Patent GB-807098-A (GB)
Title: Room air conditioning apparatus
IPC: F25B13/00
Filed: 1956-02-09
Abstract: 807,098. Heating air electrically. GENERAL ELECTRIC CO. Feb. 9, 1956 [Feb. 21, 1955], No. 4093/56. Class 39(3). [Also in Groups X and XIII] In a room air conditioning apparatus comprising a reversible cycle refrigerating system which includes a motor compressor 1 having a discharge line 2 and a suction line 3 communicating through a reversing valve 4 with lines 5, 6 which lead respectively to indoor and outdoor heat exchanger coils 7, 8, an auxiliary heater 25, which normally remains inactive during the time the indoor coil is used for cooling, is automatically switched on during a cycle when the indoor coil 7 is being used for heating and when the normal operation of the refrigerating system is interrupted to defrost the outdoor coil. The directions of refrigerant flow during the cycles when the indoor coil 7 is used for cooling and heating are indicated respectively by solid and interrupted arrows, Fig. 1, the outdoor coil 8 correspondingly either rejecting heat to, absorbing heat from, the outside atmosthere. A capillary tube 10 is arranged in heat exchange relation with a portion 12 of the line 5. An electric circuit for controlling the setting of the reversing valve 4 and the energizing of the compressor motor 1 and the auxiliary heater 25, comprises a pair of electric power lines 13, 14, the conductor 13 being connected directly to one side of the compressor 1 and the other conductor 14 to the other side through a number of switches including a manually operated "on-off" switch 15, and a double pole switch 16 having one arm engageable with one, or other, of a pair of contacts 17a, 17b both connected to a thermostat 18 which is responsive to room temperature and cycles the compressor 1 on-and-off during the heating and cooling modes of operation. When the arm 17 engages the contact 17b an associated arm 19 engages a contact 19a to energize a reversing solenoid 9 and send the refrigerant in the direction of the interrupted arrows so that the indoor coil 7 acts as a heater. A switch for interrupting the circuit to the compressor 1 in order to defrost the outdoor coil 8 during the heating cycle comprises a pair of contacts 20, 20, which are arranged between the thermostat 18 and the compressor 1 and can be opened or shorted by an arm 21 controlled by a frost sensing actuating device, e.g., a temperature responsive bellows 22. The latter is connected by a line 24 to a thermostat bulb 23 mounted on the line 6. When the outside coil 8 has become frosted, the bellows 22 contract and the arm 21 opens the contacts 20, 20, to de-energize the compressor 1, at the same time the arm 21 closes a pair of contacts 26, 26, to energize the auxiliary electric heater 25 which then takes over the function of the indoor coil 7, now not openating as a heater. When the temperature of the outdoor coil has risen considerably above freezing, e.g., 45‹F., the bellows 22 expand and the auxiliary heater 25 is de-energized, the compressor 1 again being brought into circuit for the normal operation of the refrigeration system. A motor 27, controlled by a manually actuated switch 30, serves to drive indoor and outdoor fans 28, 29 respectively, the auxiliary heater 25 perferably being mounted in the unit so that air which normally flows over the coil, also flows over it. The fans 28, 29 normally remain running when the refrigeration system is inactivated for defrosting.