GB1349576A - Refrigerating systems - Google Patents

Abstract

1349576 Refrigerating BRAYTON CYCLE IMPROVEMENT ASSOCIATES 19 April 1971 [5 May 1970] 26397/71 Heading F4H In the refrigeration system as shown, air enters an air cooler, is cooled and passes to a compressor and a recuperator where the air is heated by heat exchange with the exhaust from the Brayton cycle expander and passes into a conventional Brayton cycle combustion chamber. In this chamber fuel is burned and the temperature of the compressed air is raised further, before passing via the expander and recuperator, to and through a refrigerant heater in which pump 2 keeps the refrigerant liquid at a sufficient pressure so that it does not boil. The hot refrigerant liquid flows to an insulated hot storage tank 1. From time to time valve 4 is opened and a batch of hot liquid is transferred from 1 to hot flash tank 3 where it flashes at decreasing temperatures and pressures until it reaches a minimum temperature and pressure. Valve 10 then is opened, the remaining unvapourized liquid flowing into tank 11. Three refrigerant expanders 7, 8, 9 drive corresponding refrigeration compressors 21, 22, and 23. At the start, the temperature and pressure in hot flash tank 3 is at a maximum and the flash vapour passes through expanders 7, 8, 9 in series. At the same time, the pressure and temperature in a cold flash tank 30 is at a maximum, and the load on compressors 21, 22, 23 is at a minimum, and they thereby are operated in parallel. The load on compressors 21, 22, 23 increases as the temperature and pressure in tank 30 drops. When expanders 7, 8, 9 can no longer produce sufficient power to drive the compressors, valves 17, 19, 20, 26 are closed. This has the effect of cutting off expander 9 and compressor 21, and expanders 7 and 8 in series drive compressors 22, 23 in parallel. As the pressure and temperature in tanks 3 and 30 drop still further, valves 13, 15 are opened and valve 14 closed. Now expanders 7, 8 in parallel drive compressors 22, 23 in parallel. As the temperature and pressure drop in stages, expanders 7, 8 in parallel drive two compressors 22, 23 in series; then three expanders 7, 8, 9 operate in parallel to drive the three compressors in series. During the operation, all the exhaust vapours flow to a condenser 34 and to storage tank 11. When the expanders can no longer drive the compressors, valve 10 is opened, and unvapourized liquid in tank 3 enters into tank 11. Unvapourized cold liquid in tank 30 is discharged into storage tank 31, a pump 32 pumping the cold refrigerant liquid through the air cooler and into storage tank 11. Valves 10, 35 now are closed and valves 4, 6 are opened. A new batch of refrigerant liquid from tank 1 thus is introduced into tank 3 and a new batch of ambient temperature liquid is thus introduced into tank 30. The refrigeration cycle is then repeated. The system is self-regulating.