Theory for Closed Systems

Abstract

This chapter describes the fundamentals of thermodynamics focusing on a closed system, through which no matter comes in and out. The discussion starts from the concepts of heat, temperature, and work, and then moves on to the two concepts of energy and entropy. An emphasis is placed on the essential characteristics of energy as “to be conserved” and that of entropy as “the measure quantifying dispersion”. The concept of entropy is introduced with a manner different from most of thermodynamic textbooks so that the readers who are totally new to the science of thermodynamics can grasp the essential image of entropy together with that of energy as easily as possible. After establishing the relationships between heat, work, energy, entropy, Carnot engine, absolute temperature, and ideal-gas temperature, the fundamental equation for exergy balance is given and then how we can proceed exergy calculation is described in terms of heat transfer by long-wavelength radiation, convection, conduction both at steady state and at unsteady state, solar radiation, and finally long-wavelength effective sky radiation. All of them are discussed with numerical examples.