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Determination of thermal properties of gloves by means of thermal manikin
Pidrová, Kateřina ; Pokorný, Jan (referee) ; Fišer, Jan (advisor)
This diploma thesis is focused on determination of thermal properties of gloves by means of thermal manikin. The background research with relation to this topic together with derivation of the computational equations used for the following measurement are presented in the first part. The most significant part of this work is suggestion of procedure for measuring the heat resistance of gloves with thermal manikin based on procedure from ČSN EN 511. This methodics was verificated with 5 pairs of gloves together with analysing the uncertainties and testing the repeatability of this measurement. This work also contains the outline for all of the measured pairs with posibilities of their usage in specific situations and surrounding air temperatures. At the end of this work is mentioned brief summary of achieved results.
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Thermal comfort and its estimation
Žáková, Monika ; Vondra, Vlastimil (referee) ; Nováková, Zuzana (advisor)
This paper summarizes the problems of human thermoregulation and its measurement, with a focus on the method of indirect calorimetry in resting conditions at different ambient temperatures and during physical activity. It also introduces the issue of human thermal comfort and the methodology of its monitoring using thermal manikin. It describes PowerCube Ergo (Ganshorn, Germany) and Cardiovit AT-104 (Schiller, Switzerland), the diagnostic devices used to spiro-ergometry measurements. It introduces the options to export data. The work proposes the protocol for measuring the thermoregulation of the small group of volunteers, which is realized by the practical part. According to the same protocol is monitored thermal comfort of the thermal manikin. In MATLAB is created the application, allowing clear analysis of measurement records. The data are evaluated and discussed.
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Ventilated protective clothing for healthcare staff in contaminated environments
Štenclová, Kristýna ; Kopečková, Barbora (referee) ; Fišer, Jan (advisor)
Focus of the masters thesis is experimental verification of cooling effect of ambient air stream directed under a protective clothing of a human. The first part is a review of literature encompassing concepts related to thermal comfort and heat transfer. Possibilities of cooling a human who is moving in high ambient temperature environment are introduced in this part. The second part is focused on hypotheses devised and experiments performed. The last part is focused on results of the experiments and their comparison with an experiment described in literature.
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The influence of moisture on the thermal properties of the gloves
Janíčková, Žaneta ; Toma, Róbert (referee) ; Fišer, Jan (advisor)
This diploma thesis is focused on the assessment of the influence of moisture on the thermal properties of the gloves. The first part of the thesis deals with the research of topics related to the given issue as well as with the derivation of the computational relations needed for evaluation of experimental measurements. The main focus of the work lies on defining the hypotheses and experiments that are used to verify the influence of moisture on the thermal resistance of gloves. As for the experimental part, it describes the individual methods of moistening the gloves from which the moistening through the air humidity and the moistening by the immersion were analysed. To verify the suitability of selected moistening methods, the tested glove samples were measured on the thermal manikin both in a dry and a moistened state under the conditions defined by ČSN EN 511 and ČSN EN ISO 15831 standards. Individual states were repeatedly measured and afterwards the progresses of thermal resistance depending on time were graphically displayed. The thesis also includes analysis of measurement uncertainties as well as evaluation of measurement repeatability. From the obtained results, both the defined hypotheses and theoretical assumptions about the decrease of the thermal resistance of a textile material due to the influence of moisture were confirmed in the conclusion of the diploma thesis.
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Analysis of a heat loss of passive manikin
Kodajková, Zuzana ; Krejčí, Vladimír (referee) ; Forman, Matěj (advisor)
This thesis is about problematics of creating Computational Fluid Dynamics (CFD) model suited for analysis of airflow around sitting passive person. Thesis includes analysis of velocity field distribution, thermal distribution and thermal losses in the surroundings of sitting thermal dummy (computational model) and comparison of these values with experimental measurements. Thesis is a part of large experimental research (this research is not included here) focused on creating of functional method used for person-surrounding airflow analysis in future commercial use.
