Faculty Publications

Now showing 1 - 3 of 3

Computational and experimental studies on the development of an energy-efficient drier using ribbed triangular duct solar air heater
(Elsevier Ltd, 2020) Nidhul, K.; Kumar, S.; Yadav, A.; Anish, S.
Triangular duct cross-section is introduced for solar air heater (SAH) of an indirect type of solar dryer (ITSD). Using computational study, the thermo-hydraulic performance of triangular duct SAH with inclined ribs for varying rib inclination (30° < ? < 75°) in the turbulent flow regime (5000 < Re < 17500) is studied. With the rib configuration providing maximum thermos-hydraulic performance, a ribbed rectangular duct SAH is designed, and the performance of the same is compared to the former for similar heat input. Results show that the ribbed (? = 45°) triangular duct has 17% higher effectiveness compared to the latter and 79% when compared to smooth SAH. Ribs in triangular duct solar air heater facilitate the increase in temperature even in the core of the duct, delivering the air at 6 K additional temperature relative to a rectangular ribbed duct for same heat input and flow Re. The superiority of the ribbed triangular SAH is further confirmed by studying the drying characteristics of Okra and two variants of banana, namely Nendran and Robusta for the maximum temperature obtained at the outlet of the respective SAH. Various thin layer drying models available in the literature were analyzed, and Modified page model represented the drying behaviour with R2 = 0.99. For ITSD, ribbed triangular duct SAH exhibits a maximum of 60.3% reduction in moisture ratio with a maximum increase of 97.9% increase in average values of diffusivity coefficient confirming that it is an energy-efficient design for an ITSD. © 2020 International Solar Energy Society
AN ITERATIVE ALGORITHM FOR DESIGNING AND SCALING OF PARABOLIC TROUGH COLLECTOR BASED SOLAR AGRO-DRYING SYSTEM
(Begell House Inc., 2025) Kabeer, V.P.A.; Maniyeri, R.; Anish, S.
This work proposes a simple and robust iterative algorithm for designing and scaling an indirect solar agro-drying system, which harvests thermal energy for drying using a parabolic trough collector (PTC). Separate computational procedures are developed for the design of the PTC by considering receiver tubes with and without a glass envelope. The computational procedure starts with the total heat requirement in the drying chamber and considers various heat losses and heat loss coefficients for the PTC receiver tube. The equations for various modes of heat losses in receiver tubes with and without a glass envelope are identified and formulated. Using thermal network and heat balance analysis, the expressions for various heat losses and overall heat loss coefficient are formulated in both cases. Required aperture area for the reflector surface of the PTC can be obtained in terms of overall heat loss coefficient and the collector heat removal factor. The tedious equations involved in computational procedure are solved using an iterative algorithm by developing a code in MATLAB. The results obtained from parametric analysis conducted using computational procedure reveals that heat losses and area of PTC required for providing drying thermal energy will be more if the receiver tube of PTC is without glass cover. The iterative algorithm described here can be used to optimize the design parameters and thus helps researchers in designing and sizing the components required for drying agro-based products. The algorithm will also help to scale the size of PTC and drying chamber based on the quantity and item to be dried. © 2025 by Begell House, Inc.
Multi-criteria decision-making techniques based optimum selection of phase change material and its implementation in a solar crop dryer for agricultural products
(Elsevier Ltd, 2025) Kabeer, V.P.A.; Maniyeri, R.; Anish, S.
The energy storage in solar thermal systems is crucial as the fluctuations in solar energy and its unavailability in the night periods adversely affects the system effectiveness. The proper selection of phase change material (PCM) for energy storage in a particular application is vital important as it directly affects the overall performance of the system. The selection of an optimum PCM for a specific application is a complex problem, requiring consideration of multiple criteria involving thermal, economic, environmental and physical aspects. The present study aims to select the optimum PCM for energy storage in a solar crop dryer, while being sustainable and cost-effective. The organic PCM alternatives with their melting temperature in the range suitable for crop drying application are selected for the study. Six widely recognized multi-criteria decision-making (MCDM) methods viz. EDAS, MOOSRA, TOPSIS, PROMETHEE, MOORA and CODAS have been employed to identify the most suitable PCM from the available alternatives. The criteria weights for optimization are determined using AHP, CRITIC and ENTROPY techniques, and their combinations. All MCDM techniques gives paraffin wax as the optimum PCM to be used as energy storage material in solar dryer. The average scores such as TOPSIS: 0.75, EDAS: 0.82, MOOSRA: 0.94, MOORA: 0.36, CODAS: 0.13 and PROMETHEE: 0.094 are obtained for paraffin wax, and are found to be highest compared with other alternatives. The sensitivity analysis carried out with weight variation method ensures the robustness and reliability of applied methods. Further, a simplified iterative computational procedure is developed to compute the required quantity of PCM and its container dimension to maintain the drying temperature for a specific duration during off-sun shine hours. The computational procedure also selects paraffin wax as the best PCM, as its required quantity is less and thus container size is small. The experimental investigation on the solar dryer, incorporating paraffin wax as the thermal storage material exhibits good agreement with the computational procedure, thereby substantiating the effectiveness of the PCM selection methodology. The paraffin wax in its optimum quantity could deliver the heat at a constant temperature of nearly 60 °C for six hours, during sun down hours and night (from 3.00 pm to 9.00 pm), which supports the PCM selection using MCDM techniques and agrees with findings of computational procedure. The absorber temperature is also able to be maintained above 50 °C for an extended period of six hours. The average air temperature of 45 °C is maintained in the dryer during the sun-down period (3.00 pm to 9.00 pm), using paraffin wax as energy storage material. With the highest benefit-cost ratio of 8.17, paraffin wax also emerged as the most cost-effective option among the PCM alternatives. © 2025 Elsevier Ltd

Faculty Publications

Browse

Filters

Settings

Sort By

Results per page

Search Results