THERMAL ENERGY STORAGE -- Contents -- About the Authors -- Preface -- Acknowledgements -- 1 General Introductory Aspects for Thermal Engineering -- 1.1 Introduction -- 1.2 Systems of Units -- 1.3 Fundamental Properties and Quantities -- 1.3.1 Mass, Time, Length, and Force -- 1.3.2 Pressure -- 1.3.3 Temperature -- 1.3.4 Specific Volume and Density -- 1.3.5 Mass and Volumetric Flow Rates -- 1.4 General Aspects of Thermodynamics -- 1.4.1 Thermodynamic Systems -- 1.4.2 Process -- 1.4.3 Cycle -- 1.4.4 Thermodynamic Property -- 1.4.5 Sensible and Latent Heats -- 1.4.6 Latent Heat of Fusion -- 1.4.7 Vapor -- 1.4.8 Thermodynamic Tables -- 1.4.9 State and Change of State -- 1.4.10 Specific Internal Energy -- 1.4.11 Specific Enthalpy -- 1.4.12 Specific Entropy -- 1.4.13 Pure Substance -- 1.4.14 Ideal Gases -- 1.4.15 Energy Transfer -- 1.4.16 Heat -- 1.4.17 Work -- 1.4.18 The First Law of Thermodynamics -- 1.4.19 The Second Law of Thermodynamics -- 1.4.20 Reversibility and Irreversibility -- 1.4.21 Exergy -- 1.5 General Aspects of Fluid Flow -- 1.5.1 Classification of Fluid Flows -- 1.5.2 Viscosity -- 1.5.3 Equations of Flow -- 1.5.4 Boundary Layer -- 1.6 General Aspects of Heat Transfer -- 1.6.1 Conduction Heat Transfer -- 1.6.2 Convection Heat Transfer -- 1.6.3 Radiation Heat Transfer -- 1.6.4 Thermal Resistance -- 1.6.5 The Composite Wall -- 1.6.6 The Cylinder -- 1.6.7 The Sphere -- 1.6.8 Conduction with Heat Generation -- 1.6.9 Natural Convection -- 1.6.10 Forced Convection -- 1.7 Concluding Remarks -- 2 Energy Storage Systems -- 2.1 Introduction -- 2.2 Energy Demand -- 2.3 Energy Storage -- 2.4 Energy Storage Methods -- 2.4.1 Mechanical Energy Storage -- 2.4.2 Chemical Energy Storage -- 2.4.3 Biological Storage -- 2.4.4 Magnetic Storage -- 2.4.5 Thermal Energy Storage (TES) -- 2.5 Hydrogen for Energy Storage -- 2.5.1 Storage Characteristics of Hydrogen.

2.5.2 Hydrogen Storage Technologies -- 2.5.3 Hydrogen Production -- 2.6 Comparison of ES Technologies -- 2.7 Concluding Remarks -- 3 Thermal Energy Storage (TES) Methods -- 3.1 Introduction -- 3.2 Thermal Energy -- 3.3 Thermal Energy Storage -- 3.3.1 Basic Principle of TES -- 3.3.2 Benefits of TES -- 3.3.3 Criteria for TES Evaluation -- 3.3.4 TES Market Considerations -- 3.3.5 TES Heating and Cooling Applications -- 3.3.6 TES Operating Characteristics -- 3.3.7 ASHRAE TES Standards -- 3.4 Solar Energy and TES -- 3.4.1 TES Challenges for Solar Applications -- 3.4.2 TES Types and Solar Energy Systems -- 3.4.3 Storage Durations and Solar Applications -- 3.4.4 Building Applications of TES and Solar Energy -- 3.4.5 Design Considerations for Solar Energy-Based TES -- 3.5 TES Methods -- 3.6 Sensible TES -- 3.6.1 Thermally Stratified TES Tanks -- 3.6.2 Concrete TES -- 3.6.3 Rock and Water/Rock TES -- 3.6.4 Aquifer Thermal Energy Storage (ATES) -- 3.6.5 Solar Ponds -- 3.6.6 Evacuated Solar Collector TES -- 3.7 Latent TES -- 3.7.1 Operational Aspects of Latent TES -- 3.7.2 Phase Change Materials (PCMs) -- 3.8 Cold Thermal Energy Storage (CTES) -- 3.8.1 Working Principle -- 3.8.2 Operational Loading of CTES -- 3.8.3 Design Considerations -- 3.8.4 CTES Sizing Strategies -- 3.8.5 Load Control and Monitoring in CTES -- 3.8.6 CTES Storage Media Selection and Characteristics -- 3.8.7 Storage Tank Types for CTES -- 3.8.8 Chilled-Water CTES -- 3.8.9 Ice CTES -- 3.8.10 Ice Forming -- 3.8.11 Ice Thickness Controls -- 3.8.12 Technical and Design Aspects of CTES -- 3.8.13 Selection Aspects of CTES -- 3.8.14 Cold-Air Distribution in CTES -- 3.8.15 Potential Benefits of CTES -- 3.8.16 Electric Utilities and CTES -- 3.9 Seasonal TES -- 3.9.1 Seasonal TES for Heating Capacity -- 3.9.2 Seasonal TES for Cooling Capacity -- 3.9.3 Illustration -- 3.10 Concluding Remarks.

