A Proposed New Concept for a Solar-Energy Converter

1972 ◽  
Vol 94 (2) ◽  
pp. 73-77 ◽  
Author(s):  
R. L. Bailey

The potential advantages of terrestrially utilizing nonpolluting solar energy are well-known. One of the more promising approaches to achieving the desired high solar-electrical conversion efficiency is the direct process, avoiding Carnot efficiency limitations of heat engines. The chief present-art example is the large area silicon solar cell based on utilization of quantum properties of light. In the United States it is now an established technology created from the space program. This paper presents the results of some preliminary new research exploring the possibilities of creating high efficiency solar-electricity converters utilizing wave-like properties of radiation interacting with absorber-converter elements. The concept is revealed for what is believed to be a new, unique, and potentially useful pyramidical solar radiation absorber-converter structure. It is based on the possibility of extending concepts of power absorbing antennas and converters to the visible light range. The resulting proposed converter structure would have a rough surface texture and yield a d-c output. It may have, if subsequently researched, significant efficiency, cost, and fabricating advantages, particularly for large-scale terrestrial utilization of solar energy. The concept is called an Electromagnetic Wave Energy Converter (EWEC). Concept validity evidences of a preliminary kind at both microwave and near light wavelengths are presented.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peipei Du ◽  
Jinghui Li ◽  
Liang Wang ◽  
Liang Sun ◽  
Xi Wang ◽  
...  

AbstractWith rapid advances of perovskite light-emitting diodes (PeLEDs), the large-scale fabrication of patterned PeLEDs towards display panels is of increasing importance. However, most state-of-the-art PeLEDs are fabricated by solution-processed techniques, which are difficult to simultaneously achieve high-resolution pixels and large-scale production. To this end, we construct efficient CsPbBr3 PeLEDs employing a vacuum deposition technique, which has been demonstrated as the most successful route for commercial organic LED displays. By carefully controlling the strength of the spatial confinement in CsPbBr3 film, its radiative recombination is greatly enhanced while the nonradiative recombination is suppressed. As a result, the external quantum efficiency (EQE) of thermally evaporated PeLED reaches 8.0%, a record for vacuum processed PeLEDs. Benefitting from the excellent uniformity and scalability of the thermal evaporation, we demonstrate PeLED with a functional area up to 40.2 cm2 and a peak EQE of 7.1%, representing one of the most efficient large-area PeLEDs. We further achieve high-resolution patterned perovskite film with 100 μm pixels using fine metal masks, laying the foundation for potential display applications. We believe the strategy of confinement strength regulation in thermally evaporated perovskites provides an effective way to process high-efficiency and large-area PeLEDs towards commercial display panels.


Author(s):  
Yi Zheng ◽  
Zhi-Zhu He ◽  
Jun Yang ◽  
Jing Liu

The advancement of printed electronics technology has significantly facilitated the development of electronic engineering. However, so far there still remain big barriers to impede the currently available printing technologies from being extensively used. Many of the difficulties came from the factors like: complicated ink-configurations, high post-treatment temperature, poor conductivity in room temperature and extremely high cost and time consuming fabrication process. From an alternative strategy, our recently invented desktop liquid metal printer offered a flexible way to better address the above deficiencies. Through modifying the system developed in the authors’ lab, here we demonstrated the feasibility of the method in quickly and reliably printing out various large area electronic circuits. Particularly, the liquid metal ink made of GaIn24.5 alloy, with a high electrical resistivity of 2.98×10−7 Ω·m, can be rapidly printed on polyvinyl chloride (PVC) substrate with maximum sizes spanning from centimeter size to meter large. Most important of all, all these manufactures were achieved at an extremely low cost level which clearly shows the ubiquitous value of the liquid metal printer. To evaluate the working performance of the present electronics fabrication method, the electrical resistance and wire width of the printed circuits were investigated under multiple overprinting cycles. For practical illustration purpose, LED lighting conductive patterns which can serve as a functional electronic decoration art were fabricated on the flexible plastic substrate. The present work sets up an example for directly making large-scale ending consumer electronics via a high-efficiency and low-cost way.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 295
Author(s):  
Tianzhao Dai ◽  
Qiaojun Cao ◽  
Lifeng Yang ◽  
Mahmoud Aldamasy ◽  
Meng Li ◽  
...  

