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The suspension of nanoparticles with common heat transfer fluids like Ethylene glycol and water yields nanofluid exhibits superior thermal properties than their host fluids. Ionic liquids have the potential to demonstrate remarkable thermophysical properties (especially thermal conductivity) that ordinary nanofluids cannot achieve. On the other hand, the quantity and structure of nanoparticles porosity affects the nanofluid’s thermal conductivity considerably. Various investigations have revealed the improved thermophysical characteristicts of Multiwalled Carbon nanotubes (MWCNTs) nanofluids containing common solvents or base fluids. However, only limited studies are available on the impact of thermal conductivity in Ionic liquid-based nanofluids (Ionanofluids) owing to their high cost and viscosity. Ultrasonication technique is employed in preparing the three different Ionanofluids containing 0.5 Wt.% via the two-step method to achieve a greater stability and thermal conductivity without utilizing surfactants. Experimental investigations are performed to boost the thermal conductivity of MWCNT/Propylene glycol nanofluid using 1,3-dimethyl imidazolium dimethyl phosphate [Mmim][DMP], 1-ethyl-3-methyl imidazolium octyl sulfate [Emim][OSO4] and 1-ethyl-3-methyl imidazolium diethyl phosphate [Emim][DEP] at a temperature ranging from 295 K to 355 K. The acquired results illustrated that the thermal conductivity of MWCNT Ionanofluids incorporated with [Mmim][DMP], [Emim][OSO4] and [Emim][DEP] increased by 37.5%, 5% and 2% respectively. This unique class of Ionanofluids shows incredible capacity for use in high temperature applications as conventional heat transfer fluids.

In this study, aqueous poly (ethylene) glycol (PEG)-based MXene nanoflakes dispersed nanofluids as a novel heat transfer fluid (HTF) with highly promising thermal and rheological properties were prepared. Synthesis of MXene (Ti3C2) flakes was conducted using wet chemistry etching method (lithium fluoride & HCL). Amphiphilic structure of poly (ethylene) glycol allows the dispersion of water and MXene nanoflakes appropriately. The studied nanofluids were prepared with mixing of 70 % of PEG with molecular weight of 400 and 30% of deionized (DI) water. The prepared aqueous PEG was mixed with Ti3C2 nanoflakes with two different loading concentrations of 0.05 and 0.1 wt.%. Thermal conductivity measurements of the prepared PEG/Water/MXene nanofluids were conducted using a Tempos thermal properties analyzer (METER group). KS-3 sensor was utilized for thermal conductivity measurements. Enhancements of thermal conductivity of the PEG/Water/MXene nanofluids (0.1 wt.%) were found ∼23-29% over aqueous PEG with the rising temperature from 25 to 45 °C. The high thermal conductivity values proved that this promising heat transfer fluid is dependent on temperature and loading concentrations of MXene nanoflakes in terms of thermal conduction performance. This high thermal conductivity might be due to the presence of extremely large basal plane of MXene sheets in aqueous PEG which can conduct heat through the MXene nanoflake’s basal plane. The viscosity of this nanofluid was measured using Rheometer Anton Paar (MCR92). Shear rate measurement as a function of temperature was conducted for all samples in three different individual temperatures (25, 50 and 85 °C). T-Ramp measurements were conducted within the rising temperature ranges from 25 to 85 °C. The promising results proved that aqueous PEG/Water/MXene nanofluids behave as Newtonian fluid. This finding is perceived for all three different investigated temperatures as well. It was observed that viscosity was decreased at elevated temperatures. The acquired viscosity values for aqueous PEG at the temperatures of 25, 50 and 85 °C were ∼35, ∼16 and ∼5 mPa.S respectively, which shows ∼85% decrease at temperature of 85 °C, over temperature of 25 °C. Similar trend was observed for PEG/Water/MXene nanofluids with loading concentration of 0.05 and 0.1 wt.%.

Methane reforming with the application of combined H2O and CO2 is appropriately known as bi-reforming of methane (BRM). The method is promising because it has potential to deliver an alternative energy source and is effective in mitigating greenhouse gases (GHGs). In this study, Ni-based catalyst with 5 wt% supported Al2O3 and various Ca (2–4 wt%) loadings were prepared by following the wetness impregnation method. Characterization techniques, including Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD), were applied to observe prepared catalysts' structural morphology and physicochemical properties. Based on XRD analysis, the CaO-4wt% catalyst exhibited higher crystallinity than the CaO-2wt% catalyst, enabling it to withstand greater forces and take longer to deteriorate. To improve the catalyst activity, CaO was added as a promoter that altered the contact between Ni and Al2O3 and modified the properties of the catalysts for an excellent activity. A fixed-bed continuous reactor with a feed ratio CH4: CO2: H2O of 3:1:2 at 1073 K was used to observe the catalysts performance. BRM catalytic reaction at 800 °C having Ni-4CaO/Al2O3 catalyst, proved greatly in converting CH4 and CO2 with 79.6% and 87.2% respectively during the 6 h reaction.

