Machine Learning Paradigms for Building Energy Performance
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Machine Learning Paradigms for Building Energy Performance Simulations by Arfa Nawal Aijazi Bachelor of Science in Materials Science and Engineering, Massachusetts Institute of Technology (2013) Submitted to the Department of Architecture in partial fulfillment of the requirements for the degree of Master of Science in Building Technology at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2017 ○c Massachusetts Institute of Technology 2017. All rights reserved. Author................................................................ Department of Architecture May 25, 2017 Certified by . Leon R. Glicksman Professor of Building Technology and Mechanical Engineering Thesis Supervisor Accepted by........................................................... Sheila Kennedy Professor of Architecture Chair, Department Committee on Graduate Students Machine Learning Paradigms for Building Energy Performance Simulations by Arfa Nawal Aijazi Submitted to the Department of Architecture on May 25, 2017, in partial fulfillment of the requirements for the degree of Master of Science in Building Technology Abstract This research seeks to overcome a technical limitation of building energy performance simulations, the computation time, by using surrogate modeling, a class of supervised machine learning techniques where the output is a performance metric. Though early machine learning methods were introduced decades ago, the convergence of computation power, more data collection, and maturation of methods has led to an explosion in the types of problems machine learning can be applied to. A comparison of several common surrogate modeling techniques found that para- metric radial basis functions and Kriging are highly accurate regression techniques for predicting building energy consumption. For a single climate, these regression techniques can predict the total energy consumption to within 2% of a detailed en- ergy simulation, but in a fraction of a second, about five orders of magnitude faster. Integrating a Kriging surrogate model with multi-objective optimization, allowed for finding retrofit recommendations in Lisbon that are cost effective and canreduce the present-day energy consumption of an existing apartment by up to 20%. Simi- larly, integrating surrogate model with multi-objective optimization can find retrofit options in Boston that can reduce the present-day energy consumption and unmet hours in the future. Combined this body of works strives to add value to existing building energy performance simulation tools as more than just an exercise for code compliance but as a real design tool that can guide decision making. Thesis Supervisor: Leon R. Glicksman Title: Professor of Building Technology and Mechanical Engineering 2 Acknowledgments I begin in the name of God, for to Him belongs all praise and thanks. Sir Isaac Newton famously observed that "if I have seen further, it is by standing on the shoulders of giants" and this certainly holds true for me. I am tremendously grateful for the support of the many individuals who made this thesis possible. First, I would like to thank my academic and thesis advisor, Professor Leon Glicksman for his mentorship over the past two years. His skepticism of simulations and espousal of back-of-the-envelope calculations have made me a better engineer and researcher. In addition to our discussions on research, I am grateful for our talks on politics, religion, period dramas, and anything else under the sun. I would also like to thank Professor Caitlin Mueller for helping me draw inspiration from computational science techniques across disciplines, which greatly enriched my academic experience and research. I also thank the other faculty in the Building Technology Group, Professors John Fernandez, Les Norford, John Ochsendorf, and Christoph Reinhart for their feedback and encouragement during the Building Technology Seminar and other meetings. I deeply appreciate the other students currently or previously affiliated with the Building Technology group for their feedback on my research, assistance with soft- ware tools, and making the lab a friendly space to work. Notably these include: Alpha Arsano, David Blum, Nathan Brown, Carlos Cerezo Davila, Noor Khouri, Shreshth Nagpal, and Cody Rose. A special thanks to our administrative assistant, Kathleen Ross for expertly handling logistical details and gathering the group for social events. Together, the faculty, staff, and students of the Building Technology group foster a learning and research environment that explores critical topics for the future of the built environ- 3 ment and natural resources and it has been an honor to be a part of it. An additional thanks to staff and administrators in the Department of Architec- ture for their support. I am grateful to CRON, especially Philip Thompson, for quickly resolving problems with computer hardware and software. I thank the