Search results for: solar fuels

Authors: Dimassi Wissem

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In this work, we investigate the effect of combination between the porous silicon (PS) layer passivized with Lithium Bromide (LiBr) and grooving of grain boundaries (GB) in multi crystalline silicon. The grain boundaries were grooved in order to reduce the area of these highly recombining regions. Using optimized conditions, grooved GB's enable deep phosphorus diffusion and deep metallic contacts. We have evaluated the effects of LiBr on the surface properties of porous silicon on the performance of silicon solar cells. The results show a significant improvement of the internal quantum efficiency, which is strongly related to the photo-generated current. We have also shown a reduction of the surface recombination velocity and an improvement of the diffusion length after the LiBr process. As a result, the I–V characteristics under the dark and AM1.5 illumination were improved. It was also observed a reduction of the GB recombination velocity, which was deduced from light-beam-induced-current (LBIC) measurements. Such grooving in multi crystalline silicon enables passivization of GB-related defects. These results are discussed and compared to solar cells based on untreated multi crystalline silicon wafers.

Keywords: Multicrystalline silicon, LiBr, porous silicon, passivation

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Authors: A. Adelhafidhi, I. M. Babaghayou, S. F. Chabira, M. Sebaa

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This study deals with the photodegradation of unformulated polyethylene films for greenhouse covering. The UV range of solar light appears as the most deleterious factor of plastic degradation in outdoor exposure. The reasons of this photosensitivity are structural defects which are light-absorbing. The use of FTIR as an investigation tool has revealed that the material reacts with surrounding oxygen via a photooxidation process. Although the photochemical process is quite complex, it appears through this study than crosslinking and chain scissions are the most important events taking place during aging These two key reactions change irremediably the average molecular weight affecting thus drastically the mechanical properties and reducing, in the same way, the service lifetime of the films.

Keywords: polyethylene, films, unformulated, FTIR, ageing

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Authors: Paolo Magnata

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The energy market in the Philippines remains to have one of the highest electricity rates in the region averaging at US$0.16/kWh (PHP6.89/kWh), excluding VAT, as opposed to the overall energy market average of US$0.13/kWh. The movement towards renewable energy, specifically solar energy, will pose as an expensive one with the country’s energy sector providing Feed-in-Tariff rates as high as US$0.17/kWh (PHP8.69/kWh) for solar energy power plants. Increasing the share of renewables at the current state of the energy regulatory background would yield a three-fold increase in residential electricity bills. The issue lies in the uniform charge that consumers bear regardless of where the electricity is sourced resulting in rates that only consider costs and not the consumers. But if they are given the option to choose where their electricity comes from, a number of consumers may potentially choose economically costlier sources of electricity due to higher levels of utility coupled with the willingness to pay of consuming environmentally-friendly sourced electricity. A contingent valuation survey was conducted to determine their willingness-to-pay for solar energy on a sample that was representative of Metro Manila to elicit their willingness-to-pay and a Single Bounded Dichotomous Choice and Double Bounded Dichotomous Choice analysis was used to estimate the amount they were willing to pay. The results showed that Metro Manila residents are willing to pay a premium on top of their current electricity bill amounting to US$5.71 (PHP268.42) – US$9.26 (PHP435.37) per month which is approximately 0.97% - 1.29% of their monthly household income. It was also discovered that besides higher income of households, a higher level of self-perceived knowledge on environmental awareness significantly affected the likelihood of a consumer to pay the premium. Shifting towards renewable energy is an expensive move not only for the government because of high capital investment but also to consumers; however, the Green Energy Option (a policy mechanism which gives consumers the option to decide where their electricity comes from) can potentially balance the shift of the economic burden by transitioning from a uniformly charged electricity rate to equitably charging consumers based on their willingness to pay for renewably sourced energy.

Keywords: contingent valuation, dichotomous choice, Philippines, solar energy

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Authors: Rodrigo I. Ullauri, Santiago E. Tinajero, Omar O. Ramos, Paola R. Quintana

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The increase of CO₂ emissions in the atmosphere and its impact on climate change is a global concern. The transportation sector is a significant consumer of fossil fuels and contributes significantly to greenhouse gas emissions. The current challenge is to find ways to reduce the use of fossil fuels in transportation. In Ecuador, where 92% of electricity is generated from clean sources, the concept of e-mobility is considered an attractive alternative to address the challenge of sustainable mobility. The proposal is to migrate from combustion-powered vehicles to electric vehicles in the electric companies of Ecuador, using a methodology to standardize criteria, determine specific requirements, contrast technical characteristics, and estimate emission reductions. The results showed that there are three categories of vehicles that have electric counterparts suitable for performing activities under certain operation parameters inherent to current technology limitations but with a significant contribution to the reduction of annual CO₂ emissions.

Keywords: climate change, electro mobility, energy, sustainable transportation

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Authors: Louise Ödlund, Danica Djuric Ilic

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Sustainable development includes many challenges related to energy use, such as (1) developing flexibility on the demand side of the electricity systems due to an increased share of intermittent electricity sources (e.g., wind and solar power), (2) overcoming economic challenges related to an increased share of renewable energy in the transport sector, (3) increasing efficiency of the biomass use, (4) increasing utilization of industrial excess heat (e.g., approximately two thirds of the energy currently used in EU is lost in the form of excess and waste heat). The European Commission has been recognized DH technology as of essential importance to reach sustainability. Flexibility in the fuel mix, and possibilities of industrial waste heat utilization, combined heat, and power (CHP) production and energy recovery through waste incineration, are only some of the benefits which characterize DH technology. The aim of this study is to provide an overview of the possible business strategies which would enable DH to have an important role in future sustainable energy systems. The methodology used in this study is a systematic literature review. The study includes a systematic approach where DH is seen as a part of an integrated system that consists of transport , industrial-, and electricity sectors as well. The DH technology can play a decisive role in overcoming the sustainability challenges related to our energy use. The introduction of biofuels in the transport sector can be facilitated by integrating biofuel and DH production in local DH systems. This would enable the development of local biofuel supply chains and reduce biofuel production costs. In this way, DH can also promote the development of biofuel production technologies that are not yet developed. Converting energy for running the industrial processes from fossil fuels and electricity to DH (above all biomass and waste-based DH) and delivering excess heat from industrial processes to the local DH systems would make the industry less dependent on fossil fuels and fossil fuel-based electricity, as well as the increasing energy efficiency of the industrial sector and reduce production costs. The electricity sector would also benefit from these measures. Reducing the electricity use in the industry sector while at the same time increasing the CHP production in the local DH systems would (1) replace fossil-based electricity production with electricity in biomass- or waste-fueled CHP plants and reduce the capacity requirements from the national electricity grid (i.e., it would reduce the pressure on the bottlenecks in the grid). Furthermore, by operating their central controlled heat pumps and CHP plants depending on the intermittent electricity production variation, the DH companies may enable an increased share of intermittent electricity production in the national electricity grid.

