This book provides the fundamentals for calculating refrigeration systems and heat pumps. It covers the sizing of cooling loads, the selection of methods and refrigerants, as well as the calculation of the required components. Relationships are clearly explained and discussed through detailed practical examples. The structure of the book follows a clear didactic approach. The cooling behavior of various substances leads to refrigeration methods of different complexities and ultimately to the topic of heat transfer. The difficulty level of the underlying thermodynamic concepts is gradually increased. Therefore, the book is also suitable for self-study. The target audience for this book includes students in the fields of mechanical engineering, process engineering, supply engineering, energy engineering, and environmental engineering. It is also aimed at engineers.