The industrial sector accounts for more than 54% of the total energy produced in the world with a predicted annual growth of 1.2%. Currently, most of the industrial sectors use fossil fuels to meet ...their heat energy requirements and it can be replaced by renewable energy resources particularly solar energy. In this article, an extensive review of various solar thermal energy technologies and their industrial applications are presented. The following industries are covered: power generation, oil and gas, pulp & paper, textile, food processing & beverage, pharmaceutical, leather, automotive, and metal industries. For each of the applications, quality and quantity of heat requirements are identified. Though all the applications are consuming heat in the form of steam/hot water, power plant and enhanced oil recovery have huge potential for solar steam augmentation as compared to other applications. Similarly, applications such as petroleum refining, pulp & paper, and rice mill require a huge amount of steam/hot water. The process heat requirements for textile, food & beverage, pharmaceutical, leather, and automotive industries are at a lower temperature. The integration of solar thermal energy systems with the industrial processes mainly depends on the local solar radiation, availability of land, conventional fuel prices, quality of steam required, and flexibility of system integration with the existing process. Furthermore, challenges involved in the integration of solar thermal energy systems with the process heat industries are explored along with the economics. The future outlook has been proposed to overcome the challenges involved in the integration.
•Solar thermal technologies help in reducing the carbon footprint in industries.•Quality & quantity of heat requirements are identified for various process industries.•Enhanced oil recovery has huge potential for solar steam augmentation.•Challenges in the integration of solar energy system with the processes are listed.
Abstract
The prime intention of the current research is to enhance the freshwater productivity of the solar still (SS) by using Luffa acutangula fibres (LAF). The dried LA fibres were introduced into ...the absorber basin of a solar still to enhance the wet surface area through its porous structure that leads to augmented evaporation of water from the absorber basin. The effect of the number of LAF in the absorber basin such as 10,13,14,15,16,20 and 25 on freshwater productivity was estimated. The results revealed that SSLAF with 15 fibres in the absorber basin increased the yield by 25.23%. Besides, a solar still with 10,13,14,16,20 and 25 fibres in the absorber basin increased the yield by 12.27%, 17.45%, 22.04%, 22.69%, 14.64% and 4.09% respectively when compared to conventional solar still (CSS). The average thermal efficiency of the SSLAF with 15 LAF was increased by 28.35% whereas, for 10,13,14,16,20 and 25 LAF, the average thermal efficiency was increasedby 11.05%, 16.99%, 22.53%, 19.93%, 11.29% and 3.9% respectively when compared to CSS.The economic analysis resulted that the cost per litre freshwater yield from the SSLAF is 22.5% lower than CSS. Also, the payback period of SSLAF is comparatively lesser than that of CSS.
Research background. Traditionally, open sun drying method serves to dry the products for long time preservation. Solar drying is also employed to minimise the drying time to achieve the required ...moisture content. This method inherently contains complex heat and mass transfer mechanisms, which makes difficult to describe drying kinetics at the micro level. Experimental approach. In this paper, research is carried out to investigate the drying of 5 mm thick slices of red banana (Musa acuminata 'Red Dacca') in a single slope solar dryer based on natural and forced convection. Based on the experiments, a new semi-empirical thin layer drying kinetics is proposed and compared with other existing models. The proposed model with the correlation coefficient (R.sup.2) of 0.997 is in very good agreement with other well-known models. Based on the model, we calculated the moisture diffusivity and activation energy of the red banana drying process. Results and conclusions. It was found that the moisture diffusivity of the red banana samples was in the range 0.87-1.56*10.sup.-9 m.sup.2/s for natural convection solar drying and 0.84-2.61*10.sup.