Statistical analysis of patent data relating to the organic Rankine cycle

This study analyzed patent data to explore the technological developments based on the organic Rankine cycle (ORC), which is one of the most economical and efficient methods for converting low-grade thermal energy into electricity. The patent data were obtained from the Thomson Innovation commercial database, which contains patent information from various countries and offices. After querying, filtering, and organizing the results into patent families in accordance with International Patent Documentation Center guidelines, this study analyzed data on 304 ORC-related patents. The results show that the number of patent applications increased gradually before 2006, and then rapidly from 2009 to 2011, primarily because of contributions from patent applications in China (CN) and the Republic of Korea (KR). The present findings indicate that 2009 is an important year regarding developments in ORC systems and the number of patent applications. Furthermore, the assignees from the United States (US) were the most prominent contributors. However, the most patent applications were filed in CN, indicating that the market for ORC systems in CN might offer the most potential for future development. This study also examined the top ten patent assignees, as well as the trends of the number of patent applications, size of patent families, and frequency of patent citations. The results show that all of the top ten assignees were from the US, CN, and KR. Moreover, most of them filed their patent applications in recent years, particularly after 2008. The results further indicate that the most active assignee is currently General Electric Company (US). In addition, the top five patent families and the five most frequently cited patents are briefly reviewed and discussed. The patent data analysis results indicate that the technology life cycle status of the ORC is currently in the growth stage.