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A building with zero energy consumption is characterized by significantly lower energy consumption than the corresponding mandatory requirements of building energy regulations at the beginning of the 21st century. Energy-efficient buildings place high demands on the quality of thermal insulation. It is important to characterize the parameters of the building envelope, i.e., envelope construction of the perimeter cladding, roof cladding, floor on the ground or ceiling above the unheated basement, and infill structure (windows, doors), which acts as a thermal envelope of the building. The aim of this paper is to design and compare eight perimeter cladding compositions and evaluate alternative perimeter cladding compositions using the methods used to evaluate the complex quality of buildings. Main criteria define the area of possible solutions and exclude solutions that, for example, are in conflict with legislative requirements. Optimization criteria are used as the basis for the multicriteria evaluation of complex quality. The traditional approach to building assessment requires a reduction in the number of criteria and a focus on the current essential design criteria. Perimeter claddings are designed as multilayer structures insulated with two methods of insulation with different materials based on the infill structure and thermal insulation. [ABSTRACT FROM AUTHOR]

Computer programs allowing determining accuracy of building design in advance, or its parts, from the thermal engineering point of view are on the rise. Finding correct solution for lower part of building construction helps streamlining a process of energy utilization and significantly contributes to implementation of European Directive on Energy performance of buildings 2010/31/EU in Slovakia. Thermal loses (thermal bridges) in wrongly designed thermal insulation detail of lower building parts (foundation, external wall, floor) result in a rapid rise of heating demand as well as operating cost on energy. Low surface temperatures in critical parts of lower structures of buildings are increasing a risk of mold development and can lead up to a physical nausea. Outer local climate and indoor conditions were used in this analysis according to European and National directives. In this paper two construction details of foundation were assessed on surface temperatures in critical locations and of each option. Suitability of chosen details is shown in numbers and figures, so the constructions as unit and as whole would meet valid EU standards. [ABSTRACT FROM AUTHOR]

Evaluation of validity is realized by comparing results of computer model to data measured on physical full-scale model. Evaluated are two characteristic parameters, ratio of stagnation pressure in the outer stream of the outlet and in the inlet of outer stream. Used CFD system is Ansys CFX. System Ansys CFX is applied with turbulence model of k-epsilon SST with structural numerical grid with detailed resolution in the volume of boundary layer. Computational results confirm capability of current CFD systems to accurately predict parameters of air channel, without accounting for design details and as well to accurately resolve details of the boundary layer. This work is very useful for practical communication in industry, because specifies conditions for reliable application of CFD methods in computation of air channel around the historical buildings. [ABSTRACT FROM AUTHOR]

Recently, there has been a tendency of increased complete reconstructions of historical buildings that have not been administered, nor used and have subsequently fallen into disrepair. Their current status neither meets existing building standards. These buildings generally have no, or only passive protection of structures against the ingress of moisture in contact with the soil. The acting humidity can be effectively removed, using ventilated floors. These are commonly used in connection with remedial treatments for damp masonry, especially in historic buildings, but increasingly also in new buildings (for the realization of foundation slabs, and as a protection against radon) for ventilation purposes in regards to elements in contact with the subsoil. The paradox is that these methods have been used for many centuries and until recently, only in layman's terms. There is no proven relationship or calculations nor any literature that would address the airflow in floors, ventilation ducts and galleries around the base of a building construction. The remaining problem involves drafts in air cavities in general. To assess the airflow in the air cavity, recently commonly used CFD simulations can be employed. In this article CFD simulation of underfloor air cavity created by special units is verified by means of laboratory experiment. [ABSTRACT FROM AUTHOR]

External constructions of buildings provide their protection of external influences. These constructions ought to create an optimal comfort of interior environment in winter as well as in summer. It has been shown in practice that the largest number of breakdown is in external constructions. The external constructions of walls, roofs and floors too, present a big area of problems in design of new and reconstructed buildings respectively. Heat losses of buildings trough external constructions - roof, external wall, floor on the ground are not negligible. It is therefore important to pay more attention to these constructions. The building, which is directly on the ground is in direct interaction with the subsoil and its thermal state. An amount of heat primarily destined for creation of thermal comfort in the interior escapes from foundational construction and floor on the ground to the cooler sub grade. The outgoing heat represents heat losses, which unfavorably affect the overall energetic effectiveness of the building. The heat losses represent approximately 15 to 20 % of the overall heat losses of the building. This number is clear antecedent of need of isolation and minimize of heat flow from the building to the sub grade [ABSTRACT FROM AUTHOR]

In generally, low energy building design range from architectural design to the application of technologies for energy conversation. Many applications are focused on insulation of facades, roofs and floors to those that are used systems for renewable energy sources. The aim of the innovations is not only energy saving but also reduce costs and preserve natural resources. One key element of low energy building design is using the basic form and enclosure of a building to save energy while enhancing occupant comfort. Besides energy need for building operation the significant part of the total energy is energy used in the extraction, processing and transportation of materials used in building structures. Integrated assessment of building includes the evaluation of indoor environmental quality and energy produced over the entire building life cycle. This study is aimed to analyze the building materials and structures in terms of embodied energy and embodied gas emissions and monitoring of physical and chemical factors of indoor environment. The paper deals with evaluation environmental and social aspects in selected low energy family house and its optimization in order to reduction environmental impacts. [ABSTRACT FROM AUTHOR]