-8 m.sup.2/s for forced convection solar drying. The activation energy of the red banana varied from 24.58 to 45.20 kJ/mol for passive and 22.56 to 35.49 kJ/mol for active drying. Besides, we carried out energy and exergy analyses of red banana in the dryers and found that the average exergy losses in the forced and natural convections were 16.1 and 6.63 kJ/kg and the average exergic efficiency of the natural and forced convection dryers was 57.7 and 70.9 %, respectively. Novelty and scientific contribution. A single slope direct solar dryer was designed and built to maintain the desired temperature for a specified period in both natural and forced convection mode. A novel drying kinetics model with higher correlation coefficient (R.sup.2) than the other drying kinetic models is proposed for the preservation of red bananas. Key words: single slope solar dryer, red banana drying, drying kinetics, moisture ratio correlation, moisture diffusivity, activation energy
Agriculture is the main occupation of the majority of people in India. The majority of the population in India is dependent (directly or indirectly) on agriculture as an occupation. The agriculture ...sector requires more freshwater and power for better yield in the current scenario. Nevertheless, the ever-increasing rate of energy consumption, limited fossil fuels, and rising pollution have made the expansion of renewable resources essential. Due to the suitable solar potential available in India, the deployment of solar energy has been more as compared to other renewable resources. The current study aims to discuss the various technologies, initiatives and policies of solar energy usage in agriculture. This work delivers an assessment of the advancement of solar energy vis-à-vis agricultural applications through the greenhouse concept and photovoltaic approach in India. Various agricultural applications of solar energy, such as solar water desalination system, solar water pumping system, solar crop dryer system for food safety, etc. are discussed as a means to promote solar-based technology. It also highlights the scenario of solar energy in India with important accomplishments, developmental approaches, and future potential. In-depth studies of various policies and government initiatives including those in research and development are also discussed. The current survey on solar technologies will be an aid to agribusiness frameworks to comprehend the statuses, obstructions, and extent of advancement. Finally, some future recommendations for further developments in this approach are discussed. This work sheds light on varied areas of solar energy-assisted agricultural systems as a potentially sustainable and eco-friendly pathway.
Graphical abstract
The freshwater production in a conventional solar still (CSS) is very less and it can be enhanced by either enhancing evaporation or condensation rates or both in the solar still. Therefore, the ...current investigation focused on enhancing both the evaporation rate in the absorber basin and the condensation rate over the top glass simultaneously. In this regard, the evaporation rate is enhanced by using a hollow-finned absorber basin with energy storage and novel pond fibres in the absorber basin. Likewise, the sisal fibre with a water dripping arrangement is utilized for enhancing the condensation over the top glass. The investigations on the CSS and the modified solar still (MSS) with hollow fins and energy storage, pond fibres, and sisal fibres are conducted to analyze the effect of energy storage and natural fibres on the distillate production. It is observed that the water temperatures of the MSS are increased by 12% and the glass temperatures of the MSS are reduced by 30% relative to the CSS. The outcomes reported that the productivity of the MSS is enhanced by 126%. Furthermore, the cost per litre (CPL) and the payback period (PP) of the MSS are 38.5 and 49.3% lesser than the CPL and the PP of the CSS, respectively. HIGHLIGHTS The performance of the solar still is examined with energy storage and natural fibres.; The water temperatures of the MSS are increased by 12% relative to the CSS.; The glass temperatures of the MSS are reduced by 30% relative to the CSS.; The productivity of the MSS is 126% higher than that of the CSS.; Economic analysis depicted that the MSS is more economically viable than the CSS.;
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•The recent advancements of PANI based nanocomposites in DMFCs is overviewed.•Polyaniline based electrocatalyst possess superior electrochemical performance in DMFCs.•PANIs π-electron ...combined by bonds or aromatic rings revel electronic properties.•Superior prominence placed on PANIs binary, ternary and multicomponent composition.•Underlying mechanisms for superior activity of PANI-based nanocomposites in DMFC are reviewed.
