Residential and light-commercial buildings comprise a significant portion of buildings in the United States. They account for a large fraction of the total amount of energy used in the U.S., and they also represent environments where people spend the majority of their time. Thus, the design, construction, and operation of these buildings and their systems greatly affect energy consumption and exposures to airborne pollutants of both indoor and outdoor origin. However, there remains a need to improve knowledge of some key source and removal mechanisms of indoor and outdoor pollutants in residential and light-commercial buildings, as well as their connections to energy use and peak electricity demand. Several standardized field test methods exist for characterizing energy use and indoor air quality in actual buildings, although few explicitly address residential and light-commercial buildings and they are generally limited in scope. Therefore, the work in this dissertation focuses on improving methods to characterize three particular building components for their impacts on exposures to indoor pollutants and their implications for energy consumption: (1) central forced-air heating and cooling (HAC) systems, (2) HAC filters, and (3) building envelopes. Specifically, the research in this dissertation is grouped to fulfill two primary objectives of developing and applying novel methods to: (1) characterize and evaluate central air-conditioning systems and their filters as pollutant removal devices in residential and light-commercial buildings, and to explore their implications for energy consumption, and (2) characterize and evaluate the ability of two particular outdoor pollutants of concern (ozone and particulate matter) to infiltrate indoors through leaks in building envelopes. The research in this dissertation is divided into four primary investigations that fulfill these two objectives. The first investigation (Investigation 1a) addresses Objective 1 by first providing a detailed characterization of a variety of operational characteristics measured in a sample of 17 existing central HAC systems in occupied residential and light-commercial buildings in Austin, Texas, and exploring their implications for exposure to indoor pollutants, energy use, and peak electricity demand. Among the findings in this study, central air-conditioning systems in occupied residential and light-commercial buildings did not operate most of the time, even in the hot and humid climate of Austin, Texas (i.e., ~25% of the time on average in the summer). However, average recirculation rates still make central air-conditioning systems competitive as particle removal mechanisms, given sufficient filtration efficiency. Additionally, this investigation used a larger, much broader, dataset of energy audits performed on nearly 5000 single-family homes in Austin to explore common inefficiencies in the building stock. Residential and light-commercial air-conditioning systems are often inefficient; in fact, residential central air-conditioning systems in particular likely account for nearly 20% of peak electric demand in the City of Austin. As much as 8% of peak demand could be saved by upgrading all single-family homes in Austin to higher-efficiency equipment. The second investigation (Investigation 1b) also addresses Objective 1 by developing and applying a novel test method for measuring the in-situ particle removal efficiency of HAC systems and filters in residential and light-commercial buildings. Results from the novel test method as performed with three test filters and 0.3–10 μm particles in an unoccupied test house agreed reasonably well with results from other field and laboratory test methods. Low-efficiency filters did not increase particle removal much more than simply running the HAC system without a filter, and higher-efficiency filters provided greater than ~50% removal efficiency for most particles greater than 1–2 μm in diameter. The benefit of this test method is that it can be used to measure how filters perform in actual environments, how filter removal efficiency changes with actual dust loading, and how much common HAC design and installation issues, such as low airflow rates, duct leakage, fouled coils, and filter bypass airflow, impact particle removal in real environments. The third investigation (Investigation 2a) addresses Objective 2 by developing and applying a novel test methodology for measuring the penetration of outdoor ozone, a reactive gas, through leaks in exterior building envelopes using a sample of 8 single-family residences in Austin, Texas. These measurements represent the first ever measurements of ozone penetration factors through building envelopes of which I am aware, and penetration factors were lower than the usual assumption of unity (i.e., P = 1) in seven of the eight test homes (ranging from 0.62±0.09 to 1.02±0.15), meaning that some building envelopes provide occupants with more protection from indoor exposures to ozone and ozone reaction byproducts than others. Additionally, ozone penetration factors were correlated with some building characteristics, including the amount of painted wood siding on the exterior envelope and the year of construction, suggesting that simple building details may be used to predict ozone infiltration into homes. Finally, the fourth investigation (Investigation 2b) also addresses Objective 2 by refining and applying a test methodology for measuring the penetration of ambient particulate matter through leaks in building envelopes, and using a sample of 19 single-family residences in Austin, Texas to explore correlations between experimentally-determined particle penetration factors and standardized fan pressurization air leakage tests. Penetration factors of particles 20–1000 nm in diameter ranged from 0.17±0.03 to 0.72±0.08 across 19 homes that relied solely on infiltration for ventilation air. Particle penetration factors were also significantly correlated with results from standardized fan pressurization (i.e., blower door) air leakage tests and the year of construction, suggesting that occupants of older and leakier homes are exposed to more particulate matter of outdoor origin than those in newer tighter homes. Additionally, blower door tests may actually offer some predictive ability of particle penetration factors in single-family homes, which could allow for vast improvements in making easier population exposure estimates. Overall, the work in this dissertation provides new methods and data for assessing the impacts of central air-conditioning systems, filters, and building envelopes on human exposure to indoor pollutants and energy use in residential and light-commercial buildings. Results from these four primary investigations will allow building scientists, modelers, system designers, policymakers, and health scientists to make better informed decisions and assumptions about source and removal mechanisms of indoor pollutants and their impacts on building energy consumption and peak electricity demand. / text