4 Thermal Energy Storage and Environmental Impact -- 4.1 Introduction -- 4.2 Energy and the Environment -- 4.3 Major Environmental Problems -- 4.3.1 Acid Rain -- 4.3.2 Greenhouse Effect (Global Climate Change) -- 4.3.3 Stratospheric Ozone Depletion -- 4.4 Environmental Impact and TES Systems and Applications -- 4.5 Potential Solutions to Environmental Problems -- 4.5.1 General Solutions -- 4.5.2 TES-Related Solutions -- 4.6 Sustainable Development -- 4.6.1 Conceptual Issues -- 4.6.2 The Brundtland Commission's Definition -- 4.6.3 Environmental Limits -- 4.6.4 Global, Regional, and Local Sustainability -- 4.6.5 Environmental, Social, and Economic Components of Sustainability -- 4.6.6 Energy and Sustainable Development -- 4.6.7 Environment and Sustainable Development -- 4.6.8 Achieving Sustainable Development in Larger Countries -- 4.6.9 Essential Factors for Sustainable Development -- 4.7 Illustrative Examples and Case Studies -- 4.7.1 The South Coast Air Quality Management District (California) -- 4.7.2 Anova Verzekering Co. Building (Amersfoort, The Netherlands) -- 4.7.3 The Trane Company's Technology Center (La Crosse, WI) -- 4.7.4 The Ministry of Finance Building (Bercy, France) -- 4.7.5 The City of Saarbrucken (Saarbrucken, Germany) -- 4.8 Concluding Remarks -- 5 Thermal Energy Storage and Energy Savings -- 5.1 Introduction -- 5.2 TES and Energy Savings -- 5.2.1 Utilization of Waste or Surplus Energy -- 5.2.2 Reduction of Demand Charges -- 5.2.3 Deferring Equipment Purchases -- 5.3 Additional Energy Savings Considerations for TES -- 5.3.1 Energy for Heating, Refrigeration, and Heat Pump Equipment -- 5.3.2 Storage Size Limitations -- 5.3.3 Thermal Load Profiles -- 5.3.4 Optimization of Conventional Systems -- 5.4 Energy Conservation with TES: Planning and Implementation -- 5.5 Some Limitations on Increased Efficiency.