Perovskite solar cells (PSCs) have received a great deal of attention in the science and technology field due to their outstanding power conversion efficiency (PCE), which increased rapidly from 3.9% to 25.5% in less than a decade, comparable to single crystal silicon solar cells. In the past ten years, much progress has been made, e.g. impressive ideas and advanced technologies have been proposed to enlarge PSC efficiency and stability. However, this outstanding progress has always been referred to as small-area (<0.1 cm2) PSCs. Little attention has been paid to the preparation processes and their micro-mechanisms for large-area (>1 cm2) PSCs. Meanwhile, scaling up is an inevitable way for large-scale application of PSCs. Therefore, we firstly summarize the current achievements for high efficiency and stability large-area perovskite solar cells, including precursor composition, deposition, growth control, interface engineering, packaging technology, etc. Then we include a brief discussion and outlook for the future development of large-area PSCs in commercialization.


Author(s):  
Joseph Sinai ◽  
Chemi Sugarmen ◽  
Uriyel Fisher

Adapting a gas turbine to high-temperature solar receivers and solar tower technology constitutes real progress towards commercial solar power utilization with high efficiency combined cycle power system. Solar gas turbine systems can also be adapted to hybrid solar/fossil fuel operation, thanks to its high efficiency conversion, relatively small solar field, and quick response to load fluctuations, low CO2 emissions, easy start, and more effective equipment utilization. ORMAT initiated adaptation and modification of gas turbines for solar energy applications in the early 1990s in cooperation with the Weizmann Institute of Science and later with the Boeing Corporation, with the support of the United States Israel Science and Technology Foundation (USISTF). Ultimately, the concept reached its successful realization (2001–2004) in the solar tower Plataforma Solar de Almeria (Spain) which has three solar receivers and a receiving system designed and supplied by the German Aerospace Center DLR.


Author(s):  
Erik Koepf ◽  
Suresh G. Advani ◽  
Ajay K. Prasad

Solar fuels are emerging as a viable pathway towards closing the gap between fuel production and consumption in the United States. If these fuels can be produced on large scale and achieve carbon-neutrality, a truly sustainable energy solution may be realized. Hydrogen is among the list of attractive solar fuels. Whether used in a PEM fuel cell or combustion engine, hydrogen as a fuel produced from sunlight and water represents an elegant energy harvesting cycle, with zero-emissions, high efficiency, and exceptional power-density. A novel solar-thermochemical reactor has been designed and constructed for the reduction of ZnO at temperatures close to 2000K as the first step in a closed two-step thermochemical cycle to produce hydrogen from water as a solar fuel. Abbreviated as GRAFSTRR (Gravity-Fed Solar-Thermochemical Receiver/Reactor), the reactor is closed to the atmosphere, and features an inverted conical-shaped reaction surface along which ZnO powder descends continuously as a falling sheet and undergoes a thermochemical reaction upon exposure to highly concentrated sunlight. The reactant feed is vibration-induced, metered, and gravity-driven. Beam-down, highly concentrated sunlight enters the reaction cavity through a water-cooled aperture, and Zn product gas is siphoned into a centrally-located exit stream via a stabilized vortex flow of inert gas originating from above the aperture plane. Unreacted or partially reacted solids exit annularly around the product stream. In this paper the GRAFSTRR concept is presented. Select design choices and investigations are summarized.