In the quest for improving building energy efficiency raising the level of performance of the building enclosure has become critical. As the thermal performance of the building enclosure improves so does the overall energy efficiency of the building. One key component in determining the energy performance of the building enclosure is windows. Windows have an integral role in determining the energy performance of a building by allowing light and heat from the sun to enter into a space. Energy efficient buildings take advantage of this free solar energy to help offset heating energy consumption and electric lighting loads. However, windows are traditionally the least insulating component of the modern building assembly. With excessive use, larger window areas can lead to greater occupant discomfort and energy consumption from greater night-time heat loss, higher peak and total cooling energy demand from unwanted solar gains, and discomfort glare. As a result, windows must be carefully designed to not only minimize heat loss, but also effectively control solar gains to maintain both a thermally and visually comfortable environment for the appropriate climate region and orientation. In this thesis, a complete analysis of window assemblies for commercial office buildings is presented. The analysis is divided into three sections: the Insulated Glazing Unit (IGU), the Curtain Wall Section (frames), and the overall energy performance of a typical office building. The first section investigates the performance characteristics of typical and high performance IGUs, specifically its insulating value (Ucg), its solar heat gain properties (Solar Heat Gain Coefficient, SHGC), and its visual transmittance (VT) through one-dimensional heat transfer and solar-optical modeling. Mechanisms of heat transfer across IGUs were investigated giving insight into the parameters that had the most significant effect on improving each performance characteristic. With a through understanding of IGU performance, attainable performance limits for each of property were generated from combining of different glazing materials, fill gases, and coatings. Through the right combination of materials IGU performance can be significantly altered. The U-value performance of IGUs ranges from 2.68 W/m2K (R-2.1) for a double-glazed, clear, air filled IGU to 0.27 W/m2K (R-21) for a quint-glazed, low-E, xenon filled high performance IGU. The second part of the thesis looks at the thermal performance of curtain wall sections that hold the IGU through two-dimensional heat transfer modeling. Similar to the IGUs, heat transfer mechanisms were studied to by substituting different materials to determine which components are crucial to thermal performance. From this analysis improvements were made to typical curtain wall design that significantly reduces the overall heat transfer within the frame section, producing a high performance curtain wall section. With simple modifications, a high performance curtain wall section can reduce its U-value by as much as 81% over a typical curtain wall section, going from 13.39 W/m2K to 2.57 W/m2K. Thus significantly reducing the U-value of curtain wall systems, particularly for smaller windows. The final part of the thesis examines the impact of typical and high performance windows on the energy performance of perimeter offices of a high-rise commercial building located in Southern Ontario. An hourly simulation model was set up to evaluate both the annual and peak energy consumption of a typical perimeter office space. The office faced the four cardinal directions of north, east, south, and west to evaluate the effect of orientation. The model also included continuous dimming lighting controls to make use of the available daylight. The effect of exterior shading on perimeter space energy performance was also investigated with both dynamic and static exterior shading devices. The results of the simulations revealed that window properties have very little influence on the energy performance of a high internal heat gain office, that is typical of older offices with less energy efficient office equipment and lighting and a higher occupant density. Conversely, window properties, particularly the insulating value of the window, has a greater effect on the energy performance of a mid to low internal heat gain office that is typical of most modern day commercial buildings. The results show windows with lower U-values yet higher SHGC are preferred over windows of similar U-values but with lower SHGC. The results also indicate that both static and dynamic shading have very little effect on energy performance of mid to low internal heat gain offices. From this analysis optimal window areas in the form of window-to-wall ratios (WWR) are presented for each orientation for mid to low internal heat gain offices. The optimal WWR for south-facing facades are between 0.50 to 0.66, and 0.30 to 0.50 for east-, west-, and north-facing facades, while for high internal heat gain perimeter spaces window areas should be kept to a minimum.