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Measurement of Cabin Environment by Means of Thermal Manikin and Test Subjects
Toma, Róbert ; Tuhovčák, Ján (referee) ; Fišer, Jan (advisor)
In this thesis, there is processed design of test procedure for innovative HVAC system. This design was created in consecutive phases with use of thermal manikin Newton and climate chamber. Correlation between data from thermal manikin and tests subjects and possible design changes were evaluated after each phase. There are mentioned basics of human thermoregulation, factors which affect thermal comfort and ways in which is possible to measure and rate it with use of thermal comfort scales and comfort zones diagram. The thesis includes survey for testing thermal comfort and scales which are used to complete it. In the end, we mentioned some results alongside with our approach in evaluation of correlation between thermal manikin and test. There is also final design of test procedure for innovative HVAC system which would be used for its calibration and final functionality testing.
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Determination of Clothing Evaporative Resistance for - Thermo-Physiology Modelling using a Thermal Mannequin
Toma, Róbert ; Hes,, Luboš (referee) ; Lunerová, Kamila (referee) ; Jícha, Miroslav (advisor)
Globálne otepľovanie a klimatické zmeny sú aktuálne jednou z najdiskutovanejších tém na svete. Keďže začíname vidieť jasné známky klimatických zmien, je nutné sa čoraz viac zaoberať ochranou ľudského zdravia pred tepelnou záťažou aj na miestach sveta, kde táto téma nebola v minulosti aktuálna. Pracovníci vo viacerých profesiách, hlavne v tých ktoré využívajú špeciálne ochranné odevy, môžu byť potencionálne ohrozený vplyvom tepla. Je známe že vyparovanie potu z tela je hlavným termoregulačným prvkom ľudského tela a práve použitie takýchto ochranných odevov, obmedzujúcich toto vyparovanie, v kombinácií s vysokou aktivitou môže byť zdraviu nebezpečné. Z týchto dôvodov sa do popredia dostávajú termofyziologické modeli alebo predikčné modeli tepelnej záťaže, ktoré sú neustále vylepšované a aplikované v rôznych situáciách. Jednými z najproblematickejších vstupných dát takýchto modelov patria vlastnosti odevu – tepelná izolácia, faktor oblasti prekrytia oblečením a odpor odevu proti vyparovaniu, ktorých nepresné hodnoty môžu spôsobiť veľké nepresnosti vo finálny predikciách týchto modelov. Napriek tomu že meranie tepelnej izolácie odevu pomocou tepelných manekýnov je už zavedené, spoľahlivé a presné, to isté nie je možné povedať o meraní odporu odevu proti vyparovaniu, ktoré je stále vo svojich začiatkoch. Cieľom tejto práce bolo vyvinúť a implementovať experimentálne zariadenie, procedúru merania a spôsob kalkulácie pre získanie odporu odevu proti vyparovaniu pomocou manekýna NEWTON-a na VUT v Brne. Výsledky merania boli validované na základe dát nameraných pomocou manekýna TORE na Univerzite v Lunde. Reprodukovateľnosť merania bola na úrovni do 4 % rozdielu od strednej hodnoty takmer vo všetkých prípadoch. Výsledky ukazujú že je možné dosiahnuť dobrej reprodukovateľnosti merania pri striktnom dodržaní metodológie merania. Výsledky taktiež ukázali dobru opakovateľnosť merania, kedy bol dosiahnutý výsledok opäť na úrovni 4 % na oboch manekýnoch, čo je zároveň aj požadovaná hranica určená v normách pre meranie tepelnej izolácie odevu. Ďalším bodom práce bola verifikácia samotnej kalkulácie výparného odporu. Aj keď mass loss metóda určuje priamo intenzitu prenosu hmoty vyparovaním a najbližšie opisuje samotný jav vyparovania potu z ľudského tela, nie je vhodná pre určenie lokálnych hodnôt odporu proti vyparovaniu odevov z dôvodu technických limitácií senzorov a tepelných manekýnov. Z tohto dôvodu je použitá heat loss metóda, ktorej výpočet však musí byť korigovaný. Súčasťou práce bolo testovanie a verifikácia viacerých korekcií tejto metódy, čo môže byť prínosom výskumných pracovníkov z oblasti termofyziológie, keďže tieto lokálne hodnoty vlastností odevov sú pre dosiahnutie presných predikcii priam nevyhnutné. Úspešná implementácia a validácia možnosti merania odporu odevu proti vyparovaniu na VUT v Brne pomocou tepelného manekýna prináša taktiež nové možnosti pre ďalšie projekty a kooperácie v rámci výskumnej ci komerčnej činnosti Univerzity.
