Res. Agr. Eng., 2025, 71(3):174-187 | DOI: 10.17221/98/2024-RAE

Free electricity tandem-twin-hybrid solar-biomass dryer increased the performance of coffee cherry dryingOriginal Paper

Yuwana Yuwana1, Syafnil Syafnil1
1 Department of Agricultural Technology, Faculty of Agriculture, University of Bengkulu, Bengkulu, Indonesia

A free electricity tandem-twin-hybrid-solar-biomass dryer comprised of two drying rooms and operated with solar and biomass energy combustion of 10 kg rubber wood per hour separately to dry Robusta coffee cherries with 3, 6, 9, and 12 cm bed thicknesses were studied with the drying completion time (tc), number of defects (ND), and colour parameters, i.e., lightness (L*), hue angle [H(o)], and chroma (C), used as the performance indicators. The experimental results indicated that the drying room, bed thickness, and drying room-bed thickness interaction significantly affected the tc and ND and bed thickness only significantly affected C for both the solar energy drying and the biomass energy drying. The solar energy drying generated a drying air temperature of 44.6 ± 3.5 °C with a tc of 70.9–90.2 h for the front drying room and 40.1 ± 2.8 °C with a tc of 77.2–116.5 h for the rear drying room, whereas the biomass energy drying produced a drying air temperature of 57.2 ± 3.6 °C with a tc of 34.1–44.9 h for the front drying room and 45.6 ± 6.0 °C with a tc of 56.3–96.6 h for the rear drying room. Both drying processes produced coffee beans with the NDs less than 11 qualified for Grade 1 with similar colour characteristics.

Keywords: biomass energy drying; coffee bean colour; drying completion time; number of defects; solar energy drying

Received: December 16, 2024; Accepted: June 18, 2025; Prepublished online: September 26, 2025; Published: September 29, 2025  Show citation

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Yuwana Y, Syafnil S. Free electricity tandem-twin-hybrid solar-biomass dryer increased the performance of coffee cherry drying. Res. Agr. Eng. 2025;71(3):174-187. doi: 10.17221/98/2024-RAE.
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    References

