In this book, design, fabrication and testing of instant-cooling system in vehicles is performed using liquid nitrogen. When the vehicle is parked in an open environment especially in summer season, the inner atmosphere gets warmer and results in human discomfort, it finds the solution as air- conditioner is used for reduction of human discomfort but it has limitations also that it takes almost 7-8 minutes to cool the inner environment and within this time person feels discomfort. In such a situation, a system for instant cooling with liquid nitrogen is designed. The use of liquid nitrogen increases the cooling efficiency of vehicle as well as reduces the time for cooling to 2-3 minutes, which results in the increment of human comfort.