Design and Analysis of Solar-Powered Automatic Thermoelectric Cooling System for Automobile Cabin

Abstract

The cabin temperature of a closed stationary vehicle in direct sunlight can quickly rise to a level that may damage property and harm children or pets left in the vehicle. The problem that is faced by many car users today is a hot interior after certain minutes or hours of parking in un shaded parking areas. A primary goal of cabin thermal management design is to minimize vehicle energy use while achieving a high level of passenger comfort. Vehicle heating, ventilation, and air-conditioning (HVAC) systems exert a large power demand on the vehicle’s engine and battery, which can lead to reduced fuel economy. But, when the car is parked it is not economical to use the system provided by the manufacturers to start the air conditioner as it requires the engine to remain “ON'' to match the power required. This is not economical at all. Thus, the idea of using the car's inbuilt air conditioner to cool the car while it's parked is dropped, and decided to build a new cooling system to cool the cabin and be economical at the same time which runs on solar power. In addition, for a parked car, the cooling system should be automatic as there is no one to detect the heat and run the cooling system. This problem is solved by designing a solar-powered automatic thermoelectric cooling system for automobile cabins. The heat gain by the car cabin parked in direct sunlight is analytically estimated. Heat sinks and thermoelectric modules are designed. For the optimization of the design of the thermoelectric module and the heat sinks, Mathcad software has been used. The aerodynamic effect of the cooling system for the car has also been assessed using ANSYS FLUENT 19.3. A demo is made with a 1:8 reduction scale from aluminum sheet metal of thickness 0.8 mm as the body material. Carton having a thickness of 0.2 mm has been used as an insulating material from inside. For demonstration, the TEC1-12706 module, CPU cooling fans, and aluminum heat sinks are also used. From the design, the TEC module whose optimum cooling capacity is 37.8 W obtained. Eight TEC modules each with two heat sinks and cooling fans are used for the cooling system. The total cooling capacity of the thermoelectric cooling system is 267.24 W. In general, the cooling system can have a significant role in reducing the rate of temperature rise of cabin air. The increase in the aerodynamic drag coefficient due to the assembly of the thermoelectric cooling system to the car is 0.73%. From the demonstration of the thermoelectric cooling system, the cabin air temperature of the model is found to be lower by more than 3 ℃ when the cooling system was running.