• Energy Research
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Abstract Gold nanoparticles (Au-NPs) seeded plasmonic nanofluids (PNFs) have shown promising results in overall performance enhancement of direct absorption solar collector (DASC) due to localized surface plasmon resonance (LSPR) effect. For the work presented here, Au-NPs were synthesized by the wet chemical method and were utilized to prepare plasmonic nanofluid. The surface plasmon resonance peak of Au-NPs was observed at 531 nm using UV–Visible spectrophotometer study. The testing for performance enhancement of gold plasmonic nanofluid (GPNF) laden DASC so far is limited to laboratory scale setups or simulation studies. Considering the dearth of outdoor experimental studies, an attempt has been made in the present study to evaluate the thermal performance of Au-NPs (∼40 nm) based nanofluid (∼0.0002 wt%) in full scale DASC. The experiments have been performed at different flow rates under clear sky outdoor conditions in winter season at Jalandhar, India. The maximum collector outlet temperature was measured to be 55 °C with GPNF which is about 7 °C higher than the maximum outlet temperature obtained with de-ionized water as working fluid. Thermal efficiency with GPNF is about 33% higher than de-ionized water at the optimal flow rate of 0.030 kg/s.

Electronic waste (e-waste) with an annual growth rate of 3-5% is one of the fastest-growing waste streams. The unregulated accumulation and improper recycling can cause grave hazards to human beings and the environment. On the contrary, e-waste can be considered as a secondary source of metals and energy due to its high metal content and polymeric material. Thus, the present study demonstrates technology for the metallic fraction recovery and the production of valuable gases from e-waste. The process involves pyrolysis at a temperature range of 200 °C-600 °C in a fixed bed setup for 10-60 min. Under optimized operating conditions, 35 wt% combustible gases and 60 wt% solid product were obtained at a pyrolysis temperature of 400 °C in 20 min. The gaseous product consisted of CH4, H2, CO and CO2, having the heating value 28 MJ/kg whereas, the solid product is a mixture of metals and other solid residue material. Treatment of the solid product using an ultrasonication process resulted in around 90 wt% recovery of metallic fraction, thereby leaving behind solid residue. Moreover, the transfer of precious metals (Au, Ag, Pd and Pt) was nearly 100% to the metallic fraction. This process combines mild temperature pyrolysis and ultrasonication process to provide a solution for efficient management of e-waste, metallic fraction recovery and valuable gases production.

Abstract Heat transfer and pressure drop characteristics of minichannel heat sink are analysed experimentally and numerically (two-phase mixture model) by using hybrid nanofluids. Minichannel heat sink consists of 9 parallel rectangular shaped minichannels having depth of 3 mm and width of 1 mm. The Al2O3–TiO2 hybrid nanofluid with nanoparticles volume concentration of 0.1% with different nanoparticle mixture ratios (10:0 to 0:10) has been used as coolant to analyze the effect of volume flow rate (0.1 to 0.5 LPM), Reynolds number (90

This study aims to investigate the kinetic compensation effects (KCE) and gain insights into the mechanisms, during gasification of Loy Yang brown coal char with steam, in an in-situ fluidized bed gasification operation for two-particle size ranges (106–150 and 180–212 µm). The instantaneous rate of char gasification and CO, CO₂, and H₂ formation was measured by continuous monitoring of product gas composition through a quadrupole mass spectrometer. Gasification of the smaller particle size range (106–150 µm) in kinetics-controlled regime shows less importance of char-catalyzed element on the WGS reaction, as revealed by the apparent activation energy and apparent frequency factor for CO and CO₂ formation. However, the study of kinetic parameters of char consumption on gasification using coal char with larger particle sizes (180–212 µm) indicated the limitations of intraparticle diffusion. That potentially affects the CO₂ formation by catalyzed WGS through re-adsorption of CO on catalytic char surface at a higher conversion level (> 0.3) as revealed by the difference in the extent of KCE for CO and CO₂ formation. The difference in the extent of KCE for char consumption and H₂ formation for bigger particles indicates the intraparticle diffusion limitations also appear to affect the route of H₂ formation, i.e., significantly produced through adsorption on catalytical active site with less involving the carbon active sites on char surface.

