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Abstract The effective utilization of solar energy is a big challenge as global energy demand is increasing sharply. In this paper, we present the details of design of an extremely concentrated solar energy delivery system (ECoSEnDS) and its possible utilization in daylighting and sustainable wastewater treatment. The EcoSEnDS is made with double mirror based solar concentrator coupled with pure silica optical fiber bundle. This device is capable to deliver 96 suns concentrated sunlight in first stage of testing where efficiency of the primary mirror is 50%. This device can distribute light equivalent to 813 incandescent bulbs of 60 W or 149 LED bulbs of 15 W. Therefore, this device can be used as daylighting system in the building and underground car parking area. Using appropriate semiconductor nanophotocatalysts, this device can be used for sustainable rapid wastewater purification process. We have used BiVO4 nanoparticles for photocatalytic methylene blue degradation and the complete (100%) purification of methylene blue stained wastewater was achieved within one hour using only 7 suns concentrated sunlight. Therefore, the ECoSEnDS will open new technological aspects for sustainable fastest wastewater treatment process using solar energy.

Abstract Conventional jaggery making process utilizes the bagasse for boiling of sugar cane juice which releases pollutants into the atmosphere and high particulate matter from these emissions causes air pollution. In this article, solar powered jaggery industry with freeze pre-concentration is proposed with conventional and modified heating pans. The system performance, environmental impacts and economic feasibility were assessed by carrying out 4E (Energy-Exergy-Environment-Economic) analyses using the developed mathematical model. These systems were designed to produce 300 kg of jaggery per day when operated for 7.5 h in 3 batches with average solar direct normal irradation of 662 W/m2 and 343 °C. These systems are integrated with auxiliary heating for uninterrupted production in the absence of sunlight. These systems can mitigate nearly 2015.95 to 3062.15 tons of CO2 emission during its 25 years of lifespan under 300 clear days of operation each year. Jaggery produced by this technique is rich in its colour and completely safe for human consumption as no artificial clarificants are used. Amount invested in these systems can be recovered in a span of 12.03 to 13.45 years for jaggery selling price of USD.0.514/kg or INR.36/kg.

Abstract This study analyzes the environmental and economic feasibility of ethanol produced from sugarcane for use as a potential gasoline substitute in the Mexican transport sector from 2010 to 2030. One scenario was created by projecting the historical trend of energy demand assuming that a fraction of this demand is satisfied with ethanol produced from the cultivation of 2.9 million hectares of sugarcane. A life cycle study was performed according to the recommendations from the European Union Directive on Renewable Energies (that include direct land use change emissions) and was used to estimate life cycle Greenhouse gas (GHG) emissions. The method used by Fingerman et al. (2010) was adopted to estimate the water consumption. In the economic analysis, the production cost of ethanol was calculated, and a mitigation cost for carbon dioxide equivalent emissions was estimated. The potential for employment generation was also estimated. The results demonstrate that water use increases by 29.4 times and that the costs increase by 10,706 million USD with the alternative scenario. This scenario, however, has the potential to create 560,619 direct jobs. Furthermore, GHG mitigation is confirmed since the reference scenario resulted in GHG gasoline life cycle emissions of 78.7 kgCO2e/GJ while the alternative scenario resulted in Ethanol GHG emissions in the life cycle of 57.52 kgCO2e/GJ.

Abstract This study aims to stimulate the discussion on how to optimize a sustainable energy mix from an environmental perspective and how to apply existing renewable energy sources in the most efficient way. Ground-mounted photovoltaics (PV) and the maize–biogas-electricity route are compared with regard to their potential to mitigate environmental pressure, assuming that a given agricultural area is available for energy production. Existing life cycle assessment (LCA) studies are taken as a basis to analyse environmental impacts of those technologies in relation to conventional technology for power and heat generation. The life-cycle-wide mitigation potential per area used is calculated for the impact categories non-renewable energy input, green house gas (GHG) emissions, acidification and eutrophication. The environmental performance of each system depends on the scenario that is assumed for end energy use (electricity and heat supply have been contemplated). In all scenarios under consideration, PV turns out to be superior to biogas in almost all studied impact categories. Even when maize is used for electricity production in connection with very efficient heat usage, and reduced PV performance is assumed to account for intermittence, PV can still mitigate about four times the amount of green house gas emissions and non-renewable energy input compared to maize–biogas. Soil erosion, which can be entirely avoided with PV, exceeds soil renewal rates roughly 20-fold on maize fields. Regarding the overall Eco-indicator 99 (H) score under most favourable assumptions for the maize–biogas route, PV has still a more than 100% higher potential to mitigate environmental burden. At present, the key advantages of biogas are its price and its availability without intermittence. In the long run, and with respect to more efficient land use, biogas might preferably be produced from organic waste or manure, whereas PV should be integrated into buildings and infrastructures.

