Solar-powered Devices Research Articles

Observation of Excited State-Derived Photoluminescence Decay of Organic Dye to Monitor Its Photo-Induced Charge Transfer Efficiency

Understanding photo-induced charge transfer (PCT) is crucial for optimizing the performance of solar-powered devices like photovoltaic and photoelectrochemical cells, as PCT directly impacts their operation and overall power conversion efficiency. General assessment of PCT has heavily relied on transient absorption techniques to gauge electron transfer between the donor and acceptor. However, there is a pressing need to broaden the methods for comprehensively studying PCT.In this study, we propose an alternative approach utilizing transient photoluminescence to observe PCT dynamics between organic dyes and redox mediators. This approach involves adsorbing various organic dyes onto Al2O3 surfaces along with redox mediators. When excited, the dyes facilitate charge separation from each other, leading to the instantaneous oxidized form of the dye and subsequent electron transfer from the redox mediator. This process results in a decrease in the photoluminescence lifetime of the organic dye. The extent of this decreases correlates with the Gibbs free energy of charge transfer, reflecting the efficiency of electron transfer between the organic dye and the redox mediator. Our findings introduce an alternative avenue for studying PCT, offering insights that are pertinent to various fields including photovoltaics, optoelectronics, and photocatalysis. Figure 1

Design and field installation of automated electronic Asian Elephant signage for human safety

Human-elephant interactions results in numerous deaths and injuries, often due to accidental encounters at elephant crossing points at night. Addressing this, the proposed electronic elephant signage (EES), a solar-powered device, marks crossing points with a glowing elephant-shaped light. Successfully tested in the Sathyamangalam Tiger Reserve, it activates at dusk, blinking throughout the night, effectively reducing surprise encounters and promoting safer coexistence.

Single Stage Autonomous Solar Water Pumping System Using PMSM Drive

Water supply technology has advanced significantly with the development of autonomous solar water pumping devices. These solar-powered systems offer a dependable and sustainable way to pump water in remote and off-grid areas. They are the perfect solution for solving problems with water delivery in places with restricted access to power because of their capacity to function independently and without the requirement for grid electricity. Autonomous solar water pumping systems present a viable and creative approach to a sustainable water supply at a time when demand for renewable energy solutions is only expected to increase. Sustainable and effective agricultural techniques have advanced significantly with the introduction of autonomous solar water pumping equipment. These solar-powered devices provide an economical and environmentally responsible way to address the problems of declining water supplies and growing energy expenses. Adoption of autonomous solar water pumping devices will be essential to maintaining the productivity and long-term sustainability of our world's food supply as the agricultural sector develops.

Design and Development of Automated Solar Grass Trimmer with Charge Control Circuit

The focus of this paper is the design and development of an automatic solar grass trimmer prototype, emphasizing high operational efficiency with renewable energy as the primary power source. This solar-based device not only contributes to reduced air pollution but also aligns with environmental sustainability objectives. The prototype features a charge control circuit and is powered by a rechargeable 12V battery. To address low battery levels, a solar panel is employed for automatic recharging. A DC-DC buck converter is integrated to step down the higher voltage from the solar panel to match the battery requirements. Safety features, such as a current limiter and overcharge protection circuits, have been incorporated into the design. The paper provides a detailed discussion on the conceptual design of the solar grass trimmer, including the placement of sensors and motors. Additionally, the cutting motor force analysis and total weight calculation of the prototype are presented.The solar charge control circuit, along with details on the current limiter and overcharge protection circuit, is thoroughly explored. Successful development of the prototype is reported, and the battery charging circuits are analyzed using a Bench PSU and solar panel. The paper includes plots of voltage, current, and power generated by the solar panel under various weather conditions. A comparison between Bench PSU and solar panel power is also provided. This research contributes to the advancement of automated solar-powered devices, offering sustainable solutions for environmentally friendly grass trimming.

