VAPOR CHAMBER HEATSINK

Vapor chamber cooling is a highly efficient technology in electronic devices and high-performance computing systems. It involves using a sealed chamber filled with a small amount of working fluid, which vaporizes when exposed to heat. This vapor then spreads evenly throughout the chamber, absorbing and dissipating the heat generated by the electronic components. 

Vapor chamber cooling offers several advantages over traditional cooling methods, including better heat transfer, reduced hotspots, and improved overall system performance. It is particularly beneficial in applications where space is limited or where there is a need for high thermal management capabilities.

The low pressure inside the chamber allows the fluid to vaporize at a temperature much lower than its normal boiling temperature. When heat is applied to the VCH, the fluid near that location immediately vaporizes and rushes to fill the entire volume of the chamber (driven by pressure difference). When the vapor comes into contact with a cooler wall surface, it condenses, and releases its latent heat of vaporization. The condensed fluid returns to the heat source by capillary action of the wick structure. As the vaporization and condensation cycle repeats, heat is moved for the heat source to the entire volume of the chamber, resulting in a uniform temperature distribution on its surface. The return of fluid to its boiling location is primarily driven by the capillary force, but gravity and centrifugal force can also contribute to some degree. To utilize the external forces, it is important to design the vapor chamber, such that the gravity or centrifugal force, is working in the direction that drives the fluid from its cold side to the hot side. For example, in a spinning system, the heat source (hot spot) should be located in the outer side of the PCB, and the fins should be located closer to the spinning center.

Radian Thermal Products specializes in two-phase cooling technology, known for its superior heat transfer capabilities compared to traditional cooling methods. The process is a combination of liquid and vapor phases that efficiently dissipate heat to maintain optimal operating temperatures.

One of the key advantages of our two-phase cooling solutions is the ability to handle high heat loads without compromising performance. Whether you require cooling for industrial equipment, data centers, or electronic devices, our two-phase cooling solutions can handle the most demanding thermal management requirements.

We offer a wide selection of cooling systems, including impingement cooling, direct-to-chip cooling, and cold plate cooling, among others. Our team of engineers works closely with you to understand your specific cooling requirements and recommend the most suitable solution for your application.

A vapor chamber thermal system is a cooling mechanism that utilizes the principles of phase change to transfer heat away from a heat source. It consists of a sealed copper chamber filled with a small amount of water. The chamber contains a wick structure that helps circulate the working fluid.

The vapor chamber thermal system operates on the principles of evaporation and condensation. When the heat source, such as a high-performance processor or graphics card, generates heat, the water in the chamber absorbs this heat and evaporates. The vapor then moves towards the cooler part of the chamber, where it condenses back into liquid form, releasing the accumulated heat. This cycle continues if there is a temperature difference between the heat source and the cooling fins or heat sink.

The effective thermal conductivity of vapor chambers is usually 5 to 100 times the conductivity of copper – but it is application specific. The thermal resistance of a VCH comes from many sources. The two major factors are the evaporation resistance and transport resistance. Transport resistance is distance dependent, but it is relatively small compared to the evaporation resistance. Since the dominating evaporation resistance is independent of size, the larger the VCH is compared to the heat source, the greater is the effective thermal conductivity. In a coarse calculation or CFD simulation, it is not uncommon that a uniform and isotropic thermal conductivity, say 10000 W/m-K which is 25 times the thermal conductivity of copper, is assigned to the entire volume of the vapor chamber.

Like heat pipes, vapor chambers are very reliable thermal devices. They do not have any moving parts or use any corrosive materials. The working fluid and wick structures are permanently sealed in a copper vessel. There is no mechanical or chemical degradation over time that has been reported by Radian customers. The following tests are routinely performed to confirm the durability and reliability of vapor chambers:

The following table shows the suggested operation conditions for typical applications. They are not necessarily the maximum capabilities of vapor chambers.

Want to optimize the cooling of your electronics? Use our handy heatsink calculator to find the perfect solution for your needs.