Energy Audits

Energy efficiency is today a crucial topic in the built environment

• for both designers and managers of buildings. This increased
  interest is driven by a combination of new regulations and
  directives within the EU and worldwide to combat global warming.

All buildings now must now acquire and display an EPC (energy
performance certificate), a rating similar to the A-G rating
given to white goods. But in order to understand how to be more
efficient in energy use, you need first to understand the
mechanisms of both energy requirements and how energy is used in
buildings.

Energy Audits: a workbook for energy management in
buildings tackles the fundamental principles of thermodynamics
through day-to-day engineering concepts and helps students
understand why energy losses occur and how they can be reduced. It
provides the tools to measure process efficiency and sustainability
in power and heating applications, helping engineers to recognize
why energy losses occur and how they can be reduced utilizing
familiar thermodynamic principles.

The author describes the sources of energy available today;
explains how energy is used in buildings - and how energy is
lost - and how this can be controlled and reduced. Investments in
energy efficiency are considered for a number of case studies
conducted on real buildings

The book explains the theory; illustrates it with case studies
and worked examples; and then tests students' understanding
with tutorial problems. This is an invaluable resource for students
on engineering and building courses where energy management is
now a core topic.

Autorentext

The Author Tarik Al-Shemmeri is Professor of Renewable Energy Technology, Faculty of Computing, Engineering & Technology, Staffordshire University. He teaches energy management at both MSc and BEng/MEng levels and researches renewable energy technology.

Zusammenfassung
Energy efficiency is today a crucial topic in the built environment - for both designers and managers of buildings. This increased interest is driven by a combination of new regulations and directives within the EU and worldwide to combat global warming. All buildings now must now acquire and display an EPC (energy performance certificate), a rating similar to the AG rating given to white goods. But in order to understand how to be more efficient in energy use, you need first to understand the mechanisms of both energy requirements and how energy is used in buildings.

Energy Audits: a workbook for energy management in buildings tackles the fundamental principles of thermodynamics through day-to-day engineering concepts and helps students understand why energy losses occur and how they can be reduced. It provides the tools to measure process efficiency and sustainability in power and heating applications, helping engineers to recognize why energy losses occur and how they can be reduced utilizing familiar thermodynamic principles.

The author describes the sources of energy available today; explains how energy is used in buildings and how energy is lost - and how this can be controlled and reduced. Investments in energy efficiency are considered for a number of case studies conducted on real buildings

The book explains the theory; illustrates it with case studies and worked examples; and then tests students' understanding with tutorial problems. This is an invaluable resource for students on engineering and building courses where energy management is now a core topic.

Inhalt
Preface xi Acknowledgements xiii

Dimensions and Units xv

List of Figures xxi

List of Tables xxv

1 Energy and the Environment 1

1.1 Introduction 2

1.2 Forms of energy 2

1.2.1 Mechanical energy 2

1.2.2 Electrical energy 3

1.2.3 Chemical energy 4

1.2.4 Nuclear energy 4

1.2.5 Thermal energy 5

1.3 Energy conversion 6

1.4 The burning question 8

1.4.1 Combustion of coal 9

1.4.2 Combustion of oil 10

1.4.3 Combustion of natural gas 10

1.5 Environmental impact from fossil fuels 11

1.6 Energy worldwide 12

1.7 Energy and the future 13

1.7.1 The dream scenario 15

1.7.2 The renewable scenario 15

1.8 Worked examples 15

1.9 Tutorial problems 19

1.10 Case Study: Future energy for the world 20

2 Energy Audits for Buildings 23

2.1 The need for an energy audit 24

2.2 The energy benchmarking method 25

2.2.1 Benchmarking step by step 25

2.2.2 How savings can be achieved 29

2.3 The degree-days concept 33

2.3.1 Regression of degree-day and energy consumption data 33

2.4 Energy Performance Certificates 34

2.5 Worked examples 36

2.6 Tutorial problems 43

3 Building Fabric's Heat Loss 45

3.1 Modes of heat transfer 46

3.2 Fourier's law of thermal conduction 46

3.2.1 Conduction through a planar wall 46

3.2.2 Radial conduction through a pipe wall 47

3.3 Heat transfer by convection 48

3.3.1 Convective heat transfer: experimental correlations 49

3.3.2 Free convection 50

3.3.3 Forced convection 50

3.4 Heat transfer through a composite wall separating two fluids 51

3.5 Heat exchange through a tube with convection on both sides 52

3.6 A composite tube with fluid on the inner and outer surfaces 53

3.7 Heat transfer by radiation 54

3.8 Building fabric's heat load calculations 55

3.9 Energy efficiency and the environment 57

3.9.1 Space heating 57

3.9.2 Insulation standards 58

3.9.3 The economics of heating 58

3.10 Worked examples 60

3.11 Tutorial problems 67

4 Ventilation 69

4.1 Aims of ventilation 70

4.2 Air quality 70

4.2.1 Minimum fresh air requirements 71

4.2.2 Composition of respired air 71

4.3 Ventilation methods 73

4.3.1 Natural ventilation 74

4.3.2 Mechanical or forced ventilation 75

4.4 Ventilation flow calculations 76

4.4.1 Volume flow calculations 76

4.4.2 Ventilation heat load calculations 76

4.4.3 Ventilation calculations based on CO2 build-up 76

4.5 Fans 77

4.5.1 Fan laws 78

4.5.2 Selection of fans 78

4.5.3 Calculation of ventilation fan duty 79

4.5.4 Pressure drop calculation 79

4.5.5 Energy efficiency in ventilation systems 81

4.6 Worked examples 82

4.7 Tutorial problems 91

4.8 Case Study: The National Trust's ventilation system 92

5 Heat Gains in Buildings 99

5.1 Introduction 100

5.2 Lighting 100

5.2.1 Lighting criteria 100

5.2.2 Lighting terminology 101

5.2.3 Measurement of light intensity 102

5.2.4 Types of lamp 102

5.3 Energy-saving measures for lighting 104

5.4 Casual heat gains from appliances 105

5.5 Occupants' heat gains 106

5.6 Worked examples 106

5.7 Tutorial problems 110

5.8 Case Study: Calculation of heating load for a building options 111

6 Thermal Comfort 115

6.1 Thermal comfort in human beings 116

6.2 Energy balance of the human body 116

6.3 Latent heat losses 117 ...