    1. Al-Kindi H., Purwanto Y.A., Wulandani D. (2015): Analisis CFD aliran udara panas pada pengering tipe rak dengan sumber energi gas buang [Distribution analysis of hot air flow in rack type dryer with energy source from exhaust gas using Computational Fluid Dynamics (CFD)]. Jurnal Keteknikan Pertanian, 3: 9-16 (in Indonesian). Go to original source...
    2. Bicho N., Ramalho J.C., Leitão A., Lidon F.C. (2014): Application of colour parameters for assessing the quality of Arabica and Robusta green coffee. Emirates Journal of Food and Agriculture, 26: 9-17. Go to original source...
    3. Budiyanto, Izahar T., Ukker D. (2021): Karakteristik fisik kualitas biji kopi dan kualitas kopi bubuk Sintaro 2 dan Sintaro 3 dengan berbagai tingkat sangrai (Physical characteristics of coffee beans and quality of ground coffee Sintaro 2 and Sintaro 3 with various roast levels). Jurnal Agroindustri, 11: 54-71 (in Indonesian). Go to original source...
    4. Chan Y., Sugiyanto D., Uyun A.S. (2020): Analisis pengeringan kopi menggunakan oven pengering hybrid (solar thermal dan biomassa) di Desa Gununghalu [Coffee drying analysis using a hybrid drying oven (solar thermal and biomass) in Gununghalu Village]. Jurnal Kajian Teknik Mesin, 5: 4-8 (in Indonesian). Go to original source...
    5. Dzaky M.I., Kosasih E.A., Hakim I.I., Zikri A. (2023): Investigation of thin-layer drying of coffee beans using a double-condenser compression refrigeration system: Effects of air mass flux, specific humidity and drying temperature. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 106: 90-103. Go to original source...
    6. Fatharani A., Yuwana Y., Yusuf D., Hidayat L. (2023): Drying characteristics of robusta coffee beans using YSDUNIB18 hybrid dryer based on thin-layer drying kinetics fitting model. International Journal of Agricultural Technology, 19: 37-52.
    7. Firdissa E., Mohammed A., Berecha G., Garedew W. (2022): Coffee drying and processing method influence quality of arabica coffee varieties (Coffea arabica L.) at gomma I and limmu kossa, southwest Ethiopia. Journal of Food Quality, 3: 1-8. Go to original source...
    8. Gachen A., Hirpersa Z., Woyessa L.N. (2020): Design and construction of indirect solar coffee dryer. International Journal of Innovative Technology and Exploring Engineering (IJITEE), 9: 2943-2956. Go to original source...
    9. Gunawan Y., Margono K.T., Rizky R., Putra N., Al Fatih R., Hakim I.I., Setiadanu G.T., Suntoro D., Kasbi S., Nafis S. (2021): Enhancing the performance of conventional coffee beans drying with low-temperature geothermal energy by applying HPHE: An experimental study. De Gruyter, 6: 807-818. Go to original source...
    10. Harijono, Wicaksono M.F., Wulan S.N., Ali Y.S. (2024): Changes in physico-chemical characteristics of robusta coffee (Coffea canephora) during natural process using simple solar dryer. BIO Web of Conferences, 90: 01003. Go to original source...
    11. Hidayat R., Ubaidillah F., Siswanto H. (2018): Optimasi proses pengeringan kopi di pabrik kopi PTPN XII Gumitir dengan menggunakan mason dryer (Optimization of the coffee drying process at the PTPN XII Guitir Coffee Factory using a Mason dryer). Jurnal Ilmiah Mate-matika dan Pendidikan Matematika (JMP), 10: 17-30 (in Indonesian). Go to original source...
    12. Hudin T.J., Koehuan V.A., Nurhayati (2021): Perancangan rumah pengering biji kopi menggunakan plastik ultra violet (UV solar dryer) dengan mekanisme konveksi alamiah [Design of coffee bean drying house using ultraviolet plastic (UV solar dryer) with natural convection me-chanism]. Lontar: Jurnal Teknik Mesin Undana, 8: 25-39 (in Indonesian).
    13. Irwansyah I., Nelwan L.O., Wulandari D. (2019): Desain dan uji kinerja alat pengering hybrid dengan efek cerobong tipe tumpukan untuk pengeringan biji kopi Arabika (Design and performance test of hybrid dryer with chimney effect pile type for drying Arabica coffee beans.). Jurnal Keteknikan Pertanian, 7: 163-170 (in Indonesian). Go to original source...
    14. Konsil K.K., Sazali N., Kadirgama K., Harun W.S.W., Zainol N. (2023): Analysis on the performance of designed fluidized bed dryer for drying coffee beans. Journal of Advanced Research in Applied Sciences and Engineering Technology, 31: 99-109. Go to original source...
    15. Largo-Avila E., Suarez-Rodriguez C.H., Montero J.L., Strong M., Osorio-Aries J. (2023): The influence of hot-air mechanical drying on the sensory quality of specialty Colombian coffee. AIMS Agriculture and Food, 8: 789-803. Go to original source...
