scholarly journals Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

2015 ◽  
Vol 112 (40) ◽  
pp. 12282-12287 ◽  
Author(s):  
Linxiao Zhu ◽  
Aaswath P. Raman ◽  
Shanhui Fan

A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

2021 ◽  
Author(s):  
Nicolas Gaillard ◽  
Wilman Septina ◽  
Joel Varley ◽  
Tadashi Ogitsu ◽  
Kenta Ohtaki ◽  
...  

We report on the electrical properties of 2.0 eV bandgap (EG) CuInGaS2 (CIGS) solar absorbers integrated on SnO2:F (FTO) substrates and interfaced with CdS buffer layers for multijunction solar cells...


2021 ◽  
Author(s):  
Shuai Zhang ◽  
Zhenhua Wu ◽  
Zekun Liu ◽  
Erzhen Mu ◽  
Yang Liu ◽  
...  

Abstract Harvesting energy from the environment to generate electricity is attracting tremendous interest to enrich the forms of energy utilization, reduce greenhouse gas emissions and alleviate the global energy crisis1,2. However, achieving an unlimited and uninterrupted all-day power generation from the ambient energy is still challenging3. Herein, we demonstrate a passive power device to harvest energy from the sun and cold space based on micro-fabricated thermoelectric generator (TEG) integrated with solar absorber (SA) and radiative cooling emitter (RCE) to realize continuous power generation form the ambient. The ultrathin TEG, that with a sensitivity of 10− 4 K achieved output power density of 960 W/m3 while heated to 80°C at room temperature. The solar absorber (SA) performs photothermal conversion to heat the TEG in the daytime4, while the radiative cooling emitter (RCE) radiates the heat to the cold space through the atmospheric window to cool the TEG all the clear day5,6. Our strategy provides a renewable and sustainable thermodynamic resource to build a temperature difference over TEG for all-day uninterrupted power generation for wide application scenarios. This is the first proof-of-principle uninterrupted power generation system independent of time on a small scale, and opportunities exist for environmental energy harvesting and electricity generation beyond traditional technologies.


Author(s):  
David Fisher

There are eight columns in the Periodic Table. The eighth column is comprised of the rare gases, so-called because they are the rarest elements on earth. They are also called the inert or noble gases because, like nobility, they do no work. They are colorless, odorless, invisible gases which do not react with anything, and were thought to be unimportant until the early 1960s. Starting in that era, David Fisher has spent roughly fifty years doing research on these gases, publishing nearly a hundred papers in the scientific journals, applying them to problems in geophysics and cosmochemistry, and learning how other scientists have utilized them to change our ideas about the universe, the sun, and our own planet. Much Ado about (Practically) Nothing will cover this spectrum of ideas, interspersed with the author's own work which will serve to introduce each gas and the important work others have done with them. The rare gases have participated in a wide range of scientific advances-even revolutions-but no book has ever recorded the entire story. Fisher will range from the intricacies of the atomic nucleus and the tiniest of elementary particles, the neutrino, to the energy source of the stars; from the age of the earth to its future energies; from life on Mars to cancer here on earth. A whole panoply that has never before been told as an entity.


Author(s):  
E. L. Wolf

The Sun’s spectrum on Earth is modified by the atmosphere, and is harvested either by generating heat for direct use or for running heat engines, or by quantum absorption in solar cells, to be discussed later. Focusing of sunlight requires tracking of the Sun and is defeated on cloudy days. Heat engines have efficiency limits similar to the Carnot cycle limit. The steam turbine follows the Rankine cycle and is well developed in technology, optimally using a re-heat cycle of higher efficiency. Having learned quite a bit about how the Sun’s energy is created, and how that process might be reproduced on Earth, we turn now to methods for harvesting the energy from the Sun as a sustainable replacement for fossil fuel energy.


Author(s):  
David D. Nolte

Galileo Unbound: A Path Across Life, The Universe and Everything traces the journey that brought us from Galileo’s law of free fall to today’s geneticists measuring evolutionary drift, entangled quantum particles moving among many worlds, and our lives as trajectories traversing a health space with thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets or the collapse of stars into black holes. This book tells the history of spaces of expanding dimension and increasing abstraction and how they continue today to give new insight into the physics of complex systems. Galileo published the first modern law of motion, the Law of Fall, that was ideal and simple, laying the foundation upon which Newton built the first theory of dynamics. Early in the twentieth century, geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, forcing light rays to bend past the Sun. Possibly more radical was Feynman’s dilemma of quantum particles taking all paths at once—setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant, the need to track ever more complex changes and to capture their essence, to find patterns in the chaos as we try to predict and control our world.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2460
Author(s):  
Jian Zou ◽  
Mengnan Liu ◽  
Shuyu Tan ◽  
Zhijie Bi ◽  
Yong Wan ◽  
...  

A two-dimensional perovskite photonic crystal structure of Methylamine lead iodide (CH3NH3PbI3, MAPbI3) is rationally designed as the absorption layer for solar cells. The photonic crystal (PC) structure possesses the distinct “slow light” and band gap effect, leading to the increased absorption efficiency of the absorption layer, and thus the increased photoelectric conversion efficiency of the battery. Simulation results indicate that the best absorption efficiency can be achieved when the scattering element of indium arsenide (InAs) cylinder is arranged in the absorption layer in the form of tetragonal lattice with the height of 0.6 μm, the diameter of 0.24 μm, and the lattice constant of 0.4 μm. In the wide wavelength range of 400–1200 nm, the absorption efficiency can be reached up to 82.5%, which is 70.1% higher than that of the absorption layer without the photonic crystal structure. In addition, the absorption layer with photonic crystal structure has good adaptability to the incident light angle, presenting the stable absorption efficiency of 80% in the wide incident range of 0–80°. The results demonstrate that the absorption layer with photonic crystal structure can realize the wide spectrum, wide angle, and high absorption of incident light, resulting in the increased utilization efficiency of solar energy.


Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.


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