Download or read book A Practical Method to Estimate the Effective Thermal Resistance of Exterior Masonry Walls written by Maysoun Ismaiel and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluation of the thermal resistance of building envelope elements is essential for a reliable assessment of the thermal behaviour and energy efficiency of buildings. Energy codes continue to drive the building construction industry toward more stringent thermal performance standards. To reduce energy consumption in buildings and comply with newer, more stringent energy code requirements, evaluation of the thermal resistance of above-grade wall assemblies is becoming essential. Masonry veneer cladding is typically supported by the building structure using intermittent anchors and shelf angle bearing supports. However, elements with high thermal conductivity, such as floor intersections and cladding attachment systems, often penetrate the insulation and cause thermal bridging. Thermal bridges have a significant reduction effect on the elements' thermal resistance. Moreover, condensation on thermal bridging elements is expected. As a result, damage to building elements occurs. In terms of calculating the effective thermal resistance (R-value), the lateral heat flows caused by these highly conductive elements allow heat to be transferred in multiple directions, which is considered a challenge in the R-value estimations and causes the inability of a quick estimate of the effective thermal resistance of masonry components with sufficient precision due to the complexity of masonry construction. Currently, an accurate estimation of the R-value of masonry walls is a time-consuming task, which lengthens the design process, especially in the early design stage. Therefore, this study aims to provide efficient approaches for estimating the R-values of common concrete masonry cavity walls. Two estimation approaches are presented. First, the estimation of the R-value of common concrete masonry veneer wall configurations is presented in the form of simple design charts and R-value multipliers. Parameters such as the concrete block density, thermal insulation value, as well as the types of ties and shelf angles are addressed. The approach provides simultaneously the mechanical (the masonry compressive strength, fm') and thermal (R-value) properties of different veneer wall configurations, allowing designers to obtain appropriate structural and thermal properties during the preliminary design phase. In addition, the design charts and R-value multipliers help designers evaluate and compare the impacts of changes in different parameters on R-values, thereby facilitating their design development. A comparison of the impacts of different parameters on the thermal resistance of masonry walls was presented. The results showed that the thermal resistance of masonry cavity walls was improved by using different tie types and materials. In the case of using galvanized, stainless-steel and Glass Fiber Reinforced Polymers (GFRP) perforated fastened on block's surface ties, the thermal resistance improved by 25%, 43% and 60%, respectively, compared to the traditional galvanized solid block ties. Using knife plate galvanized and stainless-steel shelf angles in the intermediate floor intersection assemblies improved the overall average R-values by 30% and 63%, respectively, compared to the traditional galvanized steel directly attached shelf angle. Moreover, the results showed that the shape and material of the ties and shelf angles are more effective in the masonry wall assemblies with higher insulation R-values. Also, the effect of the concrete block density was addressed, and the results showed that, on average, the reduction of the concrete block density by 10% showed an improvement in the effective R-value of 3.5%. In addition, configurations with an expected lower effective thermal resistance are more sensitive to the concrete block density. Also, cases using solid ties are more sensitive to block density reduction than cases using perforated ties. The second approach provides adjustments to current analytical methods of thermal resistance estimation (i.e., isothermal plane and parallel path methods) to include the effect of the thermal bridge resulting from veneer ties and slab intersections. The R-values obtained from the suggested adjustments were compared with numerical simulations using a 3D steady-state finite element method (FEM) in addition to experimental validation obtained from the literature. The clear wall adjustment factors result showed an average accuracy of 2% in the case of using the suggested adjustments, compared to 19% and 25% for isothermal plane and parallel path methods, respectively. With the presented approaches, designers can choose the optimum wall components' material properties in the early design phase to meet structural and thermal requirements without using computer simulations or experimental investigations.