Heat dissipation of various electrical and electronic devices has been a significant concern in the current years of modernisation. Many researchers proved that a liquid-cooled microchannel heat sink (MCHS) is an effective way of removing high heat load. Due to ionic liquids� unique properties such as negligible volatility, non-flammability, high thermal stability, and ionic conductivity, this liquid is combined with nanofluids to synthesise a new class of potential fluids termed Ionanofluids (ionic liquid-based nanofluids). In this research, a numerical simulation of fluid flow and heat transfer characteristics of MWCNT (Multiwalled Carbon Nanotubes) based Ionanofluids as a coolant in a rectangular-shaped microchannel heat sink is analysed. The Two-step method is used for preparing the studied Ionanofluids consisting of 0.5 wt. of MWCNT nanoparticles ultra-sonicated with a mixture of propylene glycol and 1-Butyl-3-methylimidazolium chloride (BmimCl-ionic liquid) fluids. Copper micro channelled heat sink comprising 1 m channel height, 25 µm of channel diameter, and 0.7 m channel width is modelled and simulated with ANSYS-Fluent. The results showed that the heat transfer coefficient increases about 11.4% while the thermal resistance decreases about 15.18% by using the proposed ionanofluids with the concentration of 0.5 wt.% at Re=2000 compared with that of an MCHS with propylene glycol. Moreover, the pressure drop along the studied MCHS increased up to a maximum of 30 kPa for higher heat gradients. Ionanofluids decreased the thermal resistance and temperature difference between the heated surface of the MCHS and Ionanofluids inlet to a greater extent when validated with pure base fluid and previous studies. From the simulated results, a better cooling performance is observed with Ionanofluids compared to pure propylene glycol (PG) for the proposed microchannel heat sink. © The Authors 2020. Published by Penerbit UMP. This is an open access article under the CC BY license.

Fuel cell produces clean sources of energy and yielding can be improved using emerging material (MXene) in electrocatalysis performance in a fuel cell system. However, MXene in electrocatalysis area for fuel cell is not discovered yet. Therefore, the aim of this study is to enhance the direct methanol fuel cell (DMFC) electrocatalyst performance using combination of bimetallic PtRu and MXene. Optimization is carried out using response surface methodology (RSM). Composition of MXene, Nafion content and methanol concentration are used as factors (input) and current density is used as a response (output) for the optimization analysis. A cyclic voltammetry (CV) is used to measure the current density. RSM generates optimum factors with MXene composition 78.90 wt%, Nafion content 19.71 wt% and methanol concentration of 2.82M. The optimum response is predicted to be 186.59mA/mgPtRu. The validation test is carried out and the result shows that the average current density is 187.05mA/mgPtRu. PtRu/MXene electrocatalyst produces 2.34 times higher current density compared to PtRu/C commercial electrocatalyst. This indicates that MXene has high potential as a nanocatalyst for cleaner energy production through the fuel cell.

COVID‑19 pandemic, also known as the coronavirus pandemic, has spread rapidly across the globe since the end of 2019 and brought impressive changes in our life and living through partial or full lockdown and reduced anthropogenic activities. Hence, it is imperative to investigate the impacts and consequences of COVID-19 on global eco-system and environment. The present study accordingly addresses the impacts and consequences of COVID-19 by ten environmental indicators; viz., global warming (or greenhouse gas emission), stratospheric ozone depletion, ozone formation (on human health), fine particulate matter formation, smog, ionizing radiation, human carcinogenic toxicity, human non-carcinogenic toxicity, water resource consumption, and effect on human health. The overall study has been performed in agreement with the standard principle and guidelines of life cycle assessment. Worldwide changes in consumption of fossil fuels, viz., petroleum, coal and natural gas, as a result of COVID-19 pandemic, has been the core theme of the study. Outcomes from the study show that COVID-19 has been a ‘blessing in disguise’ for the global environment with most of the above-mentioned indicators declining by approximately 20-30% in 2020 in comparison to the 2019 level.

There are various analyses for a solar system with the dish Stirling technology. One of those analyses is the finite time thermodynamic analysis. By the finite time thermodynamic analysis, the total power of system can be obtained by calculating the process time. In this study, the convection and radiation heat transfer losses from collector surface, the conduction heat transfer between hot and cold cylinders and cold side heat exchanger have been considered. During this investigation, the four objective functions have been optimized simultaneously. These objective functions are included of the power, efficiency, entropy and economic factors. In addition to the four-objective optimization, three-objective, two-objective and single-objective optimizations have been done on the dish-Stirling model. In this study, the algorithm of MOPSO with post-expression of preferences is used for multi-objective optimizations while the Branch and Bound algorithm with Pre-expression of preferences is used for single-objective and multi-objective optimizations. In case of multi-objective optimizations with post-expression of preferences, Pareto optimal front are obtained, afterward by implementing the Fuzzy, LINMAP and TOPSIS decision making algorithms, the single optimum results can be achieved. At the end, the comparison of the results shows the benefits of MOPSO in optimizing dish Stirling finite time thermodynamic equations.

