Faculty Publications
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Item Sorption–desorption characteristics of dried cow dung with PVP and clay as composite desiccants: Experimental and exergetic analysis(Elsevier Ltd, 2023) Dasar, S.R.; Boche, A.M.; Yadav, A.K.; Anish, S.The present study investigates the sorption and desorption characteristics of a natural composite desiccant based on dried cow dung (DCD). Polyvinyl Pyrrolidone (PVP) and clay are used as binders with DCD. The moisture uptake capacity of composite desiccants is measured with an isotherm experiment under different DCD to binder ratios. Based on their isotherms, composite desiccants are chosen for characteristic study under different humid conditions and validated with available literature data. Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses are carried out to understand the physical properties of DCD, DCD+PVP (3:1) and DCD+Clay (3:1). Total heat load reduction, exergy efficiency and power required for these dehumidification systems are calculated for different inlet conditions. Desorption characteristics are tested at 328 K and 6% RH. Results show the maximum moisture uptake capacity of DCD and DCD+PVP as 14.42 and 14.72 g/100 g, respectively. The maximum exergy efficiency of the DCD+PVP dehumidification system is found to be 55%. Desorption time for DCD+PVP desiccant is 17 min, which is 4 and 2 min higher compared to DCD, and DCD+Clay, respectively. With this experimental study, it is concluded that the DCD+PVP has the potential to become an alternative to chemical desiccants based on their exergy efficiency and moisture uptake capacity. © 2022 Elsevier LtdItem Application of Box-Behnken Design in Optimization of the Okra (Abelmoschus esculentus L.) Plant Growth in Loamy Sand Soil(Springer Science and Business Media Deutschland GmbH, 2023) Shilli, A.; Manikandan, S.K.; Nair, V.Seedling emergence and its vigor index are the decisive steps for increasing vegetable crop yield performance using a sustainable approach. Response surface methodology (RSM) is an effective statistical method used to determine the significance of independent variables and the range of optimum conditions to maximize seedling growth in large-scale plant production. In this study, the RSM method was used to predict the maximum germination percentage and seed vigor index of an okra (Abelmoschus esculentus L.) plant in loamy sand soil. A Box-Behnken design of RSM having 15 triplicated runs was designed for okra seed germination experiments. A second-order polynomial model having three levels of biochar (10, 5.5, and 1%), cow dung (10, 5.5, and 1%), and water content (100, 70, and 40%) was used to optimize okra seed germination and seed vigor index. We evaluated the individual effect of biochar and cow dung manure on β-glucosidase and alkaline phosphatase activity in the soil. The results showed that the water content had a significant influence on the selected response variables. Based on the plant growth studies, the use of 5.5% of both biochar and cow dung concentration and 70% of water content in the soil resulted in the highest germination percentage and seed vigor index of 93% and 2479. The ANOVA studies revealed good agreement between the experimental data and the proposed model, indicating the suitability of the employed model in optimizing germination conditions. Enzyme activity analysis revealed that the amendment of 10% cow dung enhanced 55% β-glucosidase activity compared to control, while the application of 5.5% biochar along with cow dung improved 29% of alkaline phosphatase activity. The current study found that applying biochar and cow dung manure while maintaining water content can improve okra seedling emergence and growth in loamy sand soil. Future research includes long-term field experiments and studies on various biochar and their suitability for other soil types. Moreover, the RSM method can be used to study the effect of parameters like oxygen content, salt, heavy metals, and humus substance in soil on plant growth. © 2023, The Author(s) under exclusive licence to Sociedad Chilena de la Ciencia del Suelo.Item Experimental study on sorption–desorption characteristics of natural composite desiccant with metal embedment(Elsevier Ltd, 2023) Dasar, S.R.; Anish, S.; Kadoli, R.; Yadav, A.K.The present study investigates the effect on total moisture sorption, moisture sorption rate, moisture desorption rate, and reduction in the temperature of dehumidified air of metal-embedded natural composite desiccants (MENCDs), which can be used in dehumidification systems. A natural composite desiccant, in which the unutilized portion of the spherical desiccant material is replaced with a metallic ball, is proposed. Stainless steel balls with a diameter of 4.75 and 6.35 mm are used to make different thickness ratios (TR = 1, 0.525, and 0.365) of MENCDs. The natural composite desiccant is prepared from dried cow dung and polyvinyl pyrrolidone with a ratio of 3:1. Experiments are conducted to find the optimum thickness ratio of MENCDs. The total moisture sorption, moisture sorption rate, total heat load reduction, and exergy efficiency of these dehumidification systems are investigated under different relative humidities (RH = 65% to 85%), and at a constant temperature and velocity. Desorption characteristics are tested under 328 K and 5% RH. The total moisture sorption of MENCDs with a TR of 0.365 is found to be 11.84 g/100 g, which is 17% higher compared to natural composite desiccants (i.e., TR = 1) at 85% RH, whereas, the total moisture sorption rate is 0.4 g/100 g⋅min, which is 20.57% higher for TR of 0.365 compared to TR = 1. Moisture desorption rate for TR = 0.365 is 16.66% higher compared to TR = 1. The average exergy efficiency of these systems is 60%. The average exergy efficiency of these composite desiccants with a TR = 0.365 is 9.6% higher compared to TR = 1. The average total heat load reduction for composite desiccants with a TR = 0.365 is 24% higher compared to TR = 1. The experimental study shows that the MENCDs will help to increase total heat load reduction, sorption and desorption rate, and total moisture sorption of dehumidified air with optimum thickness ratio for enhanced utilization of a composite desiccant for dehumidification systems. © 2023 Elsevier LtdItem Experimental analysis of dehumidification system with natural composite desiccant coating on staggered hexagonal aluminium channels(Elsevier B.V., 2025) Dasar, S.R.; Bharti, N.K.; Sah, S.K.; Anish, S.; Yadav, A.K.This study aimed to develop an eco-friendly natural composite desiccant (NCD) for building cooling. NCD is a mixture of dried cow dung (DCD) and polyvinyl pyrrolidone (PVP) for use in a dehumidification bed with staggered hexagonal aluminium channels (SHACs). The natural composite desiccant was prepared by coating the mixture onto the channels with a 2:1 ratio of DCD:PVP. The maximum moisture uptake (MUC) and moisture uptake rate of the NCD was tested under different relative humidities (RH) and temperatures, and regeneration of NCDs was performed to maintain optimal performance. The results of the study showed that the NCD-coated SHACs dehumidification system had a high uptake capacity, with MUC values ranging from 8.34 to 14.31 g/100 g at different RH and temperature conditions. The system also showed an average uptake capacity rate of 0.26 g/100 g?min and a desorption rate of 0.51 g/100 g?min. Furthermore, the moisture flow design of the NCD-coated SHACs bed resulted in a low-pressure drop of 0.13 kPa, which was significantly lower than the NCD-packed bed. The study also calculated total heat load reduction at different inlet conditions. Eco-friendly dehumidification offers significant environmental benefits, and promising sustainable solutions. © 2024 Elsevier B.V.