Patent GB-634574-A (GB)
Title: Improvements relating to refrigeration and heating apparatus
IPC: F25B29/00
Filed: 1946-11-04
Abstract: 634,574. Combined refrigeration and heating apparatus. CRADDOCK, H. S. Nov. 4, 1946, No. 32752. Convention date, Oct. 25, 1945. [Classes 29 and 64(iii)] [Also in Group XXXVII] A combined system for heating and/or cooling comprises a refrigerant compressor 10, a high-pressure condenser 18 used for heating, e.g., water, a low-pressure evaporator 27 and an intermediate pressure heat exchanger 23 which can be used either as an evaporator, when cooling is not required at 27, as a condenser when heating is not required at 18, or as a liquid refrigerant receiver when both .heating and cooling are required. The system is automatically controlled by thermostats in accordance with the heating and cooling requirements. When both heating and cooling are required, compressed refrigerant from the compressor 10 passes through a two-way valve 15 and non-return valve 17 to the inlet pipe 48 of the water heater 18 and thence to a coil within an inner heating tank 49 connected with the hot water outlet 43 through which the refrigerant inlet pipe passes. The coil 48 is connected to a header 50 joined by helical pipes 52 to a lower header 51 which collects the condensed refrigerant and passes it by a pipe 53 to a vessel 55 containing a float 56 which regulates the supply of liquid refrigerant to.the evaporator. Water to be heated is supplied through a float valve 47 and pipe 61 to the lower part of .the water heater. ' A thermostatic 'safety valve 45 allows water to pass to a drain when the water temperature becomes excessive. The liquid refrigerant passes by a pipe 20 to the lower header 22 of the heat exchanger 23 and thence through a heatexchanger 28 where it is cooled by outgoing refrigerant vapour, and an expansion valve 26 to the evaporator of the refrigerator 27. Evaporated refrigerant returns to the compressor through heat exchanger 28, pipe 28A, check valve 29 and two-way valve 31. When the temperature of the refrigerator 27 falls below a predetermined value a thermostat operates the two-way valve 31 to close the suction pipe 28A and open a pipe 39 leading from the top header 37 of the heat exchanger, which then acts as an evaporator, and a fan 63 is started up to blow over the gilled pipes 23 air from which the heat is extracted. Alternatively, water may be used as the source of heat. When the temperature of the water in the water heater 18 rises above a predetermined value a thermostat 82 in the tank 49 operates the two-way valve 15 to close the pipe 16 and connect the compressor outlet to a pipe 35 leading to the heat exchanger 23 which then acts as a condenser, giving up heat to the air blown by the fan 63, or to the water. The condensed refrigerant passes through pipe 24 to the refrigerator and the evaporated refrigerant returns to the compressor through pipe 28A and two-way valve 31. When both heating and refrigeration are taking place the fan 63 is stopped, and when neither heating nor refrigeration is required the compressor motor 11 is automatically switched off. Fig. 4 shows the circuit for controlling the compressor motor 11, fan motor 63 and electromagnets 81, 83 operating the two-way valves 15, 31. If the water temperature in the water heater falls below a predetermined value. thermostat 82 closes contacts 90. 91 to start the motor 11 through a starting circuit including resistances or inductances 112, 113. The two-way valves 15, 31 being both connected to the heat exchanger 23, the motor starts with a minimum of effort' since the refrigerant is circulated around a short circuit. After a time delay by means of dash pots, solenoid 81 operates to move a switch 85 to a contact 100 connecting the motor to a running circuit cutting out the resistances or inductances, and to operate the two-way valve 15 to connect the compressor to the water heater. A corresponding action initiated by the refrigerator thermostat 84 takes place when refrigeration is required. The double contacts of the thermostatic switches 82, 84 avoid too frequent starting and stopping of the motor, and when the compressor has come into operation for the purpose of heating (after contact 91 has closed) a slight rise of temperature of the refrigerator (sufficient to close contact 94 only) causes the refrigerating function to operate also, and vice versa. The two-way valves 15 may be replaced by valves 79, 80 in the pipes 35, 39 in conjunction with the check valves 17, 29. The compressor and motor may be jacketed and' -connected in the hot water circulation by a pipe 41A with a non-return valve 44. The two-way valves are fixed to snap-over diaphragms and operated by the electromagnets 81, 83. The Specification as open to inspection under Sect. 91 includes also an absorption refrigerating system in which the heatemitting parts, i.e., the boiler, rectifier, condenser.and absorber are arranged in concentric chambers of a water heater and an auxiliary evaporator outside the refrigerator is used to extract heat from the atmosphere when no refrigeration is required. This subject-matter does not appear in the Specification as accepted.