Building energy design is currently going through a period of major changes. One key factor of this is the adoption of net-zero energy as a long term goal for new buildings in most developed countries. To achieve this goal a lot of research is needed to accumulate knowledge and to utilize it in practical applications. In this book, accomplished international experts present advanced modeling techniques as well as in-depth case studies in order to aid designers in optimally using simulation tools for net-zero energy building design. The strategies and technologies discussed in this book are, however, also applicable for the design of energy-plus buildings. This book was facilitated by International Energy Agency's Solar Heating and Cooling (SHC) Programs and the Energy in Buildings and Communities (EBC) Programs through the joint SHC Task 40/EBC Annex 52: Towards Net Zero Energy Solar Buildings R&D collaboration. After presenting the fundamental concepts, design strategies, and technologies required to achieve net-zero energy in buildings, the book discusses different design processes and tools to support the design of net-zero energy buildings (NZEBs). A substantial chapter reports on four diverse NZEBs that have been operating for at least two years. These case studies are extremely high quality because they all have high resolution measured data and the authors were intimately involved in all of them from conception to operating. By comparing the projections made using the respective design tools with the actual performance data, successful (and unsuccessful) design techniques and processes, design and simulation tools, and technologies are identified. Written by both academics and practitioners (building designers) and by North Americans as well as Europeans, this book provides a very broad perspective. It includes a detailed description of design processes and a list of appropriate tools for each design phase, plus methods for parametric analysis and mathematical optimization. It is a guideline for building designers that draws from both the profound theoretical background and the vast practical experience of the authors.

Table of Contents:
About the editors xiii List of contributors  xv Preface  xvii Foreword xix Acknowledgments  xxi 1 Introduction 1 1.1 Evolution to net-zero energy buildings  1 1.1.1 Net ZEB concepts  2 1.1.2 Design of smart Net ZEBs and modeling issues  4 1.2 Scope of this book 4 References 7 2 Modeling and design of Net ZEBs as integrated energy systems 9 2.1 Introduction 9 2.1.1 Passive design, energy efficiency, thermal dynamics, and comfort  10 2.1.2 Detailed frequency domain wall model and transfer functions  16 2.1.2.1 Distributed parameter model for multilayered wall 16 2.1.2.2 Admittance transfer functions for walls  17 2.1.3 Z-Transfer function method  22 2.1.4 Detailed zone model and building transfer functions  25 2.1.4.1 Analysis of building transfer functions  30 2.1.4.2 Heating/cooling load and room temperature calculation 32 2.1.4.3 Discrete Fourier Series (DFS) method for simulation  32 2.1.5 Building transient response analysis  33 2.1.5.1 Nomenclature 34 2.2 Renewable energy generation systems/technologies integrated in Net ZEBs  34 2.2.1 Building-integrated photovoltaics as an enabling technology for Net ZEBs 35 2.2.1.1 Technologies 36 2.2.1.2 Modeling 39 2.2.2 Solar thermal systems  45 2.2.2.1 Solar thermal collectors 45 2.2.2.2 Modeling of solar thermal collectors 49 2.2.2.3 Thermal storage tanks  51 2.2.2.4 Modeling of thermal storage tanks 52 2.2.2.5 Solar combi-systems  55 2.2.3 Active building-integrated thermal energy storage and panel/radiant heating/cooling systems  55 2.2.3.1 Radiant heating/cooling systems integrated with thermal mass  57 2.2.3.2 Modeling active BITES  58 2.2.3.3 Methods used in two mainstream building simulation software 62 2.2.3.4 Nomenclature 63 2.2.4 Heat pump systems – a promising technology for Net ZEBs 63 2.2.4.1 Solar air-conditioning  64 2.2.4.2 Solar assisted/source heat pump systems  64 2.2.4.3 Ground source heat pumps 65 2.2.5 Combined heat and power (CHP) for Net ZEBs 66 References 67 3 Comfort considerations in Net ZEBs: theory and