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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 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 This paper represents perovskite material based hybrid (ITO/ZnO-ZnMgO (nano)/PCBM/CH3NH3PbI3-xClx/PEDOT: PSS/C3-SAM/Ag) organic solar cell with high quantum and power conversion efficiency. Due to the insertion of 3-aminopropanoic acid as an ambipolar self-assembled monolayer (C3-SAM) and ZnO/ZnMgO layer carrier collection efficiency increases. An optical modified structure is proposed (through the modification of ZnO/ZnMgO layer) to increase the surface to volume ratio and enhance the photon collection efficiency. As a result, the Internal quantum efficiency (IQE) increases 83.2% to 91.7% fill factor (FF) changes from 77% to 85%, short circuit current density (Jsc) changes from 14.9 mA/cm2 to 21 mA/cm2, and overall solar cell efficiency increases from 9.17 to 14.7%.

Abstract Photovoltaics (PV) as a renewable source of energy has received renewed interest in the immediate provision of sustainable energy to meet market demand in recent years. A key challenge in clean energy research is to ensure that the technology not only provides a sustainable energy source during device operation, but is also environmentally sustainable during the manufacturing phase of the device lifecycle. Plasma sources have been conventionally employed in numerous surface nucleation and nanostructure growth processes due to highly controllable process parameters that enable precise control of material properties at the nanoscale. However, these processes usually employ toxic feedstock as a means to obtain favourable PV characteristics, such as nanotexturing. In this work, an inductively coupled plasma (ICP) system in a cascading cluster configuration setup was employed for fabrication of highly efficient nanotextured PV cells. A 2-step process was developed to use a high density N2 discharge for high density plasma immersion ion implantation (HD-PIII) in group V doping of c-Si samples for high quality junction formation. Subsequently, an Ar + H2 discharge was utilized for the simultaneous nanotexturing of the surface as well as passivation of surface defects through intense hydrogenation from the plasma generated radical flux. The resulting black silicon (b-Si) PV cells fabricated through this process typically have ultra-low reflectance of

Abstract Purification techniques like ozonization, chlorination and filtration have their own limitations of corresponding energy sources and harmful waste generation. However, heterogeneous photo catalysis is used for producing oxidative agent (hydroxyl radical) which has been used as an environmentally harmonious decontamination process. Such safe and low energy consumable photo catalytic system is required for purification of polluted water. Degradation of dyes is a standard method to check the photocatalytic activity of any type of photo catalyst. In this paper thioglycerol capped and uncapped ZnS nanoparticles are studied in detail for their photocatalytic activity and generation of electron hole pairs. Bromophenol blue, crystal violet and reactive red dyes were successfully photo reduced using ZnS nanoparticles after 3.0 h of irradiation. Since the photocatalytic activity depends on the generation of electron hole pairs and the existence of different phases, we have tried to correlate the optical and morphological studies with these results to understand the phenomenon of photocatalytic activity at nanoscale. Though the Ultra violet irradiation can efficiently degrade the dyes, naturally abundant solar radiation is also very effective in the mineralization of dyes. Hence, it may be a viable technique for the safe disposal of textile wastewater into the water streams.

Abstract In this work, effective treatment of RO reject and domestic sewage water in a single step using indigenously developed tilted solar distillation unit has been proposed. Behavior of the unit along with its characteristics, treated water quality, environmental benefits and economics has been reported based on experimental observations. Around, 4.79 and 4.48 L/d of treated water are produced by the unit at a thermal efficiency of 48.5% and 45.3% during RO reject and sewage water distillation, respectively. Suspended particles of re-circulated sewage water caused clogging of wick and affected tilted solar distillation unit’s performance and efficiency. Smooth operation of the unit is noticed during RO reject distillation. The proposed unit could prevent at least 23.73 tons of CO2, 158.54 kg of SO2 and 64.75 kg of NO emissions during its 20 Yr life span. Wick replacement frequency and interest rate have a signification impact on distillation unit’s treated water production cost. The proposed distillation unit’s treated water production cost is lower than basin solar stills reported in literatures. Treated water is clear, odor free and bacterial free. Physical properties and heavy metal concentrations of treated water are well within the standards for safe drinking water except BOD (Biological Oxygen Demand) and COD (Chemical Oxygen Demand) such that the treated water can be used for other domestic and irrigation purposes. The results obtained from this study confirm solar distillation as an effective and sustainable option for wastewater treatment.

Abstract Ternary polymer solar cells employing two polymers (P2, PTB7-Th) and one non-fullerene small molecule acceptor (Y6) were constructed using a conventional structure. The PTB7-Th, P2 and Y6 exhibit complementary absorption spectra therefore, the ternary blend consists of these three can maximize the photon harvesting efficiency which is advantageous to boost of short circuit current density of polymer solar cell. After the optimization of the weight ratios between the two donors and keeping constant the weight concentration of acceptor and following solvent vapor annealing in THF for 40 s, P2:PTB7-Th: Y6 (0.3:0.7:1.5) based polymer solar cells attained the power conversion efficiency of 15.46%, superior to that for polymer solar cells based on binary active layers i.e., P2:Y6 (12.62%) and PTB7-Th:Y6 (12.84%), respectively. The open-circuit voltage for the P2:PTB7-Th:Y6 is about 0.88 V which is in between the values for P2:Y6 (0.94 V) and PTB7-Th:Y6 (0.85 V), consistent with the different highest occupied molecular orbital energy level for P2 (−5.38 eV) and PTB7-Th (−5.27 eV). The enhancement in the short circuit current may be associated with the broader absorption profile of the ternary active layer relative to binary counterparts while the enhanced value of fill factor may be originated from the balanced charge transport, suppressed recombination, and faster charge extraction.