Terrestrial Solar Energy Research Articles

Symmetric engineered central cross-shaped broadband metamaterial absorber with high absorption and stability for solar sailing and solar energy applications

We propose a theoretical design and analysis of a broadband metamaterial absorber (MMA) with significant potential for solar sailing applications which is a method of spacecraft propulsion that usages the momentum of sunlight to propel a spacecraft through space. The absorber features a metal-dielectric-metal configuration with a tungsten (W) based resonator and ground plane, and a Silicon-dioxide (SiO₂) substrate. Addressing the critical need for materials that can efficiently harness solar radiation for propulsion in space, our design achieves an average absorption of 99.15 % over a broad spectrum from 250 nm to 1200 nm, covering the UV–Visible–NIR regions, with near-unity absorption peaks at 362 nm and 915.8 nm. It maintains high absorptions of 84.9 % and 86 % under transvers electric and transvers magnetic modes respectively, demonstrating excellent wide incident angle stability and polarization insensitivity due to its symmetric design. PCR values close to zero confirm its functionality as an absorber rather than a polarizer. The MMA shows minimal deformation across temperatures from 500 K to 1750 K and remains stable under various mechanical stresses, proving its durability and efficiency in space. Additionally, in solar thermophotovoltaic (STPV) systems, the MMA demonstrates high photothermal conversion efficiency (PTCE) over a wide temperature range (500 °C to 1500 °C) and different concentration factors. This dual functionality highlights its potential for both efficient space exploration and terrestrial solar energy harvesting, making it a versatile tool for future technological applications.

A constellation design for orbiting solar reflectors to enhance terrestrial solar energy

Orbiting solar reflectors (OSRs) are flat, thin and lightweight reflective structures that are proposed to enhance terrestrial solar energy generation by illuminating large terrestrial solar power plants locally around dawn/dusk and during night hours. The incorporation of OSRs into terrestrial energy systems may offset the daylight-only limitation of terrestrial solar energy. However, the quantity of solar energy delivered to the Earth’s surface remains low due to short duration of orbital passes and the low density of the reflected solar power due to large slant ranges. To compensate for these, this paper proposes a constellation of multiple reflectors in low-Earth orbit for scalable enhancement of the quantity of energy delivered. Circular near-polar orbits of 1000 km altitude in the terminator region are considered in a Walker-type constellation for a preliminary analysis. Starting from a simplified approach, the equations of Walker constellations describing the distribution of the reflectors are first modified by introducing a phasing parameter to ensure repeating pass-geometry over solar power farms. This approach allows for a single groundtrack optimisation to define the constellation, which was carried out by a genetic algorithm for single and two reflectors per orbit with an objective function defined as the total quantity of energy delivered per day, to existing and hypothetical solar power projects around the Earth. When full-scale constellations are considered with a number of reflectors, the quantity of solar energy delivered is substantial in the broader context of global terrestrial solar energy generation.

Soil moisture-constrained East Asian Monsoon meridional patterns over China from observations

As an internal forcing of the earth climate system, soil moisture (SM) significantly influences the water and energy cycle by controlling evapotranspiration and terrestrial solar energy. The current study used observed precipitation, remotely sensed SM, and reanalysis of atmosphere and land parameters to assess the East Asian Monsoon (EAM) precipitation variability due to meridional SM oscillations across China. A generalized linear method, namely coupled manifold technique (CMT) for assessing the reciprocal forcing between two climate fields and numerical simulations are applied to SM and EAM precipitation. We find that the EAM precipitation interannual variability between north and south China significantly correlates with SM meridional oscillation. The CMT results further showed that SM forcing has a significant (99% confidence) influence on the EAM precipitation explaining about 0.40 of the variance ratio in north and south China. The EAM and SM composite analysis show that the wetter (drier) north (south) oscillates the EAM precipitation over the north (south) of China and vice versa due to SM thermal controls. We then used control and sensitivity simulations with SM observations to further validate the findings implying that SM can potentially improve the interannual EAM forecast skills. The model results show that a wetter (drier) north (south) results in negative (positive) sensible heat (latent heat) anomalies that impact the boundary layer and propagate to change the meridional atmospheric heating profile. When positive (negative) SM anomalies exist over northern (southern) China, the zonal easterlies and extratropical westerlies move to north China causing above-normal precipitation that descends into southern China, suppressing subtropical westerlies and precipitation in southern China. On the contrary, a dry (wet) north (south) favors intensified subtropical westerlies and precipitation in southern China. The findings have dire implications for the water and energy cycle of the region in the projected wetting and drying patterns of the north (south).

