Hydrogen, a carbon-free fuel, has the potential to aid global nations in achieving eight of the 17 Sustainable Development Goals (SDG). The shortcomings associated with H2 transportation and storage can be mitigated by using NH3 as hydrogen carrier because of its better safety, physical, and environmental properties. However, to achieve the global climate target, green ammonia production must be incremented by four times (688 MT) from the current level. Hence, understanding of advanced green NH3 production and storage technologies, along with the factors that influence them becomes necessary. It also aids in identifying the factors hindering green H2 and NH3 production, which can be resolved by promoting research. At the same time, drafting policies that encourage green H2 and NH3 production can abet in overcoming the bottleneck faced by the industry. Presently, green ammonia production can be made feasible only when the renewable electricity cost is less than $20/MWh and carbon price of $150/t of CO2 emissions is levied. Approximately 80 % of the energy consumed during NH3 is spent on H2 generation; therefore, it is necessary to enact policies that promote green H2 production globally. Producing green H2 can aid in mitigating ∼90 % of the greenhouse gases emitted during NH3 manufacturing thereby facilitating to reduce the carbon footprint of H2 carrier and decarbonize NH3 industry.

Heavy industries play a crucial role in the economic growth of India through their contribution towards meeting demand, including exports and GDP. Every functional unit of the production process related to hard-to-abate industries has to depend upon power sources for manufacturing the final product. The major power source for heavy industries namely power plants, iron and steel, cement, paper, and fertilizer are coal. During the process of energy conversion from coal through combustion, they produce a large amount of greenhouse gases. As production capacity is increased to meet the growing demand, it is essential to mitigate carbon emissions. There are many routes adopted by various sectors to decarbonize the production process. These include the use of alternative fuels, using the best available techniques, carbon capture utilization, and storage. Most of these techniques have shown positive impacts after implementation. In this study, the production process of each sector is analyzed to find the hotspots, the mitigation strategies followed by each industry, and mainly the use of green hydrogen as a power source. It elaborates on the routes of production of green hydrogen, the major challenges in the implementation part, the policy making of green hydrogen in India, its relationship to heavy industries, and how green hydrogen plays a role in net-zero emission goals.

Natural gas is extracted from the subsoil which is not a renewable source, however, the dominance of this product in the international market is significantly higher in future. It reflects the global view of renewable sources (biogas) and hinders the sustainable development of bioenergy. It describes the major issues and trends in the development of biogas industry, paying special attention to current biomass upgrading technologies, methane activation for fuel production and model compounds investigation. The conducted research gives reason to believe that the valorization of organic waste generated worldwide during the production of biomethane that can potentially satisfy. No more than one fifth of global demands for natural gas due to technical difficulties and economic constraints associated with the purification of biogas. The existing production potential of biogas production is focused on obtaining biomethane and high growth rates of demand for biohydrogen. A pressing need arises the possibilities for further development of biogas industry lie in optimizing the biomethanation processes, which allows to reduce the costs of biogas modernization system and decreasing the negative effect on climate changes by replacing petrochemical derived fuels with biofuels in various sectors of economy.

The major share of energy consumption during steel manufacturing is spent on iron making. The unavailability of the required quantity of recyclable steel in India has made the industries depend on sponge iron (SI) for steel manufacturing. However, 78.5% of the SI manufactured in India uses coal as an energy source. Thus, increasing the carbon footprint of steel manufactured in India by 18% compared to the global level. Hence, in this study, the potential of palm kernel shell charcoal (PKSC) to decarbonize the rotary kiln-based SI production process was analysed by framing three scenarios and comparing them with the business-as-usual (BAU). Meanwhile, the life cycle assessment of the SI production through different scenarios was done to identify the sustainability of the process. A cradle-to-gate approach was adopted, and it was found that during BAU, the net greenhouse gas (GHG) emissions were 2525 CO2eq./t SI. However, usage of PKSC (scenario 3) in the SI production process aided in achieving negative net GHG emissions of −41 kg CO2eq./t SI. Meanwhile, the net GHG emission was 1092 kg CO2eq./t SI and 1197 kg CO2eq./t when the coal used in the feed and injection end was replaced with PKSC in scenario 1 and scenario 2, respectively. Thus, the usage of the PKSC instead of coal can abet in decarbonizing the sponge iron industry thereby aiding in reducing the GHG emitted during the production of 1 t of steel in India to 2.4 t by 2030–31.

Food waste is primarily generated in marketplaces, agricultural fields, hotels, food manufacturers units, and halls. Food waste have a major impact on food security, quality and safety, economic development, and cause environment pollution. The improper disposal of food waste without proper treatments leads to generation of new diseases, unpleasant odour, air, water, and soil pollution. Nevertheless, food waste is a good substrate which can be disintegrated by digestion process because it exhibits more water contents and biodegradability. The conversion of food waste into biomethane is an appreciable solution in food waste management steps. This manuscript reviews the physico-chemical properties of food waste, various pretreatment methods of food waste to enhance the efficiency of anaerobic digestion (AD) process used to produce biomethane and discussed the impact of operational factors on biomethane production. Subsequently, the need for a biomethane upgradation using physical, chemical, and biological purification approaches was reviewed. In order to improve the efficiency of the anaerobic digestion (AD) process to a large-scale industrial level, the challenges and possible future developments needed to enhance biomethane generation from food waste were also reviewed significantly.

Efficient thermal management system is crucial for maintaining optimal temperatures in a comprehensive range of applications, including buildings, electronic devices, the automobile industry, and solar PV systems. Spray cooling (SC) has emerged as a promising technique for effectively dissipating heat generated by these systems, offering rapid heat transfer rates with low energy requirements. This paper presents a comprehensive review of recent advancements in SC technology across multiple applications, such as solar panel cooling, fuel cells, electric vehicles, electronic devices, and the building sector. The review highlights the significant role of SC in achieving efficient thermal management and improving overall system performance. It discusses the capacity of SC systems to reduce the temperature and enhance thermal comfort levels effectively. Notably, the review emphasizes the impact of critical factors, including surface-to-nozzle distance, critical heat flux (CHF) stimulation, nozzle design, and nozzle angle, on the performance of SC systems. Furthermore, the work identifies key areas for future exploration and development, including the investigation of factors influencing CHF, such as the utilization of nanofluids in sprays, exploration of different angles of inclination, optimization of the number of nozzles, droplet size characterization, and considerations of economic feasibility. The findings underscore the immense potential of SC technology in diverse applications, highlighting its capability to enhance thermal management, reduce energy consumption, and optimize system performance. Continued research and development endeavors in this field are crucial for further advancements in SC systems, enabling their faster adoption in practical applications.

