近年來微型製冷系統有許多應用。例如，電子器件的冷却是研製更快速、更小型和更可靠的芯片的重要課題, 隨著電子芯片功耗的增加，散熱量不断增長，傳統的被動式散熱方法已經過時，新的主動式散熱方法成爲必須。又例如微型個人冷卻系統可用於救火等各種惡劣環境。与其它製冷方法相比，蒸氣壓縮製冷技術是最有潜力的方法。 / 本文闡述了两种微型蒸氣壓縮製冷系統的研製工作：一是電子冷却系统，一是個人热舒适系统。研究主要包括以下幾個方面： / 1) 微型蒸氣壓縮製冷系統的熱力學分析。對系統在不同工作條件下（包括壓縮機效率、環境溫度等）的性能進行了分析。对換熱器的設計也作了详述。 / 2) 微型蒸氣壓縮製冷系統的熵分析。通過分析發現，壓縮機和系統漏熱造成的熵是產生系統不可逆性的主要因素,因此高效的壓縮機和降低系統漏熱是提高微型蒸氣壓縮製冷系統性能的關鍵所在。 / 3) 實驗系统的詳細介紹。一共做了两套微型蒸氣壓縮製冷系統，一为電子冷卻系統和一为個人冷卻系統。爲了縮小微型蒸氣壓縮製冷系統的尺寸，系統的元件必須小型化。系統的壓縮機是在市場上直接购買的，但是換熱器包括冷板蒸發器、管翅式蒸發器和微通道冷凝器都是特別設計和製造的。實驗裝置建成可以方便的改變工作條件，諸如壓縮機轉速、製冷劑充灌量、毛細管長度、換熱器面積等。 / 4) 對電子冷卻系統和個人冷卻系統分別進行了實驗。對於電子散熱系統來，當發熱管的功率為200瓦時，冷板溫度可以控制在大約60攝氏度。系統的熱力學完善度在0.23到0.31，而壓縮機的效率介乎40%至65%。對個人冷卻系統來，系統製冷量可達321瓦，其性能係數達到4.59。系統的熱力學完善度為0.21 ~ 0.27。 兩种系統的熱力學完善度都與當前家用製冷系统的熱力學完善度相似。相信不久的将来会有不少应用。 / Micro refrigeration systems are being increasingly used nowadays. One example is electronic cooling. With the rapid advancement of chips, traditional passive heat dissipation techniques are becoming obsolete and hence, new active cooling techniques become necessary. The other example is the personal thermal comfort system demanded by people working in the hazardous environment, such as fire fighting. Among various cooling methods, Vapor Compression Refrigeration (VCR) is the most promising method. According literatures, however, few miniature refrigeration systems are available. / This thesis presents two Miniature Vapor Compression Refrigeration (MVCR) systems, one for electronics cooling and the other for personal thermal comfort. In particularly, following aspects are focused: / 1) Thermodynamic analysis. The thermodynamic models of the systems are developed and the performances are studied under various working conditions including compressor efficiencies, ambient temperature and so on. / 2) Entropy analysis. It is found that entropy of the compressor and the heat leakage play crucial roles. High efficient compressor and the heat leakage minimization are very important. / 3) Prototype building. Two prototypes are built: one for electronics cooling and the other for personal thermal comfort. The miniature compressors are purchased from market. The heat exchangers, including the cold pate, tube-fin evaporator and micro channel condenser, are custom designed and made. / 4) Experiment testing. The two prototypes are tested under various working conditions such as compressor speed, refrigerant charge and capillary tube length. For the electronics cooling system, the cold plate temperature could be maintained at about 60 ºC under the 200 W heater power input. The second-law efficiency of the system varies from 0.23 to 0.31; and the compressor efficiency is between 40% ~ 65%. For the personal thermal comfort system, its capacity could reach 321 W with 100 g refrigerant charge, 1200 mm capillary tube length, and the compressor speed of 4503 rpm. The COP is 4.59 and the second-law efficiency is between 0.21 ~ 0.27. The performances of the two systems are comparable to that of the current domestic refrigeration systems. Therefore, it is expected that they will find some practical applications in the near future. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wu, Zhihui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 99-110). