Zhang Xin, Du Jianying, Chen Jincan, Ang Lay Kee, Ang Yee Sin
Opt Lett. 2020 Nov 1;45(21):5929-5932. doi: 10.1364/OL.400349.
Energy harvesting using thermoradiative systems has been extensively explored in recent years as a novel strategy for further reducing our energy footprint. However, the nighttime application, thermodynamic limit, and optimal design of such a system remain largely unaddressed so far. Here we propose an improved nighttime thermoradiative system (NTS) for electrical power generation by optically coupling Earth's surface with outer space. Our theoretical model predicts that the NTS operating with Earth (deep space) at 300 K (3 K) yields a maximum power density of 12.3 with an efficiency limit of 18.5%, which is potentially more advantageous than previous nighttime energy harvesting systems, such as a nighttime thermoelectric generator. We find that optimizing the thickness of the active layer, enhancing thermal infrared emission, and employing a silver backreflector for photon recycling are crucially important in improving system performance. This Letter provides new insights for the optimal designs of NTSs and paves the way toward practical nighttime power generation.
近年来，利用热辐射系统进行能量收集作为进一步减少我们能源足迹的一种新策略，已得到广泛探索。然而，到目前为止，这种系统的夜间应用、热力学极限和优化设计在很大程度上仍未得到解决。在这里，我们提出了一种改进的夜间热辐射系统（NTS），通过将地球表面与外层空间进行光学耦合来发电。我们的理论模型预测，在地球（深空）温度为300 K（3 K）的条件下运行的NTS，其最大功率密度为12.3，效率极限为18.5%，这可能比以前的夜间能量收集系统（如夜间热电发电机）更具优势。我们发现，优化有源层厚度、增强热红外发射以及采用银背反射器进行光子回收对于提高系统性能至关重要。这封信为NTS的优化设计提供了新的见解，并为实际的夜间发电铺平了道路。
