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

建筑占美国能源消耗的40%；这种能量的很大一部分被消耗来抵消通过建筑围护结构产生的热损失或热增益。被动式太阳能设计旨在通过建筑围护结构与太阳能输入平衡热量损失，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，目前被动式太阳能设计的实施往往是高度具体的环境，往往需要使用昂贵的机械设备和控制。该项目旨在研究一种创新的被动式太阳能建筑围护系统，该系统使用具有可变透明度的蜂窝固体-固体相变材料（SS-PCM）。该系统依靠被动材料控制，没有机械运动部件或电子元件。SS-PCM泡沫基建筑围护材料的成功实施可以产生低成本的响应式建筑围护系统，该系统可以自我调节建筑的热舒适性。这项研究的结果可能会导致新技术减少建筑能源使用，减少对化石燃料的依赖，并提高美国的经济竞争力。预计该研究结果将对建材、建筑、能源节约等多种产业产生积极影响。一项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被动式太阳能设计、能源使用和建筑热舒适等主题的竞赛。该项目的目标是揭示在现实建筑围护结构中使用的半透明蜂窝SS-PCM系统的基本原理。将从以下方面获得基本见解：(1)发生在SS-PCM泡沫系统中的传热现象，(2)三种材料支持的太阳-光照射控制机制之间发生的协同效应，以及(3)导致建筑物高能效的结构特征和特性。这项研究将创造有关ss - pcm的热学和光学行为的知识，以便在不同的气候条件下全年被动调节建筑温度。为实现上述目标，将进行多物理场建模、材料综合、系统级集成和建筑级节能评估等综合实验和计算程序。该项目可以通过依靠辐射能量传递过程来改变PCM的使用，从而绕过PCM固有的低导热性问题。SS-PCM泡沫的低导热性也延迟了热损失，从而增强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.