Contents xiii 11.8 p-v-T Relations for Gas Mixtures 699 12.7 Psychrometric Charts 766 11.9 Analyzing Multicomponent 12.8 Analyzing Air-Conditioning Systems 703 Processes 767 1.9.1 Partial Molal Properties 704 12.8.1 Applying Mass and Energy Balances 1.9.2 Chemical Potential 706 to Air-Conditioning Systems 767 1.9.3 Fundamental Thermodynamic Functions 12.8.2 Conditioning Moist Air at Constant for Multicomponent Systems 707 Composition 769 11.9.4 Fugacity 709 12.8.3 Dehumidification 772 1.9.5 Ideal Solution 712 12.8.4 Humidification 776 1.9.6 Chemical Potential for Ideal 12.8.5 Evaporative Cooling 778 Solutions 713 12.8.6 Adiabatic Mixing of Two Moist Air Chapter Summary and Study Guide 714 Streams 781 12.9 Cooling Towers 784 12 ldeal Gas Mixture and Chapter Summary and Study Guide 787 Psychrometric Applications 731 13 Reacting Mixtures and Ideal Gas Mixtures:General Combustion 805 Considerations 732 Combustion Fundamentals 806 12.1 Describing Mixture Composition 732 13.1 Introducing Combustion 806 12.2 Relating p,V,and Tfor Ideal Gas Mixtures 736 13.1.1 Fuels 807 13.1.2 Modeling Combustion Air 807 12.3 Evaluating U,H,S,and Specific Heats 737 13.1.3 Determining Products of Combustion 810 12.3.1 Evaluating U and H 737 13.1.4 Energy and Entropy Balances for Reacting 12.3.2 Evaluating c and cp 738 Systems 814 12.3.3 Evaluating S 738 13.2 Conservation of Energy-Reacting Systems 815 12.3.4 Working on a Mass Basis 739 13.2.Evaluating Enthalpy for Reacting 12.4 Analyzing Systems Involving Systems 815 Mixtures 740 13.2.2 Energy Balances for Reacting 12.4.1 Mixture Processes at Constant Systems 817 Composition 740 13.2.3 Enthalpy of Combustion and Heating 12.4.2 Mixing of Ideal Gases 747 Values 825 Psychrometric Applications 753 13-3 Determining the Adiabatic Flame Temperature 828 12.5 Introducing Psychrometric Principles 753 13-3.1 Using Table Data 829 12.5.1 Moist Air 753 13.3.2 Using Computer Software 829 12.5.2 Humidity Ratio,Relative Humidity,Mixture Enthalpy,and Mixture Entropy 754 13-3.3 Closing Comments 832 12.5.3 Modeling Moist Air in Equilibrium with 13.4 Fuel Cells 832 Liquid Water 756 13.4.1 Proton Exchange Membrane Fuel Cell 834 12.5.4 Evaluating the Dew Point Temperature 757 13.4.2 Solid Oxide Fuel Cell 836 12.5-5 Evaluating Humidity Ratio Using the 13-5 Absolute Entropy and the Third Law Adiabatic-Saturation Temperature 763 of Thermodynamics 836 12.6 Psychrometers:Measuring the Wet-Bulb 13-5.1 Evaluating Entropy for Reacting and Dry-Bulb Temperatures 764 Systems 837
Contents xiii 11.8 p–y–T Relations for Gas Mixtures 699 11.9 Analyzing Multicomponent Systems 703 11.9.1 Partial Molal Properties 704 11.9.2 Chemical Potential 706 11.9.3 Fundamental Thermodynamic Functions for Multicomponent Systems 707 11.9.4 Fugacity 709 11.9.5 Ideal Solution 712 11.9.6 Chemical Potential for Ideal Solutions 713 Chapter Summary and Study Guide 714 12 Ideal Gas Mixture and Psychrometric Applications 731 Ideal Gas Mixtures: General Considerations 732 12.1 Describing Mixture Composition 732 12.2 Relating p, V, and T for Ideal Gas Mixtures 736 12.3 Evaluating U, H, S, and Specifi c Heats 737 12.3.1 Evaluating U and H 737 12.3.2 Evaluating cy and cp 738 12.3.3 Evaluating S 738 12.3.4 Working on a Mass Basis 739 12.4 Analyzing Systems Involving Mixtures 740 12.4.1 Mixture Processes at Constant Composition 740 12.4.2 Mixing of Ideal Gases 747 Psychrometric Applications 753 12.5 Introducing Psychrometric Principles 753 12.5.1 Moist Air 753 12.5.2 Humidity Ratio, Relative Humidity, Mixture Enthalpy, and Mixture Entropy 754 12.5.3 Modeling Moist Air in Equilibrium with Liquid Water 756 12.5.4 Evaluating the Dew Point Temperature 757 12.5.5 Evaluating Humidity Ratio Using the Adiabatic-Saturation Temperature 763 12.6 Psychrometers: Measuring the Wet-Bulb and Dry-Bulb Temperatures 764 12.7 Psychrometric Charts 766 12.8 Analyzing Air-Conditioning Processes 767 12.8.1 Applying Mass and Energy Balances to Air-Conditioning Systems 767 12.8.2 Conditioning Moist Air at Constant Composition 769 12.8.3 Dehumidifi cation 772 12.8.4 Humidifi cation 776 12.8.5 Evaporative Cooling 778 12.8.6 Adiabatic Mixing of Two Moist Air Streams 781 12.9 Cooling Towers 784 Chapter Summary and Study Guide 787 13 Reacting Mixtures and Combustion 805 Combustion Fundamentals 806 13.1 Introducing Combustion 806 13.1.1 Fuels 