This review delivers a summary of the recent advances in polyaniline based electrocatalyst for direct methanol fuel cell applications. Today’s world is urging for global energy due to the fossil fuel diminution and ecological contamination which is overthrown by the direct methanol fuel cell. Amongst the conducting polymers, polyaniline has a significant role in the direct methanol fuel cell. Due to the high conductivity, unique redox properties, high flexibility, better solubility, reasonable stability, ease synthesis, and low cost. The nanocomposite of polyaniline with other electrochemically active materials such as metallic compounds and carbonaceous materials as well as nitrogen-doped carbon materials derived from PANI based nanocomposite were in detailly discussed in this review.
► A numerical heat transfer model is developed for solar trapezoidal cavity absorber. ► Results are shown in terms of combined heat transfer Nusselt number correlation. ► In addition to that, ...separate heat transfer correlations are also developed. ► The effects of influencing parameters on combined Nusselt number are studied. ► Compared to other parameters, the effect of absorber angle is negligible.
In this paper, a numerical study of combined natural convection and surface radiation heat transfer in a solar trapezoidal cavity absorber for Compact Linear Fresnel Reflector (CLFR) is presented. The CFD package, FLUENT 6.3 is used to develop the 2-D, non-Boussinesq, steady state, laminar, combined natural convection and surface radiation heat transfer model for a trapezoidal cavity absorber. The validation of the present non-Boussinesq numerical procedure is compared with other closed cavity model. Based on the validated non-Boussinesq model, the combined heat loss coefficients are predicted for various parameters such as Grashof number, absorber angles, surface emissivity, aspect ratio, temperature ratio and radiation–conduction number. The numerical simulation results are presented in terms of Nusselt number correlation to show the effect of these parameters on combined natural convection and surface radiation heat loss.
The numerical study of solar cell temperature for concentrating PV with concentration ratio of 10× is presented in this paper. A two dimensional thermal model has been developed to predict the ...temperature for PV concentrator system (solar cell and lens) with and without passive cooling arrangements. Based on a thermal model, the result shows that maximum of four numbers of uniform fins of 5
mm height and 1
mm thickness can be effectively used to reduce the solar cell temperature. In addition to that, the effects of ambient temperature and solar radiation intensity on the solar cell temperature have also been investigated for the system with and without cooling fins. Based on the influencing parameters of ambient temperature and solar radiation, two separate solar cell temperature correlations has been proposed for systems with and without cooling fins to predict the cell temperature for the range of given parameters. In our previous studies, the present 2-D model was extensively validated with a comprehensive unified model
8–10.
► An in-house developed 2D numerical codes for photovoltaic application. ► Enhancing efficiencies of PV system through fins and without fins. ► Ambient temperature co-relation for operating cell temperatures. ► Influences of solar cell temperature with solar radiation.
Primary material supply is the heart of engineering and sciences. The depletion of natural resources and an increase in the human population by a billion in 13 to 15 years pose a critical concern ...regarding the sustainability of these materials; therefore, functionalizing renewable materials, such as nanocellulose, by possibly exploiting their properties for various practical applications, has been undertaken worldwide. Nanocellulose has emerged as a dominant green natural material with attractive and tailorable physicochemical properties, is renewable and sustainable, and shows biocompatibility and tunable surface properties. Nanocellulose is derived from cellulose, the most abundant polymer in nature with the remarkable properties of nanomaterials. This article provides a comprehensive overview of the methods used for nanocellulose preparation, structure-property and structure-property correlations, and the application of nanocellulose and its nanocomposite materials. This article differentiates the classification of nanocellulose, provides a brief account of the production methods that have been developed for isolating nanocellulose, highlights a range of unique properties of nanocellulose that have been extracted from different kinds of experiments and studies, and elaborates on nanocellulose potential applications in various areas. The present review is anticipated to provide the readers with the progress and knowledge related to nanocellulose. Pushing the boundaries of nanocellulose further into cutting-edge applications will be of particular interest in the future, especially as cost-effective commercial sources of nanocellulose continue to emerge.
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