design  75 3.1 Introduction 75 3.2 Thermal comfort  76 3.2.1 Explicit thermal comfort objectives in Net ZEBs 77 3.2.2 Principles of thermal comfort 77 3.2.2.1 A comfort model based on the heat-balance of the human body 78 3.2.2.2 The adaptive comfort models 83 3.2.2.3 Standards regarding thermal comfort  85 3.2.3 Long-term evaluation of thermal discomfort in buildings 87 3.2.3.1 Background 88 3.2.3.2 The likelihood of dissatisfied  89 3.2.3.3 Applications of the long-term (thermal) discomfort indices 91 3.3 Daylight and visual comfort 92 3.3.1 Introduction 92 3.3.2 Adaptation luminance  94 3.3.3 Illuminance-based performance metrics 95 3.3.3.1 Daylight autonomy and continuous daylight autonomy 95 3.3.3.2 Useful daylight illuminance  95 3.3.4 Luminance-based performance metrics 96 3.3.4.1 Daylight glare probability  96 3.3.5 Daylight and occupant behavior 97 3.4 Acoustic comfort 98 3.5 Indoor air quality 99 3.6 Conclusion  100 References 101 4 Net ZEB design processes and tools  107 4.1 Introduction 107 4.2 Integrating modeling tools in the Net ZEB design process  108 4.2.1 Introduction 108 4.2.2 Overview of phases in Net ZEB realization  108 4.2.3 Tools  111 4.2.4 Concept design 112 4.2.4.1 Daylight  113 4.2.4.2 Solar protection 114 4.2.4.3 Building thermal inertia  115 4.2.4.4 Natural and hybrid ventilation  116 4.2.4.5 Building envelope thermal resistance 118 4.2.4.6 Solar energy technologies integration  119 4.2.5 Design development 119 4.2.5.1 Envelope and thermal inertia 120 4.2.5.2 Daylight  120 4.2.5.3 Plug loads and electric lighting  122 4.2.5.4 RET and HVAC 123 4.2.6 Technical design  124 4.2.7 Integrated design process and project delivery methods  126 4.2.8 Conclusion  133 4.3 NET ZEB design tools, model resolution, and design methods 133 4.3.1 Introduction 133 4.3.2 Model resolution  134 4.3.3 Model resolution for specific building systems and aspects 141 4.3.3.1 Geometry and thermal zoning 141 4.3.3.2 HVAC and active renewable energy systems  144 4.3.3.3 Photovoltaics and building-integrated photovoltaics  145 4.3.3.4 Lighting and daylighting 147 4.3.3.5 Airflow 149 4.3.3.6 Occupant comfort 151 4.3.3.7 Occupant behavior  153 4.3.4 Use of tools in design 157 4.3.4.1 Climate analysis  157 4.3.4.2 Solar design days  159 4.3.4.3 Parametric analysis  160 4.3.4.4 Interactions 161 4.3.4.5 Multidimensional parametric analysis 162 4.3.4.6 Visualization  162 4.3.5 Future needs and conclusion  163 4.4 Conclusion  165 References 166 5 Building performance optimization of net zero-energy buildings 175 5.1 Introduction 175 5.1.1 What is BPO? 175 5.1.2 Importance of BPO in Net ZEB design 176 5.2 Optimization fundamentals  179 5.2.1 BPO objectives (single-objective and multi-objective functions)  179 5.2.2 Optimization problem definition  180 5.2.3 Review of optimization algorithms applicable to BPS 180 5.2.4 Integration of optimization algorithms with BPS 183 5.2.5 BPO experts interview  184 5.3 Application of optimization: cost-optimal and nearly zero-energy building  186 5.3.1 Introduction 186 5.3.2 Case study: single-family house in Finland  188 5.3.3 Results 190 5.3.4 Final considerations about the case study  194 5.4 Application of optimization: a comfortable net-zero energy house 195 5.4.1 Description of the building model 195 5.4.2 The adopted methodology and the statement of the optimization problem  196 5.4.3 Discussion of results  199 5.4.4 Final considerations  202 5.5 Conclusion  202 References 203 6 Load matching, grid interaction, and advanced control  207 6.1 Introduction 207 6.1.1 Beyond annual energy balance  207 6.1.2 Relevance of LMGI issues  207 6.1.2.1 Peak demand and peak power generation  207 6.1.2.2 Load management in the grid and buildings  209 6.1.2.3 Smart grid and other technology drivers  211 6.2 LMGI indicators 212 6.2.1 Introduction 212 6.2.2 Categories of indicators 215 6.3 Strategies for predictive control and load management 219 6.3.1 Energy storage devices 219 6.3.1.1 Electric energy storage 219 6.3.1.2 Thermal energy storage 220 6.3.2 Predictive control for buildings 220 6.3.2.1 Preliminary steps 222 6.3.2.2 Requirements of building models for control applications 223 6.3.2.3 Modeling