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Research of Systems for Providing the Quality of the Environment in the Car Cabin
Šíp, Jan ; Kavička, František (referee) ; Volavý, Jaroslav (referee) ; Lízal, František (advisor)
Optimal conditions of indoor environmental quality, especially thermal comfort and indoor air quality, are important because they lead to the active safety of passengers. Long-term exposure to inconvenient temperatures may cause thermal stress and negatively affects the driver’s cognitive functions. These include important abilities of drivers, such as concentration, vigilance, speed of decision-making and others. The inappropriate temperature in the cabin is one of the most dangerous factors causing car crashes. Air indoor quality is negatively affected by exhaust gases or particles from tire wear, which enter the car cabin during ventilation. This can be prevented by using an air recirculation system which does not supply outside air, but it is a closed circuit. This mode, however, causes high CO2 concentration in the cabin which can lead to excessive fatigue. This thesis deals with the influence of different ventilation systems on indoor environmental quality, i. e. thermal comfort and indoor air quality. A partial factor of thermal comfort is the flow field which was investigated downstream of a benchmark automotive vent. CFD was applied to determine the flow field downstream of a vent. The results were validated by experimental data acquired by Constant Temperature Anemometry. CFD has been also used for the evaluation of the thermal comfort of three novel ventilation systems (mixing, ceiling and floor ventilation). The results were validated by experimental data acquired by thermal manikin and climate chamber. Indoor air quality has been evaluated based on the Age of Air. The analytical empirical equation by Rajaratnam can be successfully used also to determine the throw of the jet, which is favorable, especially in light of the fact that both computational methods were not very accurate in velocity decay predictions. The Large Eddy Simulation and Reynolds-averaged Navier–Stokes method are suitable for evaluating the flow field downstream of the automotive vent. The diagrams of comfort zones were evaluated for all regimes based on equivalent temperatures. The best performance in terms of the highest level of human comfort was achieved by the ceiling ventilation in the summer conditions and by the floor ventilation in the winter conditions. From the point of view of the Age of Air, the ceiling air ventilation system is the most suitable for the winter conditions. In the summer conditions the Age of Air values for individual air ventilation concepts are very similar for both interior types.
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Heat transfer from the surface of the human body - validation of a CFD thermal manikin model
Kuruc, Jan ; Pokorný, Jan (referee) ; Fišer, Jan (advisor)
This master thesis is focused on CFD simulation of heat transfer from a thermal manikin in a calibration environment and its subsequent validation based on the experiments already performed in the master thesis of Ing. Fojtlín and Ing. Hrubanová. The main objective of the work is to find and test a suitable combination of physical models and set boundary conditions in the simulation model so that the actual heat transfer and airflow processes from the validation experiments are faithfully simulated. In the course of the work, 7 cases were simulated based on individual measurements made during the experiments. The calculated heat transfer coefficients of the thermal mannequin segments for each simulated case can be considered as the main results of the simulation. For the experiment of Ing. Fojtlín, these are the heat transfer coefficients by radiation and convection. For the experiment of Ing. Hrubanová, the total heat transfer coefficients for a manikin with five selected clothing assemblies were determined. Validation was performed by comparing the simulated and experimentally determined values of heat transfer coefficients. Based on the comparison, the developed simulation model could be declared validated.
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Ventilated protective clothing for healthcare staff in contaminated environments
Štenclová, Kristýna ; Kopečková, Barbora (referee) ; Fišer, Jan (advisor)
Focus of the masters thesis is experimental verification of cooling effect of ambient air stream directed under a protective clothing of a human. The first part is a review of literature encompassing concepts related to thermal comfort and heat transfer. Possibilities of cooling a human who is moving in high ambient temperature environment are introduced in this part. The second part is focused on hypotheses devised and experiments performed. The last part is focused on results of the experiments and their comparison with an experiment described in literature.
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