MIT Department of Architecture and the MIT Portugal Program for funding my graduate education at MIT. I am indebted to my research collaborators in Portugal as part of the SusCity project for their support remotely throughout my research and for their hospital- ity during my trips to Lisbon in January 2016 and 2017. Notably these include: Joana Fernandes of ADENE, Laura Aelenei and Ana Ferreira of LNEG, Ri- cardo Gomez and Claudia Sousa Monteiro of IST, and Professor Guilherme Carrilho da Graca and Ana Filipa Silva of FCUL. A special thank you to Dr. Erwan Monier at the MIT Center for Global Change Science and the Joint Program on the Science and Policy of Climate Change for guiding me through the current scientific discourse related to modeling climate change. I am grateful to my mentors at Simpson Gumpertz and Heger Inc, where I worked in the years between my bachelors and masters. They’ve instilled in me an aspiration for my research to be relevant to industry for it to have the greatest impact. Personally, I owe everything to my family. I can’t thank my parents enough for their boundless love and support of all my ventures and my siblings, Osman, Assad, and Safiya for their encouragement. 4 Contents 1 Background 16 1.1 Introduction . 16 1.2 Motivation . 17 1.2.1 Global Building Energy Consumption . 17 1.2.2 Climate Change and Global Warming . 18 1.2.3 Barriers to Building Performance Simulations . 19 1.3 Context . 21 1.3.1 Overview of Building Energy Performance Simulation . 21 1.3.2 Overview of Machine Learning . 25 1.3.3 Machine Learning and Building Performance . 26 1.4 Research Objectives . 27 2 Surrogate Modeling Techniques 28 2.1 Introduction . 28 2.1.1 Previous Work . 30 2.1.2 Research Objectives . 31 2.2 Methodology . 31 2.2.1 Building a Surrogate Model . 31 5 2.2.2 Quantifying Error and Uncertainty . 32 2.2.3 Regression Techniques . 34 2.2.4 Climatic Model Input Parameters . 36 2.2.5 Geometric Model Input Parameters . 41 2.2.6 Natural Ventilation Model Input Parameters . 48 2.2.7 Summary . 51 2.3 Results and Discussion . 51 2.3.1 Climatic Model Input Parameters . 54 2.3.2 Geometric Model Input Parameters . 66 2.3.3 Natural Ventilation Model Input Parameters . 70 2.4 Conclusions . 70 3 Optimization of Building Retrofits 71 3.1 Introduction . 71 3.1.1 Design Optimization . 72 3.1.2 The SusCity Project . 76 3.1.3 Scope of Work . 79 3.2 Methodology . 79 3.2.1 Surrogate Model Development . 79 3.2.2 Retrofit Costs Model . 85 3.2.3 Multi-objective Optimization . 87 3.2.4 Return on Investment . 88 3.2.5 Model Error . 89 3.3 Results and Discussion . 89 3.3.1 Existing Buildings Energy Consumption . 89 3.3.2 Multi-Objective Optimization . 91 6 3.3.3 Return on Investment . 99 3.3.4 Model Error . 100 3.4 Conclusions . 102 4 Modeling Climate Change Impacts 104 4.1 Introduction . 104 4.2 Methodology . 105 4.2.1 Modeling Climate Change . 105 4.2.2 Building Energy Case Study . 107 4.2.3 Building Envelope Retrofit Optimization . 109 4.3 Results and Discussion . 111 4.3.1 Future Weather . 111 4.3.2 Building Energy Case Study . 112 4.3.3 Building Envelope Retrofit Optimization . 117 4.4 Conclusions . 128 5 Conclusions 130 5.1 Key Contributions . 130 5.2 Overall Discussion . 132 5.3 Future Work . 133 5.4 Concluding Remarks . 133 7 List of Figures 2-1 Schematic represetnation of surrogate modeling concept in one dimen- sion. Graph reproduced from [27]. 29 2-2 NREL midrise apartment commercial reference building energy model visualized in SketchUp with Euclid plugin. 37 2-3 Weather file locations in ASHRAE CZ 4A-7A used in stratified sample of heating degree days. 39 2-4 Screenshot of IDF Editor for EnergyPlus showing an example of build- ing geometry definition in a text-based environment. 42 2-5 Screenshot in Rhino and Grasshopper with the Archsim plugins show- ing an example of building geometry definition in a visual environment. 43 2-6 Examples of three rectiliniear floor plates generated using Grasshopper. 44 2-7 Methodology for generating a randomized floor plate in Grasshopper. 45 2-8 Examples of three randomized floor plates generated using Grasshopper. 45 2-9 Example of thermal zoning and identification of orientation of an ex- terior face for a randomized form. 46 2-10 Visualization of building energy model with geometric model input parameters in Rhino. 47 8 2-11 Plot of Pearson correlation coefficient for transformed and untrans- formed design variables to simulation outputs for climatic model inputs. 53 2-12 Plot comparing computation time of detailed simulation versus surro- gate model parameter estimation and prediction. 55 2-13 Plots of predicted versus simulated energy consumption for surrogate model using Kriging regression on a test data set. 57 2-14 Plots of percent difference between surrogate model prediction and simulated output over the design space for multi-climate and single climate surrogate models. 58 2-15 Plots of mean absolute value of percent difference between surrogate model prediction and detailed simulation by simulation output.