In this research work, MXene with a chemical formula of Ti3C2 is used for the first time with silicone oil to improve thermo-physical properties of MXene based silicone oil. This paper focuses on preparation, characterization, thermal properties, thermal stability and performance investigation of new class of silicone oil nanofluids induced with MXene in three different concentrations for a Concentrated Solar Photovoltaic Thermal (CPVT) collector. The thermal conductivity of the silicone oil-based MXene nanofluids is measured using a Transient Hot Bridge (THB) 500. Viscosity is measured using a Rheometer at various temperatures including 25, 50, 75, 100, and 125 degrees C. PerkinElmer Lambda 750 is used to measure optical absorbance. The highest thermal conductivity enhancement is found to be 64% for 0.1 wt% concentration of silicone oil-MXene nanofluid compared to pure silicone oil at 150 degrees C. The viscosity of MXene with silicone oil nanofluids is found to be independent of addition of MXene nanoparticles in the silicone oil base fluid. Viscosity is reduced by 37% when temperature is raised from 25 degrees C to 50 degrees C for different concentrations of MXene with silicone oil. Silicone oil-based MXene nanofluid with 0.1 wt% concentration is thermally stable up to similar to 380 degrees C. Introducing more MXene nanoparticles into silicone oil improves electrical efficiency of PV module due to better cooling of MXene based nanofluids. Higher solar concentration is resulted in higher average temperature of the PV module. This consequently raises thermal energy gain which is useful for different applications.

In recent years, solar energy technologies have developed an emerging edge. The incessant research to develop a power source alternative to fossil fuel because of its scarcity and detrimental effects on the environment is the main driving force. In addition, nanofluids have gained immense interest as superior heat transfer fluid in solar technologies for the last decades. In this research, a binary solution of ionic liquid (IL) + water based ionanofluids is formulated successfully with two dimensional MXene (Ti3C2) nano additives at three distinct concentrations of 0.05, 0.10, and 0.20 wt % and the optimum concentration is used to check the performance of a hybrid solar PV/T system. The layered structure of MXene and high absorbance of prepared nanofluids have been perceived by SEM and UV&ndash, vis respectively. Rheometer and DSC are used to assess the viscosity and heat capacity respectively while transient hot wire technique is engaged for thermal conductivity measurement. A maximum improvement of 47% in thermal conductivity is observed for 0.20 wt % loading of MXene. Furthermore, the viscosity is found to rise insignificantly with addition of Ti3C2 by different concentrations. Conversely, viscosity decreases substantially as the temperature increases from 20 &deg, C to 60 &deg, C. However, based on their thermophysical properties, 0.20 wt % is found to be the optimum concentration. A comparative analysis in terms of heat transfer performance with three different nanofluids in PV/T system shows that, IL+ water/MXene ionanofluid exhibits highest thermal, electrical, and overall heat transfer efficiency compared to water/alumina, palm oil/MXene, and water alone. Maximum electrical efficiency and thermal efficiency are recorded as 13.95% and 81.15% respectively using IL + water/MXene, besides that, heat transfer coefficients are also noticed to increase by 12.6% and 2% when compared to water/alumina and palm oil/MXene respectively. In conclusion, it can be demonstrated that MXene dispersed ionanofluid might be great a prospect in the field of heat transfer applications since they can augment the heat transfer rate considerably which improves system efficiency.

Due to the increasing demand in industrial application, nanofluids have attracted the considerable attention of researchers in recent decades. The addition of nanocellulose (CNC) with water (W) and ethylene glycol (EG) to a coolant for a radiator application exhibits beneficial properties to improve the efficiency of the radiator. The focus of the present work was to investigate the performance of mono or hybrid metal oxide such as Al2O3 and TiO2 with or without plant base-extracted CNC with varying concentrations as a better heat transfer nanofluid in comparison to distilled water as a radiator coolant. The CNC is dispersed in the base fluid of EG and W with a 60:40 ratio. The highest absorption peak was noticed at 0.9% volume concentration of TiO2, Al2O3, CNC, Al2O3/TiO2, and Al2O3/CNC nanofluids which indicates a better stability of the nanofluids&rsquo, suspension. Better thermal conductivity improvement was observed for the Al2O3 nanofluids in all mono nanofluids followed by the CNC and TiO2 nanofluids, respectively. The thermal conductivity of the Al2O3/CNC hybrid nanofluids with 0.9% volume concentration was found to be superior than that of the Al2O3/TiO2 hybrid nanofluids. Al2O3/CNC hybrid nanofluid dominates over other mono and hybrid nanofluids in terms of viscosity at all volume concentrations. CNC nanofluids (all volume concentrations) exhibited the highest specific heat capacity than other mono nanofluids. Additionally, in both hybrid nanofluids, Al2O3/CNC showed the lowest specific heat capacity. The optimized volume concentration from the statistical analytical tool was found to be 0.5%. The experimental results show that the heat transfer coefficient, convective heat transfer, Reynolds number and the Nusselt number have a proportional relationship with the volumetric flow rate. Hybrid nanofluids exhibit better thermal conductivity than mono nanofluids. For instance, a better thermal conductivity improvement was shown by the mono Al2O3 nanofluids than the CNC and TiO2 nanofluids. On the other hand, superior thermal conductivity was observed for the Al2O3/CNC hybrid nanofluids compared to the other mono and hybrid ones (Al2O3/TiO2).

