Compact Autonomous Cooling Vehicle

System Architecture & Control

The "brain" of the system is the Arduino Nano, which processes commands from a user's mobile device via an HC-05 Bluetooth module.

Movement Control: An L298N motor driver manages four DC brushed gear motors to enable forward, backward, and directional turning.

Cooling Control: An L293D motor driver is used specifically to regulate the speed of the cooling fan using Pulse Width Modulation (PWM) signals.

Power Management: The system is powered by two Li-ion batteries connected in series, with a common ground to prevent electrical noise.

Cooling Mechanism

The vehicle utilizes an evaporative cooling setup designed for space efficiency and portability.

Evaporator Coil: A coiled copper tube (eight turns) where isobutane refrigerant expands, causing a significant drop in temperature.

Heat Rejection Section: A smaller copper coil (three turns) that stabilizes the refrigerant's pressure and temperature before it reaches the expansion stage.

Capillary Tube: A 20 cm tube with a 0.8 mm internal diameter that creates the necessary pressure drop for effective cooling.

12V Air Pump: Unlike a standard fan, this pump provides forced air displacement to move air through the confined passages of the cooling assembly.

3. Practical Applications

The project is designed as a prototype for Smart Cold-Chain Logistics, capable of transporting heat-sensitive cargo:

Medical/Laboratory: Transporting biological cultures, vaccines, blood samples, or sensitive chemical reagents.

Commercial: Delivering chilled beverages, gourmet chocolates, or fresh sushi.

Hardware Protection: Carrying high-power lasers or thermal cameras that require active cooling to function accurately.