Radiators provide thermal management for components in electronic or mechanical equipment that cannot dissipate heat sufficiently to moderate temperatures. For example, they are used to cool the central processing unit (CPU) and graphics processing unit (GPU), power transistors, and other high-power semiconductor devices in computers, as well as optoelectronic devices such as lasers and LEDs. Radiators protect critical components from damage or performance loss by dissipating heat.
The design and function of the radiator vary depending on the configuration of the device. Usually, they transfer heat from high-temperature components through low-temperature fluid media (air or liquid coolant). They are designed to have the maximum surface area in contact with the cooling medium. Due to natural conduction, heat moves into the medium through the radiator, and natural conduction occurs when the ambient temperature is lower than the radiator temperature. The fluid passes through the surface of the radiator and moves heat from the surface to the environment through thermal diffusion and convection. A larger surface area can enhance this ability.
Types of radiators: passive, active, and hybrid
Passive radiators work through natural convection. Buoyant hot air generates airflow in the system. The advantage of a passive radiator system is that it does not require a secondary power source or control system to operate.
Compared to passive systems, active radiators are more effective in reducing heat. They use forced air generated by the movement of fans, blowers, or equipment itself to increase the fluid flow through the hot area. An example is when the fan in a computer turns on when the computer gets hot. The fan forces unheated air through the surface of the radiator, allowing more heat to be expelled from the overall system.
The hybrid heat sink combines certain aspects of passive and active heat sinks. The temperature requirement determines the operation mode of the system. When the temperature is low, the system relies on passive cooling. When the temperature reaches a certain level, forced air (active cooling) is activated to improve the cooling capacity of the radiator system.
Heat sink material
The thermal conductivity of a radiator depends on its material. The radiator material absorbs heat energy and transfers it to the environment to achieve efficient cooling. They require high heat capacity and thermal conductivity. Aluminum and copper are usually used because they have high conductivity.
Aluminum alloys 6060, 6061, and 6063 are commonly used for heat sinks due to their thermal conductivity values. These values depend on the tempering of the alloy. Tempering is a heat treatment technique that increases the toughness of an alloy by reducing its hardness.
Copper has twice the thermal conductivity of aluminum and is resistant to corrosion and biological pollution. It also has antibacterial properties. However, copper has a density three times that of aluminum, is more expensive, and has poorer ductility.
Market and Applications:
Automobiles, consumer electronics, data communication and telecommunications, industrial, medical, military and aerospace, transportation electronics, including computers (CPU and GPU), vehicles (electric vehicle controllers), battery packs, telecommunications.