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.I / Acknowledgement --- p.IV / List of Tables --- p.VIII / List of Figures --- p.IX / Nomenclature --- p.XII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Backgound --- p.1 / Chapter 1.2 --- Thesis Outline --- p.5 / Chapter Chapter 2 --- Literature Review --- p.6 / Chapter 2.1 --- History of Refrigeration --- p.6 / Chapter 2.2 --- Availabe Refrigeration Methods --- p.7 / Chapter 2.2.1 --- Heat pipe and vapor chamber --- p.9 / Chapter 2.2.2 --- Thermoelectric cooler --- p.10 / Chapter 2.2.3 --- Stirling refrigerator --- p.10 / Chapter 2.2.4 --- Pulse tube refrigerator --- p.11 / Chapter 2.2.5 --- Absorption refrigerator --- p.12 / Chapter 2.3 --- Vapor Compression Refrigeration System --- p.14 / Chapter 2.3.1 --- Development of the miniature refrigeration system --- p.15 / Chapter 2.3.2 --- Development of the miniature compressors --- p.20 / Chapter 2.3.3 --- Development of the micro heat exchangers --- p.24 / Chapter 2.3.4 --- Applications --- p.28 / Chapter Chapter 3 --- System Analsysis and Components Design --- p.29 / Chapter 3.1 --- A Brief Review of a Typical VCR System --- p.29 / Chapter 3.1.1 --- Refrigerant comparison --- p.33 / Chapter 3.1.2 --- Effect of the compressor efficiency --- p.34 / Chapter 3.1.3 --- Effect of the ambient temperature --- p.35 / Chapter 3.1.4 --- Effect of the evaporator temperature --- p.36 / Chapter 3.2 --- Analysis on Entropy Generation of a MVCR System --- p.37 / Chapter 3.2.1 --- Derivation of coefficient of performance --- p.38 / Chapter 3.2.2 --- Entropy generation calculation for a MVCR system --- p.39 / Chapter 3.3 --- System Design --- p.46 / Chapter 3.3.1 --- System Configuration --- p.46 / Chapter 3.3.2 --- Heat Exchanger Design --- p.47 / Chapter 3.3.2.1 --- Condenser design --- p.48 / Chapter 3.3.2.2 --- Cold plate design --- p.50 / Chapter 3.3.2.3 --- Tube-fin evaporator design --- p.51 / Chapter Chapter 4 --- The MVCR System for Electronics Cooling --- p.55 / Chapter 4.1 --- Experimental Setup --- p.55 / Chapter 4.1.1 --- Components --- p.55 / Chapter 4.1.2 --- Instrumentation --- p.61 / Chapter 4.1.3 --- Testing plans --- p.63 / Chapter 4.1.4 --- Data reduction --- p.64 / Chapter 4.1.5 --- Uncertainty analysis --- p.67 / Chapter 4.2 --- Results and Discussion --- p.68 / Chapter 4.2.1 --- Effect of the compressor speed --- p.68 / Chapter 4.2.2 --- Effect of the refrigerant charge --- p.70 / Chapter 4.2.3 --- Effect of the capillary tube length --- p.71 / Chapter 4.2.4 --- Cold plate temperature comparison --- p.72 / Chapter 4.2.5 --- Location of the Cartridge heater --- p.76 / Chapter 4.2.6 --- System efficiency --- p.78 / Chapter 4.2.7 --- Thermal resistance --- p.81 / Chapter 4.3 --- Summary --- p.83 / Chapter Chapter 5 --- The MVCR System for Personal Cooling --- p.85 / Chapter 5.1 --- Experimental Setup --- p.85 / Chapter 5.2 --- Results and Discussions --- p.87 / Chapter 5.2.1 --- Effect of the compressor speed --- p.87 / Chapter 5.2.2 --- Effect of the refrigerant charge --- p.88 / Chapter 5.2.3 --- Effect of the capillary tube length --- p.89 / Chapter 5.2.4 --- Effect of the evaporator area --- p.90 / Chapter 5.2.5 --- Effect of the evaporator fan speed --- p.91 / Chapter 5.2.6 --- System efficiency --- p.92 / Chapter 5.3 --- Summary --- p.94 / Chapter Chapter 6 --- Conclusions and Future Work --- p.96 / Chapter 6.1 --- Conclusions --- p.96 / Chapter 6.2 --- Future Work --- p.98 / Bibliography --- p.99
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_327998 |
| Date | January 2012 |
| Contributors | Wu, Zhihui, Chinese University of Hong Kong Graduate School. Division of Automation and Computer-aided Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xii, 110 leaves) : ill. (some col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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