Assesment of the Thermal Environment in Vehicular Cabins
Loading...
Date
Authors
ORCID
Advisor
Referee
Mark
P
Journal Title
Journal ISSN
Volume Title
Publisher
Vysoké učení technické v Brně. Fakulta strojního inženýrství
Abstract
Ľudia žijúci vo vyspelých krajinách trávia väčšinu svojho života vo vnútorných prostrediach budov alebo dopravných prostriedkov. Z tohto dôvodu, záujem o výskum kvality vnútorných prostredím rastie, pričom hlavný dôraz je kladený na oblasti výskumu ľudského zdravia, produktivity a komfortu. Jedným z faktorov ovplyvňujúci kvalitu prostredí je ich tepelný aspekt, ktorý je najčastejšie popísaný teplotou vzduchu, radiačnou teplotou, vlhkosťou vzduchu a rýchlosťou prúdenia vzdu-chu. Zatiaľ čo tieto parametre je možné riadiť systémom pre vykurovanie, vetranie a klimatizáciu nezávisle na počasí, takéto zariadenia sa podieľajú na vysokej spotrebe energie a značnej uhlíkovej stope. V prostediach kabín áut a dopravných prostriedkov je riadenie parametrov tepelného prostredia komplikované z dôvodu ich asymetrickej a časovo premenlivej povahy. Táto situácia je obzvlášť kritická vo vozidlách na elektrický pohon s vlastnou batériou, kde je energia na úpravu vnútornej mikroklímy čerpaná na úkor dojazdu vozidla. Pre uvedené dôvody sa hľadajú nové, en-ergeticky účinnejšie spôsoby pre úpravu tepelných prostredí a zabezpečenia tepelného komfortu. Jedným z potenciálnych riešení sú zariadenia dodávajúce človeku teplo alebo chlad lokálne, ako napríklad vyhrievané a vetrané sedadlá a sálavé panely. Vzhľadom na to, že experimentálny výskum vnútorných prostredí je náročný s ohľadom na čas a potrebné vybavenie, trendy výskumu vplyvov takýchto zariadení na človeka smerujú k optimalizačným úlohám vo virtuálnych prostrediach pomocou modelov ľudksej termofyziológie a tepelného pocitu/komfortu. Avšak pre spoľahlivé výsledky modelovania sú potrebné presné vstupné parametre definujúce prostredie, odev, vplyv povrchov v kontakte s človekom (napríklad sedadlá) a pôsobenie systémov na lokálnu úpravu mikroklímy. Cieľom tejto dizertačnej práce je vytvorenie metodológie na hodnotenie tepelných prostredí v kabínach automobilov s ohľadom na pozíciu v sede a využitím technológii na lokálnu úpravu tepelných prostredí. Jedným z požiadavkov na takúto metodológiu je jej aplikovateľnosť vo virtuálnych ale aj reálnych prostrediach. V prípade hodnotenia reálnych prostredí, cieľom je vytvorenie demonštrátora, ktorý by bol využiteľný ako spätná väzba pre riadenie systémov pre úpravu mikroklímy na základe požadovaného tepeleného pocitu. Validita uvedenej metodológie bola demonštrovaná v typických podmienkach kabín automobilov (5–41 °C) a poznatky z tejto práce sú prenesiteľné do širokého spektra inžinierkych aplikácii. V oblasti osobnej dopravy a pracovných prostredí s vyššou tepelnou záťažou je táto metóda užitočná pre identifikáciu možných zdrojov diskomfortu. Navyše je táto metóda vhodná i pre rýchlo rastúci segment elektrických vozidiel, kde je možné sledovať tok energie potrebnej na dosiahnutie určitej úrovne komfortu a riešenie optimalizačných úloh za účelom úspory energie a predĺženie dojazdu. Obdobné aplikácie možno nájsť i v budovách a prostrediach s podobnými charakteristikami.
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.
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.
Description
Keywords
Modelování, Experiment, Vytápění, Větrání, Sedadlo, Člověk, Thermofyziologie, Fiala model, Equivalentná teplota, Odev, Pozice v sedu, Kabina, Vozidlo, Auto, Energie, HVAC, Tepelný pocit, Tepelný komfort, Modelling, Experiment, Heating, Ventilation, Seat, Human, Thermo-physiology, Fiala model, Equivalent temperature, Clothing, Seated position, Cabin, Vehicle, Car, Energy, HVAC, Thermal sensation, Thermal comfort
Citation
FOJTLÍN, M. Assesment of the Thermal Environment in Vehicular Cabins [online]. Brno: Vysoké učení technické v Brně. Fakulta strojního inženýrství. 2019.
Document type
Document version
Date of access to the full text
Language of document
en
Study field
Konstrukční a procesní inženýrství
Comittee
doc. Ing. Jiří Pospíšil, Ph.D. (předseda)
Dr. Roch El Khoury (člen)
Prof. George Havenith (člen)
doc. Ing. Jaroslav Machan, CSc. (člen)
doc. Ing. Vladimír Zmrhal, Ph.D. (člen)
Ing. Matěj Forman, Ph.D. (člen)
Bc. Jan Hrnčíř (člen)
Dr. Kamila Lunerová (člen)
doc. MUDr. Julie Dobrovolná, Ph.D. (člen)
doc. Ing. Petr Svoboda, Ph.D. (člen)
Date of acceptance
2019-10-18
Defence
Nadstandardní práce z oboru tepelného komfortu v kabině automobilu.
Result of defence
práce byla úspěšně obhájena
Document licence
Standardní licenční smlouva - přístup k plnému textu bez omezení