Keywords: energy system, district heating, sustainable business strategies, sustainable development

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Authors: Hend Mesbah, Yehia Youssef, Ibrahim Hassan, Shaaban Nosier, Ahmed El-Shazly, Ahmed Helal

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The problem of drinking water shortage is becoming more crucial nowadays as a result of the increased demand due to the population growth and the rise in the standard living. In recent years, desalination using electrodialysis powered by solar energy (PV-ED) is being widely used to help provide treated water and reduce the scarcity in water supply. In the present study, a water desalination laboratory scale ED cell with a fixed bed circulation system was designed, developed, and tested. The effect of three parameters (namely, cell voltage , flowrate, and salt concentration) on the removal percentage of salt ions was studied. The cell voltage was adjusted at 3 , 4 and 6 V. A flow rate of 5, 10, and 20 ml/s and an initial salt concentration of 2000, 5000, and 7000 ppm were investigated. The maximum salt percentage removal obtained was 52.5% at the lowest initial concentration (2000 ppm) and at the highest cell voltage (6 V). There was no significant effect of the flow rate on the removal percentage. A model of PV module has also been developed to calculate the dimensions of a solar cell based on the amount of energy consumed and it was calculated from the Overall ED cell voltage.

Keywords: desalination, electrodialysis, solar desalination, photovoltaic electrodialysis

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Authors: Ali Reza Ghaffari, Hassan Saghi

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Given the limitation of fossil resources to supply energy to buildings, recent years have seen a revival of interest in new technologies that produce the energy using new forms of energy in many developed countries. In this research, first the potentials of new energies in Iran are discussed and then based on case studies undertaken in a building in Tehran, the effects of utilizing new solar energy technology for supplying the energy of buildings are investigated. Then, by analyzing the data recorded over a four-year period, the technical performance of this system is investigated. According to the experimental operation plan, this system requires an auxiliary heating circuit for continuous operation over a year. Also, in the economic analysis, real conditions are considered and the results are recorded based on long-term data. Considering the purchase and commissioning building, supplementary energy consumption, etc. a comparison is drawn between the costs of using a solar water heater in a residential unit with the energy costs of a similar unit equipped with a conventional gas water heater. Given the current price of energy, using a solar water heater in the country will not economical, but considering the global energy prices, this system will have a return on investment after 4.5 years. It also produces 81% less pollution and saves about $21.5 on environmental pollution cleanup.

Keywords: energy supply, new energies, new technologies, buildings

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Authors: Marinela Miclau, Melinda Vajda, Nicolae Miclau, Daniel Ursu

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Characterized by a simple structure, easy and low cost fabrication, the dye-sensitized solar cell (DSSC) attracted the interest of the scientific community as an attractive alternative of conventional Si-based solar cells and thin-film solar cells. Over the past 20 years, the main efforts have attempted to enhance the efficiency of n-type DSSCs, the highest efficiency record of 14.30% was achieved using the co-sensitization of two metal-free organic dyes and Co (II/III) tris(phenanthroline)-based redox electrolyte. In the last years, the development of the efficient p-type DSSC has become a research focus owing to the fact that the concept of tandem solar cell was proposed as the solution to increase the power conversion efficiency. A promising alternative for the photocathodes of p-type DSSC, cuprous (Cu2O) and cupric (CuO) oxides have been investigated because of its nontoxic nature, low cost, high natural abundance, a good absorption coefficient for visible light and a higher dielectric constant than NiO. In case of p-type DSSC based on copper oxides with I3-/I- as redox mediator, the highest conversion efficiency of 0.42% (Cu2O) and 0.03% (CuO) has achieved. Towards the increase in the performance, we have fabricated and analyzed the performance of p-type DSSC prepared with the binder-free porous Cu2O photocathodes. Porous thin film could be an attractive alternative for DSSC because of their large surface areas which enable the efficient absorption of the dyes and light. We propose a simple and one-step hydrothermal method for the preparation of porous Cu2O thin film using copper substrate, cupric acetate and ethyl cellulose. The cubic structure of Cu2O has been determined by X-ray diffraction (XRD) and porous morphology of thin film was emphasized by Scanning Electron Microscope Inspect S (SEM). Optical and Mott-Schottky measurements attest of the high quality of the Cu2O thin film. The binder-free porous Cu2O photocathode has confirmed the excellent photovoltaic properties, the best value reported for p-type DSSC (1%) in similar conditions being reached.

Keywords: cuprous oxide, dye-sensitized solar cell, hydrothermal method, porous photocathode

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Authors: Manish Khanra, Shashank Prabhu

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The decarbonization of hard-to-abate sectors is currently high on the agenda in the EU and its member states, as these sectors have substantial shares in overall GHG emissions while it is facing serious challenges to decarbonize. In particular, the aviation sector accounts for 2.8% of global anthropogenic CO₂ emissions. These emissions are anticipated to grow dramatically unless immediate mitigating efforts are implemented. Hydrogen and its derivatives based on renewable electricity can have a key role in the transition towards CO₂-neutral flights. The substantial shares of energy carriers in the form of drop-in fuel, direct combustion and Hydrogen-to-Electric are promising in most scenarios towards 2050. For creating appropriate policies to ramp up the production and utilisation of hydrogen commodities in the German aviation sector, a detailed analysis of the spatial distribution of supply-demand sites is essential. The objective of this research work is to assess the demand for hydrogen-based alternative fuels in the German aviation sector to achieve the perceived goal of the ‘Net Zero’ scenario by 2050. Here, the analysis of the technological pathways for the production and utilisation of these fuels in various aircraft options is conducted for reaching mitigation targets. Our method is based on data-driven bottom-up assessment, considering production and demand sites and their spatial distribution. The resulting energy demand and its spatial distribution with consideration of technology diffusion lead to a possible transition pathway of the aviation sector to meet short-term and long-term mitigation targets. Additionally, to achieve mitigation targets in this sector, costs and policy aspects are discussed, which would support decision-makers from airline industries, policymakers and the producers of energy commodities.

