With recent emphasis on reducing building energy consumption, tools are needed that can determine the overall performance of building thermal envelopes in a manner that is accurate, efficient, and accessible. Two such methods--one experimental and one numerical--were developed for the evaluation and optimization of building thermal envelopes at the University of Wisconsin- Madison. A Rotatable Guarded Hot Box (RGHB) apparatus was designed and constructed for the large-scale thermal testing of post-frame building envelope designs. In addition to conducting standard thermal performance tests in accordance with ASTM C1363, the apparatus--capable of testing a wall or roof specimen up to 2.9 x 3.8 m--was designed to simulate the effects of air infiltration through the application of a static pressure differential across the test specimen. Utilizing a cable winch system and centralized pivot point, the entire apparatus may be rotated 360 degrees about its horizontal axis to test wall or roof specimens at any orientation. Using this apparatus, the thermal effect of various envelope design changes such as structural component placement and orientation, insulation type and geometry, and the inclusion and placement of air barriers may be studied. This apparatus employs an automated computer control system that acquires and stores temperature, pressure, air speed, and relative humidity data; varies heater and fan output; calculates and records key variables; and determines the completion of experimental objectives. Using this system, it is possible to expedite the conduction of accurate thermal experiments with a minimum of human interaction. The thermal performance of nine post-frame thermal envelopes was studied and optimized using a computational fluid dynamics model validated experimentally by the rotatable guarded hot box. In addition to providing thermal performance values for typical wall designs, this study proposed a new wall design that greatly increased thermal performance without sacrificing material efficiency. Study variables included structural geometry, level of insulation, and the presence and placement of radiant barriers. To reduce computational demand, modeling was primarily conducted using an area-weighted average of two-dimensional slices to represent three-dimensional assemblies. After modeling a portion of the assembly in three dimensions and comparing it with its two-dimensional counterpart, this simplification was found to result in less than a 6.7% error. Significant error (up to 57%); however, was determined to be integral to the simplifying assumptions commonly used by building designers, especially in envelopes common to the agricultural industry. This error was estimated to underpredict energy costs for a 2,200 m^2 cold-storage warehouse in Wisconsin by approximately $1,700 a year. The combination of these two distinct methods allows investigation of the effects that a wide array of factors have on the thermal performance of a building envelope. Through the investigation of these individual factors, thermal envelopes as a whole may be optimized for sustainability, based on a balance of the efficient use of energy, material, and labor.

The design and construction of the appropriate building envelope is one of the most effective ways for improving a building’s thermal performance. Thermal Inertia in Energy Efficient Building Envelopes provides the optimal solutions, tools and methods for designing the energy efficient envelopes that will reduce energy consumption and achieve thermal comfort and low environmental impact. Thermal Inertia in Energy Efficient Building Envelopes provides experimental data, technical solutions and methods for quantifying energy consumption and comfort levels, also considering dynamic strategies such as thermal inertia and natural ventilation. Several type of envelopes and their optimal solutions are covered, including retrofit of existing envelopes, new solutions, passive systems such as ventilated facades and solar walls. The discussion also considers various climates (mild or extreme) and seasons, building typology, mode of use of the internal environment, heating profiles and cross-ventilation Experimental investigations on real case studies, to explore in detail the behaviour of different envelopes Laboratory tests on existing insulation to quantify the actual performances Analytical simulations in dynamic conditions to extend the boundary conditions to other climates and usage profiles and to consider alternative insulation strategies Evaluation of solutions sustainability through the quantification of environmental and economic impacts with LCA analysis; including global cost comparison between the different scenarios Integrated evaluations between various aspects such as comfort, energy saving, and sustainability

Advanced Building Envelope Components: Comparative Experiments focuses on the latest research in innovative materials, systems and components, also providing a detailed technical explanation on what this breakthrough means for building exteriors and sustainability. Topics include a discussion of transparent envelope components, including intelligent kinetic skins, such as low-e coatings, high vs. low silver content in glass, solar control coatings, such as silver vs. niobium vs. tin, and more. In addition, opaque envelope components are also presented, including opaque dynamic facades, clay lining vs. plasterboard and nano clayed foams. Includes real case studies that explore, in detail, the behavior of different envelopes Presents laboratory tests on existing insulation (if any, through samples extracted on-site) to quantify actual performances Provides the tools and methods for comparing, selecting and testing materials and components for designing effective building envelopes Covers both transparent and opaque envelope components, as well as opaque dynamic facades

This book results from a Special Issue published in Energies, entitled “Building Thermal Envelope". Its intent is to identify emerging research areas within the field of building thermal envelope solutions and contribute to the increased use of more energy-efficient solutions in new and refurbished buildings. Its contents are organized in the following sections: Building envelope materials and systems envisaging indoor comfort and energy efficiency; Building thermal and energy modelling and simulation; Lab test procedures and methods of field measurement to assess the performance of materials and building solutions; Smart materials and renewable energy in building envelope; Adaptive and intelligent building envelope; and Integrated building envelope technologies for high performance buildings and cities.

