Collaborative Research: Adaptive Building Enclosure Systems Using Cellular Solid-Solid Phase Change Materials with Variable Transparency

建筑约占美国能源消耗的40%；其中很大一部分能源被用于应对建筑围护结构产生的热损失或热收益。被动式太阳能设计寻求通过建筑围护结构和太阳能输入来平衡热损失，同时还使用热质量、遮阳和/或通风来抑制日常的热波动。然而，目前的被动式太阳能设计的实施往往是高度特定于背景的，并且往往需要使用昂贵的机械设备和控制。本项目旨在研究一种创新的被动式太阳能建筑围护结构系统，该系统使用具有可变透明度的蜂窝状固体-固体相变材料(SS-PCM)。该系统依赖于被动材料控制，没有机械移动部件或电气部件。SS-PCM泡沫建筑围护结构材料的成功实施可以产生低成本、响应性强的建筑围护系统，该系统可以自我调节建筑热舒适性。这项研究的结果可以带来新的技术，减少建筑物的能源消耗，减少对化石燃料的依赖，并提高美国的经济竞争力。这项研究还有望为建材、建筑和节能等不同行业带来好处。一个创新的推广计划将以竞赛的形式实施，让不同教育水平的学生参与到被动太阳能设计、能源利用和建筑热舒适性的主题中。该项目的目标是揭示用于现实建筑围护结构的半透明蜂窝SS-PCM系统的基本原理。本课程将对(1)SS-PCM泡沫系统中发生的热传递现象，(2)三种材料启动的太阳能辐射控制机制之间的协同效应，以及(3)导致建筑物高节能的结构特征和特征，获得基本的见解。这项研究将创造关于SS-PCM热学和光学行为的知识，使建筑温度可以在不同的气候条件下全年被动调节。为实现上述目标，将实施包括多物理建模、材料综合、系统级集成和建筑级节能评估在内的综合实验和计算程序。该项目可以依靠辐射能量传递过程来传递热量，从而改变相变材料的使用，从而绕过相变材料固有的低导热问题。SS-PCM泡沫的低导热系数也延缓了热损失，从而提高了系统保持在所需温度的能力。

Buildings are responsible for about 40 percent of US energy consumption; a significant fraction of this energy is consumed to counter thermal losses or gains occurring through building envelopes. Passive-solar-design seeks to balance heat loss through the building envelope with solar energy input, while also using thermal mass, shading, and/or ventilation to dampen daily thermal swings. However, implementation of current passive-solar-design tends to be highly context-specific and often entails use of costly mechanical devices and controls. This project aims to study an innovative passive solar building enclosure system that uses cellular solid-solid phase change materials (SS-PCM) with variable transparency. The system relies on passive material-enabled controls and has no mechanically moving parts or electrical components. Successful implementation of SS-PCM foam-based building envelope materials can result in low cost responsive building enclosure systems that self-regulate building thermal comfort. The outcome of this study can lead to new technologies that reduce energy use in buildings, decrease dependence on fossil fuels, and improve the economic competitiveness of the United States. This study is also expected to result in benefits to diverse industries such as building materials, construction, and energy conservation. An innovative outreach plan will be implemented in the form of a competition that engages students at various levels of education in the topics of passive solar design, energy use, and thermal comfort in buildings.The goal of this project is to uncover the fundamental principles that govern the behavior of translucent cellular SS-PCM systems used in realistic building envelopes. Fundamental insights will be gained on (1) heat transfer phenomena occurring in SS-PCM foam systems, (2) the synergistic effects occurring between three material-enabled solar-light irradiation control mechanisms, and (3) structural features and characteristics that lead to high energy-savings in buildings. This study will create enabling knowledge on thermal and optical behavior of SS-PCMs such that building temperatures can be passively regulated year-round under different climate conditions. An integrated experimental and computational program, consisting of multi-physics modeling, materials synthesis, system level integration, and building level evaluation for energy saving, will be performed to achieve the aforementioned goal. This project can transform the use of PCM by relying on radiation energy transfer processes to deliver heat, thus bypassing the low thermal conductivity problem inherent to PCMs. The low thermal conductivity of the SS-PCM foam also delays heat-loss, thus enhancing the ability of the system to remain at a desired temperature.