. Although the traditional method of using property tables and charts is important for understanding the basic concepts, the tables and charts are not suitable for design analyses of energy-conversion systems that usually involve sensitivity and optimisation analyses in order to minimise their environmental impact and maximise their economic feasibility. In this respect, the use of computers and computer-aided methods can improve the learning process by making the students more interested in the subject and by helping them to easily apply its principles in relevant design analyses. Computer-aided methods can also make the application of these principles more realistic and more accurate compared to traditional analytical methods that adopt many idealisations and simplifying assumptions in order to model the complex energy-conversion systems. Although the commercial computer applications that are widely used for industrial and research analyses can also be used for educational purposes, they are not the ideal method either because of their cost and complexity or because they don’t allow white-box modelling of the systems to be analysed. This book shows how a general-purpose spreadsheet application, which is Microsoft Excel, can be used as an alternative educational platform for thermodynamic analyses of energy-conversion systems. Compared to the commercial software that is dedicated to such analyses, the main advantage of Excel is its wide availability on computers and mobile phones. From an educational point of view, the Excel-based modelling platform used in the book allows the students to build white-box models from the basic principles. As a modelling platform for engineering analyses, Excel provides a rich library of mathematical functions and powerful graphic tools for data visualisation. Since Excel itself does not provide functions for determining fluid properties which are necessary for thermodynamic analyse, such functions had to be developed as custom functions with the Visual Basic for Applications (VBA) programming language that comes with Microsoft Applications. The VBA functions are grouped as an Excel add-in called Thermax that provides property functions for 29 ideal gases, water and superheated steam, 28 synthetic and natural refrigerants, two aqua solutions for vapour-absorption refrigeration, humid air for psychrometric analyses, and atmospheric air at various temperatures. The automation of property calculations enables the students to deal with iterative solutions and time-consuming parametric studies and the Solver add-in that comes with Excel enables the students to perform constrained and multi-variable optimisation analyses of energy-conversion systems. With Thermax functions, Excel can deal with different types of thermodynamic analyses that range from the analyses of the basic gas viii Mohamed M. El-Awad power-generation and vapour-compression refrigeration (VCR) cycles to the analyses of single-effect and two-effect vapour-absorption refrigeration (VAR) systems. Within this range, the topics covered in the book include energy analysis of the organic Rankine cycle with different working fluids, the analyses and optimisation of multi-stage compression and cascade VCR systems, design analysis of an air-conditioning system, and development of a general sheet for combustion analyses. The last two chapters of the book deal with thermoeconomic optimisation analyses of energy-conversion systems by considering two example which are the air-bottoming cycle and the gas-turbine cycle with inlet-air cooling. Most of the cases considered in the book have been adopted from popular textbooks and published work so that the results obtained can be verified. While relevant exercises are provided at the end of Chapters 2 to 5, more challenging exercises and mini projects are given in the last appendix of the book. Thermax has been developed by the author for educational purposes with the aim of helping engineering students to use Excel for various types of thermofluid and thermoeconomic analyses. Bearing in mind that the scope of thermodynamic analyses with the Excel-based platform can be widened by using a number of other educational and research-oriented Excel add-ins that have been developed by academic institutions and individuals, it is hoped that the book can also be useful to the researchers and practicing engineers in this area. Acknowledgements The development of Thermax would not have been possible without benefitting from the efforts of many other people who have made the fruits of their efforts available in the open literature or the internet. In this respect, my special gratitude goes to the Mechanical Engineering Department at the University of Alabama (USA) whose initiatives both inspired and helped me throughout the writing of this book. My gratitude and appreciation also go to the College of Applied Sciences in Sohar (Oman) who provided the financial support that helped me to prepare most of the material covered in this book. I am also indebted the unfailing support received from my colleagues and students in Malaysia, Sudan, and Oman, and hope that they find this book a fair repay. Last, but not least, my thanks and gratitude go to my beloved family for their tolerance and unfailing support desperately needed to complete the work. Analyses and Thermoeconomic Optimisation of Energy-Conversion Systems Using Excel ix CONTENTS Nomenclature xii 1. Introduction 1 1.1. A brief review of thermodynamics 2 1.2. Advantages of computer-aided thermodynamic analyses 7 1.3. Excel as a modelling platform for thermodynamic analyses 9 1.4. Closure 10