BİYOGAZ MOTORU ATIK ISISININ REKÜPERATÖRLÜ ORGANİK RANKİNE ÇEVRİMİ İLE GERİ KAZANIMINDA İŞ AKIŞKANI SEÇİMİ VE OPTİMİZASYONU

Abstract

Bu çalışmada, birincil enerji kaynağını daha verimli kullanmak amacıyla biyogaz motoruna entegrasyonu önerilen reküperatifli bir Organik Rankine Çevrimi (ORC) sistemi analiz edilmektedir. İncelenen motor, Zonguldak katı atık sahasından toplanan biyogazla çalışan 1498 kW gücündeki bir gaz motorudur. Motorun 410 °C sıcaklığındaki egzoz gazıyla salınan ısıl enerji potansiyelinin tamamını en yüksek verimle elektriğe dönüştürebilecek ORC sistemi için en uygun iş akışkanı belirlenmekte ve optimum tasarım parametreleri ortaya konmaktadır. Önerilen reküperatifli ORC sisteminde ısı transferi aracı akışkanı olarak Therminol 66 kullanılmıştır. İş akışkanı adayı olarak doğal hidrokarbonlardan oluşan dört farklı organik iş akışkanı (n-Pentane, Toluene, n-Decane ve n-Dodecane) belirlenmiştir. Evaporatör girişindeki sıkışma noktası sıcaklığı 10 °C kabul edilerek, Termodinamiğin II. Yasasına ve uygulamada gerçekleştirilebilir işletme koşullarına uygun kızdırma sıcaklıkları tespit edilmiştir. Kızdırma sıcaklığı değişiminin her bir organik akışkan üzerindeki etkisi parametrik olarak incelenmiş ve optimum kızdırma sıcaklıkları bulunmuştur. Yapılan hesaplamalar, biyogaz motorunun atık ısı potansiyelinin 621,4 kW olduğunu ve bu potansiyelin optimum kızdırma sıcaklıklarında n-Pentane, Toluene, n-Decane ve nDodecane iş akışkanları için sırasıyla 120,3 kW, 125,8 kW, 139,5 kW ve 138,2 kW net elektrik üretimine dönüştürülebileceğini göstermiştir. En uygun iş akışkanı olarak termodinamik açıdan n-Decane, uygulamada işletme kolaylığı açısından Toluene olduğu belirlenmiştir.

Keywords

• Biyogaz Motoru
• Reküperatif Organik Rankine Çevrimi
• Atık Isı Geri Kazanımı

Working Fluid Selection and Optimization in a Recuperative Organic Rankine Cycle for Biogas Engine Waste Heat Recovery

Abstract

A recuperative Organic Rankine Cycle (ORC) is proposed and analyzed to recover waste heat of biogas engine. The engine power is 1498 kW and operates on biogas collected from the Zonguldak municipal solid waste landfill, and exhaust gases temperature is 410 °C. Therminol 66 is used as heat transfer fluid. Four working fluids based on natural hydrocarbons (n-pentane, toluene, n-decane and ndodecane) are evaluated as candidates. The pinch-point temperature at evaporator inlet is fixed at 10 °C, and superheating temperatures that satisfy the second law of thermodynamics and are compatible with realistic operating conditions are determined. The effect of superheating temperature on cycle performance is investigated parametrically, and the corresponding optimal superheating temperatures are obtained. The results indicate that the engine has a waste heat potential of 621.4 kW, which can be converted into 120.3 kW, 125.8 kW, 139.5 kW and 138.2 kW of net electrical power for n-pentane, toluene, n-decane and ndodecane, respectively, at the optimum conditions. Overall, n-decane is identified as the most favorable working fluid from a thermodynamic standpoint, while toluene offers advantages in terms of operational practicality. 

