Preface

Exergy has been defined as the maximum work that is useful, extracted from any process toward its equilibrium. Hence, it has a very strong connection with the second law of thermodynamics. In energy harvesting and management systems, the concept of exergy is very important because it represents the efficiency of the system. Exergy can be used as a tool to measure resource efficiency, as well as whole system sustainability. In addition, it can also be used to analyze and clarify the performance of each process; hence, methods of improvement can be determined.

This book is the result of a very careful selection of chapters and contributors in the related field. The book is divided into three main sections according to the approaches and purpose of each proposed chapter. The first chapter in the "Introduction" section, deals with detailed exergy analysis of developed photovoltaic/thermal systems employing nanofluid, which are designed to harvest solar energy efficiently. Various models have been developed and compared with each other to achieve optimum design and conditions. In addition, the utilization of nanofluid as optical filters of solar radiation leads to higher exergy efficiency. The second section, "Advanced energy conversions," describes several advanced technologies that are considered to have great potential in energy conversion and harvesting, and comprises three chapters. The second chapter describes the idea of power-to-gas energy storage systems coupled with a combined cycle employing chemical looping combustion technology to facilitate base and intermediate loads of power utilizing unused or surplus electricity from the grid. In addition, the idea of chemical looping also results in very clean energy conversion due to its capability to separate the produced CO2 during the reduction process. In this chapter, to achieve high total energy efficiency, the idea of enhanced process integration technology is employed resulting in efficient and optimal heat and exergy recovery throughout the system. The third chapter focuses on novel models and design for energy conversion (power generation) using the principles of electromagnetics. The text contains a detailed description related to electromagnetic induction, magnetic susceptibility, potential materials, and magnetic hysteresis. In addition, a diagram of electromagnetic systems is also provided and explained.

The third section focuses on the idea of "innovative energy management systems" toward high-quality energy systems and contains two chapters. The fourth chapter is dedicated to the utilization of electric vehicles for demand-side energy management. The vast deployment of electric vehicles is considered to have great potential when they can be utilized effectively for providing ancillary services to the grid. In addition, the utilization of electric vehicles in load scheduling can facilitate households to alleviate the network load burden, in addition to reducing electricity bills. Also in this chapter, two different models of demand response assisted using electric vehicles are described, including electric vehicle auxiliary power supply and neighbor energy-sharing models. The objective of the developed models is to optimize the load distribution for both individual and multihousehold networks via vehicle-to-home and vehicle-to-neighbor connections. Finally, the fifth chapter explains the utilization of supercapacitors as very responsive energy storage devices in low-power modules. The supercapacitor has many advantages compared to other

types of energy storage, including high charging and discharging rates, very small capacity degradation, low toxicity of used materials, and high cycle efficiency. The chapter explains in detail the characteristics and performance of a lithium-ion supercapacitor, especially its usage for low-power sensor modules.

It is expected that this book will provide and enrich the state of the art in advanced energy systems, including energy conversion and management. All the chapters cover a broad range of disciplines, which are correlated in terms of the efforts toward efficient energy systems. In addition, the correlation between energy and exergy, and their understanding, are believed to be very important to improve energy efficiency and guarantee better energy quality.

> **Muhammad Aziz** The University of Tokyo, Japan

> > **1**

Section 1

Introduction

Section 1 Introduction

**3**

**Chapter 1**

Energy Systems

*Muhammad Aziz*

tions with high sustainability.

**2. Challenges in energy systems**

**1. Introduction**

Introductory Chapter: Green

As one of the very crucial elements of life, energy has given huge impacts in forming the domestic and international policies of the country, raising the environmental issues, changing the social dimensions, accelerating the economic growth, etc. The study related to energy has focused mainly on finding and establishing the new and efficient ways to produce (convert), store, transport, and utilize the energy. The conventional energy system, coupled with the huge demand of energy due to industrial activities, has resulted in various social, psychological, and environmental problems. Concretely, conventional combustion of fossil energy sources has accelerated the emission of greenhouse gases (GHGs), leading to high concern on climatic issues. In order to tackle down the above problems, several research have been developed, especially related to the way to achieve greener energy systems. Dincer and Zamfirescu [1] have proposed the concept of greenization, which refers to the efforts to greenize the energy systems, including the processes and applica-

Some academic efforts to clearly analyze the problems also include several theoretical approaches to correlate the theories to their real implications. The intensive correlation of thermodynamics toward sustainable energy systems and environment has been studied by Hammond [2]. In addition, Bejan [3] also used the theory of entropy generation minimization in order to analyze the energy policy. Discussing the energy policy, there is a strong relationship between the exergy destruction and environmental impact. Lower exergy destruction leads to higher energy efficiency of the system; hence, the systems consumes less energy input followed by lower environmental impact, leading to the sustainability of the system.

