1This work describes the contribution of researchers around the world in the field of the organic 2Rankine cycle in the period 2000-2016. A bibliometric approach was applied to analyze the 3 scientific publications in the field using the Scopus Elsevier database, together with Science 4Citation Index Expanded. Different aspects of the publications were analyzed, such as 5 publication type, major research areas, journals, citations, authorship pattern, affiliations as 6 well as the keyword occurrence frequency. The impact factor, h-index and number of citations 7were used to investigate the strength of active countries, institutes, authors, and journals in the 8 organic Rankine cycle technology field. From 2000 to 2016, there were 2120 articles published 9 by 3443 authors from 997 research institutes scattered over 71 countries. The total number of 10 citations and impact factor are 36739 and 4597, respectively, corresponding to 17 citations per 11paper and an impact factor of 2.168 per publication. The research articles originate primarily 12 from China, the USA, and European countries. Results indicate that China, the United States, 13 Italy, Greece, Belgium, Spain, Germany and the United Kingdom are the leading countries in 14 organic Rankine cycle research and account for 64 % of the total number of publications. The 15 core research activities in the field are mainly focused on applications of the organic Rankine 16 cycle technology, working fluids selection/performance, cycle architecture, and 17 design/optimization. The most productive journal, author, institution, and country are Energy, 18 Ibrahim Dincer, Tianjin University China and China, respectively. 19 20

A novel solar electricity generation system (SEGS) using cascade cycle is proposed. The top and the bottom are steam Rankine cycle (SRC) and organic Rankine cycle (ORC). Particulary, screw expander (SE), which is characterized by good applicability in power conversion with steam-liquid mixture, is employed in the SRC. Steam is generated directly in the parabolic trough collectors (PTC) and expands in the SE. The heat released by steam condensation is used to drive the ORC. This type of SEGS has the advantages of avoidance of superheated steam, moderate operating temperature and pressure, low technical requirements in heat collection and storage, and suitableness for distributed power generation. Simulation of the system performance is conducted on the use of ten ORC fluids. Four hot/cold side temperatures of 473/313 K, 473/293 K, 523/313 K and 523/293 K are exemplified. The results indicate the ORC evaporation temperature corresponding to theoretical maximum solar power efficiency fails to provide a pressure ratio (PR) that matches the SE built-in PR. Off-design operation of the SE is recommended for the purpose of higher system efficiency and simpler ORC turbine. Efficiency of 13.68-15.62% for the proposed system can be achieved.

A novel solar organic Rankine cycle (ORC) system with direct vapor generation (DVG) is proposed. A heat storage unit is embedded in the ORC to guarantee the stability of power generation. Compared with conventional solar ORCs, the proposed system avoids the secondary heat transfer intermediate and shows good reaction to the fluctuation of solar radiation. The technical feasibility of the system is discussed. Performance is analyzed by using 17 dry and isentropic working fluids. Fluid effects on the efficiencies of ORC, collectors and the whole system are studied. The results indicate that the collector efficiency generally decreases while the ORC and system efficiencies increase with the increment in fluid critical temperature. At evaporation temperature of 120 o C and solar radiation of 800 Wm-2 , the ORC, collector and overall thermal efficiencies of R236fa are 10.59, 56.14 and 5.08% while their values for Benzene are 12.5, 52.58 and 6.57 % respectively. The difference between collector efficiencies using R236fa and Benzene gets larger at lower solar radiation. The heat collection is strongly

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