Exploring the Evolution of Solar Space-Heating–Related Research: A Schematic Review Based onGlobal and Geographical Publication Trends andKeyword Analysis

Abstract: The increased concern about rising global temperatures and the availability of abundant solar energy have driven worldwide research into solar space-heating applications. Extensive research has been carried out on solar air-heating technologies (both in patents and research papers) because of their environmentally friendly nature, and there is a need to assess global research trends on solar heating technology based on publications, author and national collaboration, keyword co-occurrence, and related factors. A brief trend of patents granted is studied and summarized; however, for a rigorous analysis of the large volume of scientific data on solar air heating, a bibliometric analysis of the literature has been conducted over the last six decades. The analysis broadly focuses on global publication trends, prominent authors, geographical contributions to publications, citation patterns, and keyword analysis. In the last five years, more than 100 articles have been published each year on SAH, resulting in a substantial increase in overall publications. Indian scholars contributed 40% of the world’s publications, placing them ahead of the other 66 nations publishing on the same topic. The most frequently occurring keyword is artificial roughness, and among all other possible shapes or configurations, V-shaped roughness with multiple symmetric gaps provides the best performance parameters. For low Reynolds numbers (4000 to 8000), dimple-shaped roughness performs the best.