熱能量儲存系統由於它的能源可分配性和多元的應用包含太陽熱能的吸收、工廠廢熱的回收再利用等，近年來被視為十分有潛力有未來展望的的能源技術。此外，核殼結構相變化材料具有極大的潛熱而成為提升能量吸收應用效率的一種方式。
然而,在應用相變化材料時，熱遲滯現象被廣泛的發現。當熱遲滯現象過於嚴重,相變化的吸放熱的溫度超過儲熱系統的工作溫度時，潛熱便無法有效的提升熱能吸收應用的能力。所以,深入探討熱遲滯的形成機制、如何減小熱遲滯和其所帶來之影響是非常重要的。
在此研究中，我們成功地把二氧化鈦和氧化鋁包覆在鋅微米粒子上並控制其厚度，從示差掃描量熱儀所量測的穩定性結果，我們也可以確認殼層: 二氧化鈦和氧化鋁能有效的保護鋅微米粒子使其不被氧化。最重要的是，在實驗與理論值上，我們皆深入研究殼層厚度變化、熱傳導係數改變、異質成核和升降溫速率對於相變化和熱遲滯的影響，其實驗結果與理論值具有相同的趨勢。再者，藉由添加不同比例的核殼結構相變化材料，儲熱能力的提升與黏度之間的關係也被深入研究探討。
此研究提供良好的核殼結構包覆技巧和對於熱遲滯深入且廣泛的研究。當我們應用相變化材料於儲熱系統時，能依此研究作為日後挑選材料或環境條件時的方針。

Thermal energy storage has been considered as one of the most promising energy technique due to its dispatchability and multiple applications including solar thermal and industrial waste heat recycling. Besides, latent heat storage of microencapsulated Phase Change Materials (PCMs) has become a feasible way to dispatch the stored energy and increase the efficiency of energy usage. However, during the operation of PCMs, an important phenomenon called thermal hysteresis is widely observed. The advantage of utilizing the latent heat of a PCM to enhance the thermal energy storage of a system would be diminished if the thermal hysteresis exceeds the operating temperature range of the system. Consequently, it is essential to understand the mechanism causing the thermal hysteresis and to minimize the thermal hysteresis.
In this study, the thickness controllable approaches to successfully encapsulating TiO2 and Al2O3 respectively on Zn micro-particles as protective layers were introduced. The DSC results showed a stable heat of fusion of Zn micro-particles which demonstrated that the shell layers can effectively prevent oxidation. Most important of all, the phase change behavior and effects of the various thickness, oxides shells with different thermal conductivities, heterogeneous nucleation and changing of ramping rate on thermal hysteresis has been investigated for both of experiment and theoretical prediction. The results showed the same trend between thermal hysteresis and the factors we researched. Moreover, the important issue: viscosity and thermal storage enhancement have also been tested by doping different weight percentage of the core-shell microparticles. With the superior of encapsulating techniques and completed of thermal hysteresis research, the study provided the guideline to choose the most proper condition to apply PCMs in thermal storage to its maximum enhancement.

摘要 I
Abstract lI
致謝 lll
Contents lV
List of Figures VIl
Chapter 1 Introduction 1
1.1 Overview of Renewable Energy 1
1.2 Utilization of Thermal 3
1.2.1 Solar Thermal Energy & Thermal Energy Recycling 4
1.2.2 The Architecture of Solar Thermal Power Plants System 7
1.2.3 Molten Salts 10
1.2.4 Phase Change Materials 12
Chapter 2 Experimental Procedures 17
2.1 Chemicals 17
2.2 Synthesis of Zn/SiO2 core-shell micro-particles 18
2.3 Synthesis of Zn/TiO2 core-shell micro-particles 19
2.4 Synthesis of Zn/Al2O3 core-shell micro-particles 20
2.5 Synthesis of ZnxSn1-x/Al2O3 core-shell micro-particles 21
2.5.1 Preparation of ZnxSn1-x Micro-particles 21
2.5.2 Aluminum oxide encapsulating of ZnxSn1-x Micro-particles 22
2.6 Analytical Characterization Equipment 23
2.6.1 X-Ray Diffraction (XRD) & Reference intensity ratio (RIR) 23
2.6.2 Scanning Electron Microscope (SEM) 24
2.6.3 Focused Ion Beam (FIB) 25
2.6.4 Transmission Electron Microscope (TEM) 27
2.6.5 Energy Dispersive Spectrometer (EDS) 27
2.6.6 Differential Scanning Calorimeter (DSC) 29
2.6.7 Viscometer 30
Chapter 3 Results and Discussion 33
3.1 Motivation 33
3.2 Results & Discussions 36
Chapter 4 Summary & Conclusions 53
Reference 54

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