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Abstract. In the construction process of modern residential buildings the aim is to achieve maximum comfort within minimum energy consumption. One of the ways to achieve this requirement is the accurate determination of the volumetric air flow rate necessary to ensure the required indoor air quality. The aim of the paper is to present a methodology for determination the volumetric air flow rate on the basis of the results obtained from experimental measurements of carbon dioxide concentrations, which were carried out inside an apartment house lived by a standard family. Based on the measured values, the mass flow rate release of carbon dioxide was calculated. Consequently, the volumetric air flow rate was calculated in two situations, during the day and during the night. The main goal of the paper is to determine the required fresh air flow rate in an occupied room, based on carbon dioxide concentration measurement, in order to maintain a comfortable level of indoor air quality. The calculated air flow rate should optimize a future investment in ventilation equipment in order to choose the proper air handling unit with low operating costs. The aim is not only to improve the energy efficiency of the ventilation system, but also to ensure a healthy indoor environment. Based on the presented research it can be stated that during the sleeping of four family members there is necessary to ensure the fresh air flow rate of 104 m 3 per hour.

The article is devoted to solving of urgent problem to eliminate damages of two types in ventilation systems for air distribution efficiency increasing in the premises by swirled air flow, compact air jet, flat air stream and rectangular air jet. A mathematical model of air supply with swirled air flow, compact air jet, flat air jet and rectangular air stream in the room has been developed. It is shown that in order to achieve the maximum efficiency of air distribution it is necessary to ensure its supply by jets. Graphical and analytical dependences on the basis of the conducted experimental research are presented. Parameters of swirled air flow, compact air jet, flat air stream and rectangular air jet during the formation of a comfortable indoor climate are determined. The results of experimental studies of air supply to the room by the air distribution devices, which form a swirled air flow, compact air stream, flat air flow and rectangular air jet with adequate turbulence and long range of the supply air flow, are presented. It is established that with the increase of the angle of swirling plates inclination and ratio of the slit sides the air jets long range increases.

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The article is devoted to decision of actual task of air distribution efficiency increase due to swirled air jets application. The aim of the paper is investigation of swirled air jets, analytical dependencies obtaining for determination of the air velocity attenuation coefficient, aerodynamic local resistance coefficient and noise level from the twisting plates inclination angle; optimization of the twisting plates inclination angle of the air distributor. It has been established that increase of the angle results in the air velocity attenuation coefficient increase and results in decrease of the noise level and resistance coefficient of air distributor. The optimum angle of the plates is determined considering aerodynamic, noise and energy aspects and equals 36°.

Living standard of people is increasing significantly recently and due to this fact energy requirements are also increasing. At the Technical University in Kosice a research examining the quality of indoor environment is carried out. There exists a constructed research centre, where an experimental house with passive standards in terms of building structures is designed. Heating and ventilation can be modelled in the house. Equipment is designed on the basis of calculated balances for the needs of heat, hot water demand and the need for ventilation of the building. This paper highlights the importance of environmental protection regarding the reduction of energy consumption while keeping the living standard. In low energy houses, up to 80% of the total heat is consumed for the heating of fresh air for a comfortable environment. The aim of this article is to examine the effect of temperature, humidity, air velocity and CO 2 concentration in regard to the human behaviour in indoor environment with natural ventilation, i.e. without a ventilation device, where ventilation is forced or an air conditioning.

Air distribution by interaction of counter non coaxial air jets at pulsing mode has been considered. Dynamic parameters of air flow that is created due to interaction of counter non coaxial flat air jets at their leakage at pulsing mode and creation of dynamic indoor climate in a room has been determined. This paper is aimed to develop a methodology for determining the intensity of ventilation of indoor premises based on the experimental measurements of the concentration of carbon dioxide. Using experimental measurements and the knowledge gained in the study of this issue, in the work the method for intensity ventilation determining of the indoor premises was developed on the basis of the measured values of carbon dioxide which was verified also by another experimental measurements. The resulting values of ventilation intensity rate obtained by calculation from the measured values of carbon dioxide were compared with the results of calculations executed according to the laws and standards, valid in Slovakia. Based on measured values of carbon dioxide concentrations a method for calculation of the ventilation intensity was developed and compared with the methods used in Slovakia.