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Multicriterial Tool for Analysis and Predict Human Thermal Stress
Řehák Kopečková, Barbora ; Soukup,, Radek (referee) ; Kolářová,, Jana (referee) ; Jícha, Miroslav (advisor)
The thesis is concerned with the development of a multi-criteria tool capable of determining, for given input conditions, the most appropriate model for predicting the thermal state of a person in a protective suit, based on developed objective decision scheme. Four heat stress indices or physiological models were selected for the development of this tool: PHS (Predicted Heat Strain), IPHS (Individual Predicted Heat Strain), Gagg's 2-node model and the FMTK model. The algorithms of PHS, IPHS and Gagge were implemented in Matlab. Subsequently, all 4 models were validated against the experimental results. Based on the results of the validations, the applicability of these models for predicting human heat stress was verified. For some models, the applicability conditions were possible to extend. The accuracy of rectal temperature prediction was the main criteria. Furthermore, based on the results of the validation studies, metrics were selected to build an objective decision system. This was used to select the most appropriate model for the given environmental conditions. In the cooperation with SÚJCHBO, the data for model validation were delivered: 140 tests were carried out for 4 protective suits (FOP, Tyhem, Tiger, OPCH) and 4 ambient temperatures (-10, 5, 25 and 35 °C). 12 test persons were involved, 6 male test persons aged 29-53 years, 170-187 cm tall and weighing 69-92 kg, and 6 female test persons aged 28-49 years, 158-176 cm tall and weighing 56-71 kg. In total, 1987 simulations have been carried out using selected models, for different initial values of rectum and skin temperature, and for different estimates of metabolic activity. A look-up table was created to find the most appropriate model for the given conditions according to the inputs to the multicriteria tool via a decision scheme, based on the evaluation of the results of the simulations against the experiments in terms of the MAE (Mean Absolute Error) and the difference between the predicted and measured rectal temperature at the end of the test. Finally, the resulting multicriteria tool was created in Excel, including a graphical interface for entering values.
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Metabolic activity and possibilities of its prediction
Štrbík, Tomáš ; Pokorný, Jan (referee) ; Řehák Kopečková, Barbora (advisor)
Metabolic rate is a set of processes in the body that convert food into energy and building materials, allowing us to grow, move, and maintain health. Therefore, it is important, and in some cases of illness also necessary, to monitor this variable. Various methods have been developed to quantify metabolic rate. The most accurate results come from direct measurements, which are often unavailable or too expensive, and are therefore primarily used for medical and scientific purposes. As an alternative, estimation methods based on easily measurable variables offer a more practical approach in everyday practice. This work discusses the different methods of determining metabolic rate and the various factors that influence it. Finally, one of these estimation methods is applied to available data. After comparing the measured and estimated values, a MAPE value of up to 11% was achieved during the performed activity, while during rest, this value reached up to 154%.
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Dynamic model of a heat pump with plate heat exchangers and ecological refrigerant
Strmiska, Pavel ; Řehák Kopečková, Barbora (referee) ; Pokorný, Jan (advisor)
For the optimization of a heat pump, there is a need to possess its dynamic model. One of the freely available tools for creating such a model is the language Modelica and its open-source compiler OpenModelica. The thesis aims to research options for creating dynamic models of refrigeration circuits with the ecological refrigerant R290 and its components in Modelica, to create the circuit and subsequently validate it using previously measured data. Models of basic components of heat pumps - compressor, condenser, evaporator and expansion valve are created in a way described in the thesis. A simplified model of a refrigerant loop is also created
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Validity of commercially available smartwatches when estimating energy expenditure
Kopecký, David ; Pokorný, Jan (referee) ; Řehák Kopečková, Barbora (advisor)
Metabolic rate is an energy quantity. Its value is a key input not only in thermophysiological models, but also in the calculation of heat stress indices or complex models predicting a person's thermal sensation. With the dynamic development of technology, sporttesters are able to estimate energy expenditure, among other things. It is a non-invasive method of estimating energy expenditure, or metabolic rate, using associated body functions to predict it. This work deals with the validity of the accuracy of metabolic rate estimation using the Garmin Fenix 6X Pro sporttester in comparison with indirect calorimetry. The accuracy of the metabolic rate estimation was tested for the activities of lying down, administrative work and cycling with regulated mechanical resistance of 100 and 150 W. 15 male subjects aged 28 ± 5 years, with a weight of 83.2 ± 13.5 kg and a height of 180 ± 7 cm participated in the study. In terms of the results, it is possible to observe a lower accuracy of prediction of metabolic rate for low-intensity activities, with the resulting MAPE being around 19-43 %. On the other hand, for activities with moderate activity, the prediction of the metabolic rate by the used sporttester proved to be sufficiently accurate, with a resulting MAPE in the range of 6–8 %.