**Figure 1** shows four essential pillars related to energy issues, covering security and resilience, economy, social, and environment. In energy security, recently, the issue is not only limited to the security of supply but also includes the capability of the system to respond and recover back when any disturbance in the energy system occurs. Therefore, the security and resilience correlate strongly to both quantitative and qualitative aspects of energy. Furthermore, the economic issues cover several major points including equity, participation, economic performance, and open opportunity to the whole players. All of the entities in the system can behave as energy producers and consumers simultaneously, leading to the concept of "prosumer." The equal opportunity provided to the all players involved in the system potentially accelerate and maximize the introduction of renewable energy, as well as improve the total economic performance. The environmental issues deal

#### **Chapter 1**

## Introductory Chapter: Green Energy Systems

*Muhammad Aziz*

#### **1. Introduction**

As one of the very crucial elements of life, energy has given huge impacts in forming the domestic and international policies of the country, raising the environmental issues, changing the social dimensions, accelerating the economic growth, etc. The study related to energy has focused mainly on finding and establishing the new and efficient ways to produce (convert), store, transport, and utilize the energy. The conventional energy system, coupled with the huge demand of energy due to industrial activities, has resulted in various social, psychological, and environmental problems. Concretely, conventional combustion of fossil energy sources has accelerated the emission of greenhouse gases (GHGs), leading to high concern on climatic issues. In order to tackle down the above problems, several research have been developed, especially related to the way to achieve greener energy systems. Dincer and Zamfirescu [1] have proposed the concept of greenization, which refers to the efforts to greenize the energy systems, including the processes and applications with high sustainability.

Some academic efforts to clearly analyze the problems also include several theoretical approaches to correlate the theories to their real implications. The intensive correlation of thermodynamics toward sustainable energy systems and environment has been studied by Hammond [2]. In addition, Bejan [3] also used the theory of entropy generation minimization in order to analyze the energy policy. Discussing the energy policy, there is a strong relationship between the exergy destruction and environmental impact. Lower exergy destruction leads to higher energy efficiency of the system; hence, the systems consumes less energy input followed by lower environmental impact, leading to the sustainability of the system.

#### **2. Challenges in energy systems**

**Figure 1** shows four essential pillars related to energy issues, covering security and resilience, economy, social, and environment. In energy security, recently, the issue is not only limited to the security of supply but also includes the capability of the system to respond and recover back when any disturbance in the energy system occurs. Therefore, the security and resilience correlate strongly to both quantitative and qualitative aspects of energy. Furthermore, the economic issues cover several major points including equity, participation, economic performance, and open opportunity to the whole players. All of the entities in the system can behave as energy producers and consumers simultaneously, leading to the concept of "prosumer." The equal opportunity provided to the all players involved in the system potentially accelerate and maximize the introduction of renewable energy, as well as improve the total economic performance. The environmental issues deal

#### **Figure 1.**

*Essential pillars in energy system.*

strongly with some challenges to realize the green and clean energy system which give a minimum influence to the environment, as well as keep both the system and environment to be sustainable. At the last, the social issues are related strongly to the problems in equal and appropriate distribution of the energy to the consumers. Energy is very essential element in human activities; therefore, the correlation and balance of those four pillars in energy system are very important.

The transition of the energy systems from currently high- to low-carbon emitting systems has led to several socioeconomic-environmental opportunities. However, there are still many unresolved issues related to the correlation among the energy, economic growth, and social welfare. The prediction and projection of energy systems in the future, especially related to the balance of both fluctuating demand and supply, face many uncertainties, due to several parameters including social, economic, weather, climate, and technological developments.

Long-term accurate and flexible (responsive) strategies on energy will gave a strong confidence to all of the energy entities involved in the system/region. The dynamic and fast changes in energy systems have occurred time by time following the technological and social changes in the community.

#### **3. Exergy**

Energy has two different measures, which are quantity and quality. The energy quantity is the amount of energy which is supplied or consumed, while the energy quality deals with the availability/usability of energy resource to be consumed. The latter has revealed the concept of exergy. It is very strongly correlated to both the first and second laws of thermodynamics. The exergy is possibly destructed, which is different with the concept of energy as it is conserved. It strongly relates to the concept of entropy generation; however, exergy can be useful in determining the system components which are responsible for the system irreversibility [4].