This study addresses 5 uncertainties that exist in the operation of HVAC systems, which will presumably affect the actual energy consumption of the HVAC system in comparison to the consumption under idealized bahavior. We consequently add these parameters and their uncertainty range into the source code, eventually resulting in an EnergyPlus program in which the HVAC operation uncertainty is embedded as so-called model form uncertainty. The upgraded EnergyPlus is tested for each parameter uncertainty separately, and to show the impact of each uncertainty albeit for hypothetical uncertainty ranges of the parameters.

This exploratory research examined the degree of adoption and impact of the concepts of Building Information Model (BIM), Integrated Project Delivery (IPD), Integrated Design Process (IDP) and Building Energy Simulation (BES) on the design processes of advanced architectural firms when executing sustainable design. Six offices identified by the press for a strong commitment to sustainable design and influence in the design of high performance buildings were selected as cases. In semi-standardized interviews, these firms presented their perceptions of the influence of BIM, BES, and IPD/IDP. The results show that a generalization of sustainable design processes is possible. A design process for sustainability (DEPROSU) model was created by collecting best practices from data gathered from the interviews and the critical literature review. Secondary contributions show that BIM, IDP/IPD and BES have a synergistic effect in sustainable design methods, and that the human resource profile from these firms has evolved towards multi-skilled professionals knowledgeable in BES, BIM, parametric design, sustainability and construction processes. This research provides evidence of commonalities found in the design processes of the selected firms. These commonalities, which have been represented in the DEPROSU model, can potentially be validated as protocols or standards for sustainable design, providing architectural design practices with concrete patterns for improvement and or validation of their design methods.

In this study, the energy conservation potential of selected retrofitting interventions on an office building were investigated, on the basis of which some rational strategies for the improvement of building envelopes in terms of energy, environment and comfort design were proposed. Examined were various measures on envelope constructions that can be retrofitted to existing buildings. By using simulation techniques, the effectiveness of such measures in reducing energy consumption and environmental threat were also assessed. Effects of glazing types, effect of insulation and thermal mass were analyzed as energy efficient retrofit measures to the Engineering Building (MM building) situated on Middle East Technical University Campus, Ankara. The Energy-10 computer program was used for the modeling and simulation of the energy flows through the envelope to examine measures for reducing thermal load. Within this framework, the energy conservation potential of single and combined retrofitting actions was investigated. Based on results from the evaluation model, it was found that a saving of 161.20 MWh in the annual heating load could result, depending on the glazing type. The evaluation showed that thermal insulation is the most effective factor in thermal performance when placed as an exterior layer on walls. The study showed thermal mass has significant impact on increasing the duration, where highest temperatures were achieved, under passive mode. The study also revealed that applying a combination of retrofitting measures which responded to the challenges and opportunities presented by different fa&ccedil / ade orientations, a saving of 52.41% can be achieved in annual heating energy use in case study building.