Performance Analysis and Optimization of a Solar Powered Device

Performance Analysis and Optimization of a Solar Powered Device

Art and design entanglements for renewable energy education: Renewable energy art and design approach

The ongoing energy transition presents a necessary shift towards renewable sources, such as wind and solar power, in the face of the challenges presented by the changing climates. This change, however, requires an understanding of the operation of renewable energy systems. In other words, the shift towards clean energy generation demands education. By combining art, design, and renewable energy education the renewable energy art and design (READ) approach provides a path for renewable energy education. READ approach is a customizable and flexible process developed to enable the creation of solar-powered devices while sharing knowledge on diverse subjects such as art, design, electronics, electricity, and computer science. Due to its versatility, READ is expected to enhance energy education and contribute to the transition towards a renewable-powered society.

Flextegrity arched structures for Lunar bases built from indigenous materials

Flextegrity is a broad structural concept, represented here by a chain of perforated massive segments in dry contact, coupled by a passing-through pre-tensioned tie-rod (tendon). Contact surfaces realize pure rolling along tailor-designed pitch lines, so that the relative rotation of adjacent segments determines the tendon elongation: the bending constitutive law can be optimized simply by re-shaping the contact surfaces. Flextegrity arches are placed side by side to form a vault, pressurized via an interposed air-tight membrane. The arch follows an almost complete circle (the vault approaches a tube), to minimize the actions on the foundations from internal pressure. The structure also supports a thick radiation shield above, made up of loose Lunar debris. The main characteristic is that the massive segments can be made from cast Lunar regolith, fused into solar-powered devices, whose weight is mitigated by the reduced Lunar gravity. Huge savings on mission budget are expected, because the only components from Earth are the tendons, made of high-performance lightweight carbon nanotube fibers, and the air-tight membrane. Small-scale prototypes are manufactured from cast concrete. The structural response is analyzed through a theoretical model. The concept is applied to a Moon base example, verifying compatibility with the strength of Lunar regolith under various actions, including meteoroid impact.

Intermediate Technologies: The Key to Eradicating Post-harvest Losses (PHLs) in Sub-Saharan Africa (SSA)

Post-harvest losses (PHLs) in Sub-Saharan Africa (SSA) pose a significant threat to food security and economic stability. PHLs account for a substantial portion of food waste and economic losses. This paper explores the potential of intermediate technologies in addressing this challenge. Intermediate technologies, including hand-operated, pedal-operated, and solar-powered devices, offer adaptable and cost-effective solutions tailored to the needs of smallholder farmers who make up the majority of SSA's agricultural sector. These technologies bridge the gap between labor-intensive traditional methods and high-end, expensive equipment. They enhance efficiency, reduce labor, and have the potential to revolutionize post-harvest processes. Additionally, emerging innovations, such as harnessing energy from footsteps and raindrop energy offer promising avenues for further enhancing the sustainability and efficiency of post-harvest operations in resource-constrained environments. Intermediate technologies represent not only tools but also catalysts for transformation. They hold the key to reducing PHLs, fostering economic growth, ensuring food security, and leading to sustainable agriculture in SSA. By harnessing these technologies' adaptability and resource efficiency, SSA can move closer to a more sustainable and prosperous future.

Recognizing Hand Gestures Using Solar Cells

We design a system, SolarGest, which can recognize hand gestures near a solar-powered device by analyzing the patterns of the photocurrent. SolarGest is based on the observation that each gesture interferes with incident light rays on the solar panel in a unique way, leaving its discernible signature in harvested photocurrent. Using solar energy harvesting laws, we develop a model to optimize design and usage of SolarGest. To further improve the robustness of SolarGest under non-deterministic operating conditions, we combine dynamic time warping with Z-score transformation in a signal processing pipeline to pre-process each gesture waveform before it is analyzed for classification. We evaluate SolarGest with both conventional opaque solar cells as well as emerging see-through transparent cells. Our experiments demonstrate that SolarGest achieves 99% for six gestures with a single cell and 95%for fifteen gesture with a22solar cell array. The power measurement study suggests that SolarGest consume 44% less power compared to light sensor based systems.

