Investigation of the electrothermal parameters of the electrocontact heating system in a combined grain dryer (using paddy rice as a case study).
Received: 2026-09-11
Published: 2026-09-11
Abstract
The study aimed to determine the electrothermal parameters of the electrocontact heating system
incorporated into a combined grain dryer using paddy rice as a case study and to evaluate the cyclic
temperature-control characteristics of the heating surface; Materials and methods. Experiments were
conducted using the “Alanga” paddy rice variety at heating-surface set temperatures of 70, 80, and
90 °C, with three independent replicates for each temperature regime. The solar air collector was
switched off during the experiments. Primary and secondary electrical parameters of the transformer,
heating time required to reach the set temperature, heating-system duty factor, and paddy rice moisture content and temperature were determined; Results. The active power in the transformer secondary
circuit ranged from 538.97 to 540.48 W, while the surface-specific power of the heating surface
ranged from 1531.2 to 1535.5 W/m². As the set temperature increased from 70 to 90 °C, the heating
time increased from 86.67±0.58 to 92.33±0.58 s, while the heating-system duty factor increased from
0.563 to 0.594. The heating-surface temperature fluctuation range was 3.0–3.4 °C. For rice grain with
an initial moisture content of 20%, the moisture content after drying decreased from 14.90±0.10% to
11.63±0.15%, while the outlet grain temperature ranged from 34.03 to 40.5 °C; Conclusion. The
electrocontact heating system enabled the heating surface to reach the required temperature rapidly
under low-voltage and high-current conditions and provided stable cyclic temperature control using
an automatic temperature controller. The results obtained for paddy rice provide a basis for further
evaluation of the applicability of the proposed heating system to combined dryers for other grain crops.
Keywords
List of references
-
Tian, J.; Ogawa, Y.; Singh, J.; Kaur, L. (Eds.). Science of Rice Chemistry and Nutrition. Springer Nature Singapore, 2023. https://doi.org/10.1007/978-981-99-3224-5.
-
Statista. Total rice consumption worldwide from 2008/2009 to 2024/2025. Statistical report, 2025.
-
Statistics Agency under the President of the Republic of Uzbekistan. Statistical data on rice production across all categories of farms, 2010–2024 (In Uzbek).
-
UNESCO Intangible Cultural Heritage. Palov culture and tradition. Representative List of the Intangible Cultural Heritage of Humanity, Uzbekistan, 2016, Nomination file No. 01166.
-
Samaddar, A.; Azam, M.M.; Singaravadivel, K.; Venkatachalapathy, N.; Swain, B.B.; Mishra, P. Postharvest Management and Value Addition of Rice and Its By-Products. In: The Future Rice Strategy for India. Elsevier, 2017; pp. 301–334.
-
Zhang, X.; He, X.; Yang, F.; Chen, T.; Wen, X.; Sun, S.; Luo, F.; Lin, Q. A Novel Evaluation Method for Rice Drying Based on Water Migration and Molecular Motion Law Analysis. Food Analytical Methods, 2024, 17, 166–177.
-
Chojnacka, K.; Mikula, K.; Izydorczyk, G.; Skrzypczak, D.; Witek-Krowiak, A.; Moustakas, K.; Ludwig, W.; Kułażyński, M. Improvements in drying technologies: Efficient solutions for cleaner production with higher energy efficiency and reduced emission. Journal of Cleaner Production, 2021, 320, 128706.
-
Huang, Y.-T.; Wu, W.; Zou, W.-X.; Wu, H.-P.; Cao, D.-D. Drying temperature affects rice seed vigor via gibberellin, abscisic acid, and antioxidant enzyme metabolism. Journal of Zhejiang University-SCIENCE B, 2020, 21(10), 796–810.
-
Xu, X.; Zhao, T.; Ma, J.; Song, Q.; Wei, Q.; Sun, W. Application of Two-Stage Variable Temperature Drying in Hot Air-Drying of Paddy Rice. Foods, 2022, 11, 888.
-
Utari, F.D.; Yasintasia, C.; Ratridewi, M.; A’yuni, D.Q.; Kumoro, A.C.; Djaeni, M.; Asiah, N. Evaluation of Paddy Drying with Vertical Screw Conveyor Dryer (VSCD) at Different Air Velocities and Temperatures. Chemical Engineering and Processing – Process Intensification, 2022, 174, 108881.
-
Moraes, R.S.; Coradi, P.C.; Nunes, M.T.; Leal, M.M.; Müller, E.I.; Teodoro, P.E.; Flores, E.M.M. Thick layer drying and storage of rice grain cultivars in silo-dryer-aerator: Quality evaluation at low drying temperature. Heliyon, 2023, 9, e17962.
-
Alam, M.S.; Wazed, M.A.; Hasan, S.M.K.; Ahmed, M.; Alam, M.S.; Sarker, M.S.H. Quality aspects of paddy grain and seed dried in HSTU mobile grain and seed dryer integrated with a dual heating system. Heliyon, 2024, 10, e40835.
-
Jyoti, Y.K.; Dash, S.K.; Rayaguru, K.; Pal, U.S.; Mishra, N.; Ananth, P.N.; Khandai, S. Enhancement of thermal and techno-economic performance and prediction of drying kinetics of paddy dried in solar bubble dryer. Energy Nexus, 2023, 11, 100224.
-
Bekkulov, B.; Aliyev, R.; Rahmonkulov, T. Mobile device for drying paddy and justification of its parameters. International Journal of Advanced Trends in Computer Science and Engineering, 2021, 10(1), 133–138.
-
Bekkulov, B.; Aliyev, R.; Rakhmonkulov, T.; Atabayev, K.; Yusupova, R.; Khadjieva, S. Study of mechanical damage of paddy (rice) during drying in the device. E3S Web of Conferences, 2024, 510, 02003.
-
Kurzin, N.N.; Normov, D.A.; Lebedev, D.V.; Rozhkov, E.A. Elektrotekhnologii v selskom khozyaystve. Krasnodar: KubGAU, 2020.
-
Logachev, M.V.; Ivanitskiy, N.I.; Davidovich, L.M. Raschety nagrevatelnykh ustroystv. Chast 2. Raschety elektricheskikh pechey i ustanovok. Minsk: BNTU, 2010.
-
Aliferov, A.; Lupi, S. Induction and Direct Resistance Heating of Metals. Novosibirsk: NSTU Publisher, 2011.
-
Xie, Q.; Gao, M.; Huang, X. Fire risk and behavior of rice during the convective drying process. Fire Safety Journal, 2020, 115, 103013.
-
Asia-Pacific Legal Metrology Forum. APLMF Guide Document on Rice Moisture Measurement. May 2017 edition.
About the Authors
License
Copyright (c) 2026 Irrigation and Melioration
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