Gamma distribution excess minority carrier concentration model for solar cell performance modeling

Concentrated photovoltaic (PV) technology represents a growing market in the field of terrestrial solar energy production. As the demand for renewable energy technologies increases, further importance is placed on the modeling, design, and simulation of these systems. Given the cultural shift toward energy awareness and conservation, several concentrated PV systems have been installed across the world. This research presents a new model for carrier concentration within a solar cell. The goal of this innovation is to facilitate the determination of the steady-state operating temperature as a function of the concentration factor for the optical part of the concentrated PV system, to calculate the optimum concentration that maximizes power output and efficiency. This model will be shown to produce a more realistic estimate of the current through a solar cell, which will enable further research into dynamic thermal modeling.

Future forecast of global land wind and light resources in the context of climate change

Based on the multi-model ensemble average results of the CMIP5 program, we predict the changes of global terrestrial wind and solar energy resources from 2020 to 2030 under different future climate change scenarios. The results show that the multi-mode ensemble average results have high confidence in the simulation of global wind and solar energy resources. Under different climate scenarios (RCPs), the changes in global terrestrial wind and solar energy resources in the next 2020-2030 (relative to 1986-2005) will have significant regional differences. Among them, wind resources in the Americas, Africa and Australia increased, while European wind-rich areas decreased; those in Asia (e.g., Northwest China and Central Asia) increased in RCP2.6, but decreased in RCP4.5 and RCP8.5. Global terrestrial solar energy resources are increasing in different RCPs scenarios in the future, especially in European solar energy-rich areas. Wind energy and solar energy resources on the global land have obvious seasonal variation characteristics, and the seasonal variation rate varies greatly in different regions. The change trend and change range of wind energy and solar energy resources in different rich areas are different. There are some differences in the RCPs scenario. It shows the complexity of future changes in wind and solar energy resources in response to global climate change.

Efficient Triplet-Triplet Annihilation Upconversion with an Anti-Stokes Shift of 1.08 eV Achieved by Chemically Tuning Sensitizers.

A series of Pt(II)-Schiff base complexes were synthesized as triplet sensitizers for the purpose of tuning the singlet and triplet energy levels so as to minimize energy loss during triplet-triplet annihilation (TTA) upconversion (UC). A deep-red to blue TTA-UC was achieved with an unprecedentedly large anti-Stokes shift of 1.08 eV. UC quantum yields of up to 21% (with a theoretical maximum efficiency of 50%) were observed in solution. The complexes also showed efficient UC emission in air-saturated hydrogels with a UC quantum yield up to 14.8%, which is much higher than the highest previously reported value. The low threshold excitation intensity provided by the present system offers promising potential for application in terrestrial solar energy conversion.

Continuous oscillation of a compact solar-pumped Cr, Nd-doped YAG ceramic rod laser for more than 6.5 h tracking the sun

Remaining key challenges for solar-pumped lasers (SPLs) to be applied for terrestrial solar energy utilization are (1) improvement of energy conversion efficiency and (2) ability of continuous laser oscillation during the day time. To address the latter challenge (2), a compact SPL employing a rigid 76.2 mm caliber paraboloidal mirror and a 10 mm-long, 1 mm diameter Cr, Nd-doped YAG ceramic rod was developed to realize more stable oscillation performance by introducing rapid cooling by free/natural air convection and increased mechanical stability during wind exposure in contrast to the conventional large solar pumped lasers (SPLs) employing typically a 2 m size conversing lens or mirror. Arrays of the compact SPLs could be used for harvesting sunlight across a large area. Outdoor, solar tracking experimentation with the compact SPL yielded continuous oscillation exceeding 6.5 h, improving upon previously determined maximum continuous oscillation times of 11 min. This is an indispensable experimental step if SPLs are to be applied to terrestrial solar energy utilization.