Keywords: the aviation sector, hard-to-abate sectors, hydrogen demand, alternative fuels, technological pathways, data-driven approach

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Authors: Sheam-Chyun Lin, Wei-Kai Chen, Hung-Cheng Yen, Yung-Jen Cheng, Yu-Cheng Chen

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Result from the constant dwindle in natural resources, the alternative way to reduce the costs in our daily life would be urgent to be found in the near future. As the ancient technique based on the theory of solar chimney since roman times, the double-skin façade are simply composed of two large glass panels in purpose of daylighting and also natural ventilation in the daytime. Double-skin façade is generally installed on the exterior side of buildings as function as the window, so there’s always a huge amount of passive solar energy the façade would receive to induce the airflow every sunny day. Therefore this article imposes a domestic double-skin window for residential usage and attempts to improve the volume flow rate inside the cavity between the panels by the frame geometry design, the installation of outlet guide plate and the solar energy collection system. Note that the numerical analyses are applied to investigate the characteristics of flow field, and the boundary conditions in the simulation are totally based on the practical experiment of the original prototype. Then we redesign the prototype from the knowledge of the numerical results and fluid dynamic theory, and later the experiments of modified prototype will be conducted to verify the simulation results. The velocities at the inlet of each case are increase by 5%, 45% and 15% from the experimental data, and also the numerical simulation results reported 20% improvement in volume flow rate both for the frame geometry design and installation of outlet guide plate.

Keywords: solar energy, double-skin façades, thermal buoyancy, fluid machinery

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Authors: Ife Elegbeleye, Nnditshedzeni Eric, Regina Maphanga, Femi Elegbeleye, Femi Agunbiade

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The global potential of other renewable energy sources such as wind, hydroelectric, bio-mass, and geothermal is estimated to be approximately 13 %, with hydroelectricity constituting a larger percentage. Sunlight provides by far the largest of all carbon-neutral energy sources. More energy from the sunlight strikes the Earth in one hour (4.3 × 1020 J) than all the energy consumed on the planet in a year (4.1 × 1020 J), hence, solar energy remains the most abundant clean, renewable energy resources for mankind. Photovoltaic (PV) devices such as silicon solar cells, dye sensitized solar cells are utilized for harnessing solar energy. Polyene-diphenylaniline organic molecules are important sets of molecules that has stirred many research interest as photosensitizers in TiO₂ semiconductor-based dye sensitized solar cells (DSSCs). The advantages of organic dye molecule over metal-based complexes are higher extinction coefficient, moderate cost, good environmental compatibility, and electrochemical properties. The polyene-diphenylaniline organic dyes with basic configuration of donor-π-acceptor are affordable, easy to synthesize and possess chemical structures that can easily be modified to optimize their photocatalytic and spectral properties. The enormous interest in polyene-diphenylaniline dyes as photosensitizers is due to their fascinating spectral properties which include visible light to near infra-red-light absorption. In this work, density functional theory approach via GPAW software, Avogadro and ASE were employed to study the effect of methoxy functionalized group on the spectral properties of polyene-diphenylaniline dyes and their photons absorbing characteristics in the visible region to near infrared region of the solar spectrum. Our results showed that the two-phenyl based complexes D5 and D7 exhibits maximum absorption peaks at 750 nm and 850 nm, while D9 and D11 with methoxy group shows maximum absorption peak at 800 nm and 900 nm respectively. The highest absorption wavelength is notable for D9 and D11 containing additional polyene and methoxy groups. Also, D9 and D11 chromophores with the methoxy group shows lower energy gap of 0.98 and 0.85 respectively than the corresponding D5 and D7 dyes complexes with energy gap of 1.32 and 1.08. The analysis of their electron injection kinetics ∆Ginject into the band gap of TiO₂ shows that D9 and D11 with the methoxy group has higher electron injection kinetics of -2.070 and -2.030 than the corresponding polyene-diphenylaniline complexes without the addition of polyene group with ∆Ginject values of -2.820 and -2.130 respectively. Our findings suggest that the addition of functionalized group as an extension of the organic complexes results in higher light harvesting efficiencies and bathochromic shift of the absorption spectra to higher wavelength which suggest higher current densities and open circuit voltage in DSSCs. The study suggests that the photocatalytic properties of organic chromophores/complexes with donor-π-acceptor configuration can be enhanced by the addition of functionalized groups.

Keywords: renewable energy resource, solar energy, dye sensitized solar cells, polyene-diphenylaniline organic chromophores

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Authors: B. Bouadjemi, S. Bentata, T. Lantri, Souidi Amel, W.Bensaali, A. Zitouni, Z. Aziz

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We performed first-principle calculations, the full-potential linearized augmented plane wave (FP-LAPW) method is used to calculate structural, optoelectronic and magnetic properties of cubic halide perovskites CsPbX3 (X= F,I). We employed for this study the GGA approach and for exchange is modeled using the modified Becke-Johnson (mBJ) potential to predicting the accurate band gap of these materials. The optical properties (namely: the real and imaginary parts of dielectric functions, optical conductivities and absorption coefficient absorption make this halide perovskites promising materials for solar cells applications.