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Models for predicting the thermal sensation and thermal comfort of a person
Nahácky, Marek ; Pokorný, Jan (referee) ; Kopečková, Barbora (advisor)
The bachelor thesis is focused on mapping of the current development of thermophysiological models for prediction of human thermal sensation and thermal comfort in thermal environment. These models vary in broad spectrum of conditions of their use. The first part is dedicated to definition of terms thermal sensation and thermal comfort. The second part focuces on comparison and more precise description of chosen thermophysiological models. At the end it was made a summarizing table of inputs and outputs of these models for prediction.
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A method for the solution of non-spherical (fiber) particles deposition by means of the Fokker-Planck equation for ODF in a laminar flow
Kopečková, Barbora ; Knotek, Stanislav (referee) ; Jícha, Miroslav (advisor)
The Bachelor's thesis deals with a deposition efficiency for a fibers by various mechanisms of a deposition. It explains deposition efficiency by diffusion, by sedimentation and by impaction. The implementation of Peterlin's analytical solution for calculation of the ODF, which is used for individual efficiencies solution, is also mentioned. Afterwards, the thesis summarizes formulas for calculation of particular efficiencies derived for spherical particles and recomputation appropriate parameters for fibers. The purpose of the thesis is to create graphs, which illustrate deposition efficiencies dependence by various mechanisms on the aspect ratio of fibers. Another goal is the graphs creation, which shows juxtaposition for various breathing modes for given deposition mechanisms. The software MATLAB is used for the whole calculation process and graphs plotting.
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Comparison of CSR Concepts in selected Companies
Kopečková, Barbora ; Králíková, Alena (referee) ; Putnová, Anna (advisor)
This diploma thesis focuses on the application of the concept of social responsibility in business practice of the companies ČSOB, a. s., Raiffeisenbank a. s. a Tesco SW, a.s. This application is based on mentioned theoretical foundations and qualitative research. The thesis also analyzes and evaluates the implementation of CSR strategy in chosen companies. The aim is to suggest activities to effective application of CSR philosophy for these companies.
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Method for the solution of conduction heat transfer in Phase change material with nanoparticles
Kopečková, Barbora ; Knotek, Stanislav (referee) ; Jícha, Miroslav (advisor)
This master thesis deals with problematic of the heat convection in phase change materials (PCM) and PCM with nanoparticles. The derivation of stationary and non-stationary equations for 1D, 2D and 3D heat convection are described in detail. The finite element volume method is used for solution to these equations, of which principle is described carefully. The aim of this thesis is model development for 2D solution to temperature distribution at heat convection in PCM and influence assessment of nanoparticle implementation into material on given temperature distribution. Software MATLAB was used for model development, solution and plotting graphs.
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Modern technologies in thermal management of passenger vehicles with alternative drivetrain
Janíčková, Žaneta ; Kopečková, Barbora (referee) ; Fojtlín, Miloš (advisor)
This bachelor thesis is focused on the assessment of the current state of modern technologies in thermal management of passenger vehicles with alternative drivetrain. The main part of the work is based on the research into advanced systems aimed at minimizing the thermal load of the passengers and at ensuring the thermal comfort in the car cabin through various forms of the heat transfer. The study deals with reversible heat pump, photovoltaic solar panels, thermoelectric Peltier device, infrared heating, heat pipe and magnetocaloric cooling. Technologies are described from the point of view of the theoretical principle of operation, further, there are mentioned benefits and limitations of the system and the application of the technology in vehicles. Finally, a calculation of the energy demands of resistance heating as well as reversible and magnetocaloric heat pump for winter and summer operation is created for illustrative purposes. In addition to that, improvements of available systems and the potential use of prototype technologies, that can significantly contribute to reducing energy consumption while providing the required thermal comfort, are proposed at the end of the thesis.
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Verification of metabolism prediction based on performed activity
Kopecký, David ; Pokorný, Jan (referee) ; Kopečková, Barbora (advisor)
Nowadays, metabolic rate or energy expenditure in general is one of the most discussed topics, especially in connection with a healthy lifestyle. Nevertheless, the metabolic rate can be used as a relatively accurate indicator of physical or thermal load as well. Usually, the value of metabolic rate is used as input into various physiological models. These models estimate the body’s thermal stress, for instance when working in a protective suit. The thesis deals not only with tabulated values of metabolic rate, but it also focuses on the accuracy of estimated metabolic rate using simple measuring devices. The Apple Watch Series 4 smartwatch, the Garmin Fenix 6 Pro Glass sports tester, and the Fitbit Inspire smart sports bracelet were used for the measurements published in the thesis. The results of the measurements show that contemporary sports testers are still inappropriate for use in healthcare or elite sports.
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