A cost-effective indirect cabinet-type solar dryer was designed and developed to remove the moisture in green peas until their moisture content reaches 14–15 % with minimal energy supplied from external sources. The green peas were placed beneath the absorber plate of the modified solar cabinet dryer (MSCD) thereby preventing its exposure to direct sunlight. The performance of MSCD was assessed at three different air velocities and was compared with a conventional solar cabinet dryer (CSCD) operated in passive mode. Experimentation showed that when hot air from the upper chamber of MSCD was fed to its lower chamber at 0.0406 kg/s, the dried green peas were free from shrinkage, uneven drying, and browning. However, when hot air was fed to the lower chamber of MSCD at 0.00585 kg/s and 0.027 kg/s the dehydrated green peas underwent shrinkage. At the same time, the green peas dried in CSCD underwent shrinkage, uneven drying, and browning despite its higher efficiency (about 13.5 %) and shorter span (2 h and 30 min) taken for drying when compared to MSCD. Hence, CSCD and MSCD operated at an air velocity of 0.00585 kg/s, and 0.027 kg/s was found to be not suitable for dehydrating green peas. The efficiency of MSCD when hot air from the upper chamber was fed to its lower chamber at 0.0406 kg/s was 10.64 % and the payback period was 0.47 years.

This research aims to carry out an experimental investigation into the performance of a solar air heater using phase change materials in combination with V-corrugated absorber plates and shot blasting. This shot blasting approach is applied to interrupt the boundary layer thickness of the absorber plate material it will increase the absorbance of the material. This study incorporates the analysis of four distinct absorber plates namely (i) V-Corrugated Plate (ii) V-Corrugated with shot blasting, incorporating PCM (iii) V-Corrugated with shot blasting, including NEPCM (0.6 %) (iv) V-Corrugated with shot blasting, including NEPCM (0.9 %). In this study, Paraffin wax was selected as the base PCM, and MWCNT dispersed into base PCM with different weight fractions. The nano-enhanced phase change material with a concentration of 0.9 wt% examined that the latent heat of melting and solidification experienced a significant augmentation. This enhancement resulted in a maximum increase of 12.5 % for melting and 8.2 % solidification was attained at 0.9 % of MWCNTs compared with paraffin wax. The average exergy efficiencies of V-corrugated plate attains an efficiency of 1.023 %, V-corrugated with PCM records 1.357 %, V-corrugated with 0.6 % NEPCM attains 1.698 %, and V-corrugated with 0.9 % NEPCM attains the highest efficiency at 2.167 %. The significant enhancement in exergy efficiency observed in NEPCM configurations with volume fractions of 0.6 % and 0.9 % is primarily attributed to two key factors namely enhanced thermal conductivity and improved heat transfer properties. The maximum sustainability index for the V-corrugated design with 0.9 % NEPCM falls within the range of 1.014 to 1.037. The average “Nu” value of 27.5 was achieved under the conditions of a mass flow rate of 0.02 kg/s and the addition of 0.9 % MWCNTs dispersed in paraffin wax.

The shelf life of food products can be increased by reducing their moisture content with the aid of solar dryers. However, the poor efficiency of solar collectors increases the time and energy required for drying the food crops. Hence, the present work aims to overcome the above bottleneck by employing corrugated shot-blasted absorbers in solar air heaters and comparing their performance with flat plate solar air heaters. Subsequently, the drying kinetics of bitter gourd and tapioca cassava were subject to experimental investigation using indirect solar dryers in their natural mode, aiming to assess the dryers' overall performance. The experiments revealed that the average thermal efficiencies of the SAHs equipped with flat plate absorber plates and corrugation with shot-blasted absorber plate treatment displayed variations ranging from 39.05 to 53.12 % while maintaining a constant MFR of 0.02 kg/s. The average exergy efficiency of the FPAP is 1.103 % and the CSB absorber plate is 1.755 % with a constant flow rate of 0.02 kg/s. The research findings indicate that the CSBAP (surface-improved SAH) demonstrates a higher heat-absorbing capacity when compared to the FPAP SAH. The utilization of the CSBAP design along with the incorporation of pebble stone results in a greater ability to efficiently absorb and retain heat when compared to the traditional FPAP design with a shot-blasted surface. The inclusion of pebble stones in the drying process, as observed in Case II for Tapioca cassava, led to a remarkable improvement in drying efficiency by approximately 36 % when compared to Case I. Furthermore, the drying efficiency for bitter gourd in Case IV experienced a notable improvement of around 30 % when pebble stones were integrated into the drying process, in contrast to Case III. Eventually, the experimental results specified that the carbon credits accrued for the CO2 mitigated by the FPAP and CSBAP systems in the natural convection mode were calculated to be approximately 226.48 and 308.11 Rate $/year, respectively. These alterations synergistically contribute to enhancing the SAH's effectiveness and effectively utilizing solar heat directly contributes to reducing greenhouse gas emissions and, subsequently, the carbon footprint.

This research work deals with the examination of the techno-economic, exergy, and energy analyses of biomass gasification of the invasive weed Parthenium hysterophorus (PHP) using Steam - Carbon dioxide (CO2) as a gasifying agent with the support of simulation modeling for sustainable energy conversion process. The aim of this work is to simulate the gasification process through consideration of the impacts of various operating factors on gasification. This study attains the gradual increase in hydrogen (H2) concentration from 51% to 63% along with the rise in carbon monoxide (CO) from 14.5% to 19% using Aspen Plus simulation. CO2 falls concurrently from 24% to 13.5%. The findings demonstrate significant advancements over earlier studies in terms of both gas composition and overall system performance. A computational model has been developed for the estimation of energy performance indicators such as total energy input, and energy consumed per mass of biomass gasified, which are used in the determination of the system's energy efficiency. The exergy analysis of the system is performed to assess the system's total losses in terms of efficiency gathered from the system's exergy ratios. The economic analysis evaluates the system's economies of scale by gas production at ₹.15/kg and long-term sustainability. The proposed system has been found with the potential to produce a high yield of alternative energy from PHP with increased economic efficiency and lower environmental impact.

Biofouling is an important biological constrain in the water treatment process, and the control or management strategies using green principles have gained recent attention. Antibiofouling agents based on the biological source are now extensively studied due to their high efficacy and are environmentally friendly. In this present study, Poly Acrylo Nitrile (PAN)/Ulvan hollow fibre membranes of four different modules were fabricated for water treatment studies by testing against B. subtilis and E. coli along with separation efficiency studies on proteins such as albumin, pepsin, and clay. Ulvan (Ulv), green seaweed sulfated polysaccharide extracted from Ulva fasciata, was coated on PAN hollow fibres, fabricated using a wet-spinning process. Ulvan was dip-coated on membrane surface followed by cross-linking and resultant changes in terms of performance and morphology. PAN/Ulv hollow fibre membranes were examined for the pure water flux and protein separation analysis to analyse the membrane efficiency. SEM was used to analyse the membrane structure and ATR- FTIR for the determination of functional groups. Ulvan coated (310 C) hollow fibre membrane showed better performance than the other three membranes with a flux of 398.1 L m−2 h−1. Higher sample concentration of suspended solids paved simpler route for enhanced COD sequestration efficacy. Pepsin, albumin, and clay particles were rejected by the 310C Ulvan adorned membranes at rates greater than 80%. By incrementing suspended particles beyond 3200 mg/L, the greatest power recovery was reduced that portrays an adverse influence of bio-fouling process on membrane operation. Experimental results demonstrated that synthesised 310 C membrane possessed better separation performance and antifouling characteristics for aquatic water systems.

