Control Techniques for Greenhouse Phenomena in Car Cabins to Enhance Fuel Consumption, Emission Reduction, and Air Quality: A Review

This review paper examines various technologies that aimed at reducing the interior temperature of car cabins when parked under direct sunlight. The key technologies explored include solar ventilation, phase change materials (PCM), electric glazing, car covers, heat pipes, car color selection, and insulation. These technologies are designed with several critical objectives in mind. Firstly, they aim to enhance air quality within car cabins, a concern of growing importance as rising cabin temperatures have been shown to increase emissions of volatile organic compounds (VOCs) from interior materials by 3 to 36 times. Secondly, they address a significant safety issue: vehicular heatstroke, which tragically results in the death of approximately 40 children annually in the USA, with similar figures reported globally. Furthermore, these technologies contribute to preserving the integrity of car cabin materials, improving fuel efficiency, and reducing pollutants. For instance, studies indicate that the use of solar ventilation systems can lead to a 38% reduction in fuel consumption and a 36% decrease in CO2 emissions during idle states. The review also delves into the phenomenon of cabin hot soaking, where car interiors can exceed ambient temperatures by 20 to 30 °C, with peak temperatures surpassing 80 °C. It highlights the effectiveness of certain methods, such as solar ventilation, PCM, reflecting glass, and car covers, in reducing cabin temperatures by over 15 °C. On the other hand, technologies like solar chimneys, heat pipes, and heat exchangers face practical challenges due to their size and weight, limiting their widespread application. Additionally, methods like insulation, cracked windows, and sunroofs are found to be less effective, typically achieving reductions of no more than 5 °C. The methodology of this review includes setting inclusion and exclusion criteria, gathering data from various sources, identifying relevant information, and conducting data extraction along with rigorous evaluation. Our review stands out by comprehensively analyzing multiple critical aspects. Beyond examining the impact of greenhouse phenomena on cabin temperature and fuel consumption, our focus extends to air quality, a crucial health consideration, particularly in enclosed spaces like car cabins, where volatile organic compounds (VOCs) can pose significant risks. This approach offers a unique synthesis across various dimensions of vehicle cabin environment management, providing valuable insights into the interactions between greenhouse effects, fuel efficiency, and human health.