A novel design of a portable solar thermoelectric refrigerator is proposed in this study. The cooling effect of the thermoelectric module is utilized to provide cooling to the refrigerator space. To use the full potential of the thermoelectric module (TEM), the heat rejected from the hot side of the module is harnessed for a low-temperature heating application. The cooling chamber used is a well-insulated rectangular container made of Aluminum. The system was designed to achieve 10 °C in the cold chamber to act as a refrigerator. Experimental results demonstrated that the system could reach the desired temperature of about 10 °C in the coldchamber, while on the hot side; theobtained temperature was about 40 °C. A higher coefficient of performance (COP) of about 0.61 was obtained for both cooling and heating effects. A computational model was also developed to simulate the electro-thermal dynamic behavior of the thermoelectric refrigerator using TRNSYS software.The simulation results showed a good agreement with experimental results. Life cycle analyses were also carried out using Eco Audit CES Edu pack software to study the viability of the new design. The results showed that the proposed novel system is economically viable and environmentally friendly. Keywords: Thermoelectric refrigerator, Solarphotovoltaic system (PV), Computational modeling, Life cycle assessment

Energy usage in buildings has become a critical issue due to increase in occupants’ time spent inside a building and use of energy intensive equipment for providing comfort. Utilization of an alternate source of energy can be considered one of the promising solutions to tackle this issue. In the present paper, a review of photovoltaic (PV) and thermoelectric (TE) technologies implemented for energy efficient building development is presented, discussed and critically analyzed. Then, the basics of the solar panel and its performance parameters are introduced. After that, the integration of the PV technology in the building particularly on the wall and its benefits with respect to the building energy consumption has been thoroughly studied. It was found that about half of building thermal load was reduced by installation of a PV panel over the wall. In addition, the thermoelectric module as a substitute to the air conditioning technology is reviewed and literature that focuses on the integration of both TE and PV for building applications has been studied. It can be seen that the PV integrated with the TE system increases the energy saving potential by 22% and reduces 5–10 °C indoor temperature from the ambient conditions. At the end of this article, few challenges, environmental aspect and future research directions are also addressed in detail.

Polycyclic aromatic hydrocarbons (PAHs) that increasingly emanating from natural and human activity sources are invisible pollutants and the presence of even minute amounts of these substances makes them undesirable due to their negative attributes. The PAHs extraction and removal from effluents are major steps for analysis and removal. Chemical, biological and physical approaches are used for the removal of PAHs from wastewater. However, some of these techniques have toxic by-products. Currently, physical approaches such as liquid-liquid solvent extraction, filtration, and adsorption appear to be the best methods due to their safety, affordability, universal nature and ease of operation. However, some of the materials used in the currently available physical methods face the challenges of fouling, low recovery, their relatively long extraction time and high usage of toxic solvent. To overcome these limitations, and for the cleaner production of water, the incorporation of carbon nanotubes (CNTs) into existing physical procedures without distorting their existing structural architectures is proposed. CNTs are considered because hydrophobic hollow pores of CNTs absorb most aromatic pollutants while allowing the friction-free passage of water without consuming much energy. The functionalization of CNTs with various receptors and groups further permit the selective trapping of pollutants of interest. The ability of the proposed methods to cheaply and sustainably remove PAHs from contaminated water will make hitherto carcinogenic polluted water cleaner for public consumption. This comprehensive article presents an extensive literature review of CNTs and their use for various physical techniques. It further presents CNT as a central focus, with an in-depth critical analysis of the state-of-the-art trends of PAH removal using CNTs, current hurdles and future challenges, so that it could be used as a reference manual adding scientific value for developing any future methods for water purification and the removal of any aromatic pollutants.

Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs). The impact of using four surfactants (SDS, CTAB, Tween-80, and Triton X-100) was studied with four test times (15, 30, 60, and 90 min) and four weight concentrations. The stable thermal conductivity and viscosity were measured as a function of temperature. Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy verified the fundamental efficient and stable CF. Several techniques, such as dispersion of particle size, FESEM, FETEM, EDX, zeta potential, and UV-vis spectrophotometry, were employed to characterize both the dispersion stability and morphology of functionalized materials. At ultrasonic test time, the highest stability of nanofluids was achieved at 60 min. As a result, the thermal conductivity displayed by CF-GNPs was higher than NCF-GNPs and distilled water. In conclusion, the improvement in thermal conductivity and stability displayed by CF-GNPs was higher than those of NCF-GNPs, while the lowest viscosity was 8% higher than distilled water, and the best thermal conductivity improvement was recorded at 29.2%.

