臺灣博碩士論文加值系統

本研究主要分析在不同環境溫度下，蒸氣壓縮循環系統對整體散熱效能影響與結露問題。首先設置一套蒸氣壓縮循環系統，藉由冷媒填充量實驗找出適用於本系統的最佳冷媒填充量，接著分析噴灑式蒸發器與多通道蒸發器對系統的效能影響，進而探討不同壓縮機轉速、冷凝器散熱風扇轉速對系統造成散熱效能，最後應用於不同環境溫度下，蒸發溫度對系統造成的結露情形及散熱影響，再以相關理論與實驗結果進行比較，以得知此系統的效能及可行性分析。經實驗結果顯示，系統冷媒填充量最佳值為100g，且系統使用噴灑式蒸發器時，確實能有效降低CPU溫度；散熱能力於400W時，有最高COP值約7.5。在環境溫度實驗中發現，小型蒸氣壓縮循環系統，容易受到環境溫度變化影響散熱效能，主要與系統冷凝器散熱有關；當環境溫度越低能有效增加其熱交換量，使整體系統散熱效能提升。在結露實驗中發現，環境溫度越低能有效降低露點溫度，減少結露現象，而採用噴灑式蒸發器，可防止蒸發器表面結露現象，因此能減少電子散熱所注重的結露問題。未來因可選擇適當的環境溫度，依電子元件熱量，控制適當的壓縮機轉速及蒸發溫度，能有效降低熱源溫度及增加其性能，此外可使蒸氣壓縮循環系統較為節能及減少系統結露產生。

This study analyzed the impact on the overall thermal performance in case of different ambient temperatures and the condensation problem. It first established a vapor compression cycle system, and found the optimal refrigerant filling quantity by the refrigerant filling quantity experiment. It then analyzed the impact of spray type evaporator and multi-channel evaporator on system performance in order to further discuss the system condensation caused by vaporization temperature in case of different compressor rotation speeds, condenser cooling fan speeds and ambient temperatures. Finally, it compared relevant theories and experimental results to learn the system performance, and conducted the feasibility analysis. The experimental results suggested that the optimal system refrigerant filling quantity was 100g. When the system used the spray type evaporator, the CPU temperature can be reduced as the highest COP value was about 7.5 when the cooling capacity was 400W. The ambient temperature experiments found that small type vapor compression cycle system was prone to the impact of changes in ambient temperatures. As a result, cooling performance would be affected. It was related to the cooling of system condenser; when the ambient temperature was lower, the thermal exchange would increase to enhance the overall system cooling performance. The condensation experiment suggested that, lower ambient temperatures can effectively reduce dew–point temperature and condensation. Using the spray type condenser can prevent the phenomenon of condenser surface condensation and alleviate the problem of condensation of electronic cooling. In the future, appropriate ambient temperatures can be selected to properly control compressor rotation speed and vaporization temperature according to the heat of electronic components. Thus, it can effectively reduce heat source temperature and improve performance, while making the vapor compression cycle system more energy-efficient and reduce system condensation.

摘 要 ii
ABSTRACT iii
誌 謝 v
目 錄 vi
表目錄 viii
圖目錄 x
第一章 緒論 1
1.1 前言 1
1.2 研究動機 4
1.3 研究目的 8
1.4 文獻回顧 9
1.5 論文架構 14
第二章 相關理論分析與探討 15
2.1 蒸氣壓縮循環理論 15
2.1.1 理想蒸氣壓縮循環 16
2.1.2 實際蒸氣壓縮循環 17
2.1.3 熱力性質分析 18
2.2 熱阻分析 22
2.2.1 熱阻概述 22
2.2.2 接觸界面熱阻 25
2.2.3 蒸發器底板熱阻 26
2.2.4 蒸發器內部熱阻 27
2.2.5 蒸發器內部表面效率與兩相熱對流係數 28
第三章 實驗裝置與方法 34
3.1 實驗系統設置 35
3.2 實驗設備介紹 44
3.3 量測設備介紹 50
3.4 實驗方法與程序 59
3.4.1 冷媒填充量實驗 59
3.4.2 多通道與噴灑式不同蒸發器之實驗 61
3.4.3 壓縮機變轉速之實驗 63
3.4.4 冷凝器風扇變轉速之實驗 65
3.4.5 環境溫度對系統影響之實驗 67
第四章 實驗結果與討論 73
4.1 冷媒填充量最佳化研究結果 73
4.2 多通道與噴灑式蒸發器分別對系統影響 76
4.3 壓縮機變轉速對系統之影響 84
4.4 冷凝器風扇變轉速對系統之影響 89
4.5 環境溫度對系統造成影響 93
4.5.1 穩態環境溫度對系統影響 93
4.5.2 動態環境溫度對系統之影響 99
4.5.3 動態CPU加熱瓦數對系統之影響 100
第五章 結論與建議 105
5.1 結論 105
5.2 建議 107
參考文獻 108
符號整理 111

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