5.5.1 Practical and Theoretical Limitations -- 5.5.2 Efficiency Limitations and Exergy -- 5.6 Energy Savings for Cold TES -- 5.6.1 Economic Aspects of TES Systems for Cooling Capacity -- 5.6.2 Energy Savings by Cold TES -- 5.6.3 Case Studies for TES Energy Savings -- 5.7 Concluding Remarks -- 6 Energy and Exergy Analyses of Thermal Energy Storage Systems -- 6.1 Introduction -- 6.2 Theory: Energy and Exergy Analyses -- 6.2.1 Motivation for Energy and Exergy Analyses -- 6.2.2 Conceptual Balance Equations for Mass, Energy, and Entropy -- 6.2.3 Detailed Balance Equations for Mass, Energy, and Entropy -- 6.2.4 Basic Quantities for Exergy Analysis -- 6.2.5 Detailed Exergy Balance -- 6.2.6 The Reference Environment -- 6.2.7 Efficiencies -- 6.2.8 Properties for Energy and Exergy Analyses -- 6.2.9 Implications of Results of Exergy Analyses -- 6.2.10 Steps for Energy and Exergy Analyses -- 6.3 Thermodynamic Considerations in TES Evaluation -- 6.3.1 Determining Important Analysis Quantities -- 6.3.2 Obtaining Appropriate Measures of Efficiency -- 6.3.3 Pinpointing Losses -- 6.3.4 Assessing the Effects of Stratification -- 6.3.5 Accounting for Time Duration of Storage -- 6.3.6 Accounting for Variations in Reference-Environment Temperature -- 6.3.7 Closure -- 6.4 Exergy Evaluation of a Closed TES System -- 6.4.1 Description of the Case Considered -- 6.4.2 Analysis of the Overall Process -- 6.4.3 Analysis of Subprocesses -- 6.4.4 Alternative Formulations of Subprocess Efficiencies -- 6.4.5 Relations between Performance of Subprocesses and Overall Process -- 6.4.6 Example -- 6.4.7 Closure -- 6.5 Appropriate Efficiency Measures for Closed TES Systems -- 6.5.1 TES Model Considered -- 6.5.2 Energy and Exergy Balances -- 6.5.3 Energy and Exergy Efficiencies -- 6.5.4 Overall Efficiencies -- 6.5.5 Charging-Period Efficiencies -- 6.5.6 Storing-Period Efficiencies.

6.5.7 Discharging-Period Efficiencies -- 6.5.8 Summary of Efficiency Definitions -- 6.5.9 Illustrative Example -- 6.5.10 Closure -- 6.6 Importance of Temperature in Performance Evaluations for Sensible TES Systems -- 6.6.1 Energy, Entropy, and Exergy Balances for the TES System -- 6.6.2 TES System Model Considered -- 6.6.3 Analysis -- 6.6.4 Comparison of Energy and Exergy Efficiencies -- 6.6.5 Illustration -- 6.6.6 Closure -- 6.7 Exergy Analysis of Aquifer TES Systems -- 6.7.1 ATES Model -- 6.7.2 Energy and Exergy Analyses -- 6.7.3 Effect of a Threshold Temperature -- 6.7.4 Case Study -- 6.7.5 Closure -- 6.8 Exergy Analysis of Thermally Stratified Storages -- 6.8.1 General Stratified TES Energy and Exergy Expressions -- 6.8.2 Temperature-Distribution Models and Relevant Expressions -- 6.8.3 Discussion and Comparison of Models -- 6.8.4 Illustrative Example: The Exergy-Based Advantage of Stratification -- 6.8.5 Illustrative Example: Evaluating Stratified TES Energy and Exergy -- 6.8.6 Increasing TES Exergy-Storage Capacity Using Stratification -- 6.8.7 Illustrative Example: Increasing TES Exergy with Stratification -- 6.8.8 Closure -- 6.9 Energy and Exergy Analyses of Cold TES Systems -- 6.9.1 Energy Balances -- 6.9.2 Exergy Balances -- 6.9.3 Energy and Exergy Efficiencies -- 6.9.4 Illustrative Example -- 6.9.5 Case Study: Thermodynamic Performance of a Commercial Ice TES System -- 6.9.6 Closure -- 6.10 Exergy-Based Optimal Discharge Periods for Closed TES Systems -- 6.10.1 Analysis Description and Assumptions -- 6.10.2 Evaluation of Storage-Fluid Temperature During Discharge -- 6.10.3 Discharge Efficiencies -- 6.10.4 Exergy-Based Optimum Discharge Period -- 6.10.5 Illustrative Example -- 6.10.6 Closure -- 6.11 Exergy Analysis of Solar Ponds -- 6.11.1 Experimental Solar Pond -- 6.11.2 Data Acquisition and Analysis.

6.11.3 Energy and Exergy Assessments.