Electric vehicles (EVs) energized with electricity derived from renewable energy power systems can aid in reducing carbon emissions from road transport. But to enable faster adoption of EVs, increasing the distance traveled when the battery is fully charged, and fast charging is necessary. At the same time, effective thermal management in battery systems plays a vital role in enhancing the performance, safety, and longevity of Li-ion batteries (LiBs). Thus, designing a cost-effective battery TM system is necessary for faster adoption of EVs. Among the various available TM systems for LiBs, the external thermal management technique was found to be more effective when compared to passive thermal management. The external LiB thermal management system incorporated with phase change material (PCM) can enable effective dissipation of heat from it with minimal energy requirement. However, the performance of these systems can be further enhanced by enhancing their thermal conductivity by suspending nanoparticles. However, the selection of appropriate PCM is essential to ensure effective thermal management. Hence, the central focus of this review is to identify the key parameters that affect the performance of PCM-based thermal management in LiBs. The paper also explores different battery thermal management (BTM) system architectures, encompassing carbon-based, metal-based, and hybrid solutions, delineating their respective strengths and limitations. The review integrates insights on thermal conductivity correlations established by previous research works. These correlations enable the prediction of thermal behavior in BTM materials, streamlining the design and optimization process. By addressing these limitations, the transition to sustainable and environmentally friendly transportation systems is a global imperative to combat climate change.

The growing demand for energy and the necessity to enhance the efficiency of heat exchangers have triggered numerous studies aimed at improving convective heat transfer rates while simultaneously reducing the size and investment costs of industrial devices. In this comprehensive review, a thorough analysis of recent literature has been undertaken to explore the latest advancements in tubular, plate, and extended surface heat exchangers, considering factors such as geometry, materials, and heat transfer fluids. The review comprehensively covers passive, and combined approaches to convective heat transfer (CHT) enhancement in these heat exchangers. Consideration is afforded to research studies exploring passive techniques in double pipe heat exchangers (DPHEXs), plate heat exchangers, and extended surface heat exchangers. The review extensively explores surface modifications such as corrugated surfaces, twisted tapes, and rough surfaces in heat exchangers. It provides detailed insights into the impact of these modifications on CHT rates and overall heat exchanger performance. The review also encompasses an examination of different chevron angles and the use of various refrigerants in plate heat exchangers. It offers a comprehensive overview of the effect of these factors on the performance of plate heat exchangers. Furthermore, the review examines an analysis of various types of fins utilized in different heat exchangers, exploring their effectiveness in conjunction with different heat transfer fluids. This examination provides insights into the interactions between fin configurations and heat transfer fluids, contributing to a comprehensive understanding of their impact on heat exchanger performance. Moreover, the review comprehensively covers the utilization of different nanoparticles and nanomaterial sizes in car radiators, highlighting advancements in real-time application. Additionally, it explores the use of various types of extended surfaces and nanofluids in different heat exchangers, providing a detailed analysis of their impact on heat transfer enhancement. The examination also includes a review of water-based nanofluids and their diverse applications in various heat exchangers, shedding light on the evolving landscape of nanofluid technology in the field.

Bioenergy resources, when harvested sustainably, have the potential not only to satisfy the growing energy demand but can also aid in achieving a negative carbon footprint. The Intergovernmental Panel on Climate Change (IPCC) has also identified bioenergy resources as an effective tool to achieve zero emissions by 2050 because biomass can be valorized into various products, namely, producer gas, syngas, bioethanol, biomethanol, biochar, bio-oil, etc. by adopting different conversion pathways, thus, aiding in the reduction in consumption of fossil fuel, thereby decreasing the anthropogenic greenhouse gas (GHGs) emission into the atmosphere. However, it is necessary to analyze the economic viability of these biorefinery systems for the faster penetration of these products into the global market and to identify the bottleneck haunting its faster dissemination. In this regard, this chapter analyses the technical and economic factors which affect the biorefinery of woody biomass by employing thermo-chemical and bio-chemical conversion processes.

The global nations are under pressure to develop a renewable and environmentally friendly fuel/technology from sustainable feedstock, such as woody biomass, to reduce greenhouse gas emissions and meet the energy demand. But several factors must be addressed to achieve the daunting task, which includes technological advancement, financial viability, environmental sustainability, and finally government backing in the form of sensible regulations and increased public awareness. To reduce the world's reliance on fossil fuels and ensure a sustainable future, biofuel policies are crucial. The production of biofuel from woody biomass makes the system not only to reduce the cost of the feedstock but also to decrement the dependency on first-generation feedstocks, which dominates the present biofuel market. Hence, this chapter deals with the need for governing bodies to draft an effective policy for the successful adoption of woody biomass-based biorefinery technologies to mitigate global emissions and to fulfill the growing energy demand thereby enabling a sustainable economy.

The energy sector accounts for three-quarters of the greenhouse gas emission happening around the world. So, it is necessary to move toward a sustainable fuel with minimal carbon emissions to mitigate the rise in global temperature. Bioenergy is considered an effective resource to satisfy the rising global energy demand with minimal carbon emissions. The presence of proven and well-mature technology to convert biomass into various forms of fuels and chemical products provides an upper hand to bioresources over other energy sources. However, the rise in the cost of feedstocks, transportation cost of low-density bioresources, and lack of reliable biomass supply chain network has made them least preferred when compared to solar and wind energy technologies. Hence, it is important to access the scope for commercialization of biomass-based products, which will aid in framing policies to create a sustainable market for them.

Hydrogen is considered as the fuel of the future not only because of its high energy density but also due to its zero-carbon emission potential during combustion. However, to achieve sustainable growth, the hydrogen generation process must be techno-economically feasible and have minimum carbon footprint. The techno-economic analysis (TEA) of various hydrogen generation process aids in identifying the effective bio-hydrogen generation process at minimal cost thereby aiding in faster dissemination of the system by attracting investors. Among the various techniques available for bio-hydrogen production, gasification was found to be most economical ($1.2/kg H2) followed by anaerobic digestion process ($1.25/kg H2). Meanwhile, after carrying out the life cycle analysis (LCA) of the different bio-hydrogen generation process, it was found that generation of bio-hydrogen by gasification of eucalyptus wood produced least carbon foot of −1.6 kg CO2eq./kg H2. Thus, the TEA and LCA of different biohydrogen production process also helps to identify the bottlenecks haunting the penetration of hydrogen in energy market which can be overcome by framing effective policies by the governing agencies.

Carbon capture storage and utilization (CCSU) has the potential to become a key tool to mitigate climate change, thus, aiding in achieving the objectives of the 2015 Paris Agreement. Even though the relevant remediation technology has achieved technical maturity to a certain extent, implementation of CCSU on a larger scale is currently limited because of non-technical parameters that include cost, legalization, lack of storage reservoir, and market mechanism to penalize CO2 emitter. Among these, cost emerges as the primary barrier to the dissemination of CCSU. Hence, necessary policy frameworks and incentives must be provided by governing agencies to enable faster dissemination of carbon capture and utilization (CCU) and carbon capture and storage (CCS) globally. Meanwhile, strict implementation of a carbon tax across nations and market demand for products generated using captured CO2 can aid in the fast adoption of CCU and CCS. This review assessed the economic feasibility and sustainability of CCS and CCU technologies to identify the barriers to commercializing these technologies.

