Establishing uniform solar energy output during periods of cloud obscuration through joint design of optical and energy converter systems

通过光学和能量转换器系统的联合设计，在云层遮蔽期间建立统一的太阳能输出即将到来的气候和燃料危机将对生活质量和社会安全产生不利影响。为了防止这一问题的发生，可再生能源解决方案必须在现有能源供应中占更大的比例。然而，目前，由于大气波动，例如云层的遮挡，传统光伏系统产生的太阳能发电量在白天变化很大。所提出的工作提供了一个路径，以解决这个问题，通过减少太阳能光伏系统的输出的影响。这将通过一种设计方法来实现，该方法集成了光伏和热能转换器的特性，本地和区域太阳能照明条件以及光学器件，以优化太阳能转换系统的时间均匀性和整体输出功率。这些系统将使用几种类型的光伏电池来提高太阳能转换效率，热转换器对云遮蔽的反应更慢，以抑制变化，以及光学技术来提高两种转换器对可用阳光的利用率，并优化整个系统的电力输出。这一设计过程将导致生产更高质量的可再生能源，这将对公用事业公司的电网应用更有用。除了技术上的好处，拟议的工作提供了机会，新的工程专业的学生学习太阳能组件和系统设计的要点。学生们渴望参与解决气候和能源问题，这个项目提供了很好的机会，教育和培训他们的研究和工作场所。此外，可靠、低成本的太阳能系统将允许在美国原住民保留地和电力不容易获得的第三世界国家使用。这项研究的目标是开发一种新的全息光管理方法，该方法集成了不同类型的太阳能转换器，以从太阳能资源中提供更有用的电力。特别是，全息光管理技术将用于优化混合光伏/太阳能热转换器的输出，以减轻白天太阳能对光伏（PV）系统性能的影响。这将通过开发光管理设计来实现，这些设计提供：全光谱利用，高效PV光谱分裂和用于短期能量存储的太阳能热转换。此外，全息配置将被检查，以允许在漫射照明条件下的高效率光谱分裂光伏系统的操作，以进一步扩展光伏系统的能量产出能力。解决这两个问题将显著提高光伏系统的能量容量因子。这项工作的潜在贡献包括：1）开发全息光管理方法，该方法集成成像和非成像光学设计、全息和常规光学、PV电池和太阳能热转换器参数以及局部和区域太阳照明数据，以设计用于全太阳光谱利用的系统，从而减轻白天大气对流对电力输出的影响; 2）设计、制造和评估全息光学器件，其控制聚光比、光谱带宽和几何形状因子，以在直射阳光照射条件下实现最佳太阳能转换;以及3）开发用于在漫射照射条件下操作的高效光谱分裂全息系统。这些贡献将导致公用事业公司更可靠地使用可再生能源系统，并更多地插入电网。这反过来将减少化石燃料对气候的负面影响，并为国家和世界人口提供更好的生活质量。

Establishing uniform solar energy output during periods of cloud obscuration through joint design of optical and energy converter systems The impending climate and fuel crises will adversely affect the quality of life and security of society. In order to prevent this problem from occurring, renewable energy solutions must become a larger percentage of the existing energy supply. However, at the current time the amount of solar energy generated electricity from conventional photovoltaic systems varies a great deal during the day due to atmospheric fluctuations such as obscurations from clouds. The proposed work provides a path to solving this problem by reducing the effect of solar intermittency on the output of photovoltaic systems. This will be accomplished through a design methodology that integrates the characteristics of photovoltaic and thermal energy converters, local and regional solar illumination conditions, and optics to optimize the solar conversion system temporal uniformity and overall output power. The systems will use several types of photovoltaic cells to increase solar conversion efficiency, thermal converters that respond more slowly to cloud obscuration to dampen variability, and optical techniques to increase utilization of the available sunlight for both types of converters and to optimize the overall system electricity output. This design process will lead to the production of higher quality renewable energy that will be more useful to utility companies for electrical grid applications. In addition to the technical benefits, the proposed work provides opportunities for new engineering students to learn the essentials of solar energy component and system design. Students are eager to become involved solving climate and energy problems and this project offers excellent opportunities to educate and train them for research and the work place. In addition, reliable, low cost solar energy systems will allow use on Native American reservations and in third world countries where electrical power is not readily available. The goal of the proposed research is to develop a novel holographic light management methodology that integrates different types of solar converters to provide more useful electrical power from the solar resource. In particular, holographic light management techniques will be used to optimize the output of hybrid photovoltaic/solar thermal converters to mitigate the effects of daytime solar intermittency on photovoltaic (PV) system performance. This will be achieved by developing light management designs that provide: full spectrum utilization, high efficiency PV spectrum splitting, and solar thermal conversion for short term energy storage. In addition, holographic configurations will be examined to allow operation of high efficiency spectrum splitting PV systems during diffuse illumination conditions to further extend the energy yield capability of PV systems. Solving these two problems will significantly increase the energy capacity factor of PV systems. The potential contributions of this work include: 1) development of a holographic light management methodology that integrates imaging and non-imaging optical design, holographic and conventional optics, PV cell and solar thermal converter parameters, and local and regional solar illumination data to design systems for full solar spectrum utilization that mitigate daytime atmospheric intermittency effects on electricity output; 2) design, fabrication, and evaluation of holographic optics that control concentration ratio, spectral bandwidth, and geometrical form factor for optimum solar energy conversion under direct sunlight illumination conditions; and 3) development of high efficiency spectrum-splitting holographic systems for operation with diffuse illumination conditions. These contributions will lead to renewable energy systems that can be used more reliably by utility companies and greater insertion into the electrical grid. This in turn will diminish the negative effects of fossil fuels on the climate and provide a better quality of life for the Nation and World's population.