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• Bifacial PVT Greenhouse dryer with PCM is designed and developed. • The operating hours and performance of the dryer with PCM are improved. • North wall insulation with aluminium foil is used for better performance. • MOGA-ANN methods have been used to explore the performance of PVT dryer. A greenhouse dryer is the most economical and environmentally friendly device used to dry various products like fruits, vegetables and meats. The operating hours and heat losses from the north wall are the main concerns for its performance. To minimize the heat losses and improve the operating hours, the present study is undertaken on a modified hybrid greenhouse dryer with a thermal energy storage system and a bifacial photovoltaic thermal for electrical (BIFPVT) and thermal energy. A thermocol was wrapped in an aluminium foil (As a reflector) and placed on the north wall to minimize energy losses. The integration of PCM made the system sustainable to use while off sunshine hours as it stores the thermal energy during daytime. It was observed that the BIFPVT system provided electrical power ranging from 2.0 to 85.5 W and 0.6–81 W with respect to solar radiation intensity on the front (I F) and rear (I R) side of BIFPVT which varied from 34–950 W/m2 and 13–350 W/m2, respectively. The drying room temperature was found to be 16–44% higher than the ambient temperature for both days. Further, the experiment result was trained using an artificial neural network and optimized with the help of multi-objective genetic algorithm tools. [ABSTRACT FROM AUTHOR]

The groundnuts were dried inside an even span roof type free convection greenhouse dryer with a useful floor area of 1.2x0.8m² in the environmental conditions of Rohtak, India (28° 54'-N 76° 34'E). Wire mesh sieves of sizes 0.15x0.25 m², 0.25x0.4 m², and 0.35x0.6 m² were used to accommodate thin layer samples of groundnuts. The groundnuts were dried till the optimum safe moisture storage level (8%-10%) was attained. Based on experimental (hourly) observations the values of constants (C and n) in the equation of Nusselt number were evaluated. The values of convective and evaporative heat transfer coefficients were calculated which were observed to decrease with the increase in the sieve size. The overall average greenhouse thermal, energy, and exergy efficiencies were evaluated as 8.83%, 22.67%, and 2.75% respectively. The overall average experimental error in terms of % uncertainty for groundnuts drying was evaluated as 37.94%. [ABSTRACT FROM AUTHOR]

• North wall insulated PCM-BIFPVT integrated greenhouse dryer (MHGD) was developed. • A detailed comparison of MHGD has been made with the PVT dryer. • The thermal and electrical efficiency of MHGD has been explored experimentally. • A comparison of computational data with experimental results has been carried out. In Covid19, it was observed that dehydrated commodity (fruits, vegetables, meat, etc.) was the most sustainable because of their long life and availability. The stored product market grew very fast after Covid19. It was predicted that the dehydrated circular economy would be the future of food demand and supply. The greenhouse dryer (GD) was the most economical and environmentally viable among various drying techniques. However, the problem associated with GD was low operating hours, sustainability, heat loss from the North wall, and operation after sunset. The present study incorporated a bifacial photovoltaic thermal (BIFPVT) on the roof, Lauric acid as a phase change material (PCM), and an aluminium foil-wrapped thermocol (Polystyrene foam) on the north wall of the GD as an insulation to overcome the above-said problem. The thermal efficiency of the modified greenhouse dryer was found to be lie in the range of 26–54%. In contrast, the electrical efficiency was found to be 20.1%. The integration of the thermal energy storage (TES) system runs the system even after sunset and improves the operation hours. The designed system not only makes the system self-sustainable but also mitigates 3136 kg of CO 2 in its whole life span. The modified TES can further improve the thermal performance of the GD. A PCM-integrated BIFPVT greenhouse dryer is recommended for cleaner production. [ABSTRACT FROM AUTHOR]

The thin layer drying behaviour of groundnut was investigated under open sun drying (OSD) and indoor forced convection drying (IFCD) modes. The groundnut samples were dried from initial moisture content of 38% (w.b.) to the safe storage moisture content of 8%-10% (w.b.). Four mathematical models were compared for describing the groundnut drying process. The performance of thin layer drying models was investigated by comparing the statistical parameters such as coefficient of correlation (R), reduced chi-square (Χ²), root mean square error (RMSE), and mean bias error (MBE) between experimental and predicted moisture ratios. Henderson and Pabis model was observed to give the highest value of R and lowest values of Χ², RMSE and MBE for the groundnut drying under both OSD and IFCD modes. The values of statistical parameters under Lewis model were also found to be very close to Henderson and Pabis model. Therefore, Henderson and Pabis and Lewis models were found to be the best for describing the drying behaviour of groundnut under both given conditions. [ABSTRACT FROM AUTHOR]

In this paper, convective and evaporative heat transfer coefficients of the Indian groundnut were computed under indoor forced convection drying (IFCD) mode. The groundnuts were dried as a single thin layer with the help of a laboratory dryer till the optimum safe moisture storage level of 8 - 10%. The experimental data were used to determine the values of experimental constants C and n in the Nusselt number expression by a simple linear regression analysis and consequently, the convective heat transfer coefficient (CHTC) was determined. The values of CHTC were used to calculate the evaporative heat transfer coefficient (EHTC). The average values of CHTC and EHTC were found to be 2.48 W/m2 oC and 35.08 W/m2 oC, respectively. The experimental error in terms of percent uncertainty was also estimated. The experimental error in terms of percent uncertainty was found to be 42.55%. The error bars for convective and evaporative heat transfer coefficients are also shown for the groundnut drying under IFCD condition. [ABSTRACT FROM AUTHOR]