Bioenergy with carbon capture and storage (BECCS) is gaining attention as an energy source and the most effective path to achieve negative CO2 emissions by photosynthesis and capturing CO2. However, BECCS has certain challenges and limitation which needs to be addressed to make the technology feasible. Concerns about food security, land, water use, and the possibility of large-scale implementation are critical in commercialization. As an emerging field, BECCS will need dynamic research and development over the next few decades, as well as strong policy backing, to clinch that it can be implemented on time for fulfilling the Paris agreement targets. The goal of this critical review is to find the impending obstacles that BECCS is facing, as well as the approaches to overcome them, while also emphasizing the advances in the field over the last decade. Detailed technology assessment is provided for a better understanding.

Woody biomass, the most abundant and high energy density bioenergy resource, is used inefficiently to satisfy the domestic heating and cooking demands of the people. Despite being a carbon-neutral source when harvested sustainably, the inefficient use of biomass to satisfy the cooking demand of marginalized people led to poor indoor air quality and causing respiratory health problems. Hence, it is necessary to identify a technology that enables the conversion of woody biomass into fuel that does not affect indoor air quality. In this regard, the conversion of woody biomass into biogas by anaerobic digestion emerges as the viable option. However, the recalcitrance nature of woody biomass necessitates a pretreatment before being fed to an anaerobic digestor, increasing the capital and operating cost of the biogas system. But usage of this technology to convert woody biomass to gaseous fuel can aid in sustainable development. The waste digested from the anaerobic digestor can be used as manure for agricultural crops in rural areas. Meanwhile, fly ash generated during the combustion of the woody biomass is also inhibited thereby resulting in an improvement in air quality. In this regard, this chapter presents the recent developments and factors affecting biogas production from woody biomass.

Nutrient recovery systems can help to mitigate the negative effects of N and P in WW (wastewater), which when not recovered causes eutrophication in aquatic ecosystems. Using SimaPro (V9.3), the lifecycle assessment (LCA) of four nutrient recovery systems and sewage treatment plant (STP) were compared in this study. The findings showed that a fuel cell with a single-pot WW treatment system can function as a negative emission system with a global warming potential (GWP) of −234 gCO2 Eq./m3 of WW. Nutrient recovery reduces carbon footprint by 56–98% when compared to traditional fertilizers like diammonium phosphate (DAP) and urea. One of the main conclusions of this research was that single-pot systems perform better for the environment than add-on systems, which suggests that microalgae could perform better for the environment in a single-pot system. Recovering nutrients from WW not only improves self-reliance in the economy by decrementing the fertilizer import but also saves the environment.

The deionized (DI) water and activated carbon (AC) nanofluids were produced at different volume concentrations (VCs) such as 0.1, 0.25, and 0.4 %. ACNMs were produced through the pyrolysis process of deadly available Kigelia Africana leaves in a muffle oven at 500 °C. The structural properties of the activated carbon nanomaterials (ACNMs) were described through the usage of SEM, EDS, XRD, and FTIR analyzers. Thermal exchange properties that as density (ρ), thermal conductivity (TC), specific heat (SH), and viscosity (µ) of DI water - AC-based nanofluids were evaluated experimentally. The five various mass flow rates (MFRs) namely 20, 40, 60, 80, and 100 g/sec were applied with different VCs of DI water - AC nanofluids in this study. In addition, the hot fluid (nanofluid) inlet temperature was constantly maintained with the help of a hot DI water bath at 50, 60, and 70 °C, respectively. The highest thermal conductivity (TC) augmentation attains up to 9.134 % is detected at 0.4 vol% of ACNMs loading at 70 °C. The addition of ACNMs augments the specific heat (SH) of the nanofluids substantially, and this augmentation diminutions with an increase in the ACNMs concentration. The addition of ACNMs in the DI water augments the Nusselt number by 21.76 %, 24.71 %, and 32.47 % for 50, 60, and 70 °C respectively, at a VCs of 0.4 % and mass flow rate of 0.1 kg/sec in the car radiator. In addition, turn up a palpable reduction in Reynolds number for specified MFRs for all the ACNM nanofluids.

The main bottleneck haunting the wide dissemination of solar still is its poor yield per unit area. This study aims to overcome the above bottleneck by augmenting the yield of SS by increasing the surface area available for condensation by incorporating an acrylic chamber filled with water beneath the top glass surface. The solar still incorporated with acrylic basin (ACSS) was operated in two different methodologies and its performance was ascertained and compared with the conventional passive solar still (CPSS). The surface area available for condensation in CPSS and ACSS operating in two different modes were 0.52 m2 and 0.87 m2, respectively. The efficiency of the CPSS and ACSS operated in mode I was 24.28% and 28.94% respectively. On the other hand, the efficiency of the CPSS and ACSS operated in mode II was 26.61% and 31.29% respectively. The rate of evaporation of water from the basin of ACSS operated in mode II is enhanced by 42.74% when compared to the CPSS. The increment in evaporation rate can be attributed not only due to the increment in surface area available for condensation but also due to the supply of hot water present in the acrylic chamber to the basin of the ACSS operated in mode II depending on its yield for every half an hour. Meanwhile, replenishment of water in the acrylic chamber every 30 min by water at 30 °C, abets in reducing the lower surface temperature of acrylic chamber which aid in increasing the temperature difference between water in the basin and lower surface of acrylic chamber. Thus, the productivity of ACSS operated in mode II is higher than that of CPSS by 17.59%.

This study aims at augmenting the distillate output of passive solar still (PSS) by incrementing the surface area available for condensation by incorporating the water jacket (WJ) around the sidewalls of PSS. In the PSS incorporated with a water jacket (WJSS), the evaporated water from the basin condenses on the surface of the WJ in addition to the inner glass surface thus enhancing the dehumidification rate. The preheated water from the WJ was filled into the basin of the WJSS at an interval of 30 min depending on the distillate water output. Meanwhile, an equivalent quantity of brackish water at 30 °C was manually added to the WJ. The thermal efficiency (ηth) of the WJSS was 43.19% higher than that of the conventional passive solar still (CPSS). The overall yield of WJSS was 2.62 L/m2/day while the yield of CPSS was 1.83 L/m2/day. The presence of the water jacket in WJSS enabled an increment in its yield not only by incrementing the available surface area for condensation by 123% (1.16 m2) when compared to CPSS but also by reducing the heat loss happening in the system. Thus, leading to an increment in the exergy efficiency of WJSS (2.5%) when compared to CPSS (1.1%).

