Experimental testing of scroll machine driven by compressed air for power generation and its integration in small scale organic Rankine cycle

Year 2021, Volume: 7 Issue: 6, 1457 - 1467, 02.09.2021

Pavan Kumar Reddy M S Bhagyashekar

https://doi.org/10.18186/thermal.990826

Cited By: 1

Abstract

Organic Rankine Cycle (ORC) is a proven technology in the field of waste heat recovery and present days ORC is extensively being used in exploiting biomass, geothermal and solar energy. The overall performance of ORC depends on the expander, making it a core component of the system. Generally, these expanders are classified into velocity type and displacement type. The velocity type expanders find their applications in large scale power generation and are not preferred in small scale power applications as their rotational speeds exponentially increase with a decrease in expander power output. As a result, the displacement type expanders are best suited for small scale power generation in ORC. Yet, till date expanders capable of producing power at small scale are not commercially available in the market for ORC application. As an effect commercially available scroll compressors are modified to work as expanders in ORC systems. The present study aims to examine the feasibility of using one such scroll compressor as an expander in ORC with and without modification. A test rig was developed to test the compressor running in reverse as expander using compressed air, before and after modifications. The scroll machine was tested for operating conditions consisting of pressure varying from 0.5 bar to 4.5 bar and the load varying from 0.2 kg to 2.2 kg for a constant airflow rate. The configurations tested were, scroll compressor with the suction port as inlet, modified scroll compressor with the suction port as inlet and modified scroll compressor with discharge port as an inlet. Based on the experimental test data obtained it is observed that, in all three configurations, for various loading conditions at given inlet air pressure there exists a maximum power generation point and a further increase in the load at given pressure has a negative effect on power output. Also, a significant increase in speed is observed from 300 to 4250 rpm at no load condition with increasing inlet air pressures. Maximum power of 210 W was achieved at a load of 1.1 kg with the inlet pressure of 4.5 bar for modified scroll machine when the discharge port was used as an inlet. Finally, it is recommended to use a modified scroll machine with discharge port as inlet as it gives more power when compared with other configurations for the same operating conditions.

Keywords

Scroll compressor, Expander, Compressed air, ORC

References

• [1] Qiu G, Liu H, Riffat S. Expanders for micro-CHP systems with organic Rankine cycle. Applied Thermal Engineering 2011;31:3301-3307. https://doi.org/10.1016/j.applthermaleng.2011.06.008
• [2] Mendoza LC, Navarro-Esbrí J, Bruno JC, Lemort V, Coronas A. Characterization and modeling of a scroll expander with air and ammonia as working fluid. Applied Thermal Engineering 2014;70:630-640. https://doi.org/10.1016/j.applthermaleng.2014.05.069
• [3] Quoilin S, Lemort V, Lebrun J. Experimental study and modeling of an organic Rankine cycle using scroll expander. Applied Energy 2010;87:1260-1268. https://doi.org/10.1016/j.apenergy.2009.06.026
• [4] Bao J, Zhao L. A review of working fluid and expander selections for organic Rankine cycle. Renewable and Sustainable Energy Reviews 2013;24:325-342. https://doi.org/10.1016/j.rser.2013.03.040
• [5] Emhardt S, Tian G, Chew J. A review of scroll expander geometries and their performance. Applied Thermal Engineering 2018;141:1020-1034. https://doi.org/10.1016/j.applthermaleng.2018.06.045
• [6] Ayachi F, Ksayer EB, Neveu P, Zoughaib A. Experimental investigation and modeling of a hermetic scroll expander. Applied Energy 2016;181:256-267. https://doi.org/10.1016/j.apenergy.2016.08.030
• [7] Lu Y, Wang Y, Wang L, Yuan Y, Liu Z, Roskilly AP. Experimental investigation of a scroll expander for power generation part of a resorption cogeneration. Energy Procedia 2015;75:1027-1032. https://doi.org/10.1016/j.egypro.2015.07.356
• [8] Qiu K, Thomas M, Douglas M. Investigation of a scroll expander driven by compressed air and its potential applications to ORC. Applied Thermal Engineering 2018;135:109-115. https://doi.org/10.1016/j.applthermaleng.2018.01.118
• [9] Gao P, Jiang L, Wang L, Wang R, Song F. Simulation and experiments on an ORC system with different scroll expanders based on energy and exergy analysis. Applied Thermal Engineering 2015;75:880-888. https://doi.org/10.1016/j.applthermaleng.2014.10.044
• [10] Lemort V, Quoilin S, Cuevas C, Lebrun J. Testing and modeling a scroll expander integrated into an organic Rankine cycle. Applied Thermal Engineering 2009;29:3094-3102. https://doi.org/10.1016/j.applthermaleng.2009.04.013
• [11] Song P, Wei M, Shi L, Danish SN, Ma C. A review of scroll expanders for organic Rankine cycle systems. Applied Thermal Engineering 2015;75:54-64. https://doi.org/10.1016/j.applthermaleng.2014.05.094
• [12] Campana C, Cioccolanti L, Renzi M, Caresana F. Experimental analysis of a small-scale scroll expander for low-temperature waste heat recovery in organic Rankine cycle. Energy 2019;187:115929. https://doi.org/10.1016/j.energy.2019.115929
• [13] Lin CH, Hsu PP, He YL, Shuai Y, Hung TC, Feng YQ, Chang YH. Investigations on experimental performance and system behavior of 10 kW organic Rankine cycle using scroll-type expander for low-grade heat source. Energy 2019;177:94-105. https://doi.org/10.1016/j.energy.2019.04.015
• [14] Liu C, Wang S, Zhang C, Li Q, Xu X, Huo E. Experimental study of micro-scale organic Rankine cycle system based on scroll expander. Energy 2019;188:115930. https://doi.org/10.1016/j.energy.2019.115930
• [15] Manolakos D, Kosmadakis G, Ntavou E, Tchanche B. Test results for characterizing two in-series scroll expanders within a low-temperature ORC unit under partial heat load. Applied Thermal Engineering 2019;163:114389. https://doi.org/10.1016/j.applthermaleng.2019.114389
• [16] Xi H, Li MJ, Zhang HH, He YL. Experimental studies of organic Rankine cycle systems using scroll expanders with different suction volumes. Journal of Cleaner Production 2019;218:241-249. https://doi.org/10.1016/j.jclepro.2019.01.302
• [17] Zhao Y, Liu G, Li L, Yang Q, Tang B, Liu Y. Expansion devices for organic Rankine cycle (ORC) using in low temperature heat recovery: A review. Energy Conversion and Management 2019;199:111944. https://doi.org/10.1016/j.enconman.2019.111944
• [18] Garg OM. Moment analysis of a scroll expander used in an organic Rankine cycle. in ASME Turbo Expo, Germany, 2014.
• [19] Wang BLXSW. A general geometrical model of scroll compressors based on discretional initial angles of involute. International Journal of Refrigeration 2005;28:958-966. https://doi.org/10.1016/j.ijrefrig.2005.01.015