Keywords: halide perovskites, mBJ, solar cells, FP-LAPW, optoelectronic properties, absorption coefficient

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Authors: K. Mondal, S. Talapatra, M. Terrones, S. Pokhrel, C. Frizzel, B. Sumpter, V. Meunier, A. L. Elias

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Worldwide energy independence is reliant on the ability to leverage locally available resources for fuel production. Recently, syngas produced through gasification of carbonaceous materials provided a gateway to a host of processes for the production of various chemicals including transportation fuels. The basis of the production of gasoline and diesel-like fuels is the Fischer Tropsch Synthesis (FTS) process: A catalyzed chemical reaction that converts a mixture of carbon monoxide (CO) and hydrogen (H₂) into long chain hydrocarbons. Until now, it has been argued that only transition metal catalysts (usually Co or Fe) are active toward the CO hydrogenation and subsequent chain growth in the presence of hydrogen. In this paper, we demonstrate that carbon nanotube (CNT) surfaces are also capable of hydro-deoxygenating CO and producing long chain hydrocarbons similar to that obtained through the FTS but with orders of magnitude higher conversion efficiencies than the present state-of-the-art FTS catalysts. We have used advanced experimental tools such as XPS and microscopy techniques to characterize CNTs and identify C-O functional groups as the active sites for the enhanced catalytic activity. Furthermore, we have conducted quantum Density Functional Theory (DFT) calculations to confirm that C-O groups (inherent on CNT surfaces) could indeed be catalytically active towards reduction of CO with H₂, and capable of sustaining chain growth. The DFT calculations have shown that the kinetically and thermodynamically feasible route for CO insertion and hydro-deoxygenation are different from that on transition metal catalysts. Experiments on a continuous flow tubular reactor with various nearly metal-free CNTs have been carried out and the products have been analyzed. CNTs functionalized by various methods were evaluated under different conditions. Reactor tests revealed that the hydrogen pre-treatment reduced the activity of the catalysts to negligible levels. Without the pretreatment, the activity for CO conversion as found to be 7 µmol CO/g CNT/s. The O-functionalized samples showed very activities greater than 85 µmol CO/g CNT/s with nearly 100% conversion. Analyses show that CO hydro-deoxygenation occurred at the C-O/O-H functional groups. It was found that while the products were similar to FT products, differences in selectivities were observed which, in turn, was a result of a different catalytic mechanism. These findings now open a new paradigm for CNT-based hydrogenation catalysts and constitute a defining point for obtaining clean, earth abundant, alternative fuels through the use of efficient and renewable catalyst.

Keywords: CNT, CO Hydrodeoxygenation, DFT, liquid fuels, XPS, XTL

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Authors: R. Akbari, M. A. Ehyaei, R. Shahi Shavvon

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Nowadays, solar energy is used for energy purposes such as the use of thermal energy for domestic, industrial and power applications, as well as the conversion of the sunlight into electricity by photovoltaic cells. In this study, the thermodynamic simulation of the solar Rankin cycle with phase change material (paraffin) was first studied. Then energy and exergy analyses were performed. For optimization, a single and multi-objective genetic optimization algorithm to maximize thermal and exergy efficiency was used. The parameters discussed in this paper included the effects of input pressure on turbines, input mass flow to turbines, the surface of converters and collector angles on thermal and exergy efficiency. In the organic Rankin cycle, where solar energy is used as input energy, the fluid selection is considered as a necessary factor to achieve reliable and efficient operation. Therefore, silicon oil is selected for a high-temperature cycle and water for a low-temperature cycle as an operating fluid. The results showed that increasing the mass flow to turbines 1 and 2 would increase thermal efficiency, while it reduces and increases the exergy efficiency in turbines 1 and 2, respectively. Increasing the inlet pressure to the turbine 1 decreases the thermal and exergy efficiency, and increasing the inlet pressure to the turbine 2 increases the thermal efficiency and exergy efficiency. Also, increasing the angle of the collector increased thermal efficiency and exergy. The thermal efficiency of the system was 22.3% which improves to 33.2 and 27.2% in single-objective and multi-objective optimization, respectively. Also, the exergy efficiency of the system was 1.33% which has been improved to 1.719 and 1.529% in single-objective and multi-objective optimization, respectively. These results showed that the thermal and exergy efficiency in a single-objective optimization is greater than the multi-objective optimization.

Keywords: exergy analysis, genetic algorithm, rankine cycle, single and multi-objective function

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Authors: Saad Odeh

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Thermal performance is considered to be a key measure in building sustainability. One of the technologies used in the current building sustainable design is the rooftop solar PV power generators. The application of this type of technology has expanded vastly during the last five years in many countries. This paper studies the effect of roof shading developed by the solar PV panels on dwellings’ thermal performance. The analysis in this work is performed by using two types of packages: “AccuRate Sustainability” for rating the energy efficiency of residential building design, and “PVSYST” for the solar PV power system design. The former package is used to calculate the annual heating and cooling load, and the later package is used to evaluate the power production from the roof top PV system. The analysis correlates the electrical energy generated from the PV panels to the change in the heating and cooling load due to roof shading. Different roof orientation, roof inclination, roof insulation, as well as PV panel area are considered in this study. The analysis shows that the drop in energy efficiency due to the shaded area of the roof by PV panels is negligible compared to the energy generated by these panels.

Keywords: PV panel, thermal performance, roof shading, energy efficiency

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Authors: Khouloud Safa Azoud, Süleyman Baştürk

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In the pursuit of cleaner and more sustainable urban environments, advanced technologies play a critical role in evolving sanitation systems. This paper presents two distinct advancements in automated cleaning machines designed to improve urban sanitation. The first advancement is a semi-automatic road surface cleaning machine that integrates human labor with solar energy to enhance environmental sustainability and adaptability, especially in regions with limited access to electricity. By reducing carbon emissions and increasing operational efficiency, this approach offers significant potential for urban sanitation enhancement. The second advancement is a multifunctional semi-automatic street cleaning machine equipped with a camera, Arduino programming, and GPS for an autonomous operation aimed at addressing cost barriers in developing countries. Prioritizing low energy consumption and cost-effectiveness, this machine provides versatile cleaning solutions adaptable to various environmental conditions. By integrating solar energy with autonomous operating systems and careful design, these developments represent substantial progress in sustainable urban sanitation, particularly in developing regions.

