Patent GB-897266-A (GB)
Title: Improvements in or relating to air conditioning systems
IPC: F24F3/00
Filed: 1959-07-07
Abstract: 897,266. Air-conditioning buildings. YORK SHIPLEY Ltd., (York Division, Borg-Warner Corporation). July 7, 1959, No. 23326/59. Class 137 [Also in Group XIII] Relates to air conditioning means for a building having interior and exterior zones, the former of which always needs cooling, the cooling and heating being effected by a compression refrigerating system. According to the invention, in hot weather both zones are cooled by evaporators the heat being rejected to ambient by the condenser; in cold weather, the interior zone is cooled by an evaporator and the exterior zone is heated by a condenser, the refrigerating system extracting additional heat from the ambient by an additional evaporator; in intermediate conditions, the system merely transfers heat from the interior to exterior zones. Air-conditioning apparatus. In conditioners 59, 75 for the interior and exterior zones respectively, air is drawn by fans 69, 82 over water coils 68, 81 the air being a misture of recirculated and fresh air. The water temperature in the coils is controlled by valves 73, 86 in by-passes, the valves being actuated in response to the temperature of the recirculated air streams. The temperature of the recirculated interior zone air also controls a damper 65 admitting fresh air and rejecting recirculated air to ambient. The water in coils 68, 81 is circulated by pumps 72, 85 through heat exchange coils 14, 15 in exchangers 11, 12. Refrigerating system and heat pump. Fig. 1 shows the system set for hot weather operation. Refrigerant from compressor 10 flows through pipe 19, valve 20 and pipe 24 to outdoor coil 16 acting as a condenser and over which ambient air is circulated by fan 17. The condensate passes to the receiver 28 through pipes 26, 27 and non-return valve 29. From the receiver the liquid flows through pipes 30, 31, 32 and expansion valve 33 to evaporator heat exchanger 12 cooling the exterior zone water, and through pipes 30, 31, 36 and expansion valve 37 to evaporator heat exchanger 11 cooling the interior zone water. The evaporators 11, 12 are connected to the compressor suction by pipe 40 including constant pressure valve 42 and pipes 43, 49 including change-over valve 44. The compressor is unloaded by a control 56 responsive to the temperature of the water leaving exterior zone cooling coil 81. For intermediate temperature operation, valve 44 is closed off altogether, fan 17 is stopped and valve 20 is rotated anticlockwise through 180 degrees. Refrigerant then flows from compressor 10 through pipes 19, 25 and valve 20 to heat exchanger 12 acting now as a condenser to heat the exterior zone water. The liquid refrigerant flows through pipes 50, 27 and non-return valve 51 to the receiver 28 whence it flows through pipes 30, 31, 36 and expansion valve 37 to evaporator heat exchanger 11 cooling the interior zone water. For low ambient temperatures, the circuit is maintained in the intermediate condition except that valve 44 is rotated to connect pipe 49 with a pipe 48 leading from outdoor heat exchanger 16 and fan 17 is started. Not only does liquid refrigerant now flow to the heat exchanger 11 from the receiver but it also flows through pipes 52, 26 and expansion valve 53 to exchanger 16 acting as an evaporator to extract heat from ambient suction through pipes 48, 49, and valve 44. In a modification (Fig. 4, not shown), a low-stage compressor is arranged in pipe 48 so that the vapour from exchanger 16, when it acts as an evaporator, is pre-compressed.