SBIR Phase II: Solar Thermal Collector Using Advection Enhanced Nano-Porous Insulating Media

小型企业创新研究(SBIR)第二阶段项目的广泛影响/商业潜力将深刻改善太阳能热水(SWH)系统的经济性。自从20世纪80年代真空管太阳能集热器问世以来，这一领域几乎没有什么创新。尽管取得了这些进展，但SWH系统的成本远远高于美国的化石燃料成本。因此，尽管全球市场繁荣，超过200亿美元，但美国的此类系统市场实际上是不存在的。正在研究中的太阳能集热器技术在效率与输出温度方面的性能已经优于最先进的集热器。经济模型进一步表明，在大批量生产中，收集器将比商业产品便宜得多。性能的提高和成本的降低相结合，有可能使SWH在美国40多个州具有经济可行性。这一结果可能为国内行业的复兴提供坚实的经济基础，并加速这些系统在全球的扩散。这个小型企业创新研究(SBIR)第二阶段项目将扩展第一阶段工作中确定的两个太阳能集热器架构的性能范围。目前的太阳能集热器表现出不经济的价格/性能指标，并且仅限于全球少数几个市场的热水应用。第一种结构利用对流来改善颗粒状纳米多孔介质的绝缘性能。第二阶段的工作将把这一架构从原型过渡到工程规模收集器的制造和表征。预计增加尺寸和太阳模拟器产量(目前低于参考标准)将显著提高效率。材料掺杂剂、换热流体动力学和光学吸收材料的热性能将通过计算和实验进行检查，以进一步提高性能。第二种架构极大地扩展了业务范围。这项工作将探索扩大这一范围的技术，包括使用材料掺杂剂来改变光学特性，以及开发用于聚光光学的无源技术。计算机模拟表明，与抛物线槽相当的输出是可能的。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project will profoundly improve the economics of solar water heating (SWH) systems. Little innovation has occurred in this area since the advent of evacuated tube solar thermal collectors in the 1980s. Despite these advances the cost of SWH systems is much higher than the cost of fossil fuels in the U.S. Thus while there exists a flourishing global market in excess of $20B, the market for such systems in the U.S. is virtually nonexistent. The solar thermal collector technology under investigation has demonstrated performance in terms of efficiency vs. output temperature that is already superior to that of state-of-the-art collectors. Economic modeling further indicates that in high volume production the collector would be substantially less expensive than commercial products. This combination of improved performance and reduced cost has the potential to make SWH economically viable in more than 40 states in the U.S. An outcome which could provide a solid economic foundation for the revival of a domestic industry, and accelerate the proliferation of these systems worldwide. This Small Business Innovation Research (SBIR) Phase II project will extend the performance envelope of two solar thermal collector architectures identified during the Phase I effort. Current solar thermal collectors exhibit non-economic price/performance metrics and are constrained to water heating applications in only a few markets worldwide. The first architecture utilizes advection to improve the insulating properties of a granular nano-porous medium. The Phase II effort will transition this architecture from prototype to the fabrication and characterization of an engineering scale collector. It is expected that increasing the size and solar simulator output (currently below reference standard) will increase efficiency significantly. Material dopants, heat transfer fluid dynamics, and optical absorber thermal properties will be examined computationally and experimentally to further improve performance. The second architecture significantly extends the operational range. This effort will explore techniques to expand this range including the use of material dopants to modify optical characteristics and the development of passive technique for concentrating optics. Computer simulations suggest that outputs comparable to that of a parabolic trough are possible.