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題名 | 成核添加物對塑膠放球內水結冰機率影響之研究=Effect of Nucleation Agents on the Freezing Probability of Encapsulated Ice Ball |
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作者姓名(中文) | 王鵬評; 劉震華; 陳希立; | 書刊名 | 國立臺灣大學工程學刊 |
卷期 | 73 1998.06[民87.06] |
頁次 | 頁87-102 |
分類號 | 446.64 |
關鍵詞 | 儲冰式空調系統; 成核添加物; 過冷現象; Ice-storage air-conditioning system; Nucleation agents; Supercooling phenomenon; |
語文 | 中文(Chinese) |
中文摘要 | 本論文以實驗方式研究不同種類的成核添加物對塑膠冰球所產生的成核結晶 現象,首先利用成核理論以微觀的觀點探討冰球內水成核現象,由自由能障觀念 知影響水成核的變因主要為界面自由能和過冷溫度,而成核添加物可影響界面自 由能降低自由能障,提高成核溫度。接著以實驗巨觀方法研究塑膠冰球內的水成 核現象,利用不同的成核添加物包括:AgI、PbI�砥B河砂和泥粉在不同的冷卻溫度 下來觀察水成核現象並探討成核劑的種類和劑量對於塑膠冰球的結冰機率。實驗 結果顯示,添加成核劑的塑膠冰球相對於純水冰球的成核機率與成核溫度均較高, 確實有效的改善水過冷現象,其中以AgI效果最好,但是就成本考量與塑膠冰球 在儲冰槽內的配重而言,吾人建議利用河砂作為成核添加物最符合經濟效益,此 將可作為儲冰式空調系統之冰球式儲冰槽的設計參考。 |
英文摘要 | An experiment was conducted to study the effect of different types of nucleation agents on the freezing phenomena of encapsulated iceballs. First, water nucleation inside iceballs was investigated from the micro perspective based on the nucleation theory. According to the concept of free-energy barrier, the primary causes of water nucleation are interface free-energy and supercooling temperature. Nucleation agents can affect interface free-energy and reduce free-energy barrier and increase nucleation temperature. Next, water nucleation inside encapsulated iceballs was studied from an experimental macro perspective. An array of different types of nucleation agents including AgI, PbI ��,river sand and mud powder, were used to achieve water nucleation under differnet cooling temperatures. The effect of the amount of nucleation agents on the freezing probability of encapsulated iceballs was also studied. The experimental results indicate that the nucleation probability and nucleation temperatures of encapsulated iceballs with added nucleation agents are both higher than those of iceballs containing pure water, which suggests that nucleation agents are effective in improving water supercooling phenomenon. Among all the agents used, AgI showed the best results. However, in terms of cost considerations and the percentage of encapsulated iceballs in an ice storage tank, the authors recommend using river sand as the nucleation agent, which is the most cost effective and can be used in the design of ice-ball ice storage tank in an ice-storage air- conditioning system. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。