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相结合的新概念为实现高度节能的建筑提供了机会。建筑物的皮肤通常被认为是一种抵抗天气的屏障。这项研究提出将建筑皮肤转变为一个主动系统，能够根据季节变化收集不同能量输出的阳光。这是通过将纳米薄膜应用于建筑皮肤来实现的，这些皮肤是多功能的，对能量收集、转换和利用具有活性。玻璃基高层建筑蒙皮为应用纳米级能量收集薄膜提供了理想的材料。这种薄膜将被设计成提供两种主要功能，根据季节性需求交替切换光伏或光热效应。在夏季，利用光伏效应将太阳能转化为电力供建筑使用。在冬天，太阳能被转化为热量，以减少建筑物的热损失。这项研究将对实现能源中立的民用基础设施产生变革性的影响。这项研究的目标是开发一种多功能建筑皮肤，能够有效地收集基于季节控制的双模式能量输出(热能或电力)。大体上，光热薄膜和光伏薄膜都有相同的光学特性：强的UV/NIR吸收和高的可见光透过率，唯一的区别是能量输出的形式。与多层玻璃窗相比，单层玻璃窗实际上是不可行的，因为建筑表面的热量传递很快。如果在窗口表面涂上光谱选择性薄膜，皮肤表面的温度可以通过光热效应从25°C增加到50°C。这有效地减少了内部的热能损失。通过这种方式，可以在没有干预介质的情况下实现光学隔热。另一方面，夏天不受欢迎的太阳红外线可以用同样的薄膜来补偿，但方式不同：光伏。吸收大红外线不仅可以减少制冷能量，还可以为其他家用电器发电。将研究光谱选择性和纳米结构之间的关系，以实现最有效的能量收集和转换。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.