Since many buildings in Canada were built prior to the advent of national and provincial energy codes and standards, quantifying building envelope thermal performance in existing buildings is an important step in identifying retrofit opportunities. Due to the lack of building codes or standards for existing buildings in Canada, development of a rapid and robust quantitative approach to evaluate and rank buildings for vertical envelope retrofits is required. Hence, this dissertation sought to develop quantitative approaches to evaluate existing building envelope thermal performance in Canada and beyond. Following current professional practices, in Chapter 1, a comprehensive study was conducted on 49 campus buildings at the University of Victoria (UVic) to evaluate potential energy savings from vertical envelope retrofits, and to further validate those savings through more detailed energy models and parametric analyses for a subset of buildings. To this end, the thermal performance of a building envelope was quantified based on its heat loss coefficient (UA), obtained from multiplying its surface area (A) by its thermal transmittance (U-value). Heat loss calculations were used as a metric to inform envelope rehabilitation prioritization, while considering other data such as age and physical condition in parallel. Archetype energy models for selected buildings were used to evaluate the impacts of envelope retrofits on energy and GHG savings. The outcomes of this study allowed the University to weigh the benefits of improved energy performance from envelope retrofits against associated capital cost expenditures. Also, the implemented methodology and studied parameters unveiled a new horizon in evaluating the thermal performance of existing building envelopes in Canada, where a building code for existing buildings has not yet been established. Considering the economic findings of the envelope retrofits studied, it was concluded that in the absence of an existing building energy code, the University would likely require additional incentives, such as higher utility costs, higher carbon taxes, or qualifying for utility incentive programs to justify improving existing building envelope performance on the basis of energy only. The strength of the proposed methodology in Chapter 1 was in its balance of effort and ultimate decision-making utility, where reasonable thermal bridging approximations based on simulation models for existing buildings can yield data accurate enough to inform a ranking exercise on a large breadth of subject buildings. However, since numerical models do not consider degradation of building materials, real moisture content, and errors associated with manufacturing and installation, actual building envelope thermal performance differs from 3D simulation models. To study this limitation, in-situ thermal assessments of building envelopes were performed to quantify their actual thermal performances. To this end, Chapters 2 to 4 of this dissertation attempted to determine the viability of an external infrared thermography (IRT) survey technique for quantification of heat losses through the opaque building envelope, and also explores its potential application in identifying and comparing sources of air leakage. The experiments were performed on wood-framed wall assemblies commonly used in Canada due to growing interest among designers, builders, and governments to encourage the use of wood as a building material. In these studies, (Chapter 2 to Chapter 4), thermal transmittances (U-values) of wall assemblies were estimated with external IRT and compared with 3D computer simulations. Furthermore, the impact of the accuracy of U-values estimated with IRT on the deviation of energy simulation outputs with metered data was examined. Finally, a novel relative quantitative infrared index (IRI) was proposed as a means to facilitate rapid evaluation and subsequent ranking of building envelope thermal performance. From the experiments in Chapters 2 & 3, it was found that the U-values obtained with IRT were comparable with simulated values suggesting IRT can be a reliable tool for estimating the thermal performance of wood-framed wall assemblies. Results also demonstrated that thermal imaging artefacts including nonlinear characteristics of infrared (IR) camera focal array, a.k.a. non-uniformity corrections (NUC) and vignetting could have a substantial influence on the accuracy of results, in particular energy model outputs. This limitation was resolved by introducing a practical approach where thermal images were taken from different incident angle. Overall, IRI was found to be a reliable metric for relative quantitative comparison of building envelope thermal performance regardless of boundary conditions. Moreover, outcomes of the IRT air leakage study in Chapter 4 indicated that combined qualitative and quantitative IRT approaches could potentially be implemented by practitioners to identify sources of air leakage and thermal bridges in buildings and compare their relative severity. Since blower door testing is gradually being introduced as a building code requirement to measure building envelope airtightness in an increasing number of Canadian jurisdictions, performing IRT simultaneously is potentially valuable exercise in this context. Ultimately, the methodologies outlined in Chapters 2 to 4 can help decision-makers to characterize building envelope retrofits from a performance perspective, and potentially serve as a basis for governments to develop policies to improve existing building energy performance. The methodologies in Chapters 2 to 4 prompted opportunities to utilize the emergent technology of small unmanned aerial vehicles (UAVs) equipped with an infrared camera for quick thermal assessments of building envelopes. The last chapter of this dissertation, Chapter 5, outlines advantages and limitations of aerial IRT (UAV-IRT) surveys compared to conventional stationary IRT. Furthermore, a set of best practices for UAV-IRT were presented to minimize dynamic measurement uncertainty. It was concluded that with the current IR camera technology, aerial surveys for quantitative thermal assessment of building envelope are not as accurate as with conventional infrared thermography; further investigations by manufacturers and researchers are recommended.

Solar Thermal Systems and Applications: New Design Techniques for Improved Thermal Performance brings together the latest advances for the improved performance, efficiency, and integration of solar thermal energy (STE) technology. The book begins by introducing solar energy and solar thermal energy as a viable option in terms of green energy for industrial, commercial, and residential applications, as well as its role and potential within hybrid energy systems. This is followed by detailed chapters that focus on key innovations in solar thermal energy systems, covering novel approaches and techniques in areas such as flat plate solar collectors, modified evacuated tube solar collectors, solar parabolic trough collectors, linear Fresnel reflectors, photovoltaic thermal systems, phase change materials, nanotechnology, combined PVT-PCM systems, solar thermal systems and Trombe wall design, solar still units, and solar dish systems. Throughout the book, the coverage is supported by experimental and numerical modelling methods, and techniques are discussed and assessed with a view to improved electrical and thermal efficiency and performance. This is a valuable resource for researchers and advanced students in solar energy, thermal engineering, hybrid energy systems, renewable energy, mechanical engineering, nanotechnology, and materials science. This is also of interest to engineers, R&D professionals, scientists, and policy makers with an interest in solar thermal energy (STE) in an industrial, residential, or commercial setting. Introduces solar thermal energy (STE) and details the current state and future opportunities Reviews and analyzes the latest advances in solar thermal energy technology, design, methods, and applications Covers, in detail, the role of phase change materials and nanomaterials in STE systems