In this report, we describe the design of a concentrated solar thermoelectric (TE) system which can provide both electricity and hot water. Today's thermoelectric materials have a relatively low efficiency (∼6% for temperature difference across the thermoelement on the order of 300°C). However since thermoelectrics don't need their cold side to be near room temperature, (in another word, one can chose the particular thermoelectric material to match to the operational temperature) it is possible to use the waste heat to provide hot water and this makes the overall efficiency of the combined system to be quite high. A key factor in the optimization of the thermoelectric module is the thermal impedance matching with the incident solar radiation, and also with the hot water heat exchanger on the cold side of the thermoelectric module. We have developed an analytic model for the whole system and optimized each component in order to minimize the material cost. TE element fill factor is found to be an important parameter to optimize at low solar concentrations (<50) in order to obtain the highest amount of electric power generated per mass of the thermoelectric elements. Similarly the co-optimization of the microchannel heat exchanger and the TE module can be used to minimize the amount of material in the heat exchanger and the pumping power required for forced convection liquid cooling. Changing the amount of solar concentration, changes the input heat flux and this is another parameter that can be optimized in order to reduce the cost of heat exchanger (by size), the tracking requirement and the whole system. A series of design curves for different solar concentration are obtained. It is shown that the overall efficiency of the system can be more than 80% at 200× concentration which is independent of the material ZT (TE figure-of-merit). For a material with ZThot∼0.9, the electrical conversion efficiency is ∼10- - %. For advanced materials with ZThot∼ 2.8, the electrical conversion efficiency could reach ∼21%.
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机译：在本报告中，我们描述了集中的太阳能热电（TE）系统的设计，该系统可以提供电和热水。今天的热电材料具有相对较低的效率（~6％，温度差的温度差约为300°C）。然而，由于热电学不需要它们的冷侧待在室温附近，（在另一个单词中，可以选择特定的热电材料与操作温度相匹配）可以使用废物热量提供热水，这使得这是可以提供热水合并系统的整体效率非常高。优化热电模块的关键因素是与入射太阳辐射的热阻抗匹配，以及热电模块冷侧的热水热交换器。我们开发了整个系统的分析模型，并优化了每个组件，以最大限度地减少材料成本。发现TE元素填充因子是在低太阳能浓度（<50）处优化的重要参数，以便获得每种热电元件产生的最高量的电力。类似地，微通道热交换器和TE模块的共同优化可用于最小化热交换器中的材料量和强制对流液冷却所需的泵送动力。改变太阳能浓度的量，改变输入热量通量，这是可以优化的另一个参数，以便降低热交换器（按大小），跟踪要求和整个系统的成本。获得了不同太阳能浓度的一系列设计曲线。结果表明，系统的整体效率可以在200×浓度下大于80％，其与材料ZT（TE型号）无关。对于具有ZT 热 ~0.9的材料，电转换效率为〜10-％。对于具有ZT HOT 〜2.8的先进材料，电转换效率可以达到〜21％。
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