Keywords: automated cleaning machines, solar energy integration, operational efficiency, urban sanitation systems

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Authors: Allouache Nadia

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Solid adsorption cooling machines have been extensively studied recently. They constitute very attractive solutions recover important amount of industrial waste heat medium temperature and to use renewable energy sources such as solar energy. The development of the technology of these machines can be carried out by experimental studies and by mathematical modelisation. This last method allows saving time and money because it is suppler to use to simulate the variation of different parameters. The adsorption cooling machines consist essentially of an evaporator, a condenser and a reactor (object of this work) containing a porous medium, which is in our case the activated carbon reacting by adsorption with ammoniac. The principle can be described as follows: When the adsorbent (at temperature T) is in exclusive contact with vapour of adsorbate (at pressure P), an amount of adsorbate is trapped inside the micro-pores in an almost liquid state. This adsorbed mass m, is a function of T and P according to a divariant equilibrium m=f (T,P). Moreover, at constant pressure, m decreases as T increases, and at constant adsorbed mass P increases with T. This makes it possible to imagine an ideal refrigerating cycle consisting of a period of heating/desorption/condensation followed by a period of cooling/adsorption/evaporation. Effect of key parameters on the machine performances are analysed and discussed.

Keywords: activated carbon-ammoniac pair, effect of key parameters, numerical modeling, solar cooling machine

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Authors: Aleksandra Boldyreva, Alexander Golubnichiy, Artem Abakumov

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Various perovskite materials have surprisingly high resistance towards high-energy electrons, protons, and hard ionization, such as X-rays and gamma-rays. Superior radiation hardness makes a family of perovskite semiconductors an attractive candidate for single- and multijunction solar cells for the space environment and as X-ray and gamma-ray detectors. One of the methods to study the radiation hardness of different materials is by exposing them to gamma photons with high energies (above 500 keV) Herein, we have explored the recombination dynamics and defect concentration of a mixed cation mixed halide perovskite Cs0.17FA0.83PbI1.8Br1.2 with 1.74 eV bandgap after exposure to a gamma-ray source (2.5 Gy/min). We performed an advanced STEM EDX analysis to reveal different types of defects formed during gamma exposure. It was found that 10 kGy dose results in significant improvement of perovskite crystallinity and homogeneous distribution of I ions. While the absorber layer withstood gamma exposure, the hole transport layer (PTAA) as well as indium tin oxide (ITO) were significantly damaged, which increased the interface recombination rate and reduction of fill factor in solar cells. Thus, STEM analysis is a powerful technique that can reveal defects formed by gamma exposure in perovskite solar cells. Methods: Data will be collected from perovskite solar cells (PSCs) and thin films exposed to gamma ionisator. For thin films 50 μL of the Cs0.17FA0.83PbI1.8Br1.2 solution in DMF was deposited (dynamically) at 3000 rpm followed by quenching with 100 μL of ethyl acetate (dropped 10 sec after perovskite precursor) applied at the same spin-coating frequency. The deposited Cs0.17FA0.83PbI1.8Br1.2 films were annealed for 10 min at 100 °C, which led to the development of a dark brown color. For the solar cells, 10% suspension of SnO2 nanoparticles (Alfa Aesar) was deposited at 4000 rpm, followed by annealing on air at 170 ˚C for 20 min. Next, samples were introduced into a nitrogen glovebox for the deposition of all remaining layers. Perovskite film was applied in the same way as in thin films described earlier. Solution of poly-triaryl amine PTAA (Sigma Aldrich) (4 mg in chlorobenzene) was applied at 1000 rpm atop of perovskite layer. Next, 30 nm of VOx was deposited atop the PTAA layer on the whole sample surface using the physical vapor deposition (PVD) technique. Silver electrodes (100 nm) were evaporated in a high vacuum (10-6 mbar) through a shadow mask, defining the active area of each device as ~0.16 cm2. The prepared samples (thin films and solar cells) were packed in Al lamination foil inside the argon glove box. The set of samples consisted of 6 thin films and 6 solar cells, which were exposed to 6, 10, and 21 kGy (2 samples per dose) with 137Cs gamma-ray source (E = 662 keV) with a dose rate of 2.5 Gy/min. The exposed samples will be studied on a focused ion beam (FIB) on a dual-beam scanning electron microscope from ThermoFisher, the Helios G4 Plasma FIB Uxe, operating with a xenon plasma.

Keywords: perovskite solar cells, transmission electron microscopy, radiation hardness, gamma irradiation

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Authors: Henry Gonzalo Acurio Flores, Alvaro Nicolas Corral Naveda, Juan Francisco Fonseca Palacios

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In Ecuador, subventions on fossil fuels for the road transportation sector have always been part of its economy throughout time, mainly because of demagogy and populism from political leaders. It is clearly seen that the government cannot maintain the subsidies anymore due to its commercial balance and its general state budget; subsidies are a key barrier to implementing the use of cleaner technologies. However, during the last few months, the elimination of subsidies has been done gradually with the purpose of reaching international prices. It is expected that with this measure, the population will opt for other means of transportation, and in a certain way, it will promote the use of private electric vehicles and public, e.g., taxis and buses (urban transport). Considering the three main elements of sustainable development, an analysis of the social, economic, and environmental impacts of eliminating subsidies will be generated at the country level. To achieve this, four scenarios will be developed in order to determine how the subsidies will contribute to the promotion of electro-mobility. 1) A Business as Usual BAU scenario; 2) the introduction of 10 000 electric vehicles by 2025; 3) the introduction of 100 000 electric vehicles by 2030; 4) the introduction of 750 000 electric vehicles by 2040 (for all the scenarios buses, taxis, lightweight duty vehicles, and private vehicles will be introduced, as it is established in the National Electro Mobility Strategy for Ecuador). The Low Emissions Analysis Platform (LEAP) will be used, and it will be suitable to determine the cost for the government in terms of importing derivatives for fossil fuels and the cost of electricity to power the electric fleet that can be changed. The elimination of subventions generates fiscal resources for the state that can be used to develop other kinds of projects that will benefit Ecuadorian society. It will definitely change the energy matrix, and it will provide energy security for the country; it will be an opportunity for the government to incentivize a greater introduction of renewable energies, e.g., solar, wind, and geothermal. At the same time, it will also reduce greenhouse gas emissions (GHG) from the transportation sector, considering its mitigation potential, which as a result, will ameliorate the inhabitant quality of life by improving the quality of air, therefore reducing respiratory diseases associated with exhaust emissions, consequently, achieving sustainability, the Sustainable Development Goals (SDGs), and complying with the agreements established in the Paris Agreement COP 21 in 2015. Electro mobility in Latin America and the Caribbean can only be achieved by the implementation of the right policies at the central government, which need to be accompanied by a National Urban Mobility Policy (NUMP) and can encompass a greater vision to develop holistic, sustainable transport systems at local governments.