The future of renewable energy lies in the efficiency of energy storage technology used for storing energy produced by the renewables. The sporadic nature of solar energy has a demand for energy storage and efficient storage materials and devices. Therefore, energy storage technologies are gaining a wide range of attention from researchers. This paper mainly focuses on the development of fatty acid/metal ion composite by incorporating sodium ions into the lauric acid to enhance its thermophysical properties. Lauric acid is doped with 0.2, 0.5, and 1 wt% of the sodium metal to form a fatty acid/metal ion composite. Fabrication of the composite without any sophisticated methods or materials is the advantage of the present work. DSC, TGA, thermal conductivity, thermal diffusivity, and FTIR characterization have been conducted to understand the thermal and structural properties of the synthesized fatty acid/metal ion composite. Morphology of the composite was studied using scanning electron microscopy imaging to study the porous nature of the composite. Enthalpy of fusion of the composite was found to be ~ 153, ~ 157, and 161 J/g by adding 0.2, 0.5, and 1 wt% of sodium metal into lauric acid, due to which the enthalpy of phase change was found to be enhanced by 5.3, 7.9, and 10.6%, respectively, in comparison with the enthalpy of pure lauric acid. Besides, the composite exhibited a small reduction in melting point with the increase in wt% of sodium metal in the composite. FTIR spectra of the prepared composite showed that there is no reaction taking place between lauric acid and sodium metal, making it a more stable composite. TGA analysis revealed that the decomposition temperature was enhanced by 30% by the addition of sodium metal into lauric acid, making it shaped-stable and suitable for thermal energy storage application.

In this study, novel nanocomposites containing the pre-defined mass ratio of binary molten salt (NaNO3-KNO3: 60-40 wt. %) dispersed with hexagonal boron nitride (hBN) nanoparticles with nominal size of 70 nm, were prepared through one-phase preparation method. Four different types of samples including pure binary molten salt and binary molten salt-based hBN nanocomposites with loading concentrations of 0.5, 1 and 1.5 wt. % were prepared. The proposed amount of sodium nitrate and potassium nitrate was added to certain amount of DI water, comprising with 0.5, 1 and 1.5 wt. % concentration of hBN nanoparticles. Scanning electronic microscopy (SEM) was conducted to evaluate the uniformity of the synthesized binary molten salt-based hBN nanocomposites. The SEM images revealed uniform dispersion of hexagonal boron nitride nanoparticles and fractal-like structures were observed clearly. Specific heat capacity (cp) and melting temperature measurements were performed using a differential scanning calorimetry (DSC). The experimental achieved data for melting temperature proved that hexagonal boron nitride nanoparticles do not affect the melting temperature of the synthesized nanocomposites. The experimentally achieved data for the average cp values of the binary molten salt in solid and liquid phases were 1.14 and 1.13 J/g K, respectively. While, the average cp values for the binary molten salt-based hBN nanocomposite with the highest loading concentration of nanoparticles (1.5 wt. %) in solid and liquid phases were 2 and 3.17 J/g K, respectively. The measured average cp value in the liquid phase for binary molten salt-based hBN nanocomposite with the highest loading concentration (1.5 wt. %) of nanoparticles revealed enhancement of ~180% in comparison with pure binary molten salt. Thermal stability measurements expressed enhancement of thermal stability in binary molten salt induced with hBN nanoparticles. Binary molten salt-based hBN nanocomposite with loading concentration of 1.5 wt. % represented ~16% enhancement in thermal stability over the binary molten salt.

The concentrating photovoltaic/thermal (PVT) collectors offer the benefits of the reduced per-unit price of electrical energy and co-generation of electrical and thermal energies by intensifying the solar irradiation falling on the hybrid receiving plane. The compound parabolic concentrating (CPC) collectors have appeared as a promising candidate for numerous applications in the field of solar energy due to their ability to collect both direct and diffuse solar radiation and suitability for stationary installation. Over the last few decades, various configurations of CPC collectors have been proposed and investigated by different researchers for the simultaneous generation of electrical and thermal energies. This article presents a comprehensive review of historical and recent developments and applications of CPC-based hybrid PVT systems. The review focuses on the heat extraction mechanisms and commonly used application areas of CPC-PVT systems. The innovative design configurations proposed by different researchers have been reviewed in detail. The outputs of CPC-PVT systems are generally found to be superior to their counterparts without CPCs, which justifies their increased popularity. Due to dual outputs, the hybrid CPC-PVT systems are considered to be suitable for rooftop and building façade integrated applications. Finally, future recommendations have been enlisted, highlighting the potential research opportunities and challenges for the prospective researchers working in the field of concentrating solar PVT systems.

Most of the incident solar energy on a PV panel is converted into waste heat. This consequently reduces the efficiency of PV system. Therefore, if certain portion of this waste heat can be utilized adding a thermoelectric generator (TEG) in the PV panel endowed by an efficient cooling system, the output performance of the system can be improved significantly. In this study, a new configuration of nanofluid-based PV/T-TEG hybrid system with cooling channel is proposed to convert certain portion of waste heat to electrical energy in order to improve the overall efficiency of hybrid system. Thus, the nanofluid acts as a coolant and absorbs the heat from the back side of TEG module raising its gradient of temperature, as well as the overall performance of the system. Through a numerical modelling approach, performance of the proposed innovative design has been investigated and compared with the conventional solar-harvesting technology systems. At the optimum value of solar concentration C , and maximum operating temperature of 35 Â ° C , the obtained results reveal that the electrical energy in NCPV/T-TEG configuration has been found higher by 10 % , 47.7 % and 49.5 % against NCPV/T, CPV and CPV/TEG-HS systems, respectively. Overall, the proposed design of NCPV/T-TEG hybrid system has potential for further development in high-concentration solar systems.

