Transport-Enhanced Thermogalvanic Energy Conversion

随着对能源效率和碳减排的重新重视，余热转化仍然是一个有吸引力的研究课题。固态热电器件已经得到了广泛的研究，但由于成本和无法以易于与热源兼容的几何形状制造它们，其实际应用仍然具有挑战性。固态热电装置的一个有趣的替代品是热原电池，它包括一种（通常）允许离子运输的液体电解质。热电原电池在电化学界早已为人所知，但在热输运界却没有受到太多关注。这是令人惊讶的，因为它们的性能高度依赖于控制热和质量（离子）输运。提议的项目是机械工程（热输运）和化学之间的跨学科合作，并且是一个主要的实验努力，旨在提高对热电系统的基本理解。热传递和质量传递都将通过在电极之间施加纳米结构膜来控制，这将利用先前的研究成果，证明通过排列的碳纳米管电极具有非常高的传质率，而通过随机定向的碳纳米管具有非常低的传热率。这项工作可能会改进废热能量转换，主要是因为像热电电池这样的流体装置可以像排气管一样符合热源的形状，而且因为热电电池最终可能比类似的热电装置制造得更便宜。最后，作为正在进行的“科学是乐趣”计划的一部分，将开展广泛的K-12外展计划，其中4至8年级的学生将进行基于演示盐水热电效应的简单实验。

CBET-1236571PhelanWaste heat energy conversion remains an inviting subject for research, given the renewed emphasis on energy efficiency and carbon emissions reduction. Solid-state thermoelectric devices have been widely investigated, but their practical application remains challenging because of cost and the inability to fabricate them in geometries that are easily compatible with heat sources. An intriguing alternative to solid-state thermoelectric devices is thermogalvanic cells, which include a (generally) liquid electrolyte that permits the transport of ions. Thermogalvanic cells have long been known in the electrochemistry community, but have not received much attention from the thermal transport community. This is surprising given that their performance is highly dependent on controlling both thermal and mass (ionic) transport. The proposed project is an interdisciplinary collaboration between mechanical engineering (thermal transport) and chemistry, and is a largely experimental effort aimed at improving fundamental understanding of thermogalvanic systems. Both thermal and mass transport will be controlled by imposing a nanostructured membrane between the electrodes, which will take advantage of previous work that demonstrated very high rates of mass transfer through aligned carbon-nanotube electrodes, and very low rates of heat transfer through randomly oriented carbon nanotubes. This work may enable improved waste heat energy conversion, largely because a fluidic device like a thermogalvanic cell can conform to the shape of a heat source like an exhaust pipe, and because thermogalvanic cells may ultimately be manufactured more cheaply than comparable thermoelectric devices. Finally, an extensive K-12 outreach program will be undertaken as part of the ongoing Science is Fun program, in which simple experiments based on demonstrating the thermogalvanic effect in salt water will be carried out by students in grades 4 through 8.