Keywords: electro mobility, energy, policy, sustainable transportation

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Authors: S. V. Kuznetsov, M. N. Mayakova, V. Yu. Proydakova, V. V. Pavlov, A. S. Nizamutdinov, O. A. Morozov, V. V. Voronov, P. P. Fedorov

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Increase in the share of electricity received by conversion of solar energy results in the reduction of the industrial impact on the environment from the use of the hydrocarbon energy sources. One way to increase said share is to improve the efficiency of solar energy conversion in silicon-based solar panels. Such efficiency increase can be achieved by transferring energy from sunlight-insensitive areas of work of silicon solar panels to the area of their photoresistivity. To achieve this goal, a transition to new luminescent materials with the high quantum yield of luminescence is necessary. Improvement in the quantum yield can be achieved by quantum cutting, which allows obtaining a quantum yield of down conversion of more than 150% due to the splitting of high-energy photons of the UV spectral range into lower-energy photons of the visible and near infrared spectral ranges. The goal of present work is to test approach of excitation through sensibilization of 4f-4f fluorescence of Yb3+ by various RE ions absorbing in UV and Vis spectral ranges. One of promising materials for quantum cutting luminophores are fluorides. In our investigation we have developed synthesis of nano- and submicron powders of calcium fluoride and strontium doped with rare-earth elements (Yb: Ce, Yb: Pr, Yb: Eu) of controlled dimensions and shape by co-precipitation from water solution technique. We have used Ca(NO3)2*4H2O, Sr(NO3)2, HF, NH4F as precursors. After initial solutions of nitrates were prepared they have been mixed with fluorine containing solution by dropwise manner. According to XRD data, the synthesis resulted in single phase samples with fluorite structure. By means of SEM measurements, we have confirmed spherical morphology and have determined sizes of particles (50-100 nm after synthesis and 150-300 nm after calcination). Temperature of calcination appeared to be 600°C. We have investigated the spectral-kinetic characteristics of above mentioned compounds. Here the diffuse reflection and laser induced fluorescence spectra of Yb3+ ions excited at around 4f-4f and 4f-5d transitions of Pr3+, Eu3+ and Ce3+ ions in the synthesized powders are reported. The investigation of down conversion luminescence capability of synthesized compounds included measurements of fluorescence decays and quantum yield of 2F5/2-2F7/2 fluorescence of Yb3+ ions as function of Yb3+ and sensitizer contents. An optimal chemical composition of CaF2-YbF3- LnF3 (Ln=Ce, Eu, Pr), SrF2-YbF3-LnF3 (Ln=Ce, Eu, Pr) micro- and nano- powders according to criteria of maximal IR fluorescence yield is proposed. We suppose that investigated materials are prospective in solar panels improvement applications. Work was supported by Russian Science Foundation grant #17-73- 20352.

Keywords: solar cell, fluorides, down-conversion luminescence, maximum quantum yield

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Authors: Venkatesan Annadurai, Kannan Ethirajalu, Anu Roshini Ramakrishnan

Abstract:

Copper oxide (CuO) and zinc oxide (ZnO) based coaxial (CuO-ZnO nanorods) heterojunction has been the interest of various research communities for solar cells, light emitting diodes (LEDs) and photodetectors applications. Copper oxide (CuO) is a p-type material with the band gap of 1.5 eV and it is considered to be an attractive absorber material in solar cells applications due to its high absorption coefficient and long minority carrier diffusion length. Similarly, n-type ZnO nanorods possess many attractive advantages over thin films such as, the light trapping ability and photosensitivity owing to the presence of oxygen related hole-traps at the surface. Moreover, the abundant availability, non-toxicity, and inexpensiveness of these materials make them suitable for potentially cheap, large area, and stable photovoltaic applications. However, the efficiency of the CuO-ZnO nanorods heterojunction based devices is greatly affected by interface defects which generally lead to the poor performance. In spite of having much potential, not much work has been carried out to understand the interface quality and transport mechanism involved across the CuO-ZnO nanorods heterojunction. Therefore, a detailed investigation of CuO-ZnO heterojunction is needed to understand the interface which affects its photovoltaic performance. Herein, we have fabricated the CuO-ZnO nanorods based heterojunction by simple hydrothermal and electrodeposition technique and investigated its interface quality by carrying out temperature (300 –10 K) dependent current-voltage (I-V) measurements under dark and illumination of visible light. Activation energies extracted from the temperature dependent I-V characteristics reveals that recombination and tunneling mechanism across the interfacial barrier plays a significant role in the current flow.

Keywords: heterojunction, electrical transport, nanorods, solar cells

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Authors: Harmel Meriem

Abstract:

The optoelectronic properties and high power conversion efficiency make lead halide perovskites ideal material for solar cell applications. However, the toxic nature of lead and the instability of organic cation are the two key challenges in the emerging perovskite solar cells. To overcome these challenges, we present our study about finding potential alternatives to lead in the form of A2BX6 perovskite using the first principles DFT-based calculations. The highly accurate modified Becke Johnson (mBJ) and hybrid functional (HSE06) have been used to investigate the Main Document Click here to view linked References to optoelectronic and thermoelectric properties of A2PdBr6 (A = K, Rb, and Cs) perovskite. The results indicate that different A-cations in A2PdBr6 can significantly alter their electronic and optical properties. Calculated band structures indicate semiconducting nature, with band gap values of 1.84, 1.53, and 1.54 eV for K2PdBr6, Rb2PdBr6, and Cs2PdBr6, respectively. We find strong optical absorption in the visible region with small effective masses for A2PdBr6. The ideal band gap and optimum light absorption suggest Rb2PdBr6 and Cs2PdBr6 potential candidates for the light absorption layer in perovskite solar cells. Additionally.

