This textbook offers a clear, progressive introduction to thermodynamics, tailored for university students and future engineers eager to understand the physical principles behind engines and refrigeration systems. It begins from the basics and progressively covers all the important concepts: 1 Fundamental Concepts Review the essential concepts for the study of thermodynamics Concept of energy; First law; Mech. energy; Work; Heat; Temperature. 2 Closed Systems Quantify energy transfers in a fixed quantity of fluid Quantification of work and heat in a closed system; Concept of irreversibility. 3 Open Systems Quantify energy transfers in a continuously-flowing fluid Usefulness of open and closed systems; Quantification of work and heat. 4 The Ideal Gas Predict air temperature and quantify its forms of energy Advantages and limits of the ideal gas model; Basic elementary processes.…