A portable high-performance self-insulated solar evaporator based on wooden sponge for seawater desalination and wastewater purification

Over 70 % of the earth's surface is water, though people are facing a shortage of clean water. Desalination and purification plants have been utilizing inexhaustible saline and dirty water for decades, but here we present a portable solar-powered device that works during the journey. The independent steam generator is based on a novel wooden material coated with carbonized carbon dots (CCD). A facile hydrothermal treatment is applied to the balsa wood to produce a superhydrophilic, salt-resisting, and self-insulated wooden sponge. The CCD microspheres show broad absorption over the solar spectrum while the wooden sponge provides a rapid water supply and heat localization. The floating CCD@wooden sponge evaporator generates steam at the rate of 2.24 kg m−2 h−1 and has an energy efficiency of 85.0 % under 1 sun irradiation. With a unique design of portable water purifier, a traveler could easily obtain clean water after collecting and purifying undrinkable water such as seawater and wastewater on the move as long as the sun shines.

Manual tracking for solar parabolic concentrator – For the case of solar injera baking, Ethiopia

The efficiency of renewable energy equipment is highly reliant on the mechanism for properly capturing the resource and the equipment's performance. For any solar-powered device tracking mechanism is critical; it must be able to follow the pattern of the sun's path. This research created a manual tracking mechanism for a solar-powered steam injera stove. The design of the tracking mechanism tracks the path of the sun seasonally and daily for 5 h, half in the morning and a half in the afternoon, beginning at solar noon, it tracks the sun's path every 10 min. It investigates the relationship between solar intensity and receiver surface temperature. There were two experimental tests, one with one receiver surface data point and the other with three data points. The correlation coefficient of solar intensity with heat temperature on the receiver surface was r = 0.726 at the first data point. And, for the three points where data was collected for one and a half hours in the afternoon, on three-point of the receiver surface lower points, the correlation of solar intensity and average heat temperate of those three points is r = 0.766. For both of the experiment, the relationship of the solar intensity pattern shows there is a strong positive correlation with the temperature on the surface of the receiver which indicates the manual tracking system move with the proper path of the sun and concentrates the sun on the point receiver of the solar injera stove.

Transparent photovoltaic-based photocathodes for see-through energy systems

Solar energy is an abundant clean energy source, which may support current and future energy demands as well as sustainable growth. The increasing energy demand in modern society promotes the commercialization of solar cells with high power conversion efficiency and low costs. However, the intermittent nature of solar power limits its practical uses, especially in solar cells and in the corresponding hydrogen production systems. Solar-powered devices and their water-splitting associated hydrogen generation offer clean and continuous energy. We propose transparent photovoltaics (TPVs) combined with the transparent photoelectrochemical cells (TPECs) uniting electric power and hydrogen generation in the domestic framework. A transparent photocathode based on an ultrathin amorphous Si (a-Si) solar absorber is applied in a TPV–TPEC energy system with good transparency, generating a high open-circuit voltage (0.852 V), and short-circuit current density (3.744 mA/cm2), noticeably device efficiency (1.66%). The transparent photocathode shows a maximum photocurrent density of 4 mA/cm2 at −0.5 V vs. RHE, driving stable solar hydrogen production. We demonstrate the promising potential of the TPV–TPEC integrated system for the unstoppable generation, supply, and alteration of energy in see-through platforms. Hereupon, the integration of this system in building windows will enable the continuous production of green energy without the loss of external vision.

Can measurements of foraging behaviour predict variation in weight gains of free-ranging cattle?

