Investigation on the applicability of screw expander in distributed solar thermal electricity generating systems
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1Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei City, Anhui Province, People’s Republic of China
Screw expander (SE), with high applicability in power conversion with steam-liquid mixture, would be successfully applied in solar electric generating systems (SEGS). A cascade steam-organic Rankine cycle (SORC) integrated with parabolic trough collectors (PTC) was proposed. The top cycle was SE-based steam Rankine cycle (SRC) and the bottom cycle was organic Rankine cycle (ORC). The SRC condensation heat was used to drive the ORC. By comparison with conventional PTC-SEGS, the proposed system averted superheated steam and was suitable for distributed power generation applications. The actual achieved thermal efficiency was lower than the theoretical value when the influence of operating PR on SE efficiency was considered. Maximum thermal efficiencies of 14.26% and 16.00% could be obtained for SORC system with benzene as bottom fluid at the design hot / cold temperatures of 200/40℃ and 200/10℃. The efficiencies exceeded those of cascade organic Rankine cycle (CORC) system by 4.0% and 1.5% respectively, even if the working fluids in CORC were carefully selected and working conditions were optimized
Keywords. screw expander; thermal efficiency; cascade system; pressure ratio
How to cite this article
Li, P., Li, J., Pei, G., Alvi, J.Z. and Ji, J. (2015). 'Investigation on the applicability of screw expander in distributed solar thermal electricity generating systems'. SET Proceedings, 14(1), pp. 299-308. https://doi.org/10.65582/set.2015.028
