Background: Concentrated solar thermal energy uses thermal energy storage. And China currently has 30 CSP projects under construction with thermal energy storage.

Various options of energy storage are described in patented solutions in the field of solar energy. They include such technologies as those using latent heat, molten materials, compressed air, and chemical reactions. In the pool of collected patent documents on solar energy storage, technical solutions disclosing the use of latent heat form the largest group of documents. In continuation of the article on energy storage technologies dated 05.06.2022 and articles dated 20.06.2022 and 22.12.2022 on CSP tracking systems, below we provide for your consideration a short analysis of patent documents related to solar energy storage systems employing latent heat approach.

More than 350 patent documents published in the twenty-year period from 2002 to 2021 were used for the present analysis by using Advanced Energy Technologies methodology. The collected documents are published in 22 patent offices of the world by 145 applicants from 21 countries.

From the chart above, we can see that in general the number of both granted patents and registered patent applications in recent years was consistently high.

In 2013-2020 in average about 40% of the technical solutions were represented by start patent applications, that didn’t belong to previously formed patent families. Although the peak of emergence of new applicants and new IPC subclasses in the collected pool of documents was in 2018, later on these values also were high, which, combined with a consistent appearance of new patent offices, can indicate that this subject attracts new participants, who expand technical and geographical coverage of the technology.

During the twenty-year period, the largest number of patents were granted in USPTO (US) – almost 35% of all collected patents. It was followed by CNIPA (CN) with about 22%. Similar picture can be seen in the collection of patent applications registered in the past 5 years, excluding that the gap between the shares of the two offices is smaller here – USPTO (US) – about 26%, and CNIPA (CN) – about 22%. EPO, JPO (JP), INPI (FR), and OEPM (ES) should also be mentioned as the patent offices that granted more than 5 patents each on the subject of interest during 2002-2021.

Residents of the USA were in the lead by the number of patents granted during the 20-year period with a share of almost 27% of all cases. In the case of recent patent applications, the first place was shared by the residents of the USA and China with a share of almost 20% for each of the two countries. High activity was also shown by residents of the United Kingdom, France, Germany, and Spain.

Fuente: HelioCSP