Context Technologies are now available to continuously monitor livestock foraging behaviours, but it remains unclear whether such measurements can meaningfully inform livestock grazing management decisions. Empirical studies in extensive rangelands are needed to quantify relationships between short-term foraging behaviours (e.g. minutes to days) and longer-term measures of animal performance. Aims The objective of this study was to examine whether four different ways of measuring daily foraging behaviour (grazing-bout duration, grazing time per day, velocity while grazing, and turn angle while grazing) were related to weight gain by free-ranging yearling steers grazing semiarid rangeland. Methods Yearling steers were fitted with neck collars supporting a solar-powered device that measured GPS locations at 5 min intervals and used an accelerometer to predict grazing activity at 4 s intervals. These devices were used to monitor steers in four different paddocks that varied in forage biomass, and across two grazing seasons encompassing a wide range of forage conditions. Steer weight gain (kg/steer.day) was measured in each paddock during each of three ∼60 day time intervals, and daily foraging behaviours were measured during 15–21 days in each interval. Results A model based on only two daily measurements of foraging behaviour, mean grazing bout duration (calculated at a 5 min resolution) and mean velocity while grazing explained 62% of the variation in animal weight gain. Conclusions Daily measurements of foraging behaviour vary substantially in response to varying foraging conditions in space and time, and can effectively serve as indicators of variation in cattle weight gain. Implications On-animal sensors that monitor foraging behaviour have the potential to transmit indicators to livestock managers in real time (e.g. daily) to help inform decisions such as when to move animals among paddocks, or when to sell or transition animals from rangeland to confined feeding operations.

A study on the characteristics of roof wind field by wind tunnel test

More and more solar-powered devices are installed on roofs, and wind load is its structural design control load. Therefore, roof wind field condition is considered to be the most important prerequisite in studies of wind load on structures. In this study, wind tunnel testing was carried out to observe the roof wind field characteristics of a multistorey building. The change rule and characteristics of the multistorey building roof wind field, under different wind directions were studied, and the roof wind field and ground wind field were then compared. The analysis showed that the closer to the roof, the greater the roof wind field effect on the building. When the distance from the roof Z ≥ 9 m, it appears that changes in roof wind speed and turbulence intensity are not affected by the building. When the height from roof Z ≤ 5 m, a turbulence intensity enlargement ratio Δ S I of 0.1–0.3 is recommended. For practical application, a speed-up ratio of the mean wind speed Δ S V of 0.9 is recommended. • The wind tunnel test is carried out to study the characteristics of roof wind field. • The wind speed and turbulence intensity are not affected by the building when Z ≥ 9 m. • When Z ≤ 5 m, the enlargement ratio Δ S I is recommended to be 0.1–0.3. • The speed-up ratio of the mean wind speed on the roof Δ S V is recommended to be 0.9. • The conclusions can provide references for structural wind resistance design of roof equipment.

Revue sur les nanofluides et leurs applications dans le domaine de l'énergie solaire

In this article, an analysis of the integration of nanofluids and their applications in the field of solar energy has been discussed. Practically, several factors affect the physical properties of nanofluids. The use of nanofluids as an absorbent fluid is an effective approach to improve heat transfer in solar-powered devices. The main objective of this review is to examine and categorize all existing formulas and correlations on the physical properties and physical models of nanofluids, including thermal conductivity, viscosity, density, and specific heat, and to summarize the research carried out in recent years on the applications of nanofluids in solar energy systems. This article also identifies future research opportunities in the field of solar energy

Strategies for tapping the energy from hot carriers

A review discusses the history, current status and future strategies for minimizing the energy loss in solar-powered devices caused by hot carrier cooling.

Solar-powered smart window design with aerosol trap and greenhouse gardening

The work is devoted to the development and testing of a solar-powered device with the functions of dust and other aerosol particles capturing both inside and outside the room, with the ability to regulate the light and heat fluxes into the room and with the greening function. The purpose of the device development is the use of solar energy in window household systems for: 1) night and adjustable daytime lighting of rooms; 2) cleaning the city’s air basin from dust and burning, 3) additional heat and sound insulation. A working model scaled down to 1:5 was created, where consumer functions were tested and finalized after modeling in AutoCAD. The device based on solar panels provides a combination of the mentioned consumer functions having three autonomous modules. They are placed on a united metal structure that is fixed in the opening and on the window frame. The model provides five static and three dynamic modes of device operation. The developed device can be used to improve the ecology of the urban environment.

