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The aim of the paper is to determine a methodology for calculating the needed airflow rate (including fresh air) in an occupied room, based on carbon dioxide measurement and calculation, in order to maintain the comfort indoor air quality. The calculated airflow rate should optimize the investment and the operating costs of HVAC equipment. In the work there are analyzed the calculation methods used to determine the ventilation airflow rate. It is presented the methodology for calculating the ventilation airflow rate for a room with people inside by using the measured values of carbon dioxide concentration. The connection between carbon dioxide concentration and ventilation airflow rate is verified by experimental measurements. This methodology is applicable in Slovakia because it complies with all current standards. The result obtained by using this calculation method is almost the same with that achieved from experimental measurements. To confirm the results, it is presented a case study of an office with occupants, in which the ventilation airflow rate calculation method is applied.In the article only a part from the total work is presented. The experimental measurements were carried out from 2011 to 2014. Approximately 54 measurements were covering total days or weeks. The following factors have been measured: indoor air temperature, outdoor air temperature, relative humidity of indoor air, relative humidity of outdoor air, concentration of CO2 in indoor air, concentration of CO2 in outdoor air, pressure difference and wind velocity. Ventilation by infiltration was calculated based on these factors using several methodologies. The methodology of measurement is not subject to the article. In this article only one aspect is investigated: CO2 concentration.

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It is the main priority in the case of office buildings to ensure a suitable comfort level. In addition, the comfort directly influences the productivity of office employees. Poor thermal comfort and poor indoor air quality deteriorates the intensity and quality of human work. On-site measurements were made in summer in an office building. The comfort evaluation could be done with continuous on-site measuring and data logging. The evaluation could be possible only by the base ground of the probability theory and for that reason the standard deviation and the 95% confidential range of the measuring results were determined.

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It is a prime aim to ensure a suitable comfort level in case of office buildings. The productivity of office employees is directly influenced by the comfort. Thermal discomfort and poor indoor air quality deteriorate the intensity and quality of human work. We investigated the comfort in office buildings with on-site measurements during the summer season. The office buildings were operating with different HVAC (Heating, Ventilating and Air-Conditioning) systems: ducted fan-coil with suspended ceiling, installation, non-ducted fan-coil with floor-mounted installation, active chilled beam with fresh air supply.

We evaluated the thermal comfort under PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied), the local discomfort based on DR (Draught Rate) and the IAQ (Indoor Air Quality) based on carbon dioxide concentration. The comfort measurements were evaluated. The measurements were evaluated with scientific research methods, comfort categories based on the requirements of CR 1752. The results of this comparison were presented in this article.

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Haszpra L. (1995): Carbon dioxide concentration measurements at a rural site in Hungary. Tellus 47, 17–22. Haszpra L. Carbon dioxide concentration measurements at a rural site in

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Adv. Space Res. 1986 18 203 211 Kramer, P. J. (1981): Carbon dioxide concentration

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Haszpra L. 1995. Carbon dioxide concentration measurements at a rural site in Hungary. Tellus 47, 17–22. Haszpra L. Carbon dioxide concentration measurements at a rural site in Hungary

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A kilélegzett levegő kondenzálása és a kondenzátum (EBC: Exhaled Breath Condensate) vizsgálata napjainkra egyre szélesebb körben terjed el pulmonológiai kutatásokban. Az eljárás során nem invazív úton nyerhetünk mintát a légutakból úgy, hogy a kilélegzett gázkeveréket egy hűtött kamrán áramoltatjuk át, és a kamra falára lecsapódó párát vizsgáljuk. A minta számos különböző mediátort, biomarkert tartalmaz. Kiemelt jelentőségű a különböző, eddig vizsgált biomarkerek közül a pH. Mérése egyszerű, olcsó és az optimális mérési tartományon belül van. Problémát a pH-érték instabilitása jelent, amit főként a minta CO 2 -koncentrációjának változása okoz. Számos publikáció jelent meg, amelyekben különböző légúti megbetegedésekben vizsgálták a kondenzátum pH-ját. Asthma bronchialéban (különösen akut exacerbatióban), valamint krónikus obstruktív tüdőbetegségben (COPD) savasabbnak találták a kondenzátumot. Szteroidkezelés hatására mindkét betegségben emelkedik a pH. Bronchiectasiában, cisztikus fibrosisban, valamint krónikus köhögésben (asthma bronchiale, gastrooesophagealis reflux, rhinitis chronica, ismeretlen eredet) is savasabbnak találták az EBC-mintákat. A légutak savasodása a különböző kórállapotokban fontos szerepet játszhat a betegségek patomechanizmusában, és az ezt jelző EBC-pH szerepet kaphat a légúti megbetegedések követésében.

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physiology and productivity of wheat ( Triticum Aestivum L.) under elevated carbon dioxide concentration, high temperature and terminal drought . University of Western Australia , Crawley , pp. 1 – 178 . FAO/WFP ( 2015 ): Crop and food security

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. 2012 . Malting revisited: Germination of barley ( Hordeum vulgare L.) is inhibited by both oxygen deficiency and high carbon dioxide concentrations . Food chem. 132 ( 1 ): 476 – 481

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Kramer, P. J. (1981): Carbon dioxide concentration, photosynthesis, and dry matter production. Bioscience , 31 , 29–33. Kramer P. J. Carbon dioxide concentration, photosynthesis, and

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