Keywords: soler cell, double perovskite, optoelectronic properties, ab-inotio study

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Authors: Bing-Shun Huang, Hung-Ju Chiu, Wen-Kai Hsieh, Hsiu-Chuan Lin, Ming-Lung Hung

Abstract:

Taiwan's solar photovoltaic target in 2025 is 20 GW, of which the fish-electricity symbiosis target is 4 GW. In the future, many solar photovoltaic installations may cause local environmental or social impacts. Therefore, the Taiwan government inspects the fish-electricity symbiosis to reduce the impact of solar photovoltaics on the local environment or society. This stuy takes the symbiosis of fishery and electricity in Kaohsiung City as an example to explore Taiwan's environmental and social inspection practices. It mainly analyzes the two aspects of environmental ecology and social economy. The results show that the environmental inspection is mainly through site surveys, ecological information mapping, on-site interviews, and public consultation meetings. Social inspection mainly includes document analysis, on-site interviews, site surveys, expert discussions, and public consultations to identify possible local problems. Although the government had recognized the local issues, the future status may also change. It is recommended that future photoelectric companies should reconfirm the current situation of development sites when applying for the installation and propose countermeasures to solve the problem.

Keywords: taiwan, fish-electricity symbiosis, environment, society, inspection

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Authors: Fatma Khaled, Khaoula Hidouri, Bechir Chaouachi

Abstract:

Desalination using solar energy coupled with membrane techniques such as vacuum membrane distillation (VMD) is considered as an interesting alternative for the production of pure water. During this work, a developed model of a polytetrafluoroethylene (PTFE) hollow fiber membrane module of a VMD unit of seawater was carried out. This simulation leads to establishing a comparison between the effects of two different equations of the vaporization latent heat on the membrane surface temperature and on the unit productivity. Besides, in order to study the effect of putting membrane modules in series on the outlet fluid temperature and on the productivity of the process, a simulation was executed.

Keywords: vacuum membrane distillation, membrane module, membrane temperature, productivity

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Authors: A. I. Al-Bassam, A. M. El-Nggar

Abstract:

Polycrystalline Cu In I-x GaxSe2 thin films have been fabricated. Some physical properties such as lattice parameters, crystal structure and microstructure of Cu In I-x GaxSe2 were determined using X-ray diffractometry and scanning electron microscopy. X-ray diffraction analysis showed that the films with x ≥ 0.5 have a chalcopyrite structure and the films with x ≤ 0.5 have a zinc blende structure. The lattice parameters were found to vary linearly with composition over a wide range from x = 0 to x =1.0. The variation of lattice parameters with composition was found to obey Vegard's law. The variation of the c/a with composition was also linear. The quality of a wide range of Cu In I-xGaxSe2 thin film absorbers from CuInSe to CuGaSe was evaluated by Photoluminescence (PL) measurements.

Keywords: grain size, polycrystalline, solar cells, lattice parameters

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Authors: K. A. D. D. Kuruppu, R. M. De Silva, K. M. N. De Silva

Abstract:

This research work was based on developing a solar responsive aircraft window panel which can be used as a self-cleaning surface and also a surface which degrade Volatile Organic compounds (VOC) available in the aircraft cabin areas. Further, this surface has the potential of harvesting energy from Solar. The transparent inorganic nano sol solution was prepared. The obtained sol solution was characterized using X-ray diffraction, Particle size analyzer and FT-IR. The existing nano material which shows the similar characteristics was also used to compare the efficiencies with the newly prepared nano sol. Nano sol solution was coated on cleaned four aircraft window pieces separately using a spin coater machine. The existing nano material was dissolved and prepared a solution having the similar concentration as nano sol solution. Pre-cleaned four aircraft window pieces were coated with this solution and the rest cleaned four aircraft window pieces were considered as control samples. The control samples were uncoated from anything. All the window pieces were allowed to dry at room temperature. All the twelve aircraft window pieces were uniform in all the factors other than the type of coating. The surface morphologies of the samples were analyzed using SEM. The photocatalytic degradation of VOC was determined after incorporating gas of Toluene to each sample followed by the analysis done by UV-VIS spectroscopy. The self- cleaning capabilities were analyzed after adding of several types of stains on the window pieces. The self-cleaning property of each sample was analyzed using UV-VIS spectroscopy. The highest photocatalytic degradation of Volatile Organic compound and the highest photocatalytic degradation of stains were obtained for the samples which were coated by the nano sol solution. Therefore, the experimental results clearly show that there is a potential of using this nano sol in aircraft window pieces which favors the self-cleaning property as well as efficient photocatalytic degradation of VOC gases. This will ensure safer environment inside aircraft cabins.

Keywords: aircraft, nano, smart windows, solar

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Authors: Mannika Garg, N. Srinivas Murthy, Sunish Nair

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TeamIndus is only Indian team participated in the Google Lunar X Prize (GLXP). GLXP is an incentive prize space competition which is organized by the XPrize Foundation and sponsored by Google. The main objective of the mission is to soft land a rover on the moon surface, travel minimum displacement of 500 meters and transmit HD and NRT videos and images to the Earth. Team Indus is designing a Lunar Lander which carries Rover with it and deliver onto the surface of the moon with a soft landing. For lander to survive throughout the mission, energy is required to operate all attitude control sensors, actuators, heaters and other necessary components. Photovoltaic solar array systems are the most common and primary source of power generation for any spacecraft. The scope of this paper is to provide a system-level approach for designing the solar array systems of the lander to generate required power to accomplish the mission. For this mission, the direction of design effort is to higher efficiency, high reliability and high specific power. Towards this approach, highly efficient multi-junction cells have been considered. The design is influenced by other constraints also like; mission profile, chosen spacecraft attitude, overall lander configuration, cost effectiveness and sizing requirements. This paper also addresses the various solar array design challenges such as operating temperature, shadowing, radiation environment and mission life and strategy of supporting required power levels (peak and average). The challenge to generate sufficient power at the time of surface touchdown, due to low sun elevation (El) and azimuth (Az) angle which depends on Lunar landing site, has also been showcased in this paper. To achieve this goal, energy balance analysis has been carried out to study the impact of the above-mentioned factors and to meet the requirements and has been discussed in this paper.