Comprehensive solar energy resource characterisation for an intricate Indian province

ABSTRACT The interception of solar radiation by earth’s surfaces is a function of their geometry and a determinant of their microclimatic interaction. Thus the design of a solar energy conversion system requires precise knowledge regarding the availability of solar irradiation and various solar geometrical parameters at the location of interest. Both weather conditions and geography of the location have an influence on solar radiation pattern and it is crucial to determine the patterns of solar radiation throughout the year as solar technologies heavily rely on solar climate characteristics. The present work evaluates the terrestrial solar energy resource characterisation for intricate north-east Indian province Tripura where solar resource is considered to be a promising alternative option to supply energy in remote areas. Both direct and indirect measured solar radiation data have been considered in the study for evaluation of solar geometrical factors and correlations.

Satellite solar wireless power transfer for baseload ground supply: clean energy for the future

Many factors are influencing the acceptability of energy technology. The transformation of the energy sector is looking for clean energy technology that is also suitable for baseload power generation. Terrestrial solar energy has many obstructions, so solar power from space without any hindrance has higher priority for adoption, and it is suitable for future energy continuous demand supply. As technology is advancing, the possibility of satellite solar-based power station is more than a science fiction now and is possible in the coming future. Microwave transmission with high beam efficiency is the key issue to be improved for the feasibility of satellite solar power station. Besides others, research should focus on the reduction of space segment’s components dimension and space vehicle dispatch cost. Concerning space segments, applying an optimized value of fractional power unit modules and assembling it for constant baseload power supply have economic advantages, as well as that the antenna size is also reduced. This work deals with system components size estimation and optimization for a selected 10-GW baseload power supply. Four case studies have been conducted considering the different unit sizes, and the system model is analyzed for suitable power unit selection.

Structural properties of sprayed CuInSSe thin films grown using different S/Se ionic ratios

We have grown nanocrystalline CuInSSe thin films on glass substrates using the spray pyrolysis technique at different S/Se ionic ratios 0.4 and 0.6. The CuInSSe films were co-deposited from aqueous solutions containing CuCl2, InCl3, thiourea and SeO2. The pH of the precursor solutions was kept at 10. Ethanolamine was used as an additive and the CuInSSe films were deposited at the constant temperature 300°C. The films were characterized by X-ray diffraction (XRD), and the results indicate that the films are single phase, polycrystalline having the chalcopyrite structure. The hot probe method indicates that the films are p-type in conductivity. Optical studies show that the optical band gap values are 1.25 eV and 1.36 eV for films grown from spray solutions having S/Se ionic ratios 0.4 and 0.6 respectively. The interesting result of this paper is that the optical band gap value (1.25 eV) is very close to the optimum band gap for terrestrial photovoltaic solar energy conversion. The Debye Scherrer formula applied to the XRD patterns show that the average crystallite size of the films is in the range 10 to 20 nm.

Infrared A radiation promotes survival of human melanocytes carrying ultraviolet radiation-induced DNA damage.

The link between solar radiation and melanoma is still elusive. Although infrared radiation (IR) accounts for over 50% of terrestrial solar energy, its influence on human skin is not well explored. There is increasing evidence that IR influences the expression patterns of several molecules independently of heat. A previous invivo study revealed that pretreatment with IR might promote the development of UVR-induced non-epithelial skin cancer and possibly of melanoma in mice. To expand on this, the aim of the present study was to evaluate the impact of IR on UVR-induced apoptosis and DNA repair in normal human epidermal melanocytes. The balance between these two effects is a key factor of malignant transformation. Human melanocytes were exposed to physiologic doses of IR and UVR. Compared to cells irradiated with UVR only, simultaneous exposure to IR significantly reduced the apoptotic rate. However, IR did not influence the repair of UVR-induced DNA damage. IR partly reversed the pro-apoptotic effects of UVR via modification of the expression and activity of proteins mainly of the extrinsic apoptotic pathway. In conclusion, IR enhances the survival of melanocytes carrying UVR-induced DNA damage and thereby might contribute to melanomagenesis.

