SOLAR HEAT AND AIR HEAT COLLECTING TYPE HEAT PUMP WATER HEATER

摘要

PURPOSE:To permit operation of maximum efficiency as well as setting of safe defrosting cycle and prevent compression of liquid in a compressor by a method wherein an expansion valve and a capillary tube are arranged in parallel through a non-return valve so as not to flow refrigerant there-into mutually. CONSTITUTION:A heat collecting circuit is constituted of the capillary tube 8 and a heat collector 9, which are arranged in parallel to a series circuit consisting of the expansion valve 5 and the non-return valve 6 through the non-return valve 7. The refrigerant flows through a route shown by a full line in a four-way valve 3 or full line arrow signs in the diagram upon collecting solar heat and air heat. When frosting is advanced in the heat collector 9 upon collecting heat, especially under the condition of low atmospheric temperature, and the temperature of a frosting sensor 11 has arrived at a temperature lower than a given temperature, the four-way valve 3 is switched by a control circuit to change the flow of refrigerant into a reverse cycle constitution and the operation enters into the defrosting operation. The refrigerant flows into the arrow sign directions of dotted lines upon defrosting operation. According to this operation, respective independent proper refrigerating cycles are permitted to be constituted as the expander upon heat collection or defrosting and the case of flowing the refrigerant liquid into the compressor becomes very rare whereby the damage of the compressor due to compressing the refrigerant liquid may be reduced.