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Assesment of the Thermal Environment in Vehicular Cabins
Fojtlín, Miloš ; Khoury, Roch El (oponent) ; Havenith, George (oponent) ; Jícha, Miroslav (vedoucí práce)
People in developed countries spend substantial parts of their lives in indoor environments both during free time and while working. For this reason, there has been increasing interest in the quality of the indoor environment. The main emphasis of past research has been directed towards understanding the fields of human health, productivity, and comfort. One important contributor to all three fields is the thermal aspect of the environment, which is often represented by physical quantities such as air temperature, radiant temperature, air humidity, and air velocity. While weather-independent control of these parameters is possible via heating, ventilation, and air-conditioning systems (HVAC), a major limitation is that these systems are related to substantial energy consumption and carbon footprint. The complexity of thermal management is amplified in vehicular cabins because of their asymmetric and transient nature. Moreover, in electric vehicles, the available energy for microclimate management comes at the cost of driving range, and therefore, new solutions for more effective and human-centred ways of managing the indoor microclimate are sought. One of the promising ways to address these issues is via local conditioning with the vehicle seats or auxiliary radiant panels operating in synergy with an HVAC unit. At the same time, the optimization and research tasks are being shifted towards virtual investigation to mitigate the need for costly and often ethically concerning human studies. To do so, models of human thermo-physiology and thermal sensation/comfort have been developed. Yet, for their reliable applications, many factors regarding high heterogeneity, clothing, the thermal mass of the adjacent surfaces, and active seat conditioning have not been resolved. The aim of this thesis was to develop a methodology to assess human thermal sensation while in a sitting body position, including local conditioning factors such as heated and ventilated seats. A requirement of the method was applicability in both virtual and real indoor spaces. In the latter case, the focus was a thermal-sensation-driven feedback loop allowing for human-centred microclimate management. The validity of the proposed methodology was demonstrated under typical cabin conditions (5–41 °C) and the findings from this PhD project are transferable to a broad variety of engineering fields. In passenger transport and occupational environments with higher heat strain, environmental engineers can benefit from a tool to identify sources of thermal discomfort and potential hazards of fatigue. Furthermore, the methodology can be of great merit to the rapidly developing electric vehicle industry, facilitating emphasis on energy efficient microclimate management. The virtual optimization of the conditioning strategies reduce the need for human studies, allow rapid prototyping, and have great potential to bring energy savings as well as increased driving range. Finally, the know-how presented is also applicable in built environments, where similar conditions apply.
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Assesment of the Thermal Environment in Vehicular Cabins
Fojtlín, Miloš ; Khoury, Roch El (oponent) ; Havenith, George (oponent) ; Jícha, Miroslav (vedoucí práce)
People in developed countries spend substantial parts of their lives in indoor environments both during free time and while working. For this reason, there has been increasing interest in the quality of the indoor environment. The main emphasis of past research has been directed towards understanding the fields of human health, productivity, and comfort. One important contributor to all three fields is the thermal aspect of the environment, which is often represented by physical quantities such as air temperature, radiant temperature, air humidity, and air velocity. While weather-independent control of these parameters is possible via heating, ventilation, and air-conditioning systems (HVAC), a major limitation is that these systems are related to substantial energy consumption and carbon footprint. The complexity of thermal management is amplified in vehicular cabins because of their asymmetric and transient nature. Moreover, in electric vehicles, the available energy for microclimate management comes at the cost of driving range, and therefore, new solutions for more effective and human-centred ways of managing the indoor microclimate are sought. One of the promising ways to address these issues is via local conditioning with the vehicle seats or auxiliary radiant panels operating in synergy with an HVAC unit. At the same time, the optimization and research tasks are being shifted towards virtual investigation to mitigate the need for costly and often ethically concerning human studies. To do so, models of human thermo-physiology and thermal sensation/comfort have been developed. Yet, for their reliable applications, many factors regarding high heterogeneity, clothing, the thermal mass of the adjacent surfaces, and active seat conditioning have not been resolved. The aim of this thesis was to develop a methodology to assess human thermal sensation while in a sitting body position, including local conditioning factors such as heated and ventilated seats. A requirement of the method was applicability in both virtual and real indoor spaces. In the latter case, the focus was a thermal-sensation-driven feedback loop allowing for human-centred microclimate management. The validity of the proposed methodology was demonstrated under typical cabin conditions (5–41 °C) and the findings from this PhD project are transferable to a broad variety of engineering fields. In passenger transport and occupational environments with higher heat strain, environmental engineers can benefit from a tool to identify sources of thermal discomfort and potential hazards of fatigue. Furthermore, the methodology can be of great merit to the rapidly developing electric vehicle industry, facilitating emphasis on energy efficient microclimate management. The virtual optimization of the conditioning strategies reduce the need for human studies, allow rapid prototyping, and have great potential to bring energy savings as well as increased driving range. Finally, the know-how presented is also applicable in built environments, where similar conditions apply.
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