The concept of exergy is very useful for economic, ecological, and sustainability measures, as its capability to describe the quality of the energy resource. The exergy analysis also includes and considers the impact of energy stream to the environment, which further influences significantly both energy and environmental policies. The exergy is a very potential indicator for the policy makers and industrial practitioners in justifying the energy system and resources [5].

**5**

*Introductory Chapter: Green Energy Systems DOI: http://dx.doi.org/10.5772/intechopen.89925*

which can be performed.

*The exergy concept for practical applications.*

**Figure 2.**

radiation [6].

**4. Conclusion**

**Figure 2** shows the possible utilization of exergy in practical applications. First of all, the exergy is very important to model and optimize the developed design of the processes or systems, before they are being developed and constructed. Furthermore, exergy is also convenient tool to analyze the performance of the developed system, as well as measure and predict the possible improvement points

*i*

 *ni(µi − µio)* (1)

The exergy of the system, *Ex*, is basically represented as follows:

defined, as well as their impacts to the environment.

*Ex = S(T − T0) − V(p − p0) + ∑*

where *S*, *T*, *V*, and *p* are entropy, temperature, volume, and pressure, respectively. In addition, *ni* and *μi* are number of moles of substance *i* and chemical potential of substance *i*. From Eq. (1), it can be understood that the exergy could be zero when the system reaches the equilibrium with the surrounding environment. Practically, the exergy depends on several condition parameters, including temperature, pressure, chemical potential, electricity, magnetism, gravity, and

By adopting the exergy, both the quantity and quality of energy are coherently considered, resulting in the holistic approach of the energy itself. This is compatible for all cases of energy systems and all types of energy resources. Therefore, the economic and social prices of the energy systems and resources can be more clearly

Development of sustainable energy system requires comprehensive knowledge, deep scenario analysis, and referable case studies. The discussion of energy requires a deep analysis of both quantitative and qualitative aspects. In addition, energy sustainability strongly imposes sustainability in other sectors, including economic, social, and environmental. The concept of exergy potentially leads to the opportunity for energy efficiency in the targeted system. The coherent understanding and application of both energy and exergy is urgently demanded. The inclusion of exergetic consideration in energy policy and practical application is strongly expected to

be able to realize the sustainable and efficient energy system in the future.

*Introductory Chapter: Green Energy Systems DOI: http://dx.doi.org/10.5772/intechopen.89925*

*Exergy and Its Application - Toward Green Energy Production and Sustainable Environment*

strongly with some challenges to realize the green and clean energy system which give a minimum influence to the environment, as well as keep both the system and environment to be sustainable. At the last, the social issues are related strongly to the problems in equal and appropriate distribution of the energy to the consumers. Energy is very essential element in human activities; therefore, the correlation and

The transition of the energy systems from currently high- to low-carbon emitting systems has led to several socioeconomic-environmental opportunities. However, there are still many unresolved issues related to the correlation among the energy, economic growth, and social welfare. The prediction and projection of energy systems in the future, especially related to the balance of both fluctuating demand and supply, face many uncertainties, due to several parameters including

Long-term accurate and flexible (responsive) strategies on energy will gave a strong confidence to all of the energy entities involved in the system/region. The dynamic and fast changes in energy systems have occurred time by time following

Energy has two different measures, which are quantity and quality. The energy quantity is the amount of energy which is supplied or consumed, while the energy quality deals with the availability/usability of energy resource to be consumed. The latter has revealed the concept of exergy. It is very strongly correlated to both the first and second laws of thermodynamics. The exergy is possibly destructed, which is different with the concept of energy as it is conserved. It strongly relates to the concept of entropy generation; however, exergy can be useful in determining the system components which are responsible for

The concept of exergy is very useful for economic, ecological, and sustainability measures, as its capability to describe the quality of the energy resource. The exergy analysis also includes and considers the impact of energy stream to the environment, which further influences significantly both energy and environmental policies. The exergy is a very potential indicator for the policy makers and industrial

balance of those four pillars in energy system are very important.

social, economic, weather, climate, and technological developments.

the technological and social changes in the community.

practitioners in justifying the energy system and resources [5].

**4**

**3. Exergy**

**Figure 1.**

*Essential pillars in energy system.*

the system irreversibility [4].

