臺灣博碩士論文加值系統

本研究將針對自然環保冷媒R-600a之空調系統進行最佳化模擬與分析。在系統整體性能評估上，以可用能分析(Exergy Analysis)，結合熱傳及流力之理論，探討其在空調系統各元件中之轉換、傳遞及摧毀之情形，並針對可用能損失較大的元件著手進行研究分析，以使能有效的提升系統整體之性能，進而達到省能之目標。
文中針對不同之系統設計參數，如蒸發器、冷凝器管徑及冷卻空氣流速等參數，尋求系統整體之最小熵產生率及其對應之最佳管徑。由數值模擬結果可知，在各操作條件及蒸發管管徑固定下，在冷凝管管徑1.0~1.2cm間，系統熵產生率呈現先降後升的趨勢，約在蒸發管管徑1.1cm附近有最小值，即在此處可用能之摧毀最小，而系統整體之COP及EER值亦在相同處有最大值。相對的，在冷凝管管徑固定下，系統熵產生率隨蒸發管管徑變化之趨勢與前者大致相同，亦在冷凝管管徑約1.1cm處有最小值。由上述可知，使用R-600a之空調系統在室外溫度 ，室內設定溫度 下，本分析最佳之熱交換器圓形直管管徑約為1.1cm，在此管徑下，系統整體之可用能損失最小。

The optimizations of air-condition systems using naturalrefrigerants R-600a are studied in this thesis. The theories including the exergy analysis, heat transfer and fluid mechanics are combined together to study the exergy transfer and destroy in each component.
The optimizing parameters in this research include cooling air velocities, the tube diameters of evaporator and condenser. If all the conditions remain constant expect the tube diameter of evaporator, the numerical results display that the values of the total entropy generation rate with R-600a decrease from tube diameter 1.0 cm to 1.1 cm and increase from 1.1 cm to 1.2 cm. The tube diameter of evaporator and condenser at a minimum value of total entropy generation rate is 1.1cm for the simulation conditions. Besides, the coefficient of performance and the energy efficiency ratios also have maximum values at the tube diameter. If all the conditions remain constant expect the tube diameters of condenser, the tendencies of total entropy generation rate arethe same as those in evaporator.

目錄
摘要……………………………………………………………………Ⅰ
英文摘要………………………………………………………………Ⅱ
目錄……………………………………………………………………Ⅲ
圖目錄…………………………………………………………………Ⅵ
表目錄…………………………………………………………………Ⅸ
符號說明………………………………………………………………Ⅹ
第一章 緒論…………………………………………………...1
1.1 前言…………………………………………………………………1
1.2 文獻回顧……………………………………………………………2
1.3 研究背景及目的……………………………………………………7
第二章 蒸氣壓縮冷凍循環(VCR)之熱力分析………………9
2.1 蒸氣壓縮冷凍循環之基本理論……………………………………9
2.1.1 理想VCR循環分析………………………………………...9
2.1.2 實際(VCR)循環分析……………………………………….11
2.1.3 壓縮過程之熱力性質分析…………………………………12
2.2 冷媒之熱物性質分析……………………………………………...12
2.3 本空調系統模擬之理論模式分析………………………………...15
2.4 VCR循環之能源效率比(EER)及性能係數(COP)分析………...17
第三章 熱傳理論及最佳化分析……………………………20
3.1 相變化熱傳………………………………………………………...20
3.2 管內雙相區熱傳係數及壓降之計算……………………………...20
3.2.1 雙相區熱傳係數之計算……………………………………21
3.2.2 雙相區管內壓降之計算……………………………………27
3.3管內單相區熱傳係數及壓降之計算……………………………...31
3.4管外空氣側熱傳係數及壓降之計算……………………………...32
3.5 總熱傳係數之計算………………………………………………...34
3.6 結合熱力、流力及熱傳之(Exergy Analysis)……………………..37
3.6.1 Exergy Analysis……………………………………………...37
3.6.2 室內熱負載之模擬條件與說明……………………………43
3.6.3 數值模擬流程與步驟………………………………………45
第四章 結果與討論…………………………………………50
4.1 各项設計參數對系統元件及整體性能之影響…………………...51
4.2 蒸發管管外徑對系統元件及整體性能之影……………………...52
4.3 冷凝管管外徑對系統元件及整體性能之影……………………...55
4.4 空氣流速對系統整體性能之影響………………………………...56
4.5 可用能分析(Exergy Analysis)……………………………………..57
第五章 結論與建議…………………………………………..60
5.1 結論………………………………………………………………..60
5.2 建議………………………………………………………………..61
參考文獻……………………………………………………………….62
圖總成………………………………………………………………….65
表總成………………………………………………………………….85
附錄一………………………………………………………………….88

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