807 13.1.2 Modeling Combustion Air 807 13.1.3 Determining Products of Combustion 810 13.1.4 Energy and Entropy Balances for Reacting Systems 814 13.2 Conservation of Energy— Reacting Systems 815 13.2.1 Evaluating Enthalpy for Reacting Systems 815 13.2.2 Energy Balances for Reacting Systems 817 13.2.3 Enthalpy of Combustion and Heating Values 825 13.3 Determining the Adiabatic Flame Temperature 828 13.3.1 Using Table Data 829 13.3.2 Using Computer Soft ware 829 13.3.3 Closing Comments 832 13.4 Fuel Cells 832 13.4.1 Proton Exchange Membrane Fuel Cell 834 13.4.2 Solid Oxide Fuel Cell 836 13.5 Absolute Entropy and the Third Law of Thermodynamics 836 13.5.1 Evaluating Entropy for Reacting Systems 837
xiv Contents 13-5.2 Entropy Balances for Reacting 14-3 Calculating Equilibrium Systems 838 Compositions 889 13-5-3 Evaluating Gibbs Function for Reacting 14.3.1 Equilibrium Constant for Ideal Gas Systems 843 Mixtures 889 Chemical Exergy 844 14-3.2 Illustrations of the Calculation of 13.6 Conceptualizing Chemical Exergy 845 Equilibrium Compositions for Reacting Ideal Gas Mixtures 892 13.6.1 Working Equations for Chemical Exergy 847 14-3.3 Equilibrium Constant for Mixtures and Solutions 897 13.6.2 Evaluating Chemical Exergy for Several Cases 847 14.4 Further Examples of the Use of the 13.6.3 Closing Comments 849 Equilibrium Constant 899 13.7 Standard Chemical Exergy 849 14-4.1 Determining Equilibrium Flame Temperature 899 13-7.1 Standard Chemical Exergy of a Hydrocarbon:CaH。85o 14.4.2 Van't Hoff Equation 903 13-7.2 Standard Chemical Exergy of Other 14.4.3 lonization 904 Substances 853 14.4.4 Simultaneous Reactions 905 13.8 Applying Total Exergy 854 Phase Equilibrium 908 13.8.1 Calculating Total Exergy 854 14-5 Equilibrium between Two Phases 13.8.2 Calculating Exergetic Efficiencies of a Pure Substance 908 of Reacting Systems 860 14.6 Equilibrium of Multicomponent, Chapter Summary and Study Guide 864 Multiphase Systems 910 14.6.1 Chemical Potential and Phase Equilibrium 910 14 Chemical and Phase Equilibrium 881 14.6.2 Gibbs Phase Rule 912 Chapter Summary and Study Guide 914 Equilibrium Fundamentals 882 14.1 Introducing Equilibrium Criteria 882 Appendix Tables,Figures,and Charts 925 14.1.1 Chemical Potential and Index to Tables in SI Units 925 Equilibrium 883 Index to Tables in English Units 973 14.1.2 Evaluating Chemical Potentials 884 Index to Figures and Charts 1021 Chemical Equilibrium 887 14.2 Equation of Reaction Index 1036 Equilibrium 887 14.2.1 Introductory Case 887 14.2.2 General Case 888
xiv Contents 13.5.2 Entropy Balances for Reacting Systems 838 13.5.3 Evaluating Gibbs Function for Reacting Systems 843 Chemical Exergy 844 13.6 Conceptualizing Chemical Exergy 845 13.6.1 Working Equations for Chemical Exergy 847 13.6.2 Evaluating Chemical Exergy for Several Cases 847 13.6.3 Closing Comments 849 13.7 Standard Chemical Exergy 849 13.7.1 Standard Chemical Exergy of a Hydrocarbon: CaHb 850 13.7.2 Standard Chemical Exergy of Other Substances 853 13.8 Applying Total Exergy 854 13.8.1 Calculating Total Exergy 854 13.8.2 Calculating Exergetic Effi ciencies of Reacting Systems 860 Chapter Summary and Study Guide 864 14 Chemical and Phase Equilibrium 881 Equilibrium Fundamentals 882 14.1 Introducing Equilibrium Criteria 882 14.1.1 Chemical Potential and Equilibrium 883 14.1.2 Evaluating Chemical Potentials 884 Chemical Equilibrium 887 14.2 Equation of Reaction Equilibrium 887 14.2.1 Introductory Case 887 14.2.2 General Case 888 14.3 Calculating Equilibrium Compositions 889 14.3.1 Equilibrium Constant for Ideal Gas Mixtures 889 14.3.2 Illustrations of the Calculation of Equilibrium Compositions for Reacting Ideal Gas Mixtures 892 14.3.3 Equilibrium Constant for Mixtures and Solutions 897 14.4 Further Examples of the Use of the Equilibrium Constant 899 14.4.1 Determining Equilibrium Flame Temperature 899 14.4.2 Van’t Hoff Equation 903 14.4.3 Ionization 904 14.4.4 Simultaneous Reactions 905 Phase Equilibrium 908 14.5 Equilibrium between Two Phases of a Pure Substance 908 14.6 Equilibrium of Multicomponent, Multiphase Systems 910 14.6.1 Chemical Potential and Phase Equilibrium 910 14.6.2 Gibbs Phase Rule 912 Chapter Summary and Study Guide 914 Appendix Tables, Figures, and Charts 925 Index to Tables in SI Units 925 Index to Tables in English Units 973 Index to Figures and Charts 1021 Index 1036