In the present work, energy, exergy, economic and environmental evaluation of single slope solar still (SS) using multiple enhancement techniques namely, sandblasting, milling, and shot-blast aided corrugation are investigated. Totally four SS types are considered, namely (1) conventional SS, (2) sandblasted surface absorber-SS, (3) milled surface absorber-SS, and (4) shot-aided corrugated surface absorber-SS. Among the methods employed, the shot-blasted aided corrugated-absorber SS produced a maximum yield of 3275 mL/m2/day, which was 1.46 times superior to that of traditional/conventional solar still (CSS) yield (2250 mL/m2/day). Activated carbon with black paint-based spray coating (14 vol%) improved mean absorptivity by 5 %, as a result, the thermal efficiency of the SS was increased up to 57.2 % as compared to traditional SS. The exergoeconomic factor of the SS with sandblasted, milling, and shot-blasted aided corrugation was SS was 25.2, 62.8, and 98.5 % respectively greater than CSS. More importantly, the energy payback time for CSS, sandblasted SS, milling SS, and shot-blasted SS were 1.49, 1.498, 1.396, and 1.065 years, respectively. Also, the exergy payback time for CSS, sandblasted SS, SS with milling, and SS with shot-blast aided corrugation were 5.99, 5.05, 3.90, and 3.23 years respectively.

Increases in population and urbanization leads to generation of a large amount of food waste (FW) and its effective waste management is a major concern. But putrescible nature and high moisture content is a major limiting factor for cost effective FW valorization. Bioconversion of FW for the production of value added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting on production of multiple products will solve these issues to greater extent. This article provides an overview of bioconversion of FW to different value added products.

This review provides an update on the state-of-the art technologies for the valorization of solid waste and its mechanism to generate various bio-products. The organic content of these wastes can be easily utilized by the microbes and produce value-added compounds. Microbial fermentation techniques can be utilized for developing waste biorefinery processes. The utilization of lignocellulosic and plastics wastes for the generation of carbon sources for microbial utilization after pre-processing steps will make the process a multi-product biorefinery. The C1 and C2 gases generated from different industries could also be utilized by various microbes, and this will help to control global warming. The review seeks to expand expertise about the potential application through several perspectives, factors influencing remediation, issues, and prospects.

This work aims to explore the optical and thermal conversion characteristics of activated carbon—solar glycol nanofluids with various volume fractions namely 0.2, 0.4, and 0.6%, respectively. Kigelia africana leaves were synthesized into porous activated carbon nanomaterials by using the high-temperature sintering process and the pyrolysis process in a muffle furnace. The experimental investigation was carried out with different nanofluid concentrations by using the solar simulator. Nanofluids were heated with the assistance of a solar simulator test system and the convection/conduction heat loss was decreased by using the glass as an insulating material around the test section. Prepared nanofluid with 0.6 vol% activated carbon augmented the thermal conductivity by 14.36% at 60°C. The maximum temperature difference of 10°C was attained at 0.6% volume concentrations of nanofluid as compared with base fluid (solar glycol). In addition, maximum receiver efficiency of 94.51% was attained at 0.6% volume fractions of activated carbon-based nanofluid compared with solar glycol thru a light radiation time of 600 s. Moreover, activated carbon–based nanofluid exhibited significantly higher absorption efficiency as the majority of the radiation was absorbed by the nanofluid. It is concluded that activated carbon-based nanofluids could be a suitable low-cost highly stable material for developing working fluid for direct absorbance solar collector–based applications.

This work aims to develop a novel nanofluid using Therminol-55 (T-55) as heat transfer fluid and multi-wall carbon nanotubes (MWCNTs) as dispersants with various volume concentrations of 0.05, 0.1, 0.3, and 0.5% and assess its thermo-physical properties for solar-thermal applications. The pH values of nanofluid MWCNT/T-55 with various particle loading were too far-flung from the pH (I) value, which confirmed the good dispersion stability of nanofluid. The measured density shows tremendous deviation from predicted density with increasing MWCNT loading owing to the non-considering of microstructural parameters in Pak & Cho correlation predication. The highest augmentation in nanofluid thermal conductivity was 16.83% for 0.5 vol. % MWCNT at 60 °C. The maximum improvement in dynamic viscosity of nanofluid with 0.5 vol. % of MWCNT is found to be 44%, and this rise is reduced at higher temperatures. The thermal effectiveness of the nanofluids demonstrates that nanofluid with all volume fractions of MWCNTs was favorable at higher temperatures in the laminar region. Mouromtseff number ratio decreases with a rise in temperature and MWCNT volume concentration. It is concluded that the excellent thermo-physical properties and prolonged thermal stability of the MWCNT will be highly beneficial in improving the overall performance of various kinds of heat transfer fluids (HTFs) for process heating and solar-thermal applications.

In this paper, an effort has been made to produce biodiesel from Neem oil (Azadirachta Indica) and to perform a comparative analysis on various blends with diethyl ether (DEE) and alumina nanomaterials at different volume fractions. The fraction of alumina oxide (Al2O3) nanomaterials with the blend (Pure Diesel 40% + Neem BD 40% + Ethanol) is varied in the range of 25, and 50 ppm. Experimental outcomes displayed that the physical and chemical properties of the biodiesel enhanced with the dispersion of alumina nanomaterials. The performance characteristics of the biodiesel blend such as brake thermal efficiency were increased up to 7.2% and brake specific fuel consumption was reduced up to 6.7% by adding the adding nanomaterial at 25 ppm of alumina nanomaterials compared with the pure diesel fuel. This is because of the higher surface area of the nanomaterial, which acts as the positive catalyst and increases the reaction rate. The Al2O3 positively altered the critical parameters like the ignition temperature and the ignition delay of a DE. Moreover, the addition of alumina nanomaterials gave better emission characteristics on the account of reduction in the HC, CO, and smoke emissions at higher loads compared to NDB. Al2O3 enhances the performance and the anti-knocking ability of the fuel. At 100% load conditions, the nitrogen oxide (NOx) emissions of NBD2 (Diesel 40% + Neem BD 40% + Ethanol 20% (90% volume + DEE 10%) are lower than NBD by 17.5%.

The effects of shot peening on the heat transfer, exergy analysis, and pressure drop in the heat exchanger were studied. Nanofluids were produced at different volume concentrations of 0.15, 0.3, and 0.45% of alumina oxide (Al2O3) nanomaterials well dispersed in solar glycol/water (80:20 by volume) as a base fluid. The outcomes point out that nanofluids (0.15, 0.3, and 0.45%) can enhance the Nusselt number by 8.098, 16.81, and 26.98%, compared with SG/H2O mixture respectively when compared with the SG-H2O blend with an impelling penalty of 1.47 folds. A higher enhancement in the CHTC of 56.32% was attained using 0.45 vol% of Al2O3 nanofluids at 0.08 kg/s. TEF of 1.118 is attained for the 0.45 vol% nanofluid inside the surface-modified (shot peening) heat exchanger. The maximal exergy efficiency was found to be 30.82% for 0.45 vol% of SG-H2O-based nanofluids and nanofluid MFR of 0.08 kg/s.