Keywords: energy balance analysis, multi junction solar cells, photovoltaic, reliability, spacecraft attitude

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Authors: Nelson Ponce Jr., Jonas R. Gazoli, Alessandro Sete, Roberto M. G. Velásquez, Valério L. Borges, Moacir A. S. de Andrade

Abstract:

The search for increased efficiency in generation systems has been of great importance in recent years to reduce the impact of greenhouse gas emissions and global warming. For clean energy sources, such as the generation systems that use concentrated solar power technology, this efficiency improvement impacts a lower investment per kW, improving the project’s viability. For the specific case of parabolic trough solar concentrators, their performance is strongly linked to their geometric precision of assembly and the individual efficiencies of their main components, such as parabolic mirrors and receiver tubes. Thus, for accurate efficiency analysis, it should be conducted empirically, looking for mounting and operating conditions like those observed in the field. The Brazilian power generation and distribution company Eletrobras Furnas, through the R&D program of the National Agency of Electrical Energy, has developed a plant for testing parabolic trough concentrators located in Aparecida de Goiânia, in the state of Goiás, Brazil. The main objective of this test plant is the characterization of the prototype concentrator that is being developed by the company itself in partnership with Eudora Energia, seeking to optimize it to obtain the same or better efficiency than the concentrators of this type already known commercially. This test plant is a closed pipe system where a pump circulates a heat transfer fluid, also calledHTF, in the concentrator that is being characterized. A flow meter and two temperature transmitters, installed at the inlet and outlet of the concentrator, record the parameters necessary to know the power absorbed by the system and then calculate its efficiency based on the direct solar irradiation available during the test period. After the HTF gains heat in the concentrator, it flows through heat exchangers that allow the acquired energy to be dissipated into the ambient. The goal is to keep the concentrator inlet temperature constant throughout the desired test period. The developed plant performs the tests in an autonomous way, where the operator must enter the HTF flow rate in the control system, the desired concentrator inlet temperature, and the test time. This paper presents the methodology employed for design and operation, as well as the instrumentation needed for the development of a parabolic trough test plant, being a guideline for standardization facilities.

Keywords: parabolic trough, concentrated solar power, CSP, solar power, test plant, energy efficiency, performance characterization, renewable energy

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Authors: Virender Singh Gurau, Akash Deep, Sarbjot S. Sandhu

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Vegetable oils are produced from numerous oil seed crops. While all vegetable oils have high energy content, most require some processing to assure safe use in internal combustion engines. Some of these oils already have been evaluated as substitutes for diesel fuels. In the present research work Bitter Apricot kernel oil was employed as a feedstock for the production of biodiesel. The physicochemical properties of the Bitter Apricot kernel oil methyl ester were investigated as per ASTM D6751. From the series of engine testing, it is concluded that the brake thermal efficiency (BTE) with biodiesel blend was little lower than that of diesel. BSEC is slightly higher for Bitter apricot kernel oil methyl ester blends than neat diesel. For biodiesel blends, CO emission was lower than diesel fuel as B 20 reduced CO emissions by 18.75%. Approximately 11% increase in NOx emission was observed with 20% biodiesel blend. It is observed that HC emissions tend to decrease for biodiesel based fuels and Smoke opacity was found lower for biodiesel blends in comparison to diesel fuel.

Keywords: biodiesel, transesterification, bitter apricot kernel oil, performance and emission testing

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Authors: Vivek Garg, Brajendra S. Sengar, Gaurav Siddharth, Nisheka Anadkat, Amitesh Kumar, Shailendra Kumar, Shaibal Mukherjee

Abstract:

CuInGaSe (CIGSe) is the dominant thin film solar cell technology. The band alignment of Buffer/CIGSe interface is one of the most crucial parameters for solar cell performance. In this article, the valence band offset (VBOff) and conduction band offset (CBOff) values of Cu(In0.70Ga0.30)Se/ 1 at.% Ga: Mg0.25Zn0.75O (GMZO) heterojunction, grown by dual ion beam sputtering system (DIBS), are calculated to understand the carrier transport mechanism at the heterojunction for the realization of all sputtered buffer-less solar cells. To determine the valence band offset (VBOff), ∆E_V at GMZO/CIGSe heterojunction interface, the standard method based on core-level photoemission is utilized. The value of ∆E_V can be evaluated by considering common core-level peaks. In our study, the values of (Valence band onset)VBOn, obtained by linear extrapolation method for GMZO and CIGSe films are calculated to be 2.86 and 0.76 eV. In the UPS spectra peak positions of Se 3d is observed in UPS spectra at 54.82 and 54.7 eV for CIGSe film and GMZO/CIGSe interface respectively, while the peak position of Mg 2p is observed at 50.09 and 50.12 eV for GMZO and GMZO/CIGSe interface respectively. The optical band gap of CIGSe and GMZO are obtained from absorption spectra procured from spectroscopic ellipsometry are 1.26 and 3.84 eV respectively. The calculated average values of ∆E_v and ∆E_C are estimated to be 2.37 and 0.21 eV, respectively, at room temperature. The calculated positive conduction band offset termed as a spike at the absorber junction is the required criterion for the high-efficiency solar cells for the efficient charge extraction from the junction. So we can conclude that the above study confirms GMZO thin films grown by the dual ion beam sputtering system are the suitable candidate for the CIGSe thin films based ultra-thin buffer-less solar cells. We investigated the band-offset properties at the GMZO/CIGSe heterojunction to verify the suitability of the GMZO for the realization of the buffer-less solar cells. The calculated average values of ∆E_V and ∆E_C are estimated to be 2.37 and 0.21 eV, respectively, at room temperature. The calculated positive conduction band offset termed as a spike at the absorber junction is the required criterion for the high-efficiency solar cells for the efficient charge extraction from the junction. So we can conclude that the above study confirms GMZO thin films grown by the dual ion beam sputtering system are the suitable candidate for the CIGSe thin films based ultra-thin buffer-less solar cells. Acknowledgment: We are thankful to DIBS, EDX, and XRD facility equipped at Sophisticated Instrument Centre (SIC) at IIT Indore. The authors B.S.S and A.K acknowledge CSIR and V.G acknowledge UGC, India for their fellowships. B.S.S is thankful to DST and IUSSTF for BASE Internship Award. Prof. Shaibal Mukherjee is thankful to DST and IUSSTF for BASE Fellowship and MEITY YFRF award. This work is partially supported by DAE BRNS, DST CERI, and DST-RFBR Project under India-Russia Programme of Cooperation in Science and Technology. We are thankful to Mukul Gupta for SIMS facility equipped at UGC-DAE Indore.

Keywords: CIGSe, DIBS, GMZO, solar cells, UPS

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