Berry R Stephen Berry 
Understanding Energy: Energy, Entropy And Thermodynamics For Everyman [PDF ebook] 

This book begins with primary concepts of atomic and molecular structure and of how atoms, molecules and bulk matter store and exchange energy. In the next stage, the macroscopic properties of energy and entropy, and of the constitutive properties of heat capacities are examined. From these, the concept of thermodynamic efficiency is developed. Then the notions of thermodynamic potentials and availability are introduced. With this set of concepts, the analysis of efficient energy use is presented.