The present study discovered the synthesis of a novel and efficient magnetic nanofiber fabricated via electrospinning of polyacrylonitrile (PAN) and magnetic zeolite (PAN–MZeo). The synthesized nanofiber was applied as magnetic solid phase extraction (MSPE) adsorbent, for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples prior to gas chromatography flame ionization detector (GC-FID). Response surface methodology based on the central composite design was employed for the optimization of the various parameters including sorbent amount, desorption solvent volume, adsorption and desorption time on the extraction efficiency. Excellent linearity was achieved at optimized conditions, with coefficients of determination (R2) between 0.9948 and 0.9977. The limit of detections for PAHs was in the range of 0.14–0.21 ng mL−1. The repeatability and reproducibility precision (RSD%) were less than 10%. The real sample analysis showed satisfactory extraction recovery (92–113%) for the five selected PAHs in agricultural, well and mineral water samples. Therefore, the newly fabricated PAN–MZeo–MSPE is an accurate, rapid, and reliable sample-pretreatment method based on comparisons from previous studies.

The design of high performance photovoltaic/thermal solar system involves many parameters related to thermal, economic and reliability issues. The current paper provides a comprehensive review for the recent studies that have discussed the design and cooling considerations to build a high performance hybrid Photovoltaic/Thermal (PV/T) system. The review highlights the importance of the nanofluids and nano phase change materials (nanoPCMs) as an alternative for the traditional ways of cooling and storage. In addition, the application of the nanofluids in optical filtration has been covered. The main conclusions that have been reached at the end of the review show that cooling from both sides of the PV, with involvement of the optical filtration using nanofluid; will result in high improvements in the performance of the PV/T system. In addition, change of the channels cross section to honeycomb and induction of nanoPCM for storage and cooling purposes can provide better distribution of the thermal load.

Conventional fossil fuels are depleting daily due to the growing human population. Previous research has proved that renewable energy sources, especially solar and wind, can be suitable alternatives to the conventional energy sources that could satisfy global demand and protect the atmospheric environment. There are many factors that influence the performance of solar and wind energy predicting tools. The accurate forecasting of solar and wind energy resources is highly needed for the optimum utilization of these resources. Different methods have been applied to forecast solar and wind energy resources. Prediction performance of the support vector machine modeling approach found to be better than other modeling approaches. The support vector machine is fast, simple-to-use, reliable and provides accurate results. Findings based on critical analysis suggests that the hybrid support vector machine models can reach much higher accuracies than other models for both solar and wind energy predictions for most of the locations. This investigation highlighted main problems, opportunities and future work in this research area. Novel hybrid models are proposed for further investigation for more accurate predictions of solar and wind energy resources.

This investigation focused on the photocatalytic treatment of pollutants in waste water using methylene blue (MB) and methyl orange (MO) as the model dyes. In this study, conducting polyaniline (PANI) based nanocomposites doped with 2D hexagonal boron nitride (h-BN) were synthesised using simplistic oxidative in-situ polymerization technique by employing ammonium persulfate as an initiator in acidic medium. The synthesised 2D h-BN doped PANI nanocomposites were comprehensively characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), elemental mapping, X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Degradation of MB and MO dyes under UV irradiations was performed to evaluate the photocatalytic performance of the synthesised nanocomposites. The results indicated that the h-BN nanosheets doped nanocomposites demonstrated better photocatalytic activities as compared to bare PANI or h-BN. Moreover, the nanocomposite P-BN-2, with 2 wt% of 2D h-BN nanosheets was found to be an optimal composition with 93% and 95% degradation efficiency for MB and MO within 90 min respectively. Keywords: Boron nitride, Polyaniline, Nanocomposite, Photocatalysis, Dyes

Solar thermal technology to supply process heat in different industrial sectors has become very promising in recent years. Industries can reduce their consumption of fossil fuels by replacing them with solar process heat with non-conventional system integration and using clean energy. In this paper, a systematic review of 10 countries is presented which demonstrated extensive use of solar industrial process heating systems in their manufacturing sectors. This country-wise analysis is then used to compare with current Australian scenario and identify future prospects of integrating solar process heating in Australian industrial sectors. The choice of countries is based on a database where promising industrial sectors and solar process heating applications are currently using incident solar energy. These are analyzed for their potential of integration to developing solar heat in industrial processes (SHIP) and a number of potential industrial sectors that have the highest potential like Motor vehicles, Textiles, Printing, Wood, Paper, Fabricated metal, Rubber and plastics, chemicals, Food, beverages, electrical equipment, machinery, and equipment are being identified. An overview of available studies is discussed in this paper focused on specific countries and the industrial heat demand of existing operational plants. Future trends due to solar energy potential are also outlined.

