台灣地處於亞熱帶區域，夏季氣候高溫高濕，需要大量的空調設施，尤其是工業生產所需的無塵室，需要大量的冰水做為溫度與濕度控制之用，冰水主機為冰水系統的核心機件，其效率的高低對能源的消耗有極大的影響。 本文討論冰水主機水側溫度變化對冰水主機效率的影響，使用田口實驗計畫法的直交表做實驗，並以TFT-LCD廠實際的運轉數據為分析依據，將冰水主機冷卻水進口溫度與COP的線性迴歸關係式找出，可以很明確的顯示COP值隨著冷卻水進口溫度降低而升高；關於冰水溫度的影響，想要提升COP值，主要在於必須增加冰水進口與出口的溫度差ΔT，若是只有提高冰水主機的冰水出口溫度而無法同時增加ΔT，則未必能夠有效的提高COP值。 Taiwan is located in the subtropical area with hot and humid climate in the summer. It requires a large number of air conditioning facilities. The chilled water is used to control the temperature and humidity in the industry, especially for the clean room to maintain the constant temperature and humidity. The chiller is the heart of the chilled water system, and its efficiency has a great influence on consumption of the energy. This research experimentally studies the performance of the chiller in different water temperature. The Taguchi method is used to analysis the results of the experiments. From the operation data of the TFT-LCD factory, a linear regression of the chiller’s COP versus its condenser inlet water temperature can be found. The result shows that the COP of the chiller will increase with decreasing condenser inlet water temperature. Because the variation of chilled water temperature tested is too small, the effect of the chilled water to the COP is not significant.