The purpose of this research is to develop and verify a simplified and concise building simulation model suitable for high-level applications such as preliminary design or for embedding into adaptive control systems. An actual complex modern building and its energy system has been monitored. The monitored energy performance of this building has been compared with the empirical performance predicted by two simulation modeling programs and, alternatively, by a simplified single-zone model. This project is composed of several related tasks. The first component is the monitoring of the energy consumption rates, pertinent environmental data, and load indicators of the new Klaus Advanced Computing Building on the Georgia Institute of Technology's Atlanta campus. The Klaus building was chosen because it represents a typical non-residential building. Subsequently, these findings have been compared with results from DOE-2 and eQUEST, well established energy simulation modeling programs. These comparisons allow for an empirical verification of the modeling program for Atlanta conditions. Finally, a simplified single-zone building model has been developed, and its predictions compared with the empirical data and with the results of the more complex programs. The results verify both the more complex programs and the single-zone model, and also demonstrate the use of a single-zone model for future work and predictions.

abstract: With the increasing interest in energy efficient building design, whole building energy simulation programs are increasingly employed in the design process to help architects and engineers determine which design alternatives save energy and are cost effective. DOE-2 is one of the most popular programs used by the building energy simulation community. eQUEST is a powerful graphic user interface for the DOE-2 engine. EnergyPlus is the newest generation simulation program under development by the U.S. Department of Energy which adds new modeling features beyond the DOE-2's capability. The new modeling capabilities of EnergyPlus make it possible to model new and complex building technologies which cannot be modeled by other whole building energy simulation programs. On the other hand, EnergyPlus models, especially with a large number of zones, run much slower than those of eQUEST. Both eQUEST and EnergyPlus offer their own set of advantages and disadvantages. The choice of which building simulation program should be used might vary in each case. The purpose of this thesis is to investigate the potential of both the programs to do the whole building energy analysis and compare the results with the actual building energy performance. For this purpose the energy simulation of a fully functional building is done in eQUEST and EnergyPlus and the results were compared with utility data of the building to identify the degree of closeness with which simulation results match with the actual heat and energy flows in building. It was observed in this study that eQUEST is easy to use and quick in producing results that would especially help in the taking critical decisions during the design phase. On the other hand EnergyPlus aids in modeling complex systems, producing more accurate results, but consumes more time. The choice of simulation program might change depending on the usability and applicability of the program to our need in different phases of a building's lifecycle. Therefore, it makes sense if a common front end is designed for both these simulation programs thereby allowing the user to select either the DOE-2.2 engine or the EnergyPlus engine based upon the need in each particular case. / Dissertation/Thesis / M.S. Architecture 2010