Keywords

• Biogas Engine
• Recuperative Organic Rankine Cycle
• Waste Heat Recovery

References

1. Akkurt, F. (2020) Düşük sıcaklıkta jeotermal enerji̇ kaynaklı organi̇k ranki̇ne çevri̇m si̇stemi̇ni̇n enerji̇ ve ekserji anali̇zi̇, Uludağ University Journal of The Faculty of Engineering, 25(2) 729–742, doi: 10.17482/uumfd.624475
2. Akkurt, F. ve Kaçanoğlu, E. (2021) Konya ili atmosferik şartlarında güneş enerjisi destekli jeotermal kaynaklı organik Rankine çevrimi sisteminin termodinamik analizi, Uludağ University Journal of The Faculty of Engineering, 26(2), 649–660, doi: 10.17482/uumfd.897340
3. Akman, M. ve Ergin, S. (2025) Performance optimization of ORC-based waste heat recovery system integrated with marine engine using alternative fuels under different operating conditions, Thermal Science and Engineering Progress, 66, 104084, doi: 10.1016/j.tsep.2025.104084
4. Bellos, E. (2024) A review of organic Rankine cycles with partial evaporation and dual-phase expansion, Sustainable Energy Technologies and Assessments, 72, 104059, doi: 10.1016/J.SETA.2024.104059
5. Bellos, E. (2025a) A detailed analysis of waste heat recovery organic Rankine cycle with partial evaporation and different working fluids, Applied Thermal Engineering, 263, 125410, doi: 10.1016/J.APPLTHERMALENG.2025.125410
6. Bellos, E. (2025b) A benchmark comparative thermodynamic investigation of different organic Rankine cycle architectures, Next Energy, 8, 100331, doi: 10.1016/j.nxener.2025.100331
7. Benato, A. ve Macor, A. (2017) Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle, Energies, 10 (3), 327, doi: 10.3390/en10030327
8. Detchusananard, T., Taweekayujan, S., Prasertcharoensuk, P., Chen, Y.S. ve Arpornwichanop, A. (2025) Synergy between a methanol reforming process, fuel cell, and organic Rankine cycle: Multi-objective optimization of a next-generation energy system, Journal of Cleaner Production, 505, 145365, doi: 10.1016/j.jclepro.2025.145365