Medical professionals rely on measurements of pressure and temperature,introduced in Secs.1.6 and 1.7.digitalskillet/iStockphoto ENGINEERING CONTEXT Although aspects of interested in gaining a fundamental understanding thermodynamics have been studied since ancient of the physical and chemical behavior of fixed quan- times,the formal study of thermodynamics began tities of matter at rest and uses the principles of in the early nineteenth century through consider-thermodynamics to relate the properties of matter. ation of the capacity of hot objects to produce work.Engineers are generally interested in studying sys- Today the scope is much larger.Thermodynamics tems and how they interact with their surroundings. now provides essential concepts and methods for To facilitate this,thermodynamics has been extended addressing critical twenty-first-century issues,such to the study of systems through which matter flows, as using fossil fuels more effectively,fostering including bioengineering and biomedical systems. renewable energy technologies,and developing The objective of this chapter is to introduce you to more fuel-efficient means of transportation.Also some of the fundamental concepts and definitions critical are the related issues of greenhouse gas that are used in our study of engineering thermody- emissions and air and water pollution. namics.In most instances this introduction is brief, Thermodynamics is both a branch of science and an and further elaboration is provided in subsequent engineering specialty.The scientist is normally chapters
2 Medical professionals rely on measurements of pressure and temperature, introduced in Secs. 1.6 and 1.7. © digitalskillet/iStockphoto ENGINEERING CONTEXT Although aspects of thermodynamics have been studied since ancient times, the formal study of thermodynamics began in the early nineteenth century through consideration of the capacity of hot objects to produce work. Today the scope is much larger. Thermodynamics now provides essential concepts and methods for addressing critical twenty-first-century issues, such as using fossil fuels more effectively, fostering renewable energy technologies, and developing more fuel-efficient means of transportation. Also critical are the related issues of greenhouse gas emissions and air and water pollution. Thermodynamics is both a branch of science and an engineering specialty. The scientist is normally interested in gaining a fundamental understanding of the physical and chemical behavior of fixed quantities of matter at rest and uses the principles of thermodynamics to relate the properties of matter. Engineers are generally interested in studying systems and how they interact with their surroundings. To facilitate this, thermodynamics has been extended to the study of systems through which matter flows, including bioengineering and biomedical systems. The objective of this chapter is to introduce you to some of the fundamental concepts and definitions that are used in our study of engineering thermodynamics. In most instances this introduction is brief, and further elaboration is provided in subsequent chapters
Getting Started Introductory Concepts and Definitions LEARNING OUTCOMES When you complete your study of this chapter,you will be able to... explain several fundamental concepts used throughout the book, including closed system,control volume,boundary and surroundings, property,state,process,the distinction between extensive and intensive properties,and equilibrium. identify Sl and English Engineering units,including units for specific volume,pressure,and temperature. describe the relationship among the Kelvin,Rankine,Celsius,and Fahrenheit temperature scales. apply appropriate unit conversion factors during calculations. apply the problem-solving methodology used in this book. 3
3 Getting Started Introductory Concepts and Defi nitions c When you complete your study of this chapter, you will be able to... c explain several fundamental concepts used throughout the book, including closed system, control volume, boundary and surroundings, property, state, process, the distinction between extensive and intensive properties, and equilibrium. c identify SI and English Engineering units, including units for specific volume, pressure, and temperature. c describe the relationship among the Kelvin, Rankine, Celsius, and Fahrenheit temperature scales. c apply appropriate unit conversion factors during calculations. c apply the problem-solving methodology used in this book. c LEARNING OUTCOMES 1 3