Microwave-Assisted Solution–Liquid–Solid Synthesis of Single-Crystal Copper Indium Sulfide Nanowires

Chalcopyrite copper indium sulfide (CuInS2) is an important semiconductor with a bandgap optimal for terrestrial solar energy conversion. Building photovoltaic and microelectronic devices using one-dimensional CuInS2 nanowires can offer directional conduits for rapid and undisrupted charge transport. Currently, single-crystal CuInS2 nanowires can be prepared only using vapor-based methods. Here, we report, for the first time, the synthesis of single-crystal CuInS2 nanowires using a microwave-assisted solution–liquid–solid (MASLS) method. We show that CuInS2 nanowires with diameters of less than 10 nm can be prepared at a rapid rate of 33 nm s–1 to more than 10 μm long in less than 10 min, producing a high mass yield of 31%. We further show that the nanowires are free of structural defects and have a near-stoichiometric composition. The success of MASLS in preparing high-quality tertiary nanowires is explained by a eutectic growth mechanism involving an overheated alloy catalyst.

Probing dual mode emission of Eu3+ in garnet phosphor

Eu3+ doped and Eu3+, Yb3+ co-doped Gd3Ga5O12 phosphors have been developed by facile solid state reaction method which can be easily scaled-up in large quantity. The synthesis has been optimized to get a single phase material at 1300 °C. The phase and crystal parameters have been analyzed by using X-ray diffraction measurement. Photoluminescence excitation (monitored for the 5D0 → 7F1 transition of Eu3+) depicts that the active ion (Eu3+) can be excited through direct excitation into 4f band of Eu3+, through charge transfer band (Eu3+-O2−) excitation and also through the excitation into 8S7/2 → 6IJ intra f–f transition of Gd3+ ion, which significantly all together cover a broad excitation region in 200–420 nm. In addition, in the presence of Yb3+ ions, the emission is also achieved by near infrared excitation (976 nm), through a typical upconversion (UC) process. Thus, the material efficiently behaves as a dual mode emitting phosphor (emission is achieved both through normal fluorescence and through UC process). The conversion efficiency of silicon solar cells is only 15% of terrestrial solar energy for 200–400 nm region and also the sub-band gap energy (in infrared region) is lost as heat; therefore, this kind of dual mode phosphors may be used to overcome the above mentioned incomplete utilization of the solar spectrum and can open realm of new possibilities for energy harvesting.

20515 リニアモーター式ディスプレーサーを用いたスターリングエンジン : 電気アシストスターリングエンジンの宇宙利用に関する一提案(エネルギー・環境問題に対応するエンジン・燃料技術(3),OS.11 エネルギー・環境問題に対応するエンジン・燃料技術)

Linear motor displacer has been used mainly for Stirling refrigerator. Stirling engines having linear motor displacer have been hardly seen because of its low thermal efficiency. On the other hand, electro assisted Stirling engines such as Semi Free Piston types have a merit on the easy control of power. When the energy such as the terrestrial heat and solar energy exists unlimitedly, the easiness of the control of power will be given priority over the thermal efficiency. In the space environment, the solar energy is unlimitedly obtained and the clean engine which does not make the inner air of the space station or space colony polluted will be demanded. Therefore, the electro assisted Stirling engine will be effective against the space application. In this paper, linear motor displacer system is proposed for the electro assisted Stirling engine for the space application.

New routes to sustainable photovoltaics: evaluation of Cu2ZnSnS4 as an alternative absorber material

AbstractThin film heterojunction solar cells based on chalcopyrites such as Cu(In,Ga)Se2 have achieved impressive efficiencies. However concern about the long term sustainability of photovoltaics based on scarce or expensive raw materials has prompted the search for alternative absorber materials. In this work, films of the p‐type absorber Cu2ZnSnS4 (CZTS) were prepared by electroplating metallic precursors sequentially onto a molybdenum‐coated glass substrate followed by an nealing in a sulfur atmosphere. The polycrystalline CZTS films were characterized by photoelectrochemical methods, which showed films were p‐type with doping densities of the order of 1016 cm–3 and a band gap of 1.49 eV, close to the optimum value for terrestrial solar energy conversion. Preliminary results obtained for solar cells fabricated with this material are promising. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Towards sustainable materials for solar energy conversion: Preparation and photoelectrochemical characterization of Cu 2ZnSnS 4

The feasibility of a new fabrication route for films of the attractive solar absorber Cu 2ZnSnS 4 (CZTS) has been studied, consisting of electrodeposition of metallic precursors followed by annealing in sulfur vapour. Photoelectrochemical measurements using a Eu 3+ contact have been used to establish that the polycrystalline CZTS films are p-type with doping densities in the range (0.5–5) × 10 16 cm −3 and band gaps of 1.49 ± 0.01 eV, making them suitable for terrestrial solar energy conversion. It has been shown that a somewhat Cu-poor composition favours good optoelectronic properties.

