近年來，板式熱交換器被廣泛應用冷凍空調系統中，但是熱交換器流道入口處存在著冷媒分佈不均的問題。當板式熱交換器作為蒸發器時，入口處的兩相冷媒因液態冷媒的慣性力與重力比汽態冷媒大，導致大部分液態冷媒流入熱交換器尾端，而汽態冷媒則流入熱交換器前端。為了解決冷媒分佈不均之問題，目前多於流道入口處設置入口分佈器以解決此問題，卻衍生出另一流道冷媒流動分佈不均之問題。 為了解決單一流道冷媒流動分佈不均之問題，本研究以不同開口方向之入口分佈器設置於板式熱交換器內。接著利用紅外線熱像儀觀察板片上的表面溫度場，分析出冷媒的飽和區與過熱區，用冷媒過熱區面積大小以判斷單一流道的冷媒流動分佈狀況，找出最佳入口分佈器的開口方向，希望能提供後人設計或改良入口分佈器之依據。; Recently, plate heat exchanger has been widely applied to air-conditioner system, but there is still a problem, maldistributive refrigerant, existed in the portal of heat exchanger. When the plate heat exchanger is used to be an evaporator, it will lead to the most liquid refrigerant flows into the tail of the heat exchanger; on the contrary, the gaseous refrigerant flow into the head of heat exchanger since the inertial force and gravity of liquid refrigerant is heavier than the gaseous refrigerant at the portal of the two phase refrigerants. To solve this problem, most manufacturers settle the inlet-distributor in the entrance of the channel at the present stage, another problem of maldistributive refrigerant in the single channel brings into this research. To solve the problem of maldistributive refrigerant in the single channel, the inlet-distributor for varying flow direction settles into plate heat exchanger in this research; then using infrared imager is to observe the surface temperature on the plate to take the gauge of the condition of flowing refrigerant distribution. By finding direction of the most proper inlet-distributor, I hope that this research can provide successors for designing or improving the basis of inlet-distributor.