Patent ID: 8701429

Claim:
A system comprising: an indoor heat exchanger that is a fan-less heat exchanger and includes an indoor tube installed so as to be inclined to the horizontal, the indoor tube contacting a high-temperature air zone in an upper part of a room and refrigerant in the indoor tube being heated by the high-temperature air zone so as to boil and vaporize with air in the high-temperature air zone flowing down through the indoor heat exchanger; an outdoor heat exchanger that includes an outdoor tube installed outside at a higher position than the indoor tube, the outdoor tube being connected to the indoor tube via connecting pipes without a compressor being interposed therebetween and the outdoor tube condensing and liquefying the refrigerant boiled and vaporized in the indoor tube and returning the refrigerant to the indoor tube; an outdoor fan that forcibly supplies outdoor air to the outdoor tube; and a control unit that controls the outdoor fan, the control unit including a functional unit that evaluates a heat absorbing capability of the indoor tube when the outdoor fan is stopped by one of temporarily stopping the outdoor fan and temporarily running the outdoor fan.