GB851891A - Improvements in or relating to heat pumps - Google Patents

Abstract

851,891. Refrigerating, heat pumps. MILLER, A. S. Oct. 15, 1956 [July 14, 1955; Oct. 26, 1955], Nos. 15862/55 and 30643/55. Class 29 The invention relates to a heat pump including a compressor 1, a condenser 2 immersed in a water tank, and two evaporators, one being a heat pick-up coil, the other a refrigerator evaporator controlled by an independent refrigerant flow control valve. As shown in Fig. 1 (Application 15862/55), the refrigerant circuit includes pressure switches 3, 4, an expansion valve 6, a preset throttle 11 and valves 9, 10. After passing through the loop 12 refrigerant returns to the compressor through service valve 13. Pressure switch 3 controls valve 9 associated with the air cooling evaporator 8, while valve 10 is controlled by a refrigerator thermostat. On both valves 9 and 10 being closed, the compressor and fan motors are switched off. Pressure switch 4 is a safety switch. In an alternative circuit, Fig. 1 (Application 30643/55), the refrigerator evaporator and an associated low pressure expansion valve 21 are arranged in parallel with the main expansion valve 6 and a solenoid valve 20. When the refrigerator temperature is at the desired level a thermostat opens solenoid 20 allowing a high pressure flow of refrigerant through the expansion valve 6 to the air-cooling evaporator 8. On a rise in refrigerator temperature the solenoid 20 is closed stopping circulation of refrigerant until the pressure is low enough to open the expansion valve 21. A thermostat in the water tank may control a switch so that when the water is above a predetermined temperature the compressor and fan motors are controlled by the refrigerator thermostat. Both compressor and condenser may be immersed in water and the heat pick-up coil may be an air or ground coil.