    16. Mackpayen A.O., Akata A.M.E.A., Barandja V.D.D.B., Napo K. (2023): Experimental study of a modified icaro solar dryer: The case of coffee drying. Journal of Power and Energy Engineering, 11: 36-48. Go to original source...
    17. Murakonda S., Patel G., Dwivedi M. (2022). Characterization of engineering properties and modeling mass and fruit fraction of wood apple (Limonia acidissima) fruit for post-harvest processing. Journal of the Saudi Society of Agricultural Sciences, 21: 267-277. Go to original source...
    18. Murdianto D., Santoso D. (2019): Pemodelan mesin pengering biji-bijian tipe batch menggunakan hybrid petri net (Modeling of batch type seed dryer machine using a petri net hybrid). Perbal: Jurnal Pertanian Berkelanjutan, 7: 115-120 (in Indonesian).
    19. Nasrin A.B.M.S., Tan A.S.T., Huey C.N., Abdullah A., Ismail W.A.A.Z.W., Januar J. (2021): Drying characteristics and nutritive analysis of coffee beans under different drying methods. Transaction on Science and Technology, 8: 439-444.
    20. Oria C.L. Palconit E.V. (2022): Performance investigation of an inflatable solar dryer with steel-can solar air heater for drying coffee and corn. Engineering, Technology & Applied Science Research, 12: 8707-8711. Go to original source...
    21. Peñuela-Martínez A.E., Hower-Garcia I.P., Guerrero A., Agudelo-Laverde L.M., Betancourt-Rodriguez H., Martinez-Giraldo J. (2023): Physical, sensorial, and physicochemical characteristics of Arabica coffee dried under two solar brightness conditions. Processes, 11: 2-17. Go to original source...
    22. Phitakwinai S., Thepa S., Nilnont W. (2019): Thin-layer drying of parchment Arabica coffee by controlling temperature and relative humidity. Food Science & Nutrition, 7: 2921-2931. Go to original source... Go to PubMed...
    23. Prasetya R.A., Irfa'I M.A., Samudra A. (2020): Rancang bangun alat pengering biji kopi menggunakan pemanas kompor gas LPG dengan model roll (Design and construction of coffee bean dryer using heater LPG stove with roll model). Reaktom: Rekayasa Keteknikan dan Optimasi, 5: 14-21 (in Indonesian).
    24. Putra I. E., Hadi P. (2013): Analisa efisiensi alat pengering tenaga surya tipe terowong berbantukan kipas angin pada proses pengeringan biji kopi (Efficiency analysis of a fan-assisted tunnel type solar dryer in the coffee bean dryng process). Jurnal Teknik Mesin, 3: 22-25 (in Indonesian).
    25. Siagian P., Napitupulu F.H., Ambarita H., Sihombing H.C., Siagian H. (2024): Comparative analysis of coffee drying on quality with variations in dryers made solar collectors. AIP Conference Proceedings, 3048: 020042. Go to original source...
    26. Soeswanto B., Wahyuni N.L.E., Prihandini G., Pratama Y., Firmansyah T.A., Widyabudiningsih D. (2023): Effect of process variables and zeolite adsorbent in coffee bean drying. Current Journal International Journal Applied Technology Research, 4: 29-40. Go to original source...
    27. Suherman S., Widuri H., Patricia S., Susanto E.E., Sutrisna R.J. (2020): Energy analysis of a hybrid solar dryer for drying coffee beans. International Journal of Renewable Energy Development, 9: 131-139. Go to original source...
    28. Sutrisno, Ariwibowo D., Yulianto M.E., Sitawati R. (2020): Characteristic of vertical mixed flow dryer in coffee bean drying process. IOP Conf. Series: Materials Science and Engineering, 771: 012070. Go to original source...
    29. Widyotomo S. (2014): Kinerja bangunan tembus cahaya skala besar untuk proses pengeringan kopi (Performance of a large scale green house for coffee drying process). Pelita Perkebunan, 30: 240-257 (in Indonesian). Go to original source...
    30. Yani E., Fajrin S. (2013): Karakteristik pengeringan biji kopi berdasarkan variasi kecepatan aliran udara pada solar dryer (Drying characteristics based on the variation of drying air velocity of solar dryer solar dryer). TeknikA, 20: 17-22 (in Indonesian).
    31. Yuwana Y., Silvia E., Sidebang B. (2021): Coffee cherries drying trials utilizing the hybrid solar dryer. Advances in Biological Sciences Research. Proceedings of the International Seminar on Promoting Local Resources for Sustainable Agriculture and Development (ISPLRSAD 2020), 13: 497-503. Go to original source...
    32. Yuwana Y., Sidebang B. (2023): Performance testing of the tandem hybrid solar-biomass dryer for coffee cherry drying. International Journal of Agricultural Technology, 19: 1969-1982.

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