Download or read book Evaluating the Thermal Impacts of Different Masonry Wall Tie Designs Using FEM written by Yue Shao and published by . This book was released on 2021 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building's space heating system accounts for more than half of the total building's energy consumption, reducing the energy use of space heating of buildings can decrease the national energy consumption of Canada and is helpful for sustainable development of the buildings. Improvement of thermal resistance of the wall is a reliable approach to decrease the energy consumption of the building. Masonry cavity walls is a commonly used type of exterior wall in Canada. It can provide reliable structural performance, considerable durability, and excellent thermal resistance. However, the presence of masonry ties, as a typical source of repeated thermal bridging, in the wall assembly significantly reduces the thermal resistance of the wall assembly. Ties are considered a typical source of repeated thermal bridging in masonry cavity wall assemblies. Thermal bridging can cause thermal resistance reduction due to its high conductivity material penetrating the thermal insulation layers. Ties thermal bridging effect provide additional heat transfer pathways in the wall assembly. Codes and industry catalogues require the thermal impact of thermal bridging to be considered when calculating the thermal resistance of exterior walls. Although a few studies have been conducted on the effect of ties in reducing the thermal performance of walls, the thermal impact of ties has not been comprehensively studied. Incomplete thermal bridging reduction effect evaluation will make insufficient HVAC system design and lead to energy consumption increase of the buildings. Also, the ties thermal impact on the thermal resistance of the ventilated air gap has not been determined. In this study, the effective thermal resistance of the ventilated air gap in masonry cavity walls considering ties thermal bridging impact was investigated, and the impact of ties on the thermal resistance of wall assemblies was addressed with different influence factors. Based on the parametric analysis, effective methods to reduce ties thermal bridging effect were suggested. The effective thermal resistance of the ventilated air gap in masonry cavity walls was studied by using coupling computational fluid dynamics (CFD) and steady-state thermal analysis in Finite element method (FEM) modelling. In addition, a parametric analysis of the impacts of ties on the effective thermal resistance of a unit wall area was performed by using FEM with variations in ties material, insulation R-values, tie depth, tie spacing, grouting in concrete masonry blocks, and the effect of adding insulation around the tie. Based on the results, the tie's thermal bridging effects and ventilation in the air gap affect the thermal resistance of the air gap. And according to the parametric analysis, the tie material is the most influential factor of the ties' thermal bridging effect. The thermal resistance of the wall assemblies varies greatly with the change of tie material, ranging from 14.68%~41.85%. Using a low thermal conductivity material (e.g., GFRP tie) can almost eliminate the thermal bridging effect of the tie. Enlarging the tie spacing also can improve the overall thermal resistance of walls up to 12%. Using a low thermal conductivity tie material such as GFRP is recommended for effective thermal resistance improvement for the masonry wall cavity wall assembly.
Download or read book U S Forest Service Research Paper FPL written by Forest Products Laboratory (U.S.) and published by . This book was released on 1967 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S D A Forest Service Research Paper FPL written by and published by . This book was released on 1968 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASHRAE Journal written by and published by . This book was released on 1984 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Performance of Buildings Determination of Thermal Resistance by Hot Box Method Using Heat Flow Meter Masonry written by British Standards Institute Staff and published by . This book was released on 1998-07-15 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stone, Walls, Thermal resistance, Thermal measurement, Thermal insulation, Thermal properties of materials, Floors, Ceilings, Construction systems parts, Construction materials, Heat transfer, Heat loss, Test equipment, Heat-measuring instruments, Temperature measurement, Calibration, Test specimens, Thickness, Specimen preparation, Errors, Error correction, Performance, Accuracy, Reproducibility, Reports
Download or read book Thermal Resistances of Various Concrete Masonry Wall Constructions Incorporating Rigid Plastic Foam Insulation written by WR. Strzepek and published by . This book was released on 1987 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Series of thermal transmission tests were conducted on large wall specimens, which measured 300 by 400 cm (118 by 157 in.), using a calibrated hot box test apparatus. The wall specimens were constructed with concrete masonry units and insulated using various interior insulation systems incorporating extruded and block molded expanded polystyrene (EPS) insulation. An exterior insulated finishing system incorporating extruded EPS insulation was also evaluated. The interior and exterior insulation systems included various methods of attachment of the insulation and finish. The impact of these attachment methods on thermal resistance was studied. Thermal resistance values for the various wall constructions were determined for two different mean temperatures. For some constructions R values were calculated using a standard heat transfer methodology commonly followed throughout the construction industry. The calculated system R values were generally only slightly greater than the measured R values, but for some insulation systems the calculation method significantly overestimated the thermal resistance of the wall construction.