Concentrating solar power (CSP) has received significant attention among researchers, power-producing companies and state policymakers for its bulk electricity generation capability, overcoming the intermittency of solar resources. The parabolic trough collector (PTC) and solar power tower (SPT) are the two dominant CSP systems that are either operational or in the construction stage. The USA and Spain are global leaders in CSP electricity generation, whereas developing countries such as China and India are emerging by aggressive investment. Each year, hundreds of articles have been published on CSP. However, there is a need to observe the overall research development of this field which is missing in the current body of literature. To bridge this gap, this study 1) provides a most up-to-date overview of the CSP technologies implemented across the globe, 2) reviews previously published review articles on this issue to highlight major findings and 3) analyzes future research trends in the CSP research. Text mining approach is utilized to analyze and visualize the scientific landscape of the research. Thermal energy storage, solar collector and policy-level analysis are found as core topics of discussion in the previous studies. With a holistic analysis, it is found that direct steam generation (DSG) is a promising innovation which is reviewed in this study. This paper provides a comprehensive outlook on the CSP technologies and its research which offers practical help to the future researchers who start to research on this topic.

This work presents the synthesis of the novel silica-cyanopropyl functionalized magnetic graphene oxide (MGO/SiO2-CN) hybrid nanomaterial derived by sol–gel method as a cheap efficient magnetic sorbent for the removal of extremely hazardous lead ions from aqueous media. The integration of the magnetic property, the carbon substrate, and the nitrile (–C ≡ N) containing organic grafted silica matrix promoted the adsorption capability against lead ions along with its simple synthesis recovery and low cost. The prepared nanocomposite was comprehensively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Adsorption of lead was found to be pH dependent because of the charged nature of both analyte and adsorbent surface. Adsorption experiments were conducted under the optimum conditions, and the obtained experimental data from atomic absorption spectroscopy were analyzed using the popular isothermal models namely Langmuir, Freundlich, and Dubinin–Radushkevich isotherms as well as kinetically studied and evaluated for adsorption standard free energy (E). The experimental results have demonstrated the enhanced adsorption capability of the proposed sorbent nanocomposite for lead ion removal with the maximum adsorption capacity of 111.11 mg/g at pH 5.0. The proposed mechanism of lead adsorption was mainly attributed to the complexation of lead positive ions with the grafted –C ≡ N bond. The synergistic effect of the combination of three components (i.e., the magnetic graphene oxide matrix, the triple bond containing organic moiety, and the inorganic porous silica framework) excelled the adsorption capability and proved to be a good candidate as adsorbent for the removal of lead ions.

The thermal conductivity is a key parameter to study the applicability of nanofluids for heat transfer enhancement of flowing liquids. This paper is an effort on implementing various methods to model the effective thermal conductivity of 26 nanofluids under different situations and evaluate the authenticity of the reported experimental data in the open literature. The most influential physical properties of nanofluids, such as the nanoparticle volume fraction, nanoparticle diameter, thermal conductivity of base fluid, temperature, and thermal conductivity of solid particle are considered as the input variables. With the purpose of introducing a comprehensive and pragmatic model with desired accuracy, a Multilayer Perceptron-Artificial Neural Network (MLP-ANN) approach is constructed and tested using data generated from 993 experiments. To appraise the creditability of the MLP-ANN model, a comparison with other 10 alternative techniques is carried out. The predictions made by the MLP-ANN yield excellent match with the experimentally generated samples against those of the other approaches. The coefficient of determination and relative root mean squared error are found to be 0.994 and 1.534%, respectively. Likewise, the results of the data analysis and the outlier detection method have proved that some of the data samples are significantly inconsistent with the remainder of the data set.

The use of solar thermal collectors is one of the promising options for heating and/or cooling due to the green nature (pollution free) and abundance of the solar energy in many parts of the world. Improvement of thermal performance of solar collectors is important for better energy conversion. In this regard, many studies reported in literature tried to modify geometry of the collectors. On the other hand, nanofluids as heat transfer fluids could be a promising option for the efficiency enhancement of solar collectors. In this study, heating performance of an evacuated tube solar collector system initially operated with water is considered for improvement using nanofluid. The collector (about 20 kW heating capacity) is a part of an absorption cooling system. The aim of the present study is to analyze the effect of Single Walled Carbon Nanotube–water nanofluid on the collector performance. Thermal efficiency improvement is assessed based on comparative analyses between collector working with ordinary water and that with nanofluid. The results indicate that up to 56.7% and 66% of efficiencies are observed when the collector is operated with water and 0.2 vol% nanofluid, respectively. Therefore, nanofluids are promising to enhance the efficiencies of solar collectors.

Solar spectrum utilization can effectively deliver a significant stake in the next century's energy demand, which lies in tandem with Sustainable Development Goals. Solar energy is a promising, sustainable, and cleaner energy source. The photovoltaic thermal system is a solar spectrum utilization technique that can generate thermal and electrical energy, but the recovered thermal energy can primarily contribute to low-temperature utilizations. This study's motivation lies in the great potential of Concentrated Photovoltaic Thermal systems in providing high-grade thermal energy and increasing the overall system efficiency. This paper collectively reviews advanced thermal management techniques such as using phase change materials and nanofluids to avert overheating of the solar panel. A comprehensive review of Concentrated Photovoltaic Thermal systems like desalination, greenhouse heating which help in attaining Sustainable Development Goals, is also summarized. Heat transfer fluid selection is critical in thermal management, and accordingly, a comparison of various cooling methods is also made. The current article is a novel attempt to deliver a comprehensive review of the recent advancements in thermal management, commercial applications involving clean energy usage, technical challenges involved, economic and environmental impacts of Concentrated Photovoltaic Thermal systems. Multigeneration Concentrated Photovoltaic Thermal systems are environment-friendly, and the carbon dioxide emission per kilowatt-hour is almost half for concentrating systems compared with photovoltaic systems. The locational and environmental dependency of these systems makes them unattractive for some general applications. For better validation of analytical results, more experimental researches are essential in this area.

