Building construction problems for ,,covered roofs´´

``Covered roof´´ is a new motif in contemporary building endeavors. The use of materials used thus far only to cover facades (stone, brick, concrete, wood, etc.) has brought about new problems on roofs, and necessitated development of new layer sequences. In accordance with a free design of buildings, optional pitches and shapes may be used on covered roofs. Conventional rules for roofing do not apply here. This paper will define concept of covered roofs, analyze possible layer sequences, and set out key designing principles. A multi-level drainage of rainwater, protection of slant layers against slide-off, handling of thermal expansion, and customized structural details are problems for which no sufficient literature and standards are available as yet

Thermal Models for Box Type Windows: Part 1

Techniques for the thermal modelling of contemporary single skin windows with insulating glass units are well developed, but their applicability for traditional box type windows is under investigated. Due to their different construction and dimensions, a different type of natural convection is encountered in their air cavity. In this article, a literature review is conducted to analyse the characteristics of this flow and its difference from the flows in contemporary windows. Finally, the best-known correlations used to quantify the convective heat transfer in glazing cavities are analysed with regards to their validity for the specific case of box type windows

Requirements for Designing Living Wall Systems – Analysing System Studies on Hungarian Projects

The concept of green façade design has recently come into prominence. Considering it as a new trade that requires its own professionals is quite new. The current innovative structural solutions have extended the research field of green walls to an interdisciplinary level. Architecture, horticulture, engineering (lighting technology, fertilizing technology) are now essential spheres, which can be supported by IT technologies. Studies concerning green walls are cost-benefit analyses, their potential for energy savings or their role in decreasing air pollutants. The fact that 22 m2 plant surface saves 1 tonne of CO2 highlights the application of vertical gardens. Hardly any research examines the practical use and requirements of living wall systems. Although serving the same purpose of creating a vertical green surface, each system has different requirements. The aim of this paper is to reference the essential requirements and important practical information that must be considered when designing a living wall

Thermal Models for Box Type Windows: Part 2

As the literature does not contain enough measurement data to create dedicated correlations for the Nusselt number and convective heat transfer inside box type windows, CFD simulations are performed to study the type of natural convection in such windows. Validation is attempted with the help of the turbulence benchmark of Betts and Bokhari (2000) and comparison with other simulations found in the literature. The k-ω SST model of Menter (1994) is selected to perform a wide range study of the cavity aspect ratios and Rayleigh numbers expected in box windows, enabling an analysis of the types of convections encountered. A new correlation is introduced to calculate the convective heat transfer, and finally, the study is augmented to investigate the effects the temperature stratification has on critical glazing surface temperatures

A proposed methodology for the improvement of the simplified calculation of thermal bridges for well typified facades

The precise calculation of the multi-dimensional heat losses through the external building fabric is a key issue in the accuracy of building energy calculations. With the help of an extensive thermal bridge database created for a well typifiable group of buildings – 19th century urban apartment houses – a detailed investigation is presented about the accuracy of the currently used simplified thermal bridge calculation method. A Monte Carlo simulation approach is applied to explore the various geometrical and constructional parameters that affect multidimensional heat losses and to generate a sufficiently large sample for the investigation. The inaccuracy of the current method is demonstrated and a possible new approach is introduced for its improvement

Tetősíkablakok beépítésének épületfizikai kérdései : A beépítési készletek haszna = Questioning Building Technology and Skylight Installation

Kits to install top quality skylight systems do not always result in satisfactory results. Too often the location of a roof's structure, tiling battens, the poor use of vapour barriers and insulation materials can lead to failure. Apart from manufacturers’ guidelines what other steps should be taken to ensure quality installation? This article examines installation methods, thermal insulation types, waterproofing, vapour barriers and good practice guidelines

Földanyagú külső falak tartóssága : Megépült példák és vizsgálati módszerek = Durability of Soil Based External Walls

As the contemporary trend for developing buildings with external earth walls increases the need to measure rates of stability, structural integrity and therefore durability has grown. Guidelines for developing these methods of construction follow research into contemporary design trends, knowledge of regional construction methods, chemical analysis, selection of suitable base materials and a harmonisation of test methods. Once these areas of study have been undertaken suitable advice into how to build against erosion can be offered

Simplified calculation of non-repeating thermal bridges of the typical Central-European small suburban houses

A new calculation method for deriving easy-to-use equations for the simplified calculation of non-repeating thermal bridges is presented and tested on several constructional variants of a common Central-Europe building type. Through the identification the main parameters affecting the difference between the one- and multidimensional heat transfer coefficients of facades their number is reducible. The method’s accuracy compares favorably to current calculations. A new formulation is introduced for the calculation of the total heat transfer coefficient of the external thermal envelope incorporating the proposed simplified thermal bridge calculation method and the window’s in-situ heat transfer coefficients