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Abstract(s)
A crescente adoção de veículos elétricos (EV) representa uma mudança significativa para a mobilidade sustentável, mas traz desafios complexos de engenharia na conceção de sistemas eficientes de Aquecimento, Ventilação e Ar Condicionado (AVAC). Os EV, ao contrário dos veículos com motor de combustão interna (ICE), dependem exclusivamente da energia elétrica para a propulsão e para o controlo da climatização da cabina, o que exige uma otimização cuidadosa da energia para aumentar a autonomia e o conforto dos passageiros. O presente estudo tem como objetivo realizar uma análise térmica ao habitáculo de um veículo elétrico, através de uma ferramenta de Dinâmica de Fluidos Computacional (CFD), de modo a ser possível determinar quais as suas cargas térmicas. O veículo em causa (Veeco RT) trata-se de um pequeno veículo desportivo, com dois lugares, e uma configuração reverse trike, originando menores áreas das superfícies envolventes. Inicialmente, efetuou-se o estudo para a situação do veículo estacionado, exposto ao sol. A temperatura aqui obtida é a máxima alcançada, 56,5 °C, e representa o ponto de partida para os restantes estudos. Ainda com o sistema de AVAC desligado, realizaram-se simulações alterando a velocidade do ar exterior para 50 km/h e 120 km/h, de modo a se conseguir fazer uma relação entre a velocidade e a temperatura no interior do habitáculo. De seguida, foram realizados os estudos com o sistema de AVAC ligado, a diferentes velocidades de ar nas saídas de ar arrefecido, alterando o número das mesmas de 2 para 4 e 6. Ainda foi simulada a abertura das janelas no início da condução através do cálculo de renovação de ar, de modo a perceber a sua influência nos resultados, diminuindo o tempo necessário para alcançar conforto térmico até 81,7%. Os estudos realizados permitiram verificar que a temperatura máxima foi de 56,5 °C, quando este estava estacionado. Para alcançar os 25 °C determinados como temperatura de conforto térmico, demorou-se 27 min com o ar condicionado ligado e o veículo a deslocar-se a 50 km/h. Ao abrir as janelas, este tempo reduz para 18 min, nas mesmas condições. Aumentando as saídas de ar, tanto para 4 e 6, foi possível reduzir este tempo para a ordem dos 25 s. Com os resultados obtidos, ainda foi possível determinar a potência de arrefecimento necessária, 1768,4 W térmicos, para se alcançar equilíbrio e conforto térmico no habitáculo. Foi realizada a seleção dos componentes principais de um ciclo frigorífico para um sistema de climatização possível de aplicar no veículo em estudo.
The growing adoption of electric vehicles (EV) represents a significant shift towards sustainable mobility but brings complex engineering challenges in the design of efficient Heating, Ventilation and Air Conditioning (HVAC) systems. EVs, unlike internal combustion engine (ICE) vehicles, rely exclusively on electrical energy for propulsion and cabin climate control, which requires careful optimization of energy to increase autonomy and passenger comfort. The aim of this study is to carry out a thermal analysis of the passenger compartment of an electric vehicle, using a Computational Fluid Dynamics (CFD) tool, to determine its thermal loads. The vehicle in question (Veeco RT) is a small sports car with two seats and a reverse trike configuration, resulting in smaller surface areas. Initially, the study was carried out in the situation of a parked vehicle exposed to the sun. The temperature obtained here is the maximum reached, 56.5 °C, and represents the starting point for the remaining studies. Still with the HVAC system switched off, simulations were carried out by changing the outside air speed to 50 km/h and 120 km/h, to establish a relationship between the speed and the temperature inside the cabin. Next, studies were carried out with the HVAC system on, at different air speeds in the cooling vents, changing the number of vents from 2 to 4 and 6. Opening the windows at the start of the drive was also simulated by calculating air renewal, to understand its influence on the results, reducing the time needed to achieve thermal comfort by up to 81.7%. The studies carried out showed that the maximum temperature was 56.5 °C when the car was parked. To reach the 25 °C determined as the thermal comfort temperature, it took 27 min with the air conditioning on and the vehicle traveling at 50 km/h. Opening the windows reduced this time to 18 minutes under the same conditions. By increasing the air vents to 4 and 6, it was possible to reduce this time to around 25 seconds. With the results obtained, it was also possible to determine the cooling power required, 1768.4 W thermal, to achieve balance and thermal comfort in the cabin. The main components of a refrigeration cycle were selected for a climate control system that could be applied to the vehicle under study.
The growing adoption of electric vehicles (EV) represents a significant shift towards sustainable mobility but brings complex engineering challenges in the design of efficient Heating, Ventilation and Air Conditioning (HVAC) systems. EVs, unlike internal combustion engine (ICE) vehicles, rely exclusively on electrical energy for propulsion and cabin climate control, which requires careful optimization of energy to increase autonomy and passenger comfort. The aim of this study is to carry out a thermal analysis of the passenger compartment of an electric vehicle, using a Computational Fluid Dynamics (CFD) tool, to determine its thermal loads. The vehicle in question (Veeco RT) is a small sports car with two seats and a reverse trike configuration, resulting in smaller surface areas. Initially, the study was carried out in the situation of a parked vehicle exposed to the sun. The temperature obtained here is the maximum reached, 56.5 °C, and represents the starting point for the remaining studies. Still with the HVAC system switched off, simulations were carried out by changing the outside air speed to 50 km/h and 120 km/h, to establish a relationship between the speed and the temperature inside the cabin. Next, studies were carried out with the HVAC system on, at different air speeds in the cooling vents, changing the number of vents from 2 to 4 and 6. Opening the windows at the start of the drive was also simulated by calculating air renewal, to understand its influence on the results, reducing the time needed to achieve thermal comfort by up to 81.7%. The studies carried out showed that the maximum temperature was 56.5 °C when the car was parked. To reach the 25 °C determined as the thermal comfort temperature, it took 27 min with the air conditioning on and the vehicle traveling at 50 km/h. Opening the windows reduced this time to 18 minutes under the same conditions. By increasing the air vents to 4 and 6, it was possible to reduce this time to around 25 seconds. With the results obtained, it was also possible to determine the cooling power required, 1768.4 W thermal, to achieve balance and thermal comfort in the cabin. The main components of a refrigeration cycle were selected for a climate control system that could be applied to the vehicle under study.
Description
Dissertação para obtenção do grau de Mestre em Engenharia Mecânica
Keywords
Conforto térmico Veículo elétrico AVAC CFD Habitáculo automóvel Thermal comfort Electric vehicle HVAC Computational fluid dynamics Car cabin
Citation
NUNES, Tiago Luís - Análise térmica do habitáculo e estudo da solução de climatização de um veículo elétrico. Lisboa: Instituto Superior de Engenharia de Lisboa, 2023. Dissertação de Mestrado.