abstract: This research is aimed at studying the impact of building design parameters in terms of their importance and mutual interaction, and how these aspects vary across climates and HVAC system types. A methodology is proposed for such a study, by examining the feasibility and use of two different statistical methods to derive all realistic ‘near-optimum’ solutions which might be lost using a simple optimization technique. DOE prototype medium office building compliant with ASHRAE 90.1-2010 was selected for the analysis and four different HVAC systems in three US climates were simulated. The interaction between building design parameters related to envelope characteristics and geometry (total of seven variables) has been studied using two different statistical methods, namely the ‘Morris method’ and ‘Predictive Learning via Rule Ensembles’. Subsequently, a simple graphical tool based on sensitivity analysis has been developed and demonstrated to present the results from parametric simulations. This tool would be useful to better inform design decisions since it allows imposition of constraints on various parameters and visualize their interaction with other parameters. It was observed that the Radiant system performed best in all three climates, followed by displacement ventilation system. However, it should be noted that this study did not deal with performance optimization of HVAC systems while there have been several studies which concluded that a VAV system with better controls can perform better than some of the newer HVAC technologies. In terms of building design parameters, it was observed that ‘Ceiling Height’, ‘Window-Wall Ratio’ and ‘Window Properties’ showed highest importance as well as interaction as compared to other parameters considered in this study, for all HVAC systems and climates. Based on the results of this study, it is suggested to extend such analysis using statistical methods such as the ‘Morris method’, which require much fewer simulations to categorize parameters based on their importance and interaction strength. Usage of statistical methods like ‘Rule Ensembles’ or other simple visual tools to analyze simulation results for all combinations of parameters that show interaction would allow designers to make informed and superior design decisions while benefiting from large reduction in computational time. / Dissertation/Thesis / Masters Thesis Built Environment 2015

abstract: Buildings consume nearly 50% of the total energy in the United States, which drives the need to develop high-fidelity models for building energy systems. Extensive methods and techniques have been developed, studied, and applied to building energy simulation and forecasting, while most of work have focused on developing dedicated modeling approach for generic buildings. In this study, an integrated computationally efficient and high-fidelity building energy modeling framework is proposed, with the concentration on developing a generalized modeling approach for various types of buildings. First, a number of data-driven simulation models are reviewed and assessed on various types of computationally expensive simulation problems. Motivated by the conclusion that no model outperforms others if amortized over diverse problems, a meta-learning based recommendation system for data-driven simulation modeling is proposed. To test the feasibility of the proposed framework on the building energy system, an extended application of the recommendation system for short-term building energy forecasting is deployed on various buildings. Finally, Kalman filter-based data fusion technique is incorporated into the building recommendation system for on-line energy forecasting. Data fusion enables model calibration to update the state estimation in real-time, which filters out the noise and renders more accurate energy forecast. The framework is composed of two modules: off-line model recommendation module and on-line model calibration module. Specifically, the off-line model recommendation module includes 6 widely used data-driven simulation models, which are ranked by meta-learning recommendation system for off-line energy modeling on a given building scenario. Only a selective set of building physical and operational characteristic features is needed to complete the recommendation task. The on-line calibration module effectively addresses system uncertainties, where data fusion on off-line model is applied based on system identification and Kalman filtering methods. The developed data-driven modeling framework is validated on various genres of buildings, and the experimental results demonstrate desired performance on building energy forecasting in terms of accuracy and computational efficiency. The framework could be easily implemented into building energy model predictive control (MPC), demand response (DR) analysis and real-time operation decision support systems. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2016

abstract: Dwindling energy resources and associated environmental costs have resulted in a serious need to design and construct energy efficient buildings. One of the strategies to develop energy efficient structural materials is through the incorporation of phase change materials (PCM) in the host matrix. This research work presents details of a finite element-based framework that is used to study the thermal performance of structural precast concrete wall elements with and without a layer of phase change material. The simulation platform developed can be implemented for a wide variety of input parameters. In this study, two different locations in the continental United States, representing different ambient temperature conditions (corresponding to hot, cold and typical days of the year) are studied. Two different types of concrete - normal weight and lightweight, different PCM types, gypsum wallboard's with varying PCM percentages and different PCM layer thicknesses are also considered with an aim of understanding the energy flow across the wall member. Effect of changing PCM location and prolonged thermal loading are also studied. The temperature of the inside face of the wall and energy flow through the inside face of the wall, which determines the indoor HVAC energy consumption are used as the defining parameters. An ad-hoc optimization scheme is also implemented where the PCM thickness is fixed but its location and properties are varied. Numerical results show that energy savings are possible with small changes in baseline values, facilitating appropriate material design for desired characteristics. / Dissertation/Thesis / M.S. Civil Engineering 2012