Title: The development of CO₂ expander technology in CO₂ transcritical cycles

Authors: Zha Shitong, Ma Yitai

Addresses: Thermal Energy Research Institute, Tianjin University, Tianjin 300072, China. ' Thermal Energy Research Institute, Tianjin University, Tianjin 300072, China

Abstract: In this study, the CO₂ expansion process in CO₂ transcritical cycles is analysed by taking a typical operation condition as an example. The expansion work is divided into two parts: the first is the work done mainly by pressure potential energy without the phase change, and the second is the work done mainly through the volume expansion of the two-phase fluid. According to the process, the ideal expander requirement was given. By the comparison and evaluation of many types of expander, the rolling piston was identified for our initial development due to its low cost, wide application, and reasonable efficiency. The rolling piston efficiency was analysed and the inlet fluid control methods were discussed.

Keywords: CO₂ transcritical cycle; expander; expansion process; rolling piston.

DOI: 10.1504/IJGEI.2003.003965

International Journal of Global Energy Issues, 2003 Vol.20 No.3, pp.233 - 244

Published online: 10 May 2004 *

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