The present invention relates to a waste heat utilizing apparatus of a dehumidifier for a greenhouse. The present invention relates to a dehumidifier for a greenhouse installed within a greenhouse, and comprising a compressor, a first heat exchanger, an expansion valve and a second heat exchanger to form one cycle through a refrigerant circulation line, wherein the refrigerant circulation line includes a four-direction valve for switching the flow of the refrigerant from the compressor to the first or second heat exchanger. In the refrigerant circulation line between the second heat exchanger and the four-direction valve, a third heat exchanger water heat exchanging is prepared, a water heat tank connected to the third heat exchanger to be circulated through a heat medium circulation line is prepared, and a heat medium circulation pump circulating the heat medium within the water heat tank from the water heat tank to the water heat tank through the heat medium circulation line, the third heat exchanger and the heat medium circulation line is prepared in the heat medium circulation line. Therefore, when the temperature of the greenhouse rises over a certain temperature (20°C) due to solar radiant heat during day time, and a heat control (cooling) mode is operated, the high temperature waste heat generated in the process of compressing the refrigerant with the compressor of the dehumidifier is collected through the third heat exchanger, stored in the water heat tank, and able to be usefully used in improving the heating performance and the dehumidification efficiency of the dehumidifier by increasing overheating of the refrigerant gas entering the compressor by using the waste heat of the heat medium stored in the water heat tank when heating is necessary as the temperature of the greenhouse drops at night.본 발명은 시설하우스 제습기의 폐열이용 장치에 관한 것이다. 본 발명은 시설하우스의 내부에 구비되며 압축기, 제1열교환기, 팽창밸브 및 제2열교환기가 냉매순환라인을 통해 하나의 사이클을 이루도록 연결되고 상기 냉매순환라인에는 압축기에서 제1 또는 제2열교환기로 냉매의 흐름을 전환시키기 위
