Collaborative Research: Solar Energy Harvesting, Photothermal-Photovoltaic Dual Modality Building Skins towards Energy Neutral Civil Structures

住宅和商业建筑占美国总能耗的40%。材料科学与建筑和土木工程交叉的新概念为实现高能效建筑提供了机会。建筑表皮通常被认为是一种耐候性屏障。这项研究提出将建筑表皮转变为一个主动系统，能够根据季节变化以不同的能量输出收集阳光。这是通过将纳米级薄膜应用于具有多功能和积极的能量收集、转换和利用的建筑表皮来实现的。基于玻璃的高层建筑表皮为应用能量收集纳米级薄膜提供了理想的材料。薄膜将被设计成提供两种主要功能，其中光伏或光热效应可根据季节需求交替切换。在夏季，利用光伏效应将太阳能转化为电能供建筑使用。在冬季，太阳能被转化为热能，以减少建筑物的热量损失。这项研究将对实现能源中性民用基础设施产生变革性影响。将为K-12和未被充分代表的少数民族建立教育项目。本研究的目标是开发一种多功能建筑表皮，能够有效地收集太阳能，以实现基于季节控制的双模态能量输出（热或电）。基本上，光热薄膜和光伏薄膜具有相同的光学特性：强紫外/近红外吸收和高可见光透过率，唯一的区别是能量输出的形式。与多窗格玻璃相比，单窗格玻璃实际上是不可行的，因为热量通过建筑表皮快速传递。如果在窗口表面应用光谱选择性薄膜，通过光热效应可将皮肤表面温度从25°C提高到50°C。这有效地减少了内部的热能损失。这样，就可以在光学上实现无介质干涉的隔热。另一方面，夏季不受欢迎的太阳红外可以通过相同的薄膜以不同的方式进行补偿：光伏。吸收大量红外辐射不仅可以减少冷却能量，还可以为其他电器发电。基本机制将研究光谱选择性和纳米结构之间的关系，从而实现最有效的能量收集和转换。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Residential and commercial buildings account for 40 percent of the total energy consumption in the United States. New concepts at the intersection of materials science and architectural and civil engineering present opportunities to achieve highly energy-efficient buildings. A building skin has been conventionally considered as a weather-resistive barrier. This research offers to transform the building skin to an active system capable of harvesting sunlight with varying energy outputs according to seasonal changes. This is achieved by applying nanoscale thin films to building skins that are multifunctional and active for energy harvesting, conversion, and utilization. Glass-based high-rise building skins provide the ideal material for applying the energy harvesting nanoscale thin films. The thin films will be engineered to offer two major functions, where photovoltaic or photothermal effects are switched alternatively depending on seasonal needs. In summer, the photovoltaic effect is used to transform the solar energy to electricity for building use. In winter, the solar energy is converted to heat to reduce heat loss in the buildings. This research will lead to transformative impacts towards achieving energy-neutral civil infrastructure. Educational programs will be established for K-12 and underrepresented minority outreach.The goal of this research is to develop a multifunctional building skin capable of efficient solar harvesting for dual modality energy outputs (thermal or electric) controlled based on seasons. Principally, both photothermal and photovoltaic films share the same optical characteristics: strong UV/NIR absorptions with high visible transmittance, the only difference is the form of energy output. Compared with multi-pane glazing, single-panes are practically not viable due to rapid heat transfer through building skin. If a spectral-selective thin film is applied on a window surface, the skin surface temperature can be increased from 25 °C to 50 °C via the photothermal effect. This effectively reduces thermal energy loss from the interior. In this way, thermal insulation can be achieved optically without intervention medium. On the other hand, the undesirable solar infrared in summer can be compensated by the same thin film but in a different modality: photovoltaic. Absorption of large infrared irradiation not only reduces cooling energy but generates electricity for other appliances. Fundamental mechanisms will be investigated on the relationship between spectral selectivity and nanostructures that enable the most efficient energy harvesting and conversion.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.