Need for increasing the shelf life of agricultural produce using renewable energy based A decentralized system are significantly increasing. The solar air heating systems (SAHs) are efiiecnet and environment fridnly systems which are used for preserving agricultural produce thourgh the reduction of moisture content. However, these systems had poor thermal efficiency and the way for increasing the effeiciney are much need in the present era. This article presents the energy, exergy, and economic analysis of a modified solar air heater system (SAH). The proposed (modified) SAH has a V-corrugation absorber plate; the inner surface was modified using shot-blasting technology. This is the first study to experimentally investigate a modified SAH and compare the results with those of a conventional SAH. Additionally, an environmental and sustainability assessment of the SAH is presented. The SAH performance was tested at airflow rates ranging from 0.01 to 0.02 kg. sec−1. The proposed SAH achieved higher energy and exergy efficiencies (15% and 34%, respectively) than a conventional SAH at a flow rate of 0.02 kg. sec−1. Although the modification significantly improves the SAH performance, the performance must be further improved as the SAH has a low exergy efficiency. Through extensive experimental investigation, it was found that the modified SAH performs well in terms of energy, exergy, and economics. Pertaining to MFR of 0.01, 0.015, and 0.02 kg. sec−1 the average energy efficiency of the modified SAH was increased by around 2.4%, 3.1%, and 5.8% greater than that of the conventional SAH, respectively. Concerning the MFR of 0.01, 0.015, and 0.02 kg. sec−1 the average exergy efficiency (AEE) was augmented about 0.21, 0.36, and 0.70 higher in the modified SAH, respectively. With MFRs of 0.01, 0.015, and 0.02 kg. sec−1, the modified SAH system mitigates approximately 10.3 tons, 18.06 tons, and 28.7 tons of CO2/year, respectively. The enviroeconomic factors of the modified (shot blasted) SAH were augmented by about 23.4%, 15.1%, and 18.2% compared with the conventional SAH at MFRs of 0.01, 0.015, and 0.02 kg. sec−1, respectively.

The main theme of the work is to examine the influence of ultrasonication time on colloidal stability and thermal conductivity (TC) of multi-walled carbon nanotubes (MWCNTs)-Therminol 55 based nanofluid. Three different volume percentages of nanofluid samples have been produced namely 0.09, 0.18, and 0.3 vol.% by adopting various ultrasonication times, varying from 30 to 120 min. The colloidal stability of the nanofluid samples has been examined over one month after formulation through carrying out zeta potential examination and visual inspection method. From the results it can be concluded that an increase in the sonication time up to 120 min results in the improved colloidal stability of nanofluid samples. Extending sonification time beyond 60 min weakened the nanofluid stability. The nanofluid TC of the samples has been measured experimentally over various temperatures ranging from 30 to 50 °C. It is noticed that rising the nanofluid temperature outcomes in decreasing the nanofluid TC, whereas it was incremented with rise in MWCNT concentration. Besides, the impacts of ultrasonication time on stability and TC have been examined, and it is noticed that rising the time of ultrasonication inducting a quiet augmentation in nanofluid TC. The highest TC was attained by employing 60 min time of ultrasonication.

This paper deals how optimisation studies were carried out on a selection of glazing materials for solar thermal applications with multi response characteristics based on Multi Criteria Decision Making Methodology using TOPSIS (Technique for order performance by similarity to ideal solution) methodology concerning seven alternatives. In this investigation, seven alternative materials and six criteria used for material selection for the optimal design. The results demonstrations that Polysulfone material is best for the solar thermal applications.

Latent heat energy storage material has been used by many researchers to achieve an enhancement in the yield of solar still. However, the poor thermal conductivity of Phase Change Materials (PCM) used in solar still led to slower charge/discharge of the energy stored in it. This led to the dissipation of most of the energy stored in the PCM as losses happening in the solar still instead of getting converted into useful work. In this study an attempt was made to improve the yield of the solar still incorporated with PCM by using a low thermal conductivity material to construct the basin of the still, thereby reducing the heat loss occurring along the bottom surface and sidewalls of the still. In the present study, the basin of the conventional solar still (CSS) used for experimentation was made of galvanized iron, which was used as a reference still. The other two stills were incorporated with PCM, whose phase change temperature ranges from 58.03 °C - 64.5 °C. Among the stills incorporated with PCM, the basin of one of the still was constructed using galvanized iron (GIBSS) while the basin of the other still was made using acrylic (ABSS). From the experimentation, it was inferred that the usage of acrylic as basin material helped to reduce the charging span of the PCM but also delayed the discharge time of the PCM, thereby enhancing the yield of the still. The yield of ABSS was 4.36 L/m2/day, which was 10.1% and 19.1% higher than GIBSS and CSS respectively. Meanwhile, the exergy efficiency of ABSS was 3.46% and that of CSS and GIBSS were 3.56% and 2.99% respectively. The cost per liter of water produced by CSS, GIBSS, and ABSS was found to be ₹0.67, ₹1.09, and ₹1.23 respectively.

The main objective of the present work is to treat tannery effluent with a total dissolved content of 150 g/L using solar energy by humidification and dehumidification process using a roof even type greenhouse evaporator. This system not only helps to effectively treat the tannery effluent by increasing its total dissolved solids content to 350 g/L but also helps to generate potable water from tannery effluent by using solar energy. In this study, the performance of the effluent was tested in six different modes. It was found that the tannery effluent total dissolved solids content increased to 350 g/L in just 2.5 days when the greenhouse evaporator was operated in Mode 6 which is the shortest duration when compared to other modes of operation. The specific fuel consumption of the roof even type greenhouse system to treat tannery effluent is 22.55 kW h/ m3 which is 8.3 % of the energy consumed by the zero liquid discharge plant. Meanwhile, the land area required to dehydrate 1 m3 of tannery effluent got decreased by 43 % when the roof even type greenhouse evaporator was used.

The spray coating technique is used in this study to spread a thin layer of nanoparticle on a large flat substrate. The proposed spray coating techniques has a great potential for large scale productions, as these techniques have no restrictions on the substrate size and low utilization of the process parameters. In this study, a simple airbrush spray coating technique is used to deposit the multiwall carbon nanotubes (MWCNTs) on copper substrates with a decent deposition control. The microstructures, surface roughness, and wettability of the coated substrates were tested and compared with the pure copper substrates. The MWCNTs coated copper substrates exhibits a significant enhancement of the mechanical properties compared to the normal surface. The thickness of the copper substrates increases with increase in coating weight concentrations, the maximum thickness 1.43 microns achieved at 0.4 wt. % of MWCNTs. The usage of copper and MWCNTs based thin film signifies a inspiring but possibly a sustaining chance for developing the future generation heat transfer materials

This article deals with the photothermal conversion performance of solar glycol – multiwall carbon nanotubes based nanofluids were studied with various weight concentrations and time. A broad investigation was performed with various nanofluid samples with the help of a sun simulator. The measurement was conducted with solar glycol-MWCNTs based nanofluids with 0.1%, 0.2%, and 0.3% volume concentration respectively. The heat loss was reduced by insulation material, whereas the nanofluid samples were heated with the help of a sun simulator. The difference in temperature of 7.7°C was attained for the 0.3 vol.% nanofluid as compared with solar glycol. Compared with solar glycol the temperature of MWCNT-SG based nanofluid at the volume concentration of 0.3% was augmented by about 69.21% with a light irradiation time of 10 min. The experimental results confirm that the SGMWCNTs based can be used as the right replacement for heat transfer fluids for direct absorption solar collector system applications.