The emphasis on exploiting solar power has efficaciously engaged the concentrated solar power (CSP) technology towards producing electricity from solar thermal energy. CSP technology's key element is molten salts, which function as thermal energy storage (TES) to absorb and store the sun's thermal energy and as a heat transfer medium to transfer the stored thermal energy to a steam generator for electrical energy production. The thermophysical properties enhancement of molten salt through the integration of additives such as nanoparticles permits the molten salt to store additional solar thermal energy by improving its heat transfer properties. This, in due course, leads to an overall enhancement of the CSP plant efficiency and electricity cost. Various types of inorganic nanoparticles such as Alumina, Copper Oxide, and Titania have been studied with different types of molten salts to enhance their thermophysical properties, especially those related to CSP applications. As such, the present review aims to discuss the recent advances in nano-enhanced molten salt (NEMS) and the nanoparticles used to date to enhance molten salts behavior for CSP systems. In addition, important topics related to NEMS, such as the stability of nanoparticles and nanostructures' formation, are also discussed. The article also focuses on the different types of nanoparticles used as thermophysical enhancers and their enhancement logics. Besides, the effect of nanoparticle assets such as mass percentage, size, and shape and how they may positively or negatively affect the thermophysical properties of molten salts are also presented in this review. The related publications in this field have shown an increasing focus on enhancing molten salts' thermophysical properties every year. Most of these experiments were focused on improving the heat capacity of nitrate or carbonate salts. Additionally, the dendritic nanostructures were reported to have a long-range effect that may enhance the heat capacity. Also, the studies on nanoparticle concentration and morphology reveal that these factors significantly influence the molten salt's thermophysical properties. This review is anticipated to provide an outline of the works done related to NEMS and to benefit the researchers in the field.

Nanofluid is a conventional fluid, blended with single or more nano additives with a dimension of less than 100 nm. Early studies revealed that dispersing a small amount of nano additives to base fluids can enhance the effective heat transfer properties of nanofluids by up to 250% relative to the base fluid. However, from a number of studies on nanofluid published, inconsistent thermophysical properties of formulated nanofluids reported due to many factors such as preparation approach, types of base fluids and morphology of nano additives. Selection of accurate parameters during nanofluids formulation can resolve this issue. The discussion on experimental studies by different authors include the stability evaluation of nanofluids and thermophysical measurement including its density, rheological and thermal conductivity studies can provide a guideline to the researchers towards the future development of nanofluids system with optimum thermophysical properties. This review article provided critical comments on biodegradable vegetable oil base fluid as one of the alternatives to non-renewable mineral oil as well it presents an overview of the remarkable research progress on conducting polymers base nanofluids witnessed in recent years. The outcome of this review paper would give an overview of further enhancements in nanofluid systems for industrial.

To meet the growing energy demand, double pipe heat exchangers (DPHEX), which are used in a variety of energy and thermal engineering applications, require improved heat transfer performance. In this study, a new class of surfactant-free Ionanofluid is formulated at three different concentrations of 0.01, 0.05 and 0.10 wt% and thermophysical and rheological properties are assessed. Zeta potential analysis is executed to assess the dispersion stability. An optimum concentration has been selected to investigate the hydrothermal performance of an insert fitted DPHEX at varying Re from 400 to 2000. The conventional twisted tape (TT) insert is modified by introducing different types of geometrical (triangular, rectangular, and circular) cuts on its surface. According to the Ionanofluid characterization, 0.10 wt % Ionanofluid has the highest thermal conductivity enhancement of 64% and heat capacity of 16.1% when compared to the base fluid, with a maximum enhancement in Nu of about 116–136% at varying Re. The rectangular-cut TT imparts highest heat transfer enhancement as the additional vortices is more intensive than other cut-inserts. Nevertheless, the value of PEC for the combination of Ionanofluid and RCTT insert, remaining between 1.61 and 1.68 over the entire range of Re, is greater than other combinations.

Generally, wind to power conversion is calculated by assuming the quality of wind as measured with a Weibull probability distribution at wind speed during power generation. We build on this method by modifying the Weibull distributions to reflect the actual range of wind speeds and wind energy density. This was combined with log law that modifies wind speed based on the height from the ground, to derive the wind power potential at windy sites. The study also provides the Levelized cost of renewable energy and hydrogen conversion capacity at the proposed sites. We have also electrolyzed the wind-generated electricity to measure the production capacity of renewable hydrogen. We found that all the sites considered are commercially viable for hydrogen production from wind-generated electricity. Wind generated electricity cost varies from $0.0844 to $0.0864 kW h, and the supply cost of renewable hydrogen is $5.30 to $ 5.80/kg-H2. Based on the findings, we propose a policy on renewable hydrogen fueled vehicles so that the consumption of fossil fuels could be reduced. This paper shall serve as a complete feasibility study on renewable hydrogen production and utilization.