Advanced Materials Research Vol. 1041

Abstract: Transparency of glazed roofs does not depend on glass as material, which enables an admission of daylight to the interior, but it depends on the share of the glazed part of the canopy and their structural part. Spaces of glazed atria and courtyards of historical buildings are covered with very difficult shape of glazed canopies, which are supported by various types of load-bearing structures. In contemporary architecture glazed atria are used for the reason of saving energy and lighting up the inner spaces. New types of structures and using glass in load-bearing function in glass canopies are important thanks to their structural subtlety, where the structure covers slight part of glazed canopy. The result of clever ideas and modern technology are lightweight structures of bold forms and spans. In this context transparency became a new expression element of architecture.

Abstract: In the last decade, society has been looking at sustainability of construction. The pressure for improved construction methods also leads to the search for new materials. One possible material with suitable technical properties based on renewable resources is hemp fibre concrete – hempcrete.Hempcrete is a construction material made from hemp fibres, lime and water. This composite breathes, as well as having good thermal and acoustic-insulation properties. The paper provides an overview of international literature and its relevance to New Zealand (where hempcrete has already been used) and the Czech Republic (where the first hempcrete house is under construction).A life cycle analysis of hempcrete will be used to examine its ecological footprint, especially in reducing carbon dioxide emissions. The construction in 2014 of a New Zealand house provides data which can be used to model performance in both countries. The preliminary results suggest that hempcrete offers both environmental and construction opportunities which can help to deliver sustainable housing solutions.

Abstract: The future of expanded polystyrene (EPS) and extruded polystyrene (XPS) as thermal insulation in the construction industry is divided into two trends. The first one contains polystyrene boards and shaped elements already built-in in the buildings, respectively problems of their liquidation as construction or demolition waste generated during reconstructions and demolition of the buildings. The second trend is focused on the future production of polystyrene foam as the material for thermal insulations. Its target in particular is the change of technological processes and finding new methods to reduce energy consumption during production, improve the thermal insulation properties and replace the existing flame retardant other, environmentally acceptable.

Abstract: Due to an increasing request for ecological building constructions, in particular straw bale buildings, a research in this regard has been performed at the Vienna University of Technology. Straw bale construction is a new rediscovered building technology, which is an alternative to conventional construction technologies. The aim of this study is caring out of hygro-thermal simulation of a straw bale wall construction to design as efficiently as possible straw bale house. The choose of other construction elements for a thermal analysis (appropriate wall, roof and a base plate construction), was based on an extensive literature researche. For the examination of the building a timber frame construction has been selected. The straw bales in this construction were plastered inside with clay plaster and externally with a combination of lime and clay plaster. The roof structure was designed as a green roof and insulated with straw bales. The base plate was also insulated with straw bales. To check the thermal behavior of the structures described above were thermal bridges calculated using a FEM program. The hygrothermal behavior was calculated with HAM4D building physic software, developed on the department for Buildings Physics and Sound Protection on Vienna University of Technology. Ecological and economic evaluation of straw bale construction was carried out with reference to the data from the literature. The performed thermal (with COMSOL) and the first hygrothermal calculations (with HAM4D Software) have demonstrated a very favorable performance of the proposed building components. The achieved low U-values ​​of the components allow the construction of passive houses. The use of self-build-service in the construction process can reduce construction costs significantly. The use of ecological materials such as: straw, clay and wood allows a low cost recycling of building materials.

Abstract: Recently, a unique Waste-based Particle Polymer Composite (WPPC) made from recycled foam glass and polypropylene has been developed at Brno University of Technology. WPPC was designed so as to provide both good thermal and mechanical properties in order to become a material of choice for thermally insulating construction details. However, before WPPC can be reliably used by construction designers, physical properties of WPPC must be accurately identified. Therefore, we studied thermal, mechanical, and moisture absorptivity of WPPC. In this work, we firstly present material structures of WPPC and difficulties related with experimental determination of WPPC´s physical properties. Secondly, we present measurements of coefficient of thermal conductivity using several experimental methods in order to show discrepancies among those methods. Thirdly, we show and discuss compressive properties of WPPC including Young´s modulus, strength and yield stress and their dependencies on testing temperature. Fourthly, we present measurement of moisture absorption. Finally, we compared experimentally identified physical parameters of WPPC with those of other common construction material in order to clearly show the application potential of WPPC. To sum up, we present an experimental study providing not only valuable data on physical properties of WPPC but also difficulties and discrepancies related to these experiments and we assess the potential of WPPC as a construction material.

Abstract: The building envelope is a barrier that separates the internal environment from the effects of weather. This barrier ought to facilitate the optimal comfort of the interior environment in winter as well as summer. It has been shown in practice that most building defects occur within the building envelope. This includes external walls, roofs and floors too, and is impartial to new or renovated buildings. Heat losses of buildings through external constructions – roof, external walls, ground slabs are not negligible. It is therefore important to pay more attention to these construction elements. Basementless buildings situated on the ground are in direct contact with the subgrade and its thermal state. An amount of heat primarily destined for the creation of thermal comfort in the interior escapes from the baseplate to the cooler subgrade. The outgoing heat represents heat losses, which unfavourably affect the overall energy efficiency of the building. The heat losses represent approximately 15 to 20 % of the overall heat losses of the building. This number is a clear antecedent for the need to isolate and minimalize heat flow from the building to the subgrade.

Abstract: This article deals with the modelling of a small domestic solar collector array using Transient System Simulation Tool. The model was developed using meteorological data included as part of the Transient System Simulation Tool , mean regional data and actual meteorological data collected near the site of the solar array during testing. The main aim of this study was to compare the results of model simulations using the different types of meteorological data. The most accurate simulation was that prepared using meteorological data collected near the site of the solar array. Even here, however, differences were observed due to the equipment used to monitor heat gain, that is earlier insolation of the meteorological station.

Abstract: This paper deals with the determination of linear thermal transmittance for buildings with acute angle shapes. Calculation of linear thermal transmittance is a standard problem in determining the influence of thermal bridges on the overall energy performance of buildings. Computational methods are known for ordinary rectangular buildings and the values of typical detail are listed in databases. Current architecture of designs buildings uses acute angle shapes quite frequently. It corresponds with new trends in architecture. In such cases the value of linear thermal transmittance is not accurate for using databases. This paper presents an analysis of the influence of the change of angle of the walls in corner to linear thermal transmittance. It provides information applicable for buildings assessment in engineering practice.

Abstract: Building of structures with high energy performance is topical. To achieve this, it is necessary to have processed besides other thing a detailed design. Thermal bridges have to be eliminated in the design period. Thermal bridges occur as point, linear and 3-dimmensional ones. Mechanical anchoring creates point thermal bridges too. In this paper will be described only the mechanical anchoring to stabilize a flat roof. In the space with anchoring elements there is increased the thermal flux. This flux depends on the composition of the flat roof and kind of anchoring elements. It could lead to the condensation of water vapour in these locations upon attainment of the critical value of surface temperature in the room. This issue has another not-less interesting side. It is behaviour in summer season, when the anchoring conducts heat to the interior of objects. These thermal bridges caused by the anchoring elements described in this article will be modelled with the Ansys software tool.

Abstract: Influence of thermal bonds when evaluating the energy performance of buildings can be included in the calculation approximately by means of a surcharge on the effect of thermal bonds or precisely by using specific linear heat transmission coefficient for thermal bonds between structures. The article presents a comparison of the two options in the energy performance of a particular building, the specific amount of heat for heating the building of a brick passive house based on the foam glass.