**Figure 2.** *The exergy concept for practical applications.*

**Figure 2** shows the possible utilization of exergy in practical applications. First of all, the exergy is very important to model and optimize the developed design of the processes or systems, before they are being developed and constructed. Furthermore, exergy is also convenient tool to analyze the performance of the developed system, as well as measure and predict the possible improvement points which can be performed.

The exergy of the system, *Ex*, is basically represented as follows:

$$\text{Ex} = \text{S} \{ T - T\_0 \} - V \langle p - p\_0 \rangle + \sum\_{i} n\_i (\mu\_i - \mu\_{io}) \tag{1}$$

where *S*, *T*, *V*, and *p* are entropy, temperature, volume, and pressure, respectively. In addition, *ni* and *μi* are number of moles of substance *i* and chemical potential of substance *i*. From Eq. (1), it can be understood that the exergy could be zero when the system reaches the equilibrium with the surrounding environment. Practically, the exergy depends on several condition parameters, including temperature, pressure, chemical potential, electricity, magnetism, gravity, and radiation [6].

By adopting the exergy, both the quantity and quality of energy are coherently considered, resulting in the holistic approach of the energy itself. This is compatible for all cases of energy systems and all types of energy resources. Therefore, the economic and social prices of the energy systems and resources can be more clearly defined, as well as their impacts to the environment.

#### **4. Conclusion**

Development of sustainable energy system requires comprehensive knowledge, deep scenario analysis, and referable case studies. The discussion of energy requires a deep analysis of both quantitative and qualitative aspects. In addition, energy sustainability strongly imposes sustainability in other sectors, including economic, social, and environmental. The concept of exergy potentially leads to the opportunity for energy efficiency in the targeted system. The coherent understanding and application of both energy and exergy is urgently demanded. The inclusion of exergetic consideration in energy policy and practical application is strongly expected to be able to realize the sustainable and efficient energy system in the future.

*Exergy and Its Application - Toward Green Energy Production and Sustainable Environment*

#### **Author details**

Muhammad Aziz Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan

\*Address all correspondence to: maziz@ssr.titech.ac.jp

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**7**

*Introductory Chapter: Green Energy Systems DOI: http://dx.doi.org/10.5772/intechopen.89925*

[1] Dincer I, Zamfirescu C. Potential options to greenize energy systems.

[3] Bejan M. Energy Policy, in Entropy Generation through Heat and Fluid Flow. New York: Wiley; 1994

[4] Jahangiri P, Sangi R, Thamm A, Streblow R, Müller D. Dynamic exergy analysis − part II: A case study of CHP district heating in Bottrop, Germany. In: Building Simulation and Optimization Conference (BSO14), 23-24 June 2014.

[5] Favrat D, Marechal F, Epelly O. The challenge of introducing an exergy indicator in a local law on energy.

[6] Wall G. Exergy flows in industrial processes. Energy. 1988;**13**:197-208

[2] Hammond G. Engineering sustainability: Thermodynamics, energy systems, and the environment. International Journal of Energy Research. 2004;**28**:613-639

**References**

Energy. 2012;**46**:5-15

London: UCL; 2014

Energy. 2008;**33**:130-136

*Introductory Chapter: Green Energy Systems DOI: http://dx.doi.org/10.5772/intechopen.89925*

#### **References**

*Exergy and Its Application - Toward Green Energy Production and Sustainable Environment*

Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: maziz@ssr.titech.ac.jp

provided the original work is properly cited.

**6**

**Author details**

Muhammad Aziz

[1] Dincer I, Zamfirescu C. Potential options to greenize energy systems. Energy. 2012;**46**:5-15

[2] Hammond G. Engineering sustainability: Thermodynamics, energy systems, and the environment. International Journal of Energy Research. 2004;**28**:613-639

[3] Bejan M. Energy Policy, in Entropy Generation through Heat and Fluid Flow. New York: Wiley; 1994

[4] Jahangiri P, Sangi R, Thamm A, Streblow R, Müller D. Dynamic exergy analysis − part II: A case study of CHP district heating in Bottrop, Germany. In: Building Simulation and Optimization Conference (BSO14), 23-24 June 2014. London: UCL; 2014

[5] Favrat D, Marechal F, Epelly O. The challenge of introducing an exergy indicator in a local law on energy. Energy. 2008;**33**:130-136

[6] Wall G. Exergy flows in industrial processes. Energy. 1988;**13**:197-208

Section 2

Advanced Energy Conversion

9

Section 2