9. E Elahi, A., Mahmud, T., Alam, M., Hossain, J. ve Biswas, B.N. (2022) Exergy analysis of organic Rankine cycle for waste heat recovery using low GWP refrigerants, International Journal of Thermofluids, 16, 100243, doi: 10.1016/J.IJFT.2022.100243
10. Guzović, Z., Kastrapeli, S., Budanko, M., Klun, M. ve Rašković, P. (2024) Improving the thermodynamic efficiency and turboexpander design in bottoming organic Rankine cycles: The impact of working fluid selection, Energy, 307, 132642, doi:10.1016/j.energy.2024.132642
11. Hoang, A.T. (2018) Waste heat recovery from diesel engines based on Organic Rankine Cycle, Applied Energy, 231, 138–166, doi: 10.1016/j.apenergy.2018.09.022
12. Jenbacher (2020), “Technical description cogeneration unit”, 2, 1–42.
13. Kankılıç, T. ve Topal, H. (2015) Belediye atıklarından düzenli depolama sahalarında biyogaz ve enerji üretimi, Mühendis ve Makine, 56(669), 58-69.
14. Khan, Y., Singh, D., Kumar, S., Mishra, S., Anjum, A. Ve Asdaque, P.M.G.B. (2024) Performance evaluation of the combined helium Brayton cycle and organic Rankine cycles for solar power tower application—A comparative study, Journal of Renewable and Sustainable Energy, 16(6), doi: 10.1063/5.0239706
15. Khan, Y. ve Singh, P.K. (2024) Working fluid selection, exergy, energy and exergoeconomic assessment of a novel combined Brayton cycle and regenerative-recuperative organic Rankine cycle for concentrated solar power application, Journal of the Brazilian Society of Mechanical Sciences and Engineering, 46(12), 1–18, doi: 10.1007/s40430-024-05236-8
16. Koç, Y., Yağlı, H. ve Kalay, I. (2020) Energy, exergy, and parametric analysis of simple and recuperative organic Rankine cycles using a gas turbine–based combined cycle, Journal of Energy Engineering, 146(5), doi: 10.1061/(ASCE)EY.1943-7897.0000693
17. Koç, Y., Yağlı, H. ve Koç, A. (2019) Exergy Analysis and Performance Improvement of a Subcritical/Supercritical Organic Rankine Cycle (ORC) for Exhaust Gas Waste Heat Recovery in a Biogas Fuelled Combined Heat and Power (CHP) Engine Through the Use of Regeneration, Energies, 12(4), 575, doi: 10.3390/en12040575
18. Kopac, M. ve Hilalci, A. (2007) Effect of ambient temperature on the efficiency of the regenerative and reheat Çatalağzı power plant in Turkey, Applied Thermal Engineering, 27 (8-9), 1377-1385, doi: 10.1016/j.applthermaleng.2006.10.029
19. Li, T., Gao, R. ve Gao, X. (2022) nergy, exergy, economic, and environment (4E) assessment of trans-critical organic Rankine cycle for combined heating and power in wastewater treatment plant, Energy Conversion and Management, 267, 115932, doi: 10.1016/j.enconman.2022.115932
20. Liu, Q., Shen, A. ve Duan, Y. (2015) Parametric optimization and performance analyses of geothermal organic Rankine cycles using R600a/R601a mixtures as working fluids, Applied Energy, 148, 410–420, doi: 10.1016/j.apenergy.2015.03.093
21. Liu, Q., Yang, F., Liu, X., Zhang, X. Ve Yang, Z. (2026) Thermo-economic evaluation and working fluid screening for supercritical ORCs driven by medium-temperature geothermal sources, Renewable Energy, 257, 124795, doi: 10.1016/j.renene.2025.124795.
22. Manente, G., Lazzaretto, A. ve Bonamico, E. (2017) Design guidelines for the choice between single and dual pressure layouts in organic Rankine cycle (ORC) systems, Energy, 123, 413–431, doi: 10.1016/j.energy.2017.01.151
23. Önal, A.S., Etemoğlu, A.B. ve Can, M. (2017), “Düşük sıcaklıklı atık akışkan destekli̇ organi̇k Ranki̇ne çevri̇mleri̇ni̇n opti̇mi̇zasyonu”, Uludağ University Journal of The Faculty of Engineering, 22(2), 35–52, doi: 10.17482/uumfd.335423
24. Ononogbo, C., Nwosu, E.C., Nwakuba, N.R., Nwaji, G.N., Nwufo, O.C., Chukwuezie, O.C., Chukwu, M.M. ve Anyanwu, E.E. (2023) Opportunities of waste heat recovery from various sources: Review of technologies and implementation, Heliyon, 9(2), e13590, doi: 10.1016/j.heliyon.2023.e13590
25. Østergaard, D.S., Smith, K.M., Tunzi, M. ve Svendsen, S. (2022) Low-temperature operation of heating systems to enable 4th generation district heating: A review, Energy, 248, 123529, doi: 10.1016/j.energy.2022.123529
26. Quoilin, S., Broek, M. Van Den, Declaye, S., Dewallef, P. ve Lemort, V. (2013) Techno-economic survey of organic rankine cycle (ORC) systems, Renewable and Sustainable Energy Reviews, 22, 168–186, doi: 10.1016/j.rser.2013.01.028
27. Quoilin, S., Declaye, S., Tchanche, B.F. ve Lemort, V. (2011) Thermo-economic optimization of waste heat recovery Organic Rankine Cycles, Applied Thermal Engineering, 31(4–15), 2885–2893, doi: 10.1016/J.APPLTHERMALENG.2011.05.014
28. Qureshi, M.F., Chandio, M.W., Memon, A.A., Kumar, L. ve Awad, M.M. (2024) Thermal analysis of solar energy based organic Rankine cycle cascaded with vapor compression refrigeration cycle, Energy Nexus, 14, 100291, doi: 10.1016/J.NEXUS.2024.100291
29. Rasi, S., Veijanen, A. ve Rintala, J. (2007) Trace compounds of biogas from different biogas production plants”, Energy, 32(8), 1375–1380, doi: 10.1016/j.energy.2006.10.018
30. Solutia (1998) Therminol, 66, 1-4
31. Song, J. ve Gu, C. (2015) Analysis of ORC (Organic Rankine Cycle) systems with pure hydrocarbons and mixtures of hydrocarbon and retardant for engine waste heat recovery, Applied Thermal Engineering, 89, 693-702, doi: 10.1016/j.applthermaleng.2015.06.055
32. Sprouse, C. ve Depcik, C. (2013) Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery, Applied Thermal Engineering, 51(1–2), 711–722, doi: 10.1016/j.applthermaleng.2012.10.017
33. Topal, H.I. ve Ozturk, S. (2025) Thermoeconomic assessment and optimization of a novel dual-loop organic Rankine cycle for enhanced waste heat recovery from a gas engine”, Thermal Science and Engineering Progress, 66, 104049, doi: 10.1016/J.TSEP.2025.104049
34. Varis, C. ve Ozcira Ozkilic, S. (2023) In a biogas power plant from waste heat power generation system using Organic Rankine Cycle and multi-criteria optimization”, Case Studies in Thermal Engineering, 44, 102729, doi: 10.1016/j.csite.2023.102729
35. Vélez, F., Segovia, J.J., Martín, M.C., Antolín, G., Chejne, F. ve Quijano, A. (2012) A technical, economical and market review of organic Rankine cycles for the conversion of low-grade heat for power generation, Renewable and Sustainable Energy Reviews, 16(6), 4175–4189, doi: 10.1016/j.rser.2012.03.022
36. Yu, H., Feng, X. ve Wang, Y. (2015) A new pinch based method for simultaneous selection of working fluid and operating conditions in an ORC (Organic Rankine Cycle) recovering waste heat, Energy, 90, 36–46, doi: 10.1016/j.energy.2015.02.059