Advanced technology paths to global climate stability: energy for a greenhouse planet.

Stabilizing the carbon dioxide-induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (approximately 10(13) watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission-free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non-primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development.

The expression of genes induced in melanocytes by exposure to 365-nm UVA: study by cDNA arrays and real-time quantitative RT-PCR

Ultraviolet A radiation (UVA; 320–400 nm) constitutes more than 90% of the terrestrial UV solar energy. This type of radiation generates reactive oxygen species and consequently induces DNA damage. UVA irradiation is now considered to be an important carcinogen agent especially in the development of melanoma. UVA radiation is known to activate several pathways in mammalian cells. We have used cDNA arrays to analyze differential gene expression in primary cultures of human melanocytes in response to 365-nm UVA. Among 588 genes studied, 11 were overexpressed. These genes included genes involved in cell cycle regulation (GADD45, CIP1/WAF1), in stress response (HSP70, HSP40, HSP86), in apoptosis (GADD153, tristetraproline) and genes encoding transcription factors (EGR-1, ETR-101, c-JUN, ATF4). This coordinate gene regulation was confirmed by real-time quantitative RT-PCR.

Plastic Solar Cells

Recent developments in conjugated-polymer-based photovoltaic elements are reviewed. The photophysics of such photoactive devices is based on the photo-induced charge transfer from donor-type semiconducting conjugated polymers to acceptor-type conjugated polymers or acceptor molecules such as Buckminsterfullerene, C60. This photo-induced charge transfer is reversible, ultrafast (within 100 fs) with a quantum efficiency approaching unity, and the charge-separated state is metastable (up to milliseconds at 80 K). Being similar to the first steps in natural photosynthesis, this photo-induced electron transfer leads to a number of potentially interesting applications, which include sensitization of the photoconductivity and photovoltaic phenomena. Examples of photovoltaic architectures are presented and their potential in terrestrial solar energy conversion discussed. Recent progress in the realization of improved photovoltaic elements with 3 % power conversion efficiency is reported.

15] Ultraviolet A- and singlet oxygen-induced mutation spectra

Publisher Summary Genetic stability is an important prerequisite for the maintenance of the integrity and functions of each cell. Several environmental agents, as well as endogenous sources, are known to play a significant role in the formation of DNA lesions. Most of these lesions are repaired, but a few may escape and can lead to mutagenesis during trans -lesion replication or to chromosomal aberrations, and, finally, to tumorigenesis or cell death. The causal relationship between solar ultraviolet (UV) radiation and carcinogenesis has been well established. UVB radiation (290-320 nm) causes the direct formation of DNA photoproducts and gives rise to mutations in proto-oncogenes and tumor suppressor genes that eventually lead to skin cancer. Genotoxicity of UVA radiation (320-400 nm), which represents more than 90% of the terrestrial UV solar energy, is most likely induced by indirect mechanisms. After UVA photon absorption by an unidentified endogenous photosensitizer, reactive oxygen species are generated that could react with DNA without further intermediates (type I photosensitized reaction) or via singlet oxygen (type II photosensitized reaction). The singlet oxygen appears to be an early intermediate of UVA cellular response, judging by its involvement in signal transduction and gene induction. It belongs to reactive oxygen species (ROS) that are ubiquitous oxidizing agents generated in all aerobic organisms, endogenously as byproducts of respiration and inflammatory response and also exogenously after exposure to a variety of agents. This chapter discusses data on DNA lesions, DNA repair, and mutation spectra, which characterize the genotoxic potential of both singlet oxygen and UVA radiation, essentially in mammalian species.