This paper presents an innovative hybrid system that serves the dual purpose of heating air and water simultaneously. To achieve an enhancement in thermal performance, the rectangular aluminum duct's inner surface in the air heater and the copper absorber plate in the water heater was roughened using a pressurized shot-blasting technique. Furthermore, the convective heat transfer performance was enhanced using solar glycol (SG) with multi-walled carbon nanotube (MWCNT)-based nanofluids. The performance of this novel combined system for a total collector area of 2 m2 was investigated experimentally. The SG/MWCNT-based nanofluid was prepared by adding a surfactant (i.e., gum arabic) at concentrations of 0.1 and 0.2 vol %. Based on the results of the experimental investigation, it was inferred that the collector efficiency is directly proportional to the volume percentage of the nanomaterials. An average temperature difference of 14.54 °C was achieved in the solar collector, whereas a maximum temperature of 18.32 °C was obtained for 0.2 vol % of MWCNT at a mass flow rate of 0.01 kg/s. Moreover, the maximum thermal efficiency of 51.03% was attained for a 0.2 vol % SG/MWCNT-based nanofluid at a mass flow rate of 0.01 kg/s.

The main theme of this research is for augmenting the yield of solar still (SS) with dual glazing, rotating cylinders, and to compare the distillate yield of these modified SS with that of the conventional solar still (CSS). In this respect, three types of SS with the same dimensions are planned, fabricated, and tested under the same climatic conditions. In addition, two cylinders wrapped with black cotton cloth are incorporated in a still (CBSS) and the other still is double-glazed (DGSS). The CSS is especially applied for the comparison with the yield of another two surface-modified SS. The yield of CBSS is 38.3% higher than CSS. While the yield of DGSS is lesser than CSS by 11%, this reduction in yield is due to the decrease in solar radiation reaching the absorber surface due to the presence of condensed water droplets in two glazing surfaces. The productivity of CBSS is higher than CSS because the evaporative surface area in CBSS is increased by rotating the two cylinders wrapped with cotton wick. Thus, it is construed that the SS with two cylinders wrapped with a cotton wick is the best option among the stills considered in this study.

This review paper focuses on the recent developments in theoretical and experimental research studies carried out to examine the electrical conductivity of different types of nanofluids. Based on it, various parameters that affect the electrical conductivity of nanofluids, namely the structure/shape and size of nanomaterials, temperature, preparation methods, instruments, surfactant, and volume concentration has been studied. It was found that the rise in volume fraction and the temperature of nanomaterials generally led to increment in electrical conductivity of all nanofluids.

This article deals with the thermal-hydraulic performance of a flat plate solar collector (FPSC) whose copper absorber plate and copper tubing surface are shot-peened to increase the fatigue life, strength, and roughness through a pressurized steel grit shot peening mechanism, to enhance the performance of FPSC. The objective of this experiment is to increase the convective heat transfer coefficient (CHTC) with lowest possible pumping power by augmenting the heat transfer between the absorber plate and the heat transfer fluid. The increase in surface area of the absorber tube and absorber plate made of the copper enables an increment in a specific length for “h” from the absorber area to the heat transfer fluid; this ensures that the surface area exposed to solar irradiance is increased. The experimental results show that the maximum thermal efficiency of the shot peened FPSC was about 54.24% when the flow rate was maintained at 0.02 kg/s. The cost per liter of hot water produced using FPSC whose absorber tube and absorber plate were painted black was about US $0.3.

This article deals with an experimental work that aims to examine the effects of MWCNTs dispersed into diesel fuels. Nano diesel fuels were prepared by dispersing multi-walled carbon nanotubes into base liquid. The MWCNT nanomaterial was mixed in the fuel blend along with a surfactant by means of an ultrasonicator, to attain stable dispersion. Physicochemical properties of nano-additive based diesel were measured and compared with pure diesel fuel. Physicochemical properties of nano-additive based diesel were measured and compared with pure diesel fuel. An experimental investigation was performed at a constant speed of 1500 revolution per minutes at different engine load conditions. The engine performance and exhaust emissions of a diesel engine burning MWCNTs were compared with pure diesel fuel. MWCNTs to diesel oil is effectively enhancing the performance and decreasing exhaust emissions in a diesel engine. The properties of N80 + JB20 with MWCNT fuel blend are changed owing to the mixing of biodiesel and the combination of the MWCNT nanomaterials.

The main objective of this work is to enhance the yield of solar still using the latent heat storage capacity of the phase change material (PCM) and to compare the distillate yield of PCM-assisted solar stills with that of the conventional solar still (Type A). In this regard, three solar stills of equal dimensions were designed, constructed and tested under identical weather conditions. In one of the solar still, 16 numbers of tubes having a diameter of 25.4 mm (Type B) were incorporated at basin, to accommodate the paraffin PCM, whereas in another solar still, PCM was embodied in between the annulus of the outer tube of diameter 31.75 mm and the inner tube of diameter 6.35 mm (Type C). The conventional solar still (Type A) was exclusively used for the comparison of the yield of the other two modified solar stills embodied with PCM. The daily freshwater productivity was 2.832 L/m 2 /d for Type C still, while the productivity of Type B and Type A still were 2.592 and 2.228 L/m 2 /d, respectively. This yield of Type C still corresponds to 6% and 27% higher than Type B and Type A stills, respectively. The higher yield in Type C still is due to the enhanced heat transfer surface and reduced thickness of the encapsulated PCM which offers less resistance compared with Type B solar still. Thus, it is construed that the geometry with PCM encapsulated in the annulus is the best option among the configuration considered.

The main aim of this present work is to explore the influence of dispersion of MWCNTs in a mixture of water-solar glycol (70:30) on its electrical conductivity and thermophysical properties such as density, rheology and thermal conductivity. The MWCNTs were seeded with a various weight percentage of 0.15, 0.3 and 0.45 via a common two-stage synthesis technique. The homogeneous stability of MWCNTs based nanofluids was confirmed by high-resolution scanning electron microscopy and ultraviolet-visible spectroscopy. The density of solar glycol and H2O mixture based MWCNTs nanofluids were measured with standard borosil volumetric flask via weighing balance mechanism and the experimental findings displayed a good agreement with the well-known correlation of Pak and Cho owing to the natural packing of H2O inside the nanomaterial in a limited quantity. The thermal conductivity of 0.45 wt. % MWCNTs seeding got augmented by 19.12% at ambient temperature while the electrical conductivity got augmented by 93.54% at 50 °C. Therefore, the augmentation in the thermal conductivity of water/solar glycol mixture with 0.45 wt. % MWCNTs seeding is because of the kinetics of nanomaterial accumulation and fluid layering. In addition, mathematical correlations were recommended for estimating the ratio of the thermal conductivity and viscosity of the nanofluid at different weight fractions.