Chapter 1 Getting Started Using Thermodynamics Engineers use principles drawn from thermodynamics and other engineering sciences, including fluid mechanics and heat and mass transfer,to analyze and design devices intended to meet human needs.Throughout the twentieth century,engineering applica- tions of thermodynamics helped pave the way for significant improvements in our qual- ity of life with advances in major areas such as surface transportation,air travel,space flight,electricity generation and transmission,building heating and cooling,and improved medical practices.The wide realm of these applications is suggested by Table 1.1. In the twenty-first century,engineers will create the technology needed to achieve a sustainable future.Thermodynamics will continue to advance human well-being by addressing looming societal challenges owing to declining supplies of energy resources: oil,natural gas,coal,and fissionable material;effects of global climate change;and burgeoning population.Life in the United States is expected to change in several important respects by mid-century.In the area of power use,for example,electricity will play an even greater role than today.Table 12 provides predictions of other changes experts say will be observed. If this vision of mid-century life is correct,it will be necessary to evolve quickly from our present energy posture.As was the case in the twentieth century,thermodynamics will contribute significantly to meeting the challenges of the twenty-first century,includ- ing using fossil fuels more effectively,advancing renewable energy technologies,and developing more energy-efficient transportation systems,buildings,and industrial prac- tices.Thermodynamics also will play a role in mitigating global climate change,air pollution,and water pollution.Applications will be observed in bioengineering,bio- medical systems,and the deployment of nanotechnology.This book provides the tools needed by specialists working in all such fields.For nonspecialists,the book provides background for making decisions about technology related to thermodynamics-on the job,as informed citizens,and as government leaders and policy makers. Defining Systems The key initial step in any engineering analysis is to describe precisely what is being studied.In mechanics,if the motion of a body is to be determined,normally the first step is to define a free body and identify all the forces exerted on it by other bodies.Newton's second law of motion is then applied.In thermodynamics the term systemn is used to identify the subject of the analysis.Once the system is defined and the relevant interac- tions with other systems are identified,one or more physical laws or relations are applied. system The system is whatever we want to study.It may be as simple as a free body or as complex as an entire chemical refinery.We may want to study a quantity of matter contained within a closed,rigid-walled tank,or we may want to consider something such as a pipeline through which natural gas flows.The composition of the matter inside the system may be fixed or may be changing through chemical or nuclear reac- tions.The shape or volume of the system being analyzed is not necessarily constant, as when a gas in a cylinder is compressed by a piston or a balloon is inflated. surroundings Everything external to the system is considered to be part of the system's surroundings. boundary The system is distinguished from its surroundings by a specified boundary,which may be at rest or in motion.You will see that the interactions between a system and its surroundings,which take place across the boundary,play an important part in engi- neering thermodynamics. Two basic kinds of systems are distinguished in this book.These are referred to,respec- tively,as closed systems and control volumes.A closed system refers to a fixed quantity of matter,whereas a control volume is a region of space through which mass may flow. The term control mass is sometimes used in place of closed system,and the term open system is used interchangeably with control volume.When the terms control mass and control volume are used,the system boundary is often referred to as a control surface