Biologging is suspect to cause corneal opacity in two populations of wild living Northern Bald Ibises (Geronticus eremita)

BackgroundIn this paper, we present evidence that biologging is strongly correlated with eye irritation, with sometimes severely impairing effects. A migratory population of the Northern Bald Ibis (Geronticus eremita, NBI) is reintroduced in Europe, in course of a LIFE + project. Since 2014, all individuals have been equipped with GPS-devices. Remote monitoring allows the implementation of focussed measures against major mortality causes.MethodsInitially all birds carried battery-powered devices, fixed on the lower back of the birds. Since 2016 an increasing amount of birds has been equipped with solar-powered devices, fixed on the upper back, the more sun-exposed position. In 2016, we observed opacity in the cornea of one eye (unilateral corneal opacity; UCO) during a regular health monitoring for the first time.ResultsBy 2018, a total of 25 birds were affected by UCO, with varying intensity up to blindness. Clinical examination of the birds revealed no clear cause for the symptoms. However, only birds carrying a device on the upper back were affected (2017 up to 70% of this group). In contrast, none of the birds carrying devices on the lower back ever showed UCO symptoms. This unexpected relationship between tagging and UCO was discovered in 2017. After we took countermeasures by removing the device or repositioning it on the lower back, we observed an immediate reduction of the incidence rate without any new cases reported since January 2019. NBI roost with their head on the back, one eye closely placed to the device if it was positioned on the upper back. Thus, we conclude that the most parsimonious explanation for the symptomatology is either a repetitive slight temperature rise in the corneal tissue due to electromagnetic radiation by the GSM module of the device or a repetitive slight mechanical irritation of the corneal surface. Concrete evidence is missing so far. Meanwhile, cases of UCO were found in another NBI population.ConclusionOur observations indicate that further research in the fast-growing field of biologging is urgently needed. The findings question the positioning of devices on the upper back in birds roosting with the head on the back.

Arquitetura vernacular sustentável em área legalmente protegida

O objetivo neste trabalho foi propor uma unidade pedagógica em uma área de proteção ambiental (APA) da Ilha do Combú com base em resultados térmico-hídricos associados à verticalização e perda de área verde em Belém. Foram realizados estudos de campo, análise de taxas evapotranspiratórias, monitoramento de espécie com fins paisagístico, testes em ferramentas computacionais para avaliar carga térmica e insolação, bem como a elaboração do projeto arquitetônico. Levantaram-se dados de materiais disponíveis na região passíveis de mitigação da “pegada de lixo” e destino eficiente de madeira ilegal apreendida por órgãos ambientais, para uso em construção imersa no ambiente insular. A utilização de estratégias sustentáveis como os tetos e superfícies verdes potencializam a redução da carga térmica nos horários de alta incidência da radiação solar em regiões de baixas latitudes, como na APA da ilha do Combú. A unidade pedagógica proposta se integra ao lugar, permitindo ventilação cruzada permanente, bem como de ventilação forçada para os períodos mais críticos do dia e do ano, além da proteção das fachadas com dispositivos solares e sombreamentos A preocupação com o conforto ambiental e o reaproveitamento de materiais, potencializa a indicação da proposta de construção bioclimática na Amazônia brasileira.

Scalable Fabrication of Biophotoelectrodes by Means of Automated Airbrush Spray-Coating.

The fabrication and electrochemical evaluation of transparent photoelectrodes consisting of Photosystem I (PSI) or Photosystem II (PSII) is described, which are embedded and electrically wired by a redox polymer. The fabrication process is performed by an automated airbrush-type spray coating system, which ensures controlled and scalable electrode preparation. As proof of concept, electrodes with a surface area of up to 25 cm2 were prepared. The macro-porous structure of the indium tin oxide electrodes allows a high loading of the photoactive protein complexes leading to enhanced photocurrents, which are essential for potentially technologically relevant solar-powered devices. In addition, we show that unpurified crude PSII extracts, which can be provided in comparatively high yields for electrode modification, are suitable for photoelectrode fabrication with comparable photocurrent densities.