresh air coming from the cooling air source 3 is available to be part of the temperature control, and part of it may be introduced in the mixing chamber 7.
While exemplary embodiments of the present inventions are disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiments. In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise.
| Number | Date | Country | Kind |
|---|---|---|---|
| 15382678.9 | Dec 2015 | EP | regional |