Download or read book Thermal Insulation from Wood for Buildings written by Wayne C. Lewis and published by . This book was released on 1968 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustical and Thermal Performance of Exterior Residential Walls Doors and Windows written by Hale J. Sabine and published by . This book was released on 1975 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Forest Service Research Paper FPL written by Forest Products Laboratory (U.S.) and published by . This book was released on with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The International Steam Engineer written by and published by . This book was released on 1925 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Passive Solar Design Handbook written by and published by . This book was released on 1984 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Concrete at High Temperatures written by Zdeněk P. Bažant and published by Prentice Hall. This book was released on 1996 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increased use of concrete in high temperature environments, it is essential for engineers to have a knowledge of the properties and mathematical modelling of concrete in such extreme conditions. Bringing together, for the first time, vast amounts of data previously scattered throughout numerous papers and periodicals, this book provides, in two parts, a comprehensive and systematic review of both the properties and the mathematical modelling of concrete at high temperatures. Part I provides a comprehensive description of the material properties of concrete at high temperatures. Assuming only a basic knowledge of mathematics, the information is presented at an elementary level suitable for graduates of civil engineering or materials science. Part II describes the response of concrete to high temperatures in precise terms based on mathematical modelling of physical processes. Suitable for advanced graduate students, researchers and specialists, it presents detailed mathematical models of phenomena such as heat transfer, moisture diffusion, creep, volume changes, cracking and fracture. Concrete at High Temperatures will prove a valuable reference source to university researchers and graduate students in civil engineering and materials science, engineers in research laboratories, and practising engineers concerned with fire resistance, concrete structures for nuclear reactors and chemical technology vessels.
Download or read book Handbook of Heating Ventilation and Air Conditioning written by Jan F. Kreider and published by CRC Press. This book was released on 2000-12-26 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 20 years, energy conservation imperatives, the use of computer based design aids, and major advances in intelligent management systems for buildings have transformed the design and operation of comfort systems for buildings. The "rules of thumb" used by designers in the1970s are no longer viable. Today, building systems engineers must
Download or read book International Steam Engineer written by and published by . This book was released on 1925 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat transfer written by Yunus Ali Cengel and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exterior Building Enclosures written by Keith Boswell and published by John Wiley & Sons. This book was released on 2013-06-11 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide to the design and execution of sophisticated exterior building enclosures Focused on the design process for architects and related professionals, this book addresses the design and execution of sophisticated exterior building enclosures for a number of commercial building types and in a variety of building materials. It focuses on the design process by delineating enclosure basics, the participants (owners, architects, engineers, consultants) and their roles and responsibilities through collaboration, and tracking the design process through construction. This comprehensive handbook covers all of the factors that affect the design of a building enclosure, including function, visual aesthetics, performance requirements, and many other criteria. In-depth case studies of projects of various scales, types, and climate conditions illustrate the successful implementation of exterior wall enclosure solutions in brick masonry, stone, architectural concrete, glass, and metals. This unique and indispensable guide: Defines the functions, physical requirements, design principles, and types of exterior building enclosures Identifies the participants in the design and construction process and specifies their roles and responsibilities Presents a step-by-step process for the design of exterior enclosures, from defining goals and developing concepts through creating construction documents Reviews the construction process from bidding and negotiation through the paper phase to the "brick and mortar" stage Provides details on the properties of exterior enclosure materials, including structural considerations, weather protection, fire safety, and more Covers a variety of materials, including brick masonry, natural stone masonry, architectural concrete, metal framing and glass, and all-glass enclosures Written by the technical director of the San Francisco office of Skidmore, Owings & Merrill, Exterior Building Enclosures is an indispensable resource for architects, engineers, facade consultants, and green design consultants working on commercial building projects.
