Heat pump

The present invention relates to a heat pump comprising: a compression part having a compressor, and a cooling and heating switching valve; an outdoor heat exchanger connected to a connection line between the compression part and the outdoor heat exchanger and having a main flow path and a sub-flow path; an indoor heat exchanger connected to a connection line between the compression part and the indoor heat exchanger; an outdoor expansion mechanism connected to a connection line between the main flow path and a first expansion mechanism; an indoor expansion mechanism connected to a connection line between the indoor heat exchanger and a second expansion mechanism, and connected to a connection line between the outdoor expansion mechanism and a third expansion mechanism; a first bypass line guiding a refrigerant compressed in the compression part to the sub-flow path; a second bypass line guiding the refrigerant passed through the sub-flow path to a connection line of the first expansion mechanism; a flow control valve installed at the first bypass line or the second bypass line; a bypass temperature sensor sensing a temperature of the second bypass line; an outdoor temperature sensor; a humidity sensor; and a control part performing an outdoor heat exchanger-freezing prevention mode to control a degree of a flow control valve in accordance with a dew point temperature calculated by the outdoor temperature sensed by the outdoor temperature sensor, outdoor humidity sensed by the humidity sensor during a heating operation, and a temperature of an exit of a bypass, which is sensed by the bypass temperature sensor. There is an advantage to rapidly control a temperature of the outdoor heat exchanger in a temperature range where no freezing is generated while minimizing reduction of heating efficiency. 본 발명은 압축기와 냉난방 절환밸브를 갖는 압축부와; 압축부와 실외열교환기 연결라인으로 연결되고 메인유로와 서브유로를 갖는 실외열교환기와; 압축부와 실내열교환기 연결라인으로 연결된 실내열교환기와; 메인유로와 제1팽창기구 연결라인으로 연결된 실외팽창기구와; 실내열교환기와 제2팽창기구 연결라인으로 연결되고 실외팽창기구와 제3팽창기구 연결라인으로 연결된 실내팽창기구와; 압축부에서 압축된 냉매를 서브유로로 안내하는 제1바이패스 라인과; 서브유로를 통과한 냉매를 제1팽창기구 연결라인으로 안내하는 제2바이패스 라인과; 제1바이패스 라인 또는 제2바이패스 라인에 설치된 유량조절밸브와; 제2바이패스 라인의 온도를 감지하는 바이패스 온도센서와; 실외온도센서와; 습도센서와; 난방운전의 도중에 실외온도센서에서 감지된 실외온도와 습도센서에서 감지된 실외습도에 의해 산출된 노점온도와, 바이패스 온도센서에서 감지된 바이패스 출구온도에 따라 유량조절밸브의 개도를 제어하는 실외열교환기 결빙방지모드를 실시하는 제어부를 포함하여, 난방효율이 저하되는 것을 최소화하면서 실외열교환기의 온도를 결빙이 발생되지 않는 온도범위로 신속하게 관리할 수 있는 이점이 있다.