English: The monograph addresses the development of the theoretical foundations for the improvement of thermal transformation technologies for their competitive implementation in the designed and modernized heat and cold supply systems. Modern methods of thermo-economic analysis and optimization of thermal transformers are widely used in the work, the synthesis of their technological schemes is considered. Original methods have been developed for testing the thermodynamic perfection of modern refrigeration machines and heat pumps, as well as evaluating their technical, economic, and environmental indicators when working in heat and cold supply systems. Methods of thermo-economic optimization of steam compressor thermo-transformers using substances of natural origin as a refrigerant are proposed. The book is designed for engineers and scientists in the field of energy and low-temperature technology, and is of interest to graduate students and students of relevant specialties.