SOLAR HEAT COLLECTING SYSTEM OF HEAT PUMP TYPE

PURPOSE:To obtain a highly efficient solar heat collecting device in which electric power consumed by a compressor is low, by providing a controller which outputs a signal to change the flow rate of water on the basis of the temperature detected by a water temperature controlling sensor when the temperature detected by the sensor gets higher than a predetermined value. CONSTITUTION:A feed hot-water in a storage tank 9 is circulated repeatedly in such a manner that it is fed into a water heater 11 by a water circulating pump of rotary speed controllable type 10, heated by absorbing the condensation heat of a refrigerant which is condensed by a condenser 3, fed back into the storage tank 9. The controllable rotary pump 10 is driven by a controller 13 so as to rotate at a predetermined speed of rotation while the temperature detected by a water temperature detecting sensor 12 is lower than a set temperature, but when the detected temperature goes up higher than the set temperature, the number of rotation of a pump 10 is changed by a water temperature controlling thermistor 14 provided at the outlet of a water heater 11, so that the outlet temperature can be kept at a constant value. That is, the flow rate of circulating water is changed, the circulated amount of water is decreased than that at the time of steady revolutions at a constant rate, then the condensation temperature becomes lower than the feed hot-water temperature, and the condensation pressure can be decreased as well. As a result the power consumption of a compressor 1 can be decreased, while hot-water in high temperature can be obtained.