EXERGY ANALYSIS OF THE ORGANIC RANKINE CYCLE BASED ON THE PINCH POINT TEMPERATURE DIFFERENCE

Abstract

Organic Rankine Cycle (ORC) is a system that uses working fluids with hydrocarbon components instead of water and generates power from the heat recovery of different heat sources. In this study, the exergy analysis of a simple ORC, which produces electrical energy with the help a geothermal source (125°C), was performed. R123, R152a, R245fa and R600a were determined as the fluids to be used in the Cycle. In this analysis, which was carried out according to the pinch point temperature differences (5-20°C) in the evaporator, the exergy performance of the cycle components was evaluated for the geothermal resource unit flow rate and the variation of the exergy efficiency of the system was calculated. With the increase of the pinch point temperature difference in the evaporator, the decrease of the system’s exergy efficiency became maximal (11.7%) with the use of R152a as a refrigerant and the loss in the system’s exergy efficiency became minimal (9.03%) with the use of R123 as a refrigerant.

Keywords

• Organic Rankine Cycle,Exergy Analysis,Pinch Point Temperature,Refrigerant,Geothermal Source

References

1. [1] Bertrand, F.T., George, P., Gregory, L., Antonios, F. (2009). Fluid selection for a low-temperature solar Rankine cycle. Applied Thermal Engineering, 29, 2468-2476.
2. [2] Drescher, U., Bruggemann, D. (2007). Fluid selection for the Organic Rankine Cycle (ORC) in biomass power and heat plants. Applied Thermal Engineering, 27, 223-228.
3. [3] Rayegan, R.,Tao, X. (2011). A procedure to select working fluids for solar Rankine cycle (ORCs). Renewable Energy, 36, 659-670.
4. [4] He, C., Liu, C., Gao, H., Xie, H., Li, Y., Wu, S., Xu, J. (2012). The optimal evaporation temperature and working fluids for subcritical organic Rankine cycle. Energy, 38, 136-143.
5. [5] Quoilin, S., Van den Broeck, M., Declaye, S., Dewallef, P., Lemort, V. (2013). Techno-economic survey of Organic Rankine Cycle (ORC) systems. Renewable & Sustainable Energy Reviews, 22, 168-186.
6. [6] Wang, Y., Ding, X., Tang, L., Weng, Y. (2016). Effect of evaporation temperature on the performance of organic Rankine Cycle in near-critical condition. ASME Journal of Energy Resources Technology, 138, 032001-032008.
7. [7] Ergun, A., Ozkaymak, M., Kılıcaslan, E. (2016). Power generation applications with Organic Rankine Cycle from low temperature heat sources. Duzce University Journal of Science & Technology, 4, 686-696.
8. [8] Kaynakli, O., Bademlioglu, A.H., Yamankaradeniz, N., Yamankaradeniz, R. (2017). Thermodynamic analysis of the Organic Rankine Cycle and the effect of refrigerant selection on cycle performance. International Journal of Energy Applications and Technologies, 4, 101-108.

9. [9] Akkaya, A.V. (2017). Performance analyzing of an organic Rankine cycle under different ambient conditions. Journal of Thermal Engineering, 3, 1498-1504.
10. [10] Cihan, E. (2014). Cooling performance investigation of a system with an organic Rankine cycle using waste heat sources. Journal of Thermal Science and Technology, 34, 101-109.
11. [11] Wang, M., Wang, J., Zhao, Y., Zhao, P., Dai, Y. (2013). Thermodynamic analysis and optimization of a solar-driven regenerative organic Rankine cycle (ORC) based on flat-plate solar collectors. Applied Thermal Engineering, 50, 816-825.
12. [12] Kai, Z., Mi, Z., Yabo, W., Zhili, S., Shengchun, L., Jinghong, N. (2015). Parametric optimization of low temperature ORC system. Energy Procedia, 75, 1596-1602.
13. [13] Gao, W., Li, H., Xu, G., Quan, Y. (2014). Working fluid selection and preliminary design of a solar organic Rankine cycle system. Environmental Progress & Sustainable Energy, 34, 619–626.
14. [14] Mago, P.J., Chamra, L.M., Somayaji, C. (2007). Performance analysis of different working fluids for use in Organic Rankine Cycles. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 221, 255-264.
15. [15] Roy, J.P., Mishra, M.K., Mishra, A. (2011). Performance analysis of an Organic Rankine Cycle with superheating under different heat source temperature conditions. Applied Energy, 88, 2995-3004.
16. [16] Dai, Y.P., Wang, J.F., Lin, G. (2009). Parametric optimization and comparative study of organic Rankine cycle (ORC) for low grade waste heat recovery. Energy Conversion and Management, 50, 576-582.
17. [17] Kerme, E.D., Orfi, J. (2015). Exergy-based thermodynamic analysis of solar driven organic Rankine cycle. Journal of Thermal Engineering, 1, 192-202.
18. [18] Li, W., Feng, X., Yu, L.J., Xu, J. (2011). Effects of evaporating temperature and internal heat exchanger on organic Rankine cycle. Applied Thermal Engineering, 31, 4014-4023.
19. [19] Yaglı, H., Koc, Y., Koc, A., Gorgulu, A., Tandiroglu, A. (2016). Parametric optimization and exergetic analysis comparison of subcritical and supercritical organic Rankine cycle (ORC) for biogas fuelled combined heat and power (CHP) engine exhaust gas waste heat. Energy, 111, 923–932.
20. [20] Guo, C., Du, X., Yang, L., Yang, Y. (2014). Performance analysis of organic Rankine cycle based on location of heat transfer pinch point in evaporator. Applied Thermal Engineering, 62, 176–186.
21. [21] Safarian, S., Aramoun, F. (2015). Energy and exergy assessments of modified Organic Rankine Cycles (ORCs). Energy Reports, 1, 1-7.