1997 ◽  
Vol 129 (S171) ◽  
pp. 5-25 ◽  
Author(s):  
C. Prior ◽  
D.A. Streett

AbstractLarge-scale applications of non-persistent but broad-spectrum chemical insecticides in Africa during the 1980s for control of acridoid pests, particularly the desert locust (Schistocerca gregaria Forskål) and Sahelian pest grasshoppers, raised concern about environmental damage and human safety. Similar concerns have been expressed in Australia, the United States, and Canada and have led to a search for alternative strategies. To lessen dependence on chemicals, an integrated pest management (IPM) approach for grasshopper control has been encouraged in the United States with emphasis on biological control as an important component and this is also desirable elsewhere, but additional biocontrol components are needed. Current strategies for most pest acridoids rely on short-term destruction of outbreak populations. Nymphs are the preferred target wherever possible and inundative augmentation of entomopathogenic deuteromycete fungi formulated as biopesticides could replace chemical spraying in some cases, especially where the major threat is to crops remote from the pest breeding areas. Entomopathogens are slower acting than chemicals and thus best suited for use where the pest is not immediately threatening to crops. Schistocerca gregaria and Oedaleus senegalensis Krauss pose particularly difficult problems because of the very large area and inaccessibility of their potential breeding grounds, their very sudden upsurges, and their great mobility as adult swarms. Fast-acting chemicals are likely to be needed when rapid intervention is required to control these pests, but an IPM strategy could incorporate biopesticide application in the early stages of upsurges and also be used for swarm control in some cases. However, improved prediction and monitoring are needed to facilitate the use of biopesticides and other IPM techniques against these pests.


2019 ◽  
Vol 5 (10) ◽  
pp. eaaw5461 ◽  
Author(s):  
Dana R. Fisher ◽  
Kenneth T. Andrews ◽  
Neal Caren ◽  
Erica Chenoweth ◽  
Michael T. Heaney ◽  
...  

Since the inauguration of Donald Trump, there has been substantial and ongoing protest against the Administration. Street demonstrations are some of the most visible forms of opposition to the Administration and its policies. This article reviews the two most central methods for studying street protest on a large scale: building comprehensive event databases and conducting field surveys of participants at demonstrations. After discussing the broader development of these methods, this article provides a detailed assessment of recent and ongoing projects studying the current wave of contention. Recommendations are offered to meet major challenges, including making data publicly available in near real time, increasing the validity and reliability of event data, expanding the scope of crowd surveys, and integrating ongoing projects in a meaningful way by building new research infrastructure.


2016 ◽  
Vol 16 (4) ◽  
pp. 1011-1018 ◽  
Author(s):  
Tatiana Molodtsova ◽  
Sergey Molodtsov ◽  
Andrei Kirilenko ◽  
Xiaodong Zhang ◽  
Jeffrey VanLooy

Abstract. Reager and Famiglietti (2009) proposed an index, Reager's Flood Potential Index (RFPI), for early large-scale flood risk monitoring using the Terrestrial Water Storage Anomaly (TWSA) product derived from the Gravity Recovery and Climate Experiment (GRACE). We evaluated the efficacy of the RFPI for flood risk assessment over the continental USA using multi-year flood observation data from 2003 to 2012 by the US Geological Survey and Dartmouth Flood Observatory. In general, we found a good agreement between the RFPI flood risks and the observed floods on regional and even local scales. RFPI demonstrated skill in predicting the large-area, long-duration floods, especially during the summer season.


1997 ◽  
Vol 471 ◽  
Author(s):  
Jun-Ying Zhang ◽  
Ian W. Boyd

ABSTRACTA large-area, high power density, high efficiency, and low cost excimer VUV and UV source, which is capable of producing narrow-band radiation tunable between the near UV (λ=354 nm) and the deep UV (λ=126 nm), is described.This UV source is based on the principle that the radiative decomposition of excimer states created by a dielectric barrier discharge (silent discharge) in a rare gas, such as Ar2* (λ=126 nm), Kr2* (λ=146 nm), Xe2* (λ=172 nm) or molecular rare gas-halide complexes, such as ArCl* (λ=175 nm), KrCl* (λ=222 nm), XeCl* (λ=308 nm). Conversion efficiencies (from input electrical to output optical energy) as high as 22% can be achieved under optimum conditions. This powerful and economical lamp provides a useful UV source for low temperature photon-initiated processes and is an interesting alternative to conventional UV lamps for industrial large-scale low temperature processes. For industrial large-area processing and for the deposition of highly complex structures, these narrow band VUV and UV sources with high photon fluxes have definite advantages. Several applications of these excimer sources are reviewed, including photo-deposition of dielectric and metallic thin films, photo-oxidation of silicon, surface modification, etching of polymer, and photo degradation of pollutants.


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