of noncontrollable inputs  225 6.3.2.4 Development of a control strategy  226 6.4 Development of models for controls  226 6.4.1 Building components: conduction heat transfer  227 6.4.2 Thermal modeling of an entire building 227 6.4.3 Linear models 228 6.4.3.1 Continuous-time transfer functions 228 6.4.3.2 Discrete-time transfer functions (z-transforms transfer functions)  229 6.4.3.3 Time series models 231 6.4.3.4 State-space representation  232 6.5 Conclusion  235 References 236 7 Net ZEB case studies  241 7.1 Introduction 241 7.2 ÉcoTerra 243 7.2.1 Description of ÉcoTerra 243 7.2.2 Design process  252 7.2.2.1 Design objectives  252 7.2.2.2 Design team and design process  252 7.2.2.3 Use of design and analysis tools  253 7.2.2.4 Assessment of the design process  255 7.2.3 Measured performance 256 7.2.4 Redesign study 259 7.2.4.1 Boundary conditions  260 7.2.4.2 Form and fabric 260 7.2.4.3 Operations 260 7.2.4.4 Renewable energy systems  261 7.2.4.5 Simulation results 261 7.2.4.6 Implementation of redesign strategies 262 7.2.5 Conclusions and lessons learned 266 7.3 Leaf house 269 7.3.1 Main features of the leaf house  269 7.3.2 Description of the design process 272 7.3.3 Purposes of the building design  272 7.3.4 Description of the thermal system plant 272 7.3.5 Monitored data  277 7.3.6 Features and limits of the employed model 278 7.3.7 Calibration of the model 280 7.3.8 Redesign  284 7.3.9 Conclusions and lessons learned 288 7.4 NREL RSF 289 7.4.1 Introduction to the RSF 290 7.4.2 Key project design features  291 7.4.2.1 Design process  291 7.4.2.2 Envelope  292 7.4.2.3 Daylighting and electric lighting 293 7.4.2.4 Space conditioning system 293 7.4.2.5 Thermal storage labyrinth  295 7.4.2.6 Transpired solar thermal collector 297 7.4.2.7 Natural ventilation 298 7.4.2.8 Building operation, typical monitored data, and thermal performance  298 7.4.2.9 Photovoltaics 301 7.4.2.10 Building simulation software support  302 7.4.2.11 Software limitations  303 7.4.2.12 Significance of the early design stage  304 7.4.3 Abstraction to archetypes 306 7.4.3.1 Model development  307 7.4.3.2 Model validation and calibration 311 7.4.3.3 Integrating design and control for daylighting and solar heat gain – option with controlled shading  312 7.4.4 Alternative design and operation for consideration 319 7.4.4.1 Building-integrated PV: optimal use of building roof and façade 319 7.4.4.2 Building-integrated PV/T and transpired collector with air-source heat pump 319 7.4.4.3 Active building-integrated thermal energy storage  320 7.4.5 Conclusions. 320 7.5 ENERPOS 321 7.5.1 Natural cross-ventilation and ceiling fans  322 7.5.2 Solar shading and daylighting 323 7.5.3 Microclimate measures  323 7.5.4 Materials  324 7.5.5 Ergonomics and interior design  324 7.5.6 Energy efficiency  325 7.5.6.1 Artificial lighting 325 7.5.6.2 Ceiling fans  325 7.5.6.3 Air-conditioning system 326 7.5.6.4 Computer network and plug loads  326 7.5.6.5 Building management system and individual controls 326 7.5.7 Integration of renewable energy technology  327 7.5.8 Description of the design process 327 7.5.8.1 Design objectives and importance of the design brief 328 7.5.8.2 Design team and timeline 328 7.5.8.3 Design tools  328 7.5.8.4 Human factors consideration in the design  330 7.5.9 Monitoring system  331 7.5.10 Monitored data  331 7.5.10.1 Measured performance 331 7.5.11 Comparison of model prediction with measurements for ENERPOS 333 7.5.11.1 Energy use 333 7.5.11.2 Thermal comfort 336 7.5.12 Thermal comfort experimental study  338 7.5.12.1 Purpose and methodology 338 7.5.12.2 Main results of the surveys  339 7.5.12.3 A comparison between the experimental data and the Givoni comfort zones  339 7.5.13 Lessons learned for future design of Net ZEBs in tropical climate  341 7.5.13.1 Interior lighting  342 7.5.13.2 Elevator energy  343 7.5.13.3 Air-conditioning 343 7.5.13.4 Occupant behavior  343 7.5.13.5 Use of building thermal mass and night cooling  343 7.6 Conclusions 343 References 345 8 Conclusion, research needs, and future directions  351 8.1 Net ZEB modeling, design, and simulation  351 8.2 Future directions and research needs 352 Glossary 355 Index 361