Author: A. E. FioratoPublisher:
ISBN:
Category : Exterior walls
Languages : en
Pages : 26
Book Description
Thermal Performance of Masonry Walls
Author: A. E. FioratoPublisher:
ISBN:
Category : Exterior walls
Languages : en
Pages : 26
Book Description
Thermal Performance of Concrete Masonry Walls in Fire
Author: T. Z. HarmathyPublisher: National Research Council of Canada, Division of Building Research
ISBN:
Category : Concrete
Languages : en
Pages : 35
Book Description
Thermal Performance of Masonry Walls in Commercial Buildings
Author: Romer AssociatesPublisher:
ISBN:
Category : Concrete
Languages : en
Pages : 82
Book Description
Dynamic Thermal Performance of an Experimental Masonry Building
Author: Bradley A. PeavyPublisher:
ISBN:
Category : Concrete houses
Languages : en
Pages : 108
Book Description
Thermal Performance of Concrete Masonry Walls in Fire
Author: T. Z. HarmathyThermal Performance of Concrete Masonry Unit Wall Systems
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 20
Book Description
New materials, modern building wall technologies now available in the building marketplace, and unique, more accurate, methods of thermal analysis of wall systems create an opportunity to design and erect buildings where thermal envelopes that use masonry wall systems can be more efficient. Thermal performance of the six masonry wall systems is analyzed. Most existing masonry systems are modifications of technologies presented in this paper. Finite difference two-dimensional and three-dimensional computer modeling and unique methods of the clear wall and overall thermal analysis were used. In the design of thermally efficient masonry wall systems is t to know how effectively the insulation material is used and how the insulation shape and its location affect the wall thermal performance. Due to the incorrect shape of the insulation or structural components, hidden thermal shorts cause additional heat losses. In this study, the thermal analysis of the clear wall was enriched with the examination of the thermal properties of the wall details and the study of a quantity defined herein the Thermal Efficiency of the insulation material.
Effect of Heating and Cooling on the Permeability of Masonry Walls
Author: Cyrus C. FishburnPublisher:
ISBN:
Category : Masonry
Languages : en
Pages : 12
Book Description
A Practical Method to Estimate the Effective Thermal Resistance of Exterior Masonry Walls
Author: Maysoun IsmaielPublisher:
ISBN:
Category : Building materials
Languages : en
Pages : 0
Book Description
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.
Concrete at High Temperatures
Author: Zdeněk P. BažantPublisher: Prentice Hall
ISBN: 9780582086265
Category : Concrete
Languages : en
Pages : 412
Book Description
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.
Improving the Thermal Performance and Durability of Historic Masonry Buildings
Author: Ekaterina TzekovaPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Historic buildings are less energy efficient than modern structures due to the nature of their construction. Although envelope improvements can reduce operating energy, such retrofits can potentially accelerate the deterioration of the historic facade. Consequently, the challenge is to improve the energy performance while maintaining a durable facade. This research proposes a retrofit approach for historic buildings that addresses both energy consumption and durability of the masonry facade. To improve energy performance, an 1879 historic solid masonry home was retrofitted using an innovative Nested Thermal Envelope Design (NTED). An envelope controlling heat, moisture and air movement was constructed around Core and Perimeter zones that were independently operated. Conditioning the entire house provided 36% space heating energy savings below the Ontario Building Code 2012, while turning off the heat to the Perimeter areas increased savings to 68%. To address durability concerns arising from insulating the masonry walls, the use of a vented airspace installed between the masonry and the thermal insulation was explored. The vented airspace at the first field trial increased the drying potential of the historic masonry during the winter when the brick was most vulnerable to freeze-thaw damage. An estimated 1.1 kg/m2/a was removed at South and East walls. The second field trial showed drying between 4.3 kg/m2/a and 5.7 kg/m2/a at the South and 0.08 kg/m2/a wetting at the North. In situ moisture content levels of the brick varied between 10% - 15% while laboratory testing of similar brick revealed a saturated moisture content of 29%. Both field trials showed that the vented airspace drying potential was influenced by facade orientation and solar radiation levels. An alternative way of constructing the airspace was then tested in the laboratory to explore the use of air permeable insulation in lieu of a clear airspace. Walls constructed with rock wool insulation and vent holes, but with no clear airspace, removed between 52% - 90% of moisture, depending on the insulation density and vent hole area. Walls featuring a clear airspace removed between 59% - 95% of moisture. These laboratory tests showed that enough air was able to move through the air permeable insulation thereby improving the drying potential of the walls.