This paper deals with an experimental investigation of mixed convection effects of flat plate solar collector with copper rod and tubes thermal performance enhancers in absorber tube and comparison was made between them for the same operating condition. The highest value of Rayleigh, Grashof, and Richardson number based on wall heat flux showed the heat exchange mode in the flat plate solar collector as of a mixed convection mode with the free convection predominant mode. The thermal performance enhancer collector significantly reduced the Rayleigh, Grashof and Richardson numbers compared to smooth pipe flat plate solar collector at all the operating condition. The experimental heat transfer coefficient for the flat plate solar collector was analyzed, and the rod thermal performance enhancer collector was found providing a higher heat transfer than tube thermal performance enhancer collector and smooth copper pipe flat plate solar collector. The highest performance evaluation factors were 1.38 and 1.29 for rod and tube thermal performance enhancers respectively.

This research study presents the experimental investigations on heat transfer performance of three different solar air heaters, without thermal insulation and with the effective use of bubble wrap and ceramic wool as thermal insulators. Thermal insulations reduce the heat losses from the bottom side of the solar collector. The selection of low cost and lower thermal conductivity (TC) insulation material plays an energetic role in enhancing the efficiency of the collector. The aluminum absorber plate of the solar collector is made of a corrugated surface area with a shot blasted of 1.96 m × 0.95 m × 0.12 m size formed in a rectangular. The thermal efficiencies of the shot blasted solar collector with and without bubble wrap, insulation and collector with ceramic wool insulation are evaluated theoretically and the expected performance results are analyzed in detail. The present paper covers the first time that eco-friendly bubble wrap has been used as an insulation material for a shot blasted solar air heater. The experimental results are collected with a shot blasted V-corrugated absorber solar air heating system (SAHS) with both bubble wrap (BW) and ceramic wool insulation. The results are compared to deviations. The climatic parameters such as wind speed, atmospheric temperature, solar irradiance and internal temperatures of the SAH are measured at repeated intervals of time to pinpoint heat losses. The investigational outcomes presented that the thermal efficiency of the ceramic wool insulated SAHS is higher than bubble wrap insulated SAHS for corrugated shot-blasted SAHS.

In recent years, several research studies were conducted to enhance the productivity of solar stills. One of the approaches was the integration of latent heat energy storage mediums (phase change materials (PCM)) in the conventional solar stills to extend the water yield ability after the sunshine hours. Though several studies were conducted in this research area, none of the studies analyzed and reported the time of day at which the PCM start to release the stored latent heat, especially in the case of use of multiple PCMs. The present study is an experimental investigation that compare the thermal performance of three same-sized passive solar stills, i.e., conventional solar still (Still 1), still with single phase change material (Still II), still with two phase change materials (Solar III). The two PCMs used in still III are chosen in such a way that both the PCMs have almost same latent heat storage capacity, but different phase change temperature range. PCM1 and PCM2 used in solar still III have the phase change temperature (PCT) range of 58.03 °C–64.5 °C and 53.05 °C–62 °C, respectively. The experiments were conducted for the climatic conditions of Chennai, India during the month of February to May. The major inference from the experiments conducted is that, when multiple PCMs are employed in a still, selection of PCM with appropriate PCT range is very important. PCM1 should start discharging the stored latent heat energy stored once the solar radiation gets diminishing and PCM2 should start to release the heat when PCM1 has almost discharged the entire stored energy. By this way, the time of yield can be prolonged. In the results, the thermal performance of Still I, II and III was analyzed in terms of hourly yield per day and exergy efficiency. The yield of Still I was 3.680 L/m2/day while the yield of Still II and III were 4.020 L/m2/day and 4.400 L/m2/day, respectively. The exergy efficiency of still I, II and III were found to be 3.92%, 3.23% and 3.52%, respectively.

Solar cooking is one of the most promising techniques to meet the cooking needs in remote areas where electricity and fuel supplies are meager. Solar box cooker is an efficient device used in solar cooking as it is simple to fabricate, easy to operate and hazard-free. In this context, the performance evaluation of a solar box cooker with varied number of reflectors has been undertaken. It was found that the time consumed for cooking in a box type solar cooker with four reflectors is lesser compared to that of a single reflector and its overall utilization efficiency increases with increase in the cooking mass. Further, a latent heat energy storage system was designed and fabricated to cook the food at off-peak hours of solar radiation. This latent heat energy storage system was combined with the solar box cooker. Oxalic acid dihydrate was used as the phase change material due to its high specific enthalpy and its melting point lying close to the cooking temperature. It was found that the solar box cooker with phase change material could be effectively utilized to cook food during off-peak hours of solar radiation.

The performance evaluation of a newly developed double walled cooking unit (tava type) suitable for an indirect type solar cooking application integrated with thermal energy storage system is presented. The experimental set-up consists of a cooking unit, a storage tank and a positive displacement pump. Therminol 55 and D-Mannitol are used as the heat transfer fluid (HTF) and storage medium respectively. During the cooking experiment the maximum temperature reached by the olive oil in the cooking unit was 152 °C within a duration of 15 min which is comparatively lesser than the time taken by a conventional LPG stove in simmering mode. A heat balance for the developed cooking unit was prepared to account for the heat input and the distribution pattern. An experiment was also conducted to evaluate the average heat loss encountered in the system under no load condition and it was found that there was considerable heat loss in the flow circuit during the discharging process. The results of the present study will be very useful for the design of solar based indoor cooking units.

Many cook stove programs implemented in South Asia and Africa were aimed at reducing fuel wood consumption and pollutants through the use of improved cook stoves. The research work presented in this paper is focused on evaluation of improved cook stoves with respect to thermal efficiency and emission levels. Since the type of biomass fuel varies in different geographical regions, the improved cook stoves must be compatible to use different types of fuel. The present research work is aimed at evaluating three types of forced draft cook stove with two types of biomass fuels. Water boiling tests were conducted to evaluate the stove performance with respect to efficiency and fuel flexibility. The findings of the study are used to evaluate the stove's performance with respect to fuel flexibility, efficiency and user acceptance. The performance results of three types of forced draft stoves tested with fuel wood and coconut shell are presented in this research paper. © 2012 Elsevier Ltd.

Rural area electrification in developing countries helps to improve the quality of life of the people. It increases productivity and supports education. It also discourages people from migrating towards urban areas. In India about 70% of the population lives in rural area, hence it is necessary to electrify these villages to achieve inclusive economic growth. Transmission and distribution of power to this less densely populated areas which are located far away from the power generating stations is the major reason for not able to achieve 100% electrification in the country. Hence it is necessary to find out an energy source which can be decentralized to supply power to these hamlets. As India is blessed with solar energy which is omnipresent in almost all parts of the country, micro grid system which uses solar photo voltaic panels seems as the finest option. The solar photo voltaic system converts light energy into direct current power using photovoltaic effect. Battery is used to store the extra power generated during the day and used during nights. Inverters and power conditioning devices are used to convert direct current power generated by solar photo voltaic systems to alternative current, which is supplied to the load using power distribution network which adds to system cost. At present the capital cost and the land requirement for this system is higher than all other renewable energy power generation system. But it has very less operation and maintenance cost which makes it superior to other system. Moreover additional modules can be added to it when the power demand increases. This paper says about how rural area electrification can be achieved in India by solar photo voltaic system micro grid system and the challenges which has to be over come during implementation. © 2012 Elsevier Ltd. All rights reserved.