Cooling system for cooling heat-generating installations and for maintaining the temperature of closed-off areas at below cabin temperature in an aircraft

1. Cooling system ( 10 ) for cooling heat-generating installations ( 44 , 46 , 48 ) and for maintaining the temperature of closed-off areas at below cabin temperature in an aircraft, the cooling system comprising:

a refrigerating installation ( 12 ) in the aircraft, including at least two refrigeration machines ( 18 , 20 ) which operate independently of one another in parallel;

at least one refrigeration consumer ( 44 , 46 , 48 ) constructed as a heat generating installation or as an area to be maintained at a temperature below cabin temperature;

a refrigeration transport system ( 14 ) connecting the refrigerating installation ( 12 ) and the refrigeration consumer ( 44 , 46 , 48 ); and

a central control unit operatively coupled to the refrigerating installation ( 12 ) and controlling the refrigeration capacity of the at least two refrigeration machines ( 18 , 20 ) depending on at least one parameter indicating the current refrigeration demand, such that each of the at least two refrigeration machines ( 18 , 20 ) operates, on the average, for substantially the same amount of time,

wherein the refrigerating installation ( 12 ) covers the maximum refrigeration requirement of the at least one refrigeration consumer ( 44 , 46 , 48 ),

wherein the at least one refrigeration consumer ( 44 , 46 , 48 ) is supplied with cold generated in the refrigerating installation ( 12 ) via a refrigerating agent circulating in the refrigeration transport system ( 14 ),

wherein a conveying pipe ( 28 ) having a shut-off valve ( 29 ) is provided, the shut-off valve ( 29 ) opening to feed at least a portion of the refrigerating agent from the refrigerating installation ( 12 ) by bypassing the at least one refrigeration consumer ( 44 , 46 , 48 ) directly to a pump unit ( 30 ) and back to the refrigerating installation ( 12 ), the shut-off valve ( 29 ) closing to force all of the refrigerating agent from the refrigerating installation ( 12 ) to the at least one refrigeration consumer ( 44 , 46 , 48 ), the shut-off valve ( 29 ) thereby controlling a refrigeration output of the cooling system based on a changing refrigeration requirement.

2. Cooling system ( 10 ) according to claim 1 ,

characterised in that the number of refrigeration machines ( 18 , 20 ) of the refrigerating installation ( 12 ) is chosen in such a way that the refrigeration requirement of the aircraft is covered during ground operation.

3. Cooling system ( 10 ) according to claim 1 ,

characterised in that at least one refrigeration machine ( 18 , 20 ) uses air inside the pressurised fuselage of the aircraft as a heat sink for emitting heat.

4. Cooling system ( 10 ) according to claim 1 ,

characterised in that at least one refrigeration machine ( 18 , 20 ) generates cold by a vapour cycle refrigeration process.

5. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigeration transport system ( 14 ) has at least one refrigerating agent pump ( 32 , 34 ) for circulating the refrigerating agent.

6. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigeration transport system ( 14 ) has at least one store ( 40 ) for compensating for thermal expansion and leakage losses of the refrigerating agent.

7. Cooling system ( 10 ) according to claim 1 ,

characterised in that the at least one refrigeration consumer ( 44 , 46 , 48 ) has a secondary refrigeration transport system in which cold is transmitted from the refrigerating agent by means of a secondary refrigerating agent.

8. Cooling system ( 10 ) according to claim 1 ,

characterised in that the parameters indicating the current refrigeration demand reproduce the temperature of the refrigerating agent at at least one point in the refrigeration transport system ( 14 ) or/and information on the refrigeration demand of the at least one refrigeration consumer ( 44 , 46 , 48 ) or/and the pressure of the refrigerating agent in the refrigeration transport system ( 14 ).

9. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigeration capacity is controllable by switching on and off individual refrigeration machines ( 18 , 20 ) of the refrigerating installation ( 12 ) to match the current refrigeration demand in the aircraft.

10. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigeration machines are controlled in decentralised manner, in particular by an automatic and time-dependent activation based on a monitoring of the actual status of all refrigeration machines via a databus.

11. Cooling system ( 10 ) according to claim 10 ,

characterised in that the refrigeration machines are activatable according to a predetermined prioritisation.

12. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigerating agent flows through both a switched on refrigeration machine ( 18 , 20 ) and a switched off refrigeration machine,

13. Cooling system ( 10 ) according to claim 1 ,

characterised in that a shut-off valve is assigned to each refrigeration machine.

14. Cooling system ( 10 ) according to claim 1 ,

characterised in that the refrigeration capacity of the at least one refrigeration machine ( 18 , 20 ) is controllable by means of the control device.

15. Cooling system ( 10 ) according to claim 1 ,

characterised in that the control unit detects the outflow temperature of the refrigerating agent leaving the refrigeration machine ( 18 , 20 ) and activates the refrigeration machine ( 18 , 20 ) in accordance with the detected outflow temperature.

16. Cooling system ( 10 ) according to claim 15 ,

characterised in that the refrigeration capacity of the at least one refrigeration machine ( 18 , 20 ) can be altered by means of a hot gas bypass valve and/or by varying the speed of a compressor used in the refrigeration machine ( 18 , 20 ).

17. Cooling system ( 10 ) according to claim 1 ,

characterised in that to influence the refrigeration capacity of the cooling system ( 10 ) the control unit alters the amount of refrigerating agent conveyed in the refrigeration transport system ( 14 ).

18. Cooling system ( 10 ) according to claim 17 ,

characterised in that to influence the refrigeration capacity the control unit alters the speed of the at least one refrigerating agent pump ( 32 , 34 ).

19. Method of cooling heat generating installations in an aircraft, the method comprising:

coupling at least two refrigeration machines in parallel to a refrigeration transport system in the aircraft, the two refrigeration machines being configured to cover the maximum refrigeration requirement of the heat generating installations;

delivering cold refrigeration agent through the refrigeration transport system to the heat generating installations;

conveying at least a portion of the cold refrigeration agent from the refrigeration transport system through a bypass pipe having a shut-off valve leading back to a pump unit and the at least two refrigeration machines, the shut-off valve opening and closing to control a refrigeration output of the cooling system based on a changing refrigeration requirement; and

controlling the at least two refrigeration machines to operate for an equal amount of time on average.