To control a degree of superheating at an inlet of a compressor while exhibiting a freeze-proofing function of an evaporator by a simple constitution.
This heating hot-water supplying system including a refrigerating cycle constituted by annularly connecting the compressor 2, a radiator 3, an expansion valve 4 and the evaporator 5 in this order further includes: a freeze-proofing flow channel 6 disposed between the radiator 3 and the expansion valve 4 for making a refrigerant from the radiator 3 pass through a lower section of the evaporator 5 to heat the lower section of the evaporator 5, and then flow into the expansion valve 4; and a superheating degree control flow channel 7 disposed between the evaporator 5 and the compressor 2 to make the refrigerant from the evaporator 5 pass through the lower section of the evaporator 5 to exchange heat with a gas refrigerant of the freeze-proofing flow channel 6, and then flow into the compressor 2.
Akiko Sato
Saito Shindai