Abstract Microencapsulated n-octadecane with titanium dioxide (TiO2) shell was prepared by a sol–gel method in a nonaqueous oil-in-water (o/w) emulsion using a green solvent as the dispersion medium. The morphology, chemical structure, and crystalloid phase of the resultant microcapsules were determined by scanning electronic microscope (SEM), Fourier transformation infrared spectroscope (FT-IR), and X-ray diffractometer (XRD), respectively. The differential scanning calorimeter (DSC) and the thermogravimetric analyzer (TGA) were used to investigate the thermal properties and thermal stabilities of the samples. The resulting microcapsules presented spherical shape with average size of 2–5 μm. The results of FT-IR and XRD showed that n-octadecane was well microencapsulated in TiO2 shell. DSC and TGA results indicated that the samples exhibited good performance of storing and releasing the latent heat during phase-change cycles and high thermal reliability. The microencapsulation process in this study is simple, high-efficiency, and environmentally friendly. The microencapsulated n-octadecane with TiO2 shell will be a potential candidate material for thermal energy storage applied in the fields of solar energy storage, building energy conservation, air-conditioning systems, and waste heat recovery.

Abstract In this effort, 10 μm thick rear contact (RC) silicon–germanium (SiGe) based solar cell device has been discussed with SiC (20 nm)-based front surface passivation for the suppression of interface recombination as well as improvement of short circuit current density ( J SC ) and open-circuit voltage ( V OC ). The design principles presented here balance the electronic and photonic effects together and is a significant step to design highly efficient thin solar cells. Photo reflectance is significantly reduced in the UV/visible spectral region due to the presence of SiC. This results in external quantum efficiency (EQE) >90% in the spectrum range of 400–650 nm wavelength. Also, at wavelengths equivalent to 300 nm, SiC passivated device shows record EQE of 85%. The presence of SiC as a surface passivating layer shows enhanced surface characteristics in terms of reduced surface recombination and higher photon absorption rate. This results in 15.4% power conversion efficiency (PCE) under standard air mass 1.5 illuminations. Further, the proposed device has also been analyzed for concentrator photovoltaics (CPV) applications, resulting in 18.4% and 19.3% efficiencies at 1 W/cm 2 (10 suns, 27 °C) and 2 W/cm 2 (20 suns, 27 °C) respectively. Till date, the proposed design proves to be highly efficient in the sub 10 μm regime. All the simulations have been done using DEVEDIT and ATLAS device simulator

Abstract This article presents the experiences learned using micro-hydro power at the village level. Site evaluation procedure, financing methods, turbine fabrication, and site construction are discussed. Micro-hydro power provides a decentralized energy source for several of the energy-intensive tasks of villagers. Low-head, small volume hydro potential is common in the Zairian countryside. Often a potential site also serves as the village water source, hence it is located near potential beneficiaries of the power. Over the past three decades, a religous NGO in the Ubangi and Mongala Subregions of northwest Zaire has been developing this small hydro potential as part of its technology transfer and village development program. Local materials and knowledge are used as much as possible in construction. Experiences gained constructing a 370 kW hydro-electric site, as well as building water wheels for water pumping has led to the construction of micro-hydro sites using locally made cross-flow turbines. Four water wheel sites and six micro-hydro sites have been built. The hydropower is used to mill flour and hull coffee. One site also generates 220 V electricity, and two others have 12 V generation planned.

Abstract Between 1992 and 1994 a 200 kWp-rooftop programme to promote small grid-connected Photovoltaic (PV) systems was conducted in Austria. Within this programme about 100 PV systems with an average capacity of 2.28 kWp were installed. This paper investigates the socio-economic aspects of this programme and the prospects for a further dissemination of this technology. The major conclusions of this investigation are as follows: (1) The motives to invest in a PV system are: (i) environmental protection; (ii) an alternative to nuclear power; (iii) technical interest. Yet, it is also important that the public supports this purchase by means providing subsidies. (2) The purchase of a PV system leads to different changes in consumer behaviour. Consumers with low initial consumption increased their electricity demand slightly, while the majority of consumers with high initial electricity demand saved electricity. (3) The financial incentives in the programme were not optimally designed. With the same amount of total subsidies it would have been possible to promote more PV systems. (4) The key factors for a further dissemination of PV systems are: (i) financial incentives; (ii) a reduction of the investment costs; (iii) increase in reliability; (iv) distribution of information; (v) enhancement of environmental awareness.

Abstract Owing to the superior optoelectronic properties of perovskite materials, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been increased dramatically within several years, but the poor thermal, humidity, and light stability of these PSC devices hinders the progress to their practical application. We obtained an inspiration from two-dimensional (2D) Ruddlesden–Popper perovskite solar cells with good photovoltaic performance and placed the organic-inorganic hybrid perovskite layer inside two fully-inorganic CsPbI3 perovskite layers in the cubic α phase. The middle layer has lower stability than the two outer ones, which protect the middle layer by impeding the organic ions of the organic-inorganic hybrid perovskite middle layer from diffusing outside and causing damage to neighbor CTLs. Water molecules from air are also obstructed from reaching the hybrid perovskite layer. We used 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4) ionic liquid and 3-(decyldimethylammonio) propane-1-sulfonate (DDMAPS) and obtained phase-stable fully-inorganic α phase CsPbI3. The constructed PSCs have extremely high stabilities and high PCEs. After 1000 h of illumination under AM1.5 illumination in air at 60 °C (Humility: ~60%), PSCs with a sandwich structure of three perovskite layers maintain nearly all the original PCE of 21.32%, while those without that only remain 76.63%.