Limited sources and rising cost of fossil fuels has instigated researchers to look towards renewable energy resources. Among renewable energy resources, solar energy is required to become indispensable in the future, as it is inexpensive, abundant, inexhaustible, environmental friendly and non-pollutant. Most of the people living in developing countries are dependent on agriculture. Agricultural products are dried to increase the storage life, minimize the packaging requirement and reduce the transportation weight. Solar drying for drying agricultural products is being practiced since long back throughout the world. Because of its drawbacks, advance technique, i.e. greenhouse drying, is being adopted for drying crops to reduce the drying time and increase the quality of the food products. Some new methods have also been attempted to increase the drying efficiency of greenhouse. In this paper, a comprehensive review of greenhouse drying of various commodities is presented. Different parameters such as thermal analysis, drying characteristics of crops, energy and exergy analysis, and greenhouse drying performance were discussed. In addition, the economical aspects of greenhouse dryers were also highlighted. This review paper will be helpful to the new researchers to know about the various technical aspects of the greenhouse dryer. [ABSTRACT FROM AUTHOR]

Peanut or groundnut is one of the major oilseed crops in the world. It is rich in oil and proteins. Developing countries account for about 95% of the world peanut production. Asia alone accounts for 70% of this amount where the major producers India and China together represent over two-third of global output. Traditionally, groundnuts are dried in open sun to its safe moisture level for storage. Natural and artificial (hot air drying) drying methods of groundnuts are being used throughout the world. Artificial peanuts drying devices consume very large amount of energy. In this paper, present status of peanut and a comprehensive review of its drying methods are discussed. Recent developments in preservation and storage of groundnuts are also highlighted. [ABSTRACT FROM AUTHOR]

This article is a comparison of the date fruits drying performance of two most simple and common type of solar dryers. A simple even span type forced convection greenhouse dryer (FCGHD) and a forced convection cabinet solar dryer (FCCSD) were developed and tested under the climate of Hisar, India. The average values of convective heat transfer coefficients (HTC) were calculated as 0.46 and 0.53 W m−2 °C−1 for FCGHD and FCCSD, respectively. The respective average evaporative HTC was evaluated as 64.58 and 276.06 W m−2 °C−1. The drying efficiency and specific energy consumption for date fruits drying under FCCSD were, respectively, 55.2% higher and 37.87% lower than that of FCGHD. Amongst seven considered thin layer drying models, Midilli–Kucuk model showed the highest commensuration to the experimentally evaluated drying data of moisture ratio for date fruits. Higher values of effective moisture diffusivity and lower values of activation energy were observed under FCCSD. The economic prospective of both the drying arrangements has also been presented. [ABSTRACT FROM AUTHOR]

Turning biomass waste into briquettes using densification techniques is one of the most promising steps toward mitigating biomass waste pollution and fuel issues in developing countries. Despite the continuous growth of scientific output over the past few decades, only a limited amount of information is available in the literature on biomass briquette optimization and mathematical modeling, as well as the physiochemical characterization of biomass feedstocks and briquette operating variables. In light of this gap in the current literature, this study summarizes the current state of the art and recent advances in biomass-based briquettes generated from agro-residues as an alternative source of clean energy. The primary research method for this study is literature review and conceptual modeling. First, many densification processes, such as piston press, screw press, roller press, hydraulic press, and quality variables such as ash content, calorific value, moisture content, density, compressive strength, shatter index, etc., are thoroughly discussed and compared. Then characteristics of different biomass wastes are studied, together with process parameters, including temperature, type of binder used, particle size, and influence on densification process choice. The current evaluation concentrated on the mathematical modeling and optimization of the briquetting technology and the usefulness of briquettes in applications for heating, cooking, and energy production. Overall, this manuscript will help new researchers understand the basic methodology, classification, limitations, and future perspective of briquetting technology in the production of solid biofuels. [ABSTRACT FROM AUTHOR]

This work explores the effect of latent heat storage on the performance of a passive‐type mixed‐mode greenhouse dryer for groundnuts drying. Experiments were conducted for mixed‐mode greenhouse groundnuts drying (MMGGD), modified mixed‐mode greenhouse groundnuts drying (MMMGGD), and open sun groundnuts drying (OSGD) under the climate of Hisar (India). Average convective heat transfer coefficients for MMGGD, MMMGGD, and OSGD were 0.738, 0.607, and 0.555 W/m2 °C, respectively, and the respective average evaporative heat transfer coefficients were 113.304, 41.483, and 14.266 W/m2 °C. Energy and exergy efficiencies were found higher for MMMGGD, whereas the specific energy consumption was found lower as compared to MMGGD. Statistical analysis has shown the appropriateness of the page model for predicting the thin‐layer drying behavior of groundnuts for MMGGD, MMMGGD, and OSGD. The lower value of energy payback time (4.47 years) and the higher value of CO2 mitigation (953.299 tons) for MMMGGD show the environmental suitability as compared to MMGGD. Practical applications: The present study focuses on the development of drying systems to prevent post‐harvest losses in groundnuts due to moisture and uncontrolled weather conditions. The temperature range of the proposed modified mixed‐mode greenhouse dryer is suitable for drying for most of the agricultural commodities. This drying system can be used for a range of food crops in different small and medium industries. Due to electrical independence, the proposed system seems best suited for small farms and farmers in remote and rural areas. The modified mixed‐mode greenhouse may also be used as a field‐based storage house for grains and freshly harvested crops. [ABSTRACT FROM AUTHOR]