The practical significance of the research results lies in the development of improved designs of self-regulating active elements of the confuser-diffuser type with improved hydrodynamic characteristics, as well as engineering methods for calculating self-regulating active elements and solar heating plants based on them. The results of the completed scientific research allow us to develop designs of the simplest self-regulating active elements that provide a significant increase in energy efficiency, cost-effectiveness and reliability of solar systems, a reduction in material consumption and...