مطالعات ترمودینامیکی مایعات یونی بر پایه اتانول آمین ها و کارایی آنها به عنوان سیستم های ذخیره انرژی حرارتی
سعید فرجی
شیمی
۱۴۰۱
۱۶۳ص.
سی دی
دکتری
شیمی
۱۴۰۱/۱۲/۱۰
با توجه به افزایش تقاضا برای انرژی¬های تجدیدپذیر، سیستم¬های ذخیره انرژی حرارتی توجه روزافزونی را به خود جلب کرده¬اند. مواد شیمیایی ذخیرهسازی انرژی به دلیل خواص حرارتی و شیمیایی، نقش مهمی در طراحی این نوع از سیستمها دارند. در این راستا، مایعات یونی (ILs) می¬توانند به عنوان کاندید بالقوه برای ذخیره انرژی حرارتی به دلیل خواص ترموفیزیکی قابل توجه، استفاده گردند. دانش مطلق کاربرد مایعات یونی پروتیک و درک خواص ترموفیزیکی متنوع این مواد در فرآیندهای مختلف ضروری است. در این پروژه، مایعات یونی پروتیک 2-هیدروکسی اتیل آمونیوم لاکتات [HEA]La، بیس(2-هیدروکسی اتیل آمونیوم) لاکتات [BHEA]La و تریس(2-هیدروکسی اتیل آمونیوم) لاکتات [THEA]La سنتز شدند. در این راستا، خواص حجم سنجی، تراکم پذیری و ضرایب اسمزی برای محلول¬های آبی مایعات یونی سنتز شده در منطقه غلظت رقیق اندازه¬گیری شدند. حجم مولی جزئی استاندارد و تراکم پذیری آیزنتروپیک مولی جزئی از پارامترهای معادله Redlich-Mayer تعیین شدند. ضرایب اسمزی مهمترین کمیت برای سیستم الکترولیت است که می¬تواند برای توصیف رفتار و مطالعه برهمکنش¬های رخ داده در سیستم¬ها تعیین شد.
Abstract: Due to the increase in demand for renewable energy, thermal energy storage systems have attracted increasing attention. Energy storage chemicals play an important role in the design of these types of systems due to their thermal and chemical properties. In this regard, ionic liquids (ILs) can be used as potential candidates for thermal energy storage due to their remarkable thermophysical properties.Absolute knowledge of the application of protic ionic liquids and understanding the diverse thermophysical properties of these materials in various processes is essential. In this project, protic ionic liquids 2-hydroxyethylammonium lactate [HEA]La, bis(2-hydroxyethylammonium)lactate [BHEA]La and tris(2-hydroxyethylammonium)lactate [THEA]La were synthesized. In this regard, volumetric, compressibility properties and osmotic coefficients were measured for aqueous solutions of synthesized ionic liquids in the dilute concentration region. The standard partial molar volume and partial molar isentropic compressibility were determined from the parameters of the Redlich-Mayer equation. Osmotic coefficients are the most important quantity for the electrolyte system that can be determined to describe the behavior and study the interactions occurring in the systems.Energy storage chemicals play an important role in the design of thermal energy storage systems due to their thermal and chemical properties. In this regard, ionic liquids can be used as potential candidates for thermal energy storage due to their remarkable thermophysical properties. Synthesized ionic liquids have low toxicity, high thermal stability, easy and economical synthesis with suitable physical and chemical properties for use in thermal energy storage systems. Next, thermophysical measurements such as thermal conductivity, heat capacity, surface tension, density, sound speed, and electrochemical potential windows were performed for pure ionic liquids at different temperatures to evaluate the efficiency of these systems as thermal energy storage. The results of differential scanning calorimetry analysis show that [HEA]L ionic liquid has a heat capacity of 1.800 J·g-1·K-1 at T = 298.15 K compared to the other two ionic liquids due to the cation and small structure. It is. Heat capacity also increases with increasing temperature. The electrochemical potential window values for [HEA]L, [BHEA]L and [THEA]L were obtained as 2.5 V, 2.2 V and 1.7 V, respectively. Efficient thermal energy storage systems have high enough heat capacity and thermal energy density with useful thermal conductivity. Ionic liquid [HEA]L with maximum thermal conductivity of 0.255 W·m-1·K-1 is recommended as a suitable candidate for thermal energy storage compared to other two ionic liquids.A promising solution to the challenges of thermal management and thermal energy storage (TES) is the use of phase change materials (PCM). TES using PCM are an important class of new materials that significantly contribute to the efficient use and preservation of solar energy and wasted heat. This work presents for the first time a new family of PCMs based on the ionic liquids [HEA]L, [BHEA]L and [THEA]L and the ionic liquid tris(2-hydroxyethylammonium) formate ([THEA]F) and fatty acids. It provides that they work in the temperature range of 50 to 150 degrees Celsius and provide safe and cheap capacity. Good chemical and thermal stability, low flammability, and low volatility, along with the potential to tune chemical and phase properties, provide ILs with inherent "green" properties that are well suited for PCMs. Using tris(2-hydroxyethylammonium) formate/stearic acid PCM, the effective latent heat of 246 J·g-1 was obtained. Thermal stability analysis shows maximum stability (98%) for tis (2-hydroxyethylammonium)formate/stearic acid. Furthermore, based on the structure of these ionic materials, this study investigates the molecular basis of the high thermal energy storage capacity of these materials and highlights the importance of hydrogen bonds in PCM performance. By using simple and affordable materials, this method bypasses the complexity and cost of composite PCMs. We provide design recommendations for implementing our approach in managing thermal energy storage applications.
Thermodynamic studies of ethanolamines-based ionic liquids and their performance as thermal energy storage systems