This paper aims at comparing different optimisation techniques, for finding the charge and discharge schedule of a battery energy storage system (BESS) in a grid-connected microgrid. One of the techniques, based on linear programming (LP), targets to reduce the energy intake from the grid and the diesel generator present in the microgrid. The other technique based on dynamic programming (DP-I), aims towards developing a day-ahead schedule which ensures minimum operating cost of the microgrid throughout the day. The paper also proposes a modified charge/discharge cycle constrained dynamic programming technique with an objective similar to DP-I, but it also aims towards bringing down the number of charge/discharge cycles in a planning day. The effects of the battery schedules prepared from all the three strategies on the lifetime time of the battery, are also compared. This work uses an 192-hour model of aggregated seasonal data of solar, wind, and load demand, along with an aging model in predicting the lifetime of the battery. The proposed work is demonstrated in a 33-bus distribution network.

Abstract Analytical model for temperature dependent electrical and thermal efficiency for four different photovoltaic-thermal configurations integrated on identical prototype test cells namely; Case 1: glass to glass photovoltaic with duct integrated on a test cell, Case 2: glass to glass photovoltaic without duct integrated on a test cell, Case 3: glass to tedlar photovoltaic with duct integrated on a test cell and, Case 4: glass to tedlar photovoltaic without duct integrated on a test cell is developed in absence of ambient air exchange and experimentally validated in New Delhi’s winter and summer seasonal conditions. The glass to glass photovoltaic module gives better performance in both electrical as well as thermal aspects, and gives daily average ηm 11.91% and 11.96% in summer whereas in winter, it gives 12.65% and 12.70% for case 1 and 2 respectively. Similarly, daily average ηith was 32.77% and 25.44% for case 1 and 2 respectively in winter. Ducted cases 1 and 3 have higher ηm and ηith due to the large heat dissipation capacity. Constant temperature mode operations inside test cells were attained, and we also discuss the effect of varying mass flow rate on electrical efficiency for ducted cases. Further, the yearly-round electrical, thermal, overall thermal, and overall exergy efficiencies for case 1 were found respectively 10.41%, 34.35%, 61.52% and 13.72% under typical New Delhi weather condition. The characteristic equations for all four cases were also been developed.

Abstract In this article, a novel analytical approach (named as zero bus load flow (ZBLF)) is proposed for DG placement to the distribution network under the scenario of known power injection from the utility/substation. The study is carried out for deferent load levels and for two different distribution networks (viz. 33- and 69-bus distribution networks). In this work, biomass (working at the power factor same as that of the load power factor) is considered as the DG source. From this study, it may be noticed that, by placing the DG at the selected bus, the active power loss of the network may be reduced even when the power supply from the utility grid is zero. In this paper, a combined approach of ZBLF and symbiotic organism search (SOS) has been proposed for the placement of multiple numbers of DGs for the scenario when the power supply from the utility/substation is known. Both the technical as well as the economic aspects of the DG placement for both the distribution networks are studied and presented in this research paper. DG placement using the proposed method also founds to be economical to the utility.

AbstractThe development of pseudocapacitive materials for energy‐oriented applications has stimulated considerable interest in recent years due to their high energy‐storing capacity with high power outputs. Nevertheless, the utilization of nanosized active materials in batteries leads to fast redox kinetics due to the improved surface area and short diffusion pathways, which shifts their electrochemical signatures from battery‐like to the pseudocapacitive‐like behavior. As a result, it becomes challenging to distinguish “pseudocapacitive” and “battery” materials. Such misconceptions have further impacted on the final device configurations. This Review is an earnest effort to clarify the confusion between the battery and pseudocapacitive materials by providing their true meanings and correct performance metrics. A method to distinguish battery‐type and pseudocapacitive materials using the electrochemical signatures and quantitative kinetics analysis is outlined. Taking solid‐state supercapacitors (SSCs, only polymer gel electrolytes) as an example, the distinction between asymmetric and hybrid supercapacitors is discussed. The state‐of‐the‐art progress in the engineering of active materials is summarized, which will guide for the development of real‐pseudocapacitive energy storage systems.