https://orcid.org/0000-0001-7775-8627
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ABSTRACT
This study presents an innovative, economically viable and energy-efficient greenhouse solar dryer integrated with a solar air heater. The focus is on drying tomato flakes using advanced 3-dimensional computational models based on Finite Element (FE) methods. The dryer’s bed incorporates a unique mixed heat storage material comprising paraffin wax and black-painted gravel. The Finite Element approach allows for the simulation of a hybrid greenhouse dryer, which enables a detailed examination of mass transfer within the dryer and the transient behavior of heat transfer during tomato flakes drying using COMSOL Multiphysics @ 6.0 software. A complete assessment was performed by creating a 3-D computational model of hybrid greenhouse dryer of tomato flakes drying considering heat-mass transfer, environomic and drying kinetics perspectives. The drying chamber consistently maintains temperature and humidity levels, with the highest temperature (55.3°C) and lowest humidity (33.2%) observed during the mid-day hour. Remarkably, the drying efficiency reaches 38.04% by reducing the initial moisture content from 96% to 1.28% in just five hours. The system demonstrates notable energy efficiency, boasting exergy efficiencies of 83.2% and 56.3%, respectively. The total embodied energy is calculated at 1591.07 kWh and the proposed dryer system allocate funds to support its operation is 273.43 USD. Additionally, the study compared the proposed model with twelve other mathematical models for drying of tomato flakes. The results showed that the proposed model performed better than the others. The impact analysis highlights the hybrid greenhouse dryer’s suitability for mitigating post-harvest losses while emphasizing environmental sustainability.
GRAPHICAL ABSTRACT
Highlights
Employed COMSOL to model energy, mass balance in hybrid dryer effectively.
Model accurately predicted and validated experimentally.
Efficiencies demonstrated efficient energy utilization.
System achieved optimal drying temperatures.
Moisture reduced effectively to 1.28%.
Used energy cost-effectively.
Abbreviation
| Mi | = | Initial moisture content |
| Mf | = | Final moisture content |
| = | Thermal efficiency | |
| = | Heat removed | |
| = | Total incident energy | |
| = | Energy-exergy efficiency | |
| Eu | = | Outlet energy |
| Ei | = | Inlet energy |
| Md,amb | = | Mass flow rate of dryer at ambient condition |
| = | Specific heat of drying air (J/Kg/K) | |
| Tdi | = | Temperature of absorber plate (oC) |
| Tdo | = | Temperature of absorber plate (oC) |
| Tamb | = | Ambient Temperature (oC) |
| = | Exergy Inlet | |
| = | Exergy of useful energy output | |
| = | Convective heat transfer coefficient from absorber plate to ambient (W m −2 K −1) | |
| = | Temperature of absorber plate (oC) | |
| = | Temperature of surrounding air (oC) | |
| = | Solar intensity (W/m2) | |
| = | Temperature (oC) | |
| = | Drying time | |
| Greek letters | = | |
| = | Density (kg/m3) | |
| = | Standard deviation of moisture content | |
| = | Mean moisture content. | |
| = | Thermal diffusivity | |
| = | Porosity in space | |
| Subscripts | = | |
| = | Ambient temperature | |
| = | Evaporation | |
| = | Porosity | |
| Abbreviations | = | |
| = | Finite element method | |
| = | Greenhouse dryer |
Acknowledgements
The authors would like to thank Birla Institute of Technology, Mesra, Ranchi, India for providing instrumentation facilities for this research work.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Notes on contributors
Lalan Kumar
Lalan Kumar is graduated in Mechanical Engineering from PTU, Jalandhar in the year 2012. He did M.Tech in thermal engineering from RGPV Bhopal in 2018 and Ph.D from BIT Mesra in 2024. Recently he is working as Assistant Professor in Deptt. of Mech. Engg, Usha Martin University, Ranchi,India.He has published approximately eight research papers in international journals He is working in the field of renewable energy, especially in greenhouse solar dryers as well as in the modeling sector. [email protected]; [email protected]
Om Prakash
Om Prakash is awarded P.hD. in energy from MNIT, Bhopal in year 2014, Recently he is working as a assistant professor in the Department of Mechanical Engineering at BIT, Mesra, Ranchi, India. He has published several research papers in international journals and conferences. His research interests are in energy, heat transfer, and power [email protected]