4 Chapter 1 Getting Started 1.1 Using Thermodynamics Engineers use principles drawn from thermodynamics and other engineering sciences, including fluid mechanics and heat and mass transfer, to analyze and design devices intended to meet human needs. Throughout the twentieth century, engineering applications of thermodynamics helped pave the way for significant improvements in our quality of life with advances in major areas such as surface transportation, air travel, space flight, electricity generation and transmission, building heating and cooling, and improved medical practices. The wide realm of these applications is suggested by Table 1.1. In the twenty-first century, engineers will create the technology needed to achieve a sustainable future. Thermodynamics will continue to advance human well-being by addressing looming societal challenges owing to declining supplies of energy resources: oil, natural gas, coal, and fissionable material; effects of global climate change; and burgeoning population. Life in the United States is expected to change in several important respects by mid-century. In the area of power use, for example, electricity will play an even greater role than today. Table 1.2 provides predictions of other changes experts say will be observed. If this vision of mid-century life is correct, it will be necessary to evolve quickly from our present energy posture. As was the case in the twentieth century, thermodynamics will contribute significantly to meeting the challenges of the twenty-first century, including using fossil fuels more effectively, advancing renewable energy technologies, and developing more energy-efficient transportation systems, buildings, and industrial practices. Thermodynamics also will play a role in mitigating global climate change, air pollution, and water pollution. Applications will be observed in bioengineering, biomedical systems, and the deployment of nanotechnology. This book provides the tools needed by specialists working in all such fields. For nonspecialists, the book provides background for making decisions about technology related to thermodynamics—on the job, as informed citizens, and as government leaders and policy makers. 1.2 Defining Systems The key initial step in any engineering analysis is to describe precisely what is being studied. In mechanics, if the motion of a body is to be determined, normally the first step is to define a free body and identify all the forces exerted on it by other bodies. Newton’s second law of motion is then applied. In thermodynamics the term system is used to identify the subject of the analysis. Once the system is defined and the relevant interactions with other systems are identified, one or more physical laws or relations are applied. The system is whatever we want to study. It may be as simple as a free body or as complex as an entire chemical refinery. We may want to study a quantity of matter contained within a closed, rigid-walled tank, or we may want to consider something such as a pipeline through which natural gas flows. The composition of the matter inside the system may be fixed or may be changing through chemical or nuclear reactions. The shape or volume of the system being analyzed is not necessarily constant, as when a gas in a cylinder is compressed by a piston or a balloon is inflated. Everything external to the system is considered to be part of the system’s surroundings. The system is distinguished from its surroundings by a specified boundary, which may be at rest or in motion. You will see that the interactions between a system and its surroundings, which take place across the boundary, play an important part in engineering thermodynamics. Two basic kinds of systems are distinguished in this book. These are referred to, respectively, as closed systems and control volumes. A closed system refers to a fixed quantity of matter, whereas a control volume is a region of space through which mass may flow. The term control mass is sometimes used in place of closed system, and the term open system is used interchangeably with control volume. When the terms control mass and control volume are used, the system boundary is often referred to as a control surface. system surroundings boundary