Applied Mechanics and Materials Vol. 824

Abstract: CO₂ concentration in rooms, where we spend most of our lives, has become a problem that is solved by ventilation. In buildings, where is the ventilation additionally implemented, has become a problem with distribution systems. Between professionals is solved system so called “Cascade ventilation”, where is enough to incriminated room was at the junction of the inlet and exhaust air. If this assumption will be confirmed, it will facilitate the management of air distribution systems, especially in the case of renovations. Therefore would be no implementation of ceilings, which constitute a considerable part of the budget. Cascade system is based on the principle of Dalton's Law of partial pressures. For test of this theory has been used room, where is located 8 CO₂ sensors. Here was monitored the movement of CO₂ concentration from resources (human) and its distribution through the room in horizontal and vertical direction. The experiment was also simplified simulated in a computer program ANSYS Fluent and simulation results are compared with measured values.

Abstract: The paper analyzes the microbial constituents residing in buildings with more people, such as basic school or office spaces. The aim is to determine whether these areas with similar equipment and similar cleaning regime have similar parameters of microbial environment. Within the quantitative analysis we have carried out the collection of microbial particles dispersed in the air and deposited on floors, furniture and walls inequalities. It was found that the internal environment of buildings with natural ventilation is significantly on the condition of ambient air. In the environment of greater occupancy there are more bacteria than fungi. Rooms in the same building, but not directly neighbouring, have an independent environment.

Abstract: The paper is aimed at analyzes of environmental stressors in indoor environment such as incorrect spatial arrangement or improper setting of limits and less control of own territory /personal space and diminished choice of body positions. There is emphasized the topic of body positions/postures in standard office working environment whereas more choices of body position is a instrument for reduction of stress and increasing of well–being and chance to get new perspectives, approaches and outputs from human resources as well . Nowadays there is a strong need to incorporate a non-formal working style which is also related to non-formal spatial design that can be then occupied by different body positions and using of space in more dynamic way which we can call dynamisation of space. There are also analyzed its main strategies In the paper there are shown theoretical assumptions of relation between work efficiency, creativity and body working position.There is analyzed process of setting methodology for measuring environmental stress through physiological parameters. It shows results of first experimental tests of biometric responses by different working postures by simulation of standard non-industrial working environment. There we chosen 5 working locations – standard set, dynamic seat, stand, perching and reclining. The paper presents results of the pilot test and shows further perspectives of this research.

Abstract: Protection of historical roof trusses is an important part of efforts to protect our cultural heritage. These timber structures carry a lot of information about used tools, technologies or construction processes. Roof trusses are generally threatened by many dangers, which could cause irreparable damage and loss of the carried information. Wood destroying insects and fungi are the gravest threat to historical roof trusses in our climatic conditions. Their spreading depends on several specific (interior) conditions. These include critical moisture content in the wood, relative humidity, amount of natural light and ventilation. In addition to these commonly monitored parameters (and their critical levels) we also must not forget the influence of local geography, biotope or orientation to the cardinal. This paper describes temporal fluctuations of some of the mentioned physical parameters in a historical roof truss with regard to external climatic conditions and orientation to the cardinal.

Abstract: According to the EPBD (2010) whilst improving the thermal performance of buildings good or at least tolerable thermal comfort conditions must be provided. But better thermal insulation and more airtight buildings increase the risk of summer overheating which makes mechanical cooling inevitable. This idea has been verified by the tendency of the last decade, when people were willing to install and use more frequently air conditioning devices during the summer heatwaves – increasing their energy consumption and electricity bills at the same time. We cannot neglect the importance of studies triggering an efficient way to minimise the cooling load of residential buildings by obstructing solar radiation. The usage of plants in front of transparent surfaces of the façade can avoid indoor overheating. Deciduous plants obstruct buildings’ solar access so that the microclimate around the building is improved too. The use of Green Infrastructure in different levels of planning processes, which would provide sustainable solutions for urban management, is also prescribed in the EU Biodiversity Strategy 2020. Of course in order to investigate the actual effect of trees on indoor thermal comfort we should take into consideration a list of other factors: such as orientation the type and thermal properties of the windows / transparent structures used, and the thermal transmittance values and heat storage capacity of the building. If we have taken into consideration the mentioned factors during simulation we can prove the effectiveness of vegetation for each case. Simulations are made on the base of transparency measurements carried out during the summer of 2014. The shading efficiency of trees is a species-specific attribute because of the varying crown structure and leaf density. Our analyses aimed at the quantification of the transmissivity of characteristic individuals of three frequently planted species (Celtis occidentalis, Sophora japonica, Tilia cordata). The measured data were the amount of transmitted shortwave radiation, compared with a measurement point under unobstructed sunlight. In preliminary studies we have shown that depending on species – a tree in front of the façade can decrease the solar gain on internal horizontal surface up to ~18-30 per cents. As the tree obstructs the solar access of the wall and that of transparent surfaces, a difference in indoor comfort is to be observed too.

Abstract: Implementation of double transparent facades (DTF) into architectural concept of modern intelligent buildings is a well established trend of modern administrative building design. The Positive influence on acoustic comfort of a working place caused by this type of envelope construction is evident. DTF allow building designing in high noise exposure urban areas. Comparison of eight DTF from structural and acoustic properties point of view is presented in this paper. Results from acoustic measurements of buildings situated in Bratislava were analyzed.

Abstract: The following article describes the designed and implemented mathematical model of the distribution model of heat consumption in an urban agglomeration. The model is intended for the prediction of heat supply, which can be applied in the regulation system. Depending on the structure of a given real-life system it is usually required for the heating water temperature to be predicted.For the purposes of describing the heat consumption characteristics a function characterizing the heat consumption fluctuation has been established. The fluctuation is defined by number of variables such as outdoor temperatures, solar radiation etc.

Abstract: The contribution deals with the influence of additional heat loss caused by thermal bridges of a building on the energy need for heating. Calculations and comparisons were carried out for a simple characteristic family house built in the sixties in the last century. The family house was evaluated in original state and in four variants of a renewal.

Abstract: Current requirements for energy savings lead to improve heat insulation properties of claddings. That is the reason why thermal insulation properties are improved in existing buildings, such as additional insulation of the building envelope and replacing filling holes in the facade. The reason for the implementation of the glazing of these areas is the idea of improving the indoor climate of the living space. It is assumed that condensation of water vapor and occurrence of moulds on inner surface of the structures can happened in certain conditions of indoor air.

Abstract: In compliance with the today’s trend of designing sustainable and energy-saving architecture, it is necessary to firstly solve the factors influencing the energy balance. In this respect, the thermal bridges in buildings constitute a crucial factor. In case of their occurrence, the use of construction and insulation building materials is significant for finding the solution. The aim of this paper is to analyse the thermal bridges in buildings constructed on the basis of light constructions. The subject of analysis was an implemented wood frame house with common sandwich construction, designed in a low-energy standard. The house analysis is divided in theoretical and experimental part. The house in question has been directly exposed to dynamic boundary conditions. In order to analyse the thermal bridges, critical details have been selected methodically, verified by thermography. The experimental and theoretical results were compared by the simulation method for calculating critical surface temperatures. Both the measurements and results show how attention shall be paid to this issue at the project stage already. With increasing demands for overall energy balance of buildings, it is necessary to exactly define the critical details and consider the thermal bridges in the project documentation already.