This book is designed for a first course in Refrigeration and Air Conditioning. The subject matter has been developed in a logical and coherent manner with neat illustrations and a fairly large number of solved examples and unsolved problems. The text, developed from the author’s teaching experience of many years, is suitable for the senior-level undergraduate and first-year postgraduate students of mechanical engineering, automobile engineering as well as chemical engineering. The text commences with an introduction to the funda- mentals of thermodynamics and a brief treatment of the various methods of refrigeration. Then follows the detailed discussion and analysis of air refrigeration systems, vapour compression and vapour absorption refrigeration systems with special emphasis on developing sound physical concepts and gaining problem solving skills. Refrigerants are exhaustively dealt with in a separate chapter. The remainder chapters of the book deal with psychrometry and various processes required for the analysis of air conditioning systems. Technical descriptions of compressors, evaporators, condensers, expansion devices and ducts are provided along with design practices for cooling and heating load calculations. The basic principles of cryogenic systems and applications of cryogenic gases and air liquefaction systems have also been dealt with. The Second Edition incorporates: New sections on vortex tube, solar refrigeration and magnetic refrigeration, in Chapter 2. Additional solved examples on vapour compression refrigeration system using the R134a refrigerant, in Chapter 4. New sections on duct arrangement systems and air distribution systems, in Chapter 15. A new Chapter 17 on Food Preservation.