Spectral Selectivity in Building Envelope Materials

JULIAN WANG, PhD, is an Associate Professor in the Department of Architectural Engineering at Penn State University. His research centers on spectrally selective materials and sustainable building practices, with over 120 published journal papers advancing the field of energy-efficient building design and envelope performance. CHAO SHEN is a Professor in the Department of Building Technology at Harbin Institute of Technology. His work focuses on advanced building materials and their role in optimizing energy performance, thermal regulation, and occupant comfort within the built environment. VIVIEN LIN LU is a Professor in the Department of Building Environment and Energy Engineering at Hong Kong Polytechnic University. Her research encompasses building energy systems and environmental engineering, contributing to advances in sustainable design and thermal performance of building envelopes across diverse climatic conditions.

• Preface xi1 Fundamentals of Spectral Selectivity in Envelope Materials 11.1 Introduction to Spectral Selectivity 11.1.1 Spectral Selectivity in Energy-Efficient Building Design 21.1.2 Role in Thermal and Optical Energy Management 21.1.3 Indoor Comfort, Human Experience, and Passive Performance 31.1.4 Sustainability, Decarbonization, and Renewable Energy Alignment 31.1.5 Shortwave and Longwave Spectral Selectivity: A Unified Design Framework 41.2 Photometric and Radiometric Basics 51.2.1 Photometric–Radiometric Conversion Framework 51.2.2 Paired Radiometric and Photometric Quantities 101.2.3 Radiometric Measurement in the Built Environment 191.2.4 Metrics and Measurement Techniques in Spectral Selectivity in Building Envelopes 232 Mechanisms and Fundamental Principles of Spectral Control 292.1 Theoretical Foundations of Spectral Selectivity 292.1.1 Electromagnetic Wave Theory and Optical Interactions 292.1.2 Mie Theory for Scattering in Nanostructures 372.1.3 Kirchhoff's Law in Spectral Selectivity 412.2 Intrinsic Material Properties and Spectral Selectivity 422.2.1 Intrinsic Materials for Shortwave Spectral Selectivity 432.2.2 Intrinsic Materials for Longwave Spectral Selectivity 452.3 Thin-film Coatings 492.3.1 General Theoretical Framework for Thin-film Coatings 492.3.2 Thin-film Coatings for Shortwave Spectral Selectivity 512.3.3 Thin-film Coatings for Longwave Spectral Selectivity 562.3.4 Multilayer Structures for Spectral Selectivity 582.3.5 Thin-film Deposition Techniques for Spectral Selectivity 603 Energy Performance of Spectrally Selective Materials in Building Envelopes 713.1 Shortwave Control and Energy Performance 713.1.1 Reflection-Based Shortwave Spectral Control 753.1.2 Absorption-Based Shortwave Spectral Control 783.1.3 Summary of Shortwave Spectral Control and Energy Performance 1003.2 Longwave Control and Energy Performance 1013.2.1 Heat Transfer Mechanisms in the Longwave Spectrum 1013.2.2 Energy Benefits of Longwave Spectral Selectivity 1063.2.3 Case Studies and Simulated Performance Evaluations 1083.2.4 Summary of Longwave Spectral Control and Energy Performance 1184 Photovoltaic Integration with Spectrally Selective Materials 1254.1 Fundamental Relationship Between PV and Spectral Selectivity 1254.2 Shortwave Spectral Selectivity for PV Performance 1274.2.1 Spectrally Selective Coatings for PV Enhancement 1274.2.2 Transparent BIPVs 1344.2.3 Case Studies and Experimental Studies of Spectrally Selective PVs 1404.3 Longwave Spectral Selectivity for PV Thermal Management 1444.3.1 Thermal Challenges in PV Systems 1474.3.2 Longwave Solutions for PV Cooling and Stability 1484.3.3 Case Studies and Experimental Validation 1514.4 PV-PT Dual Mode for Spectral Optimization 1624.4.1 Working Principle 1634.4.2 Experimental Verification 1634.4.3 Energy-saving Simulations Setup 1654.4.4 Windows' Surface Temperatures 1674.4.5 Total Energy-consumption Analysis 1704.5 Case Study of Emerging Semi-transparent Solar Cells in Building Sectors 1744.6 Summary 1815 Spectral-Selective Surfaces for Human Comfort, Health, and Environmental Sustainability 1895.1 Spectrally Selective Surfaces for Indoors 1905.1.1 General Framework for Spectral Selective Envelope Analysis on IEQ 1905.1.2 Thermal Effects 1915.1.3 Visual and Circadian Effects 2035.2 Spectrally Selective Surfaces for Outdoors 2195.2.1 Spectral-based Method to Quantify Thermal Effects 2215.2.2 Façade Reflectance Impacts on Outdoor Thermal Environments 2305.2.3 Façade Reflectance Impacts on District-Level Energy use Intensity 2335.2.4 Optimization of Façade's Solar Reflectance 2375.3 Summary: Spectral Selectivity as a Human–Environment Interface 2386 Challenges, Opportunities, and Future Directions of Spectrally Selective Building Envelopes 2436.1 Technical and Practical Challenges in Deploying Spectrally Selective Envelopes 2446.1.1 Scale Translation: From Material Spectra to Building Performance 2456.1.2 Durability and Long-term Spectral Stability 2456.1.3 Metric-workflow Misalignment 2476.2 Emerging Opportunities Through System-level and Cross-domain Integration 2506.3 Future Research Directions and the Evolving Role of Spectral Selectivity 252References 253Index 255