Two Phase Thermal Solution Guide

As electronics around the world demand more power functionality, and reliability, heat remains one of the major to barriers to achieving maximized performance and to realizing major innovations. Every industry, especially Mobile, Medical, Telecommunications and IoT are developing new applications that are lightweight, multi functional, high power, and required to be more reliable. Engineers are struggling to effectively handle excess heat as consumers demand smaller, thinner, more powerful devices with more options and capabilities.

Two phase cooling is rapidly gaining more popularity in solving these issues. These are technologies are especially ideal for heat spreading for faster dissipation, light weighting, higher reliability and lifetime, but their most significant benefit is design flexibility and the ability to easily integrate them into a system to vastly improve cooling efficiency and capacity. Active air cooling or liquid cooling alone are often too large and cumbersome and come with their own complications such as acoustics, weight, and vibration. By integrating or designing out more active components, two phase can also solve acoustic and vibration issues,

While most engineers are most familiar with heat pipes, which provide the benefits of to phase cooling in a more linear and very flexible for factor, there are several major types of two phase technologies that can handle more heat or feature their own specific benefits and features. Vapor chambers transfer heat in a planar geometry allowing for my uniform heat spreading. Thermosiphons do not require a wicking structure and can be more cost efficient by using gravity to move fluid. Meanwhile, Immersion Cooling is becoming more popular in high power markets as they can work with higher heat loads.

The following guide will touch on each of these technologies and the benefits and considerations when utilizing them to cool your applications.

The wicking structure allows vapor chambers and heat pipes to operate in any orientation, including against gravity with the evaporator higher than the condenser, with minimal effects on performance. This ability makes them ideal for mobile, portable, and consumer electronics that need to operate in various orientations including landscape, portrait and inverted.

In addition to multiple orientations, these solutions offer increased design flexibility for unique and high tolerance geometries. While heat pipes can be bent, flattened, and arranged to optimize heat transfer and flow; vapor chambers can accommodate various device heights and through holes for mounting. Utilizing alternate materials, such as titanium or stainless steel, increases the level of customization, offering better performance and key market differentiation.

As Boyd continues to innovate, our techniques have evolved to make the best use of design and materials to further enhance application performance and optimize size and weight. Boyd two-phase innovations incorporate new manufacturing processes and advanced additive manufacturing practices to further improve cost savings, ease of manufacture, design flexibility and overall thermal performance.

• Reaching an unprecedented level of wick customizations and performance matching to highly specific or varying application and user requirements.
• Proprietary methods for enabling unique and complex geometries in a way that traditional methods could not produce easily or with the required level of cost efficiency.
• Advanced manufacturing techniques to integrate multiple geometries and features in a single process to reduce fabrication times. This enables cost savings in labor and materials as well as shorter lead times.
• New and improved technologies such as Immersion Cooling Boiler Plates to Advanced Ultra Thin Vapor Chambers.
• The consideration and optimization given to thermal management has become a key selling point for many of our customers marketing new technologies. Heat is one of the final barriers to end-user device innovation.

Heat pipe assemblies combine the proven reliability of passive two phase heat transport with a variety of other thermal management technologies to generate effective, long lasting cooling solutions. Boyd has been innovating and fabricating heat pipe solutions for more than five decades. Our experience enables us to design and fabricate effective and long-lasting cooling solutions that operate under the most demanding environmental conditions.

Ductile copper walls and wick enable bending or flattening to meet an application’s thermal and geometric requirements. This can be used to reduce overall height, increase surface contact, or route heat pipes around keep-out areas like mounting hardware.

Heat pipes can be embedded in other technologies for faster heat spreading or utilized within a system to transport heat from the heat source to where is can safely dissipated. Copper-water heat pipes are often integrated into thermal management assemblies to improve effective conductivity and efficiency, improving overall system performance.

3D Vapor Chambers are typically used where extremely high performance is required within a local heat sink volume at the heat source. These solutions are specialized air-cooled heat sinks with vapor chambers incorporated into the base and fins for fast heat spreading and more efficient heat dissipation. These innovative assemblies solve challenges for isothermal, high performance cooling where space is limited, and efficiency is key.

In addition to advanced, integrated design and assembly, Boyd vapor chamber innovations also include utilizing advanced working fluids. Although water is still the primary working fluid and highly effective, some applications such as those used in aerospace and extreme environments have requirements that make water unsuitable. This is especially true in environments with extreme temperatures or thermal cycling. It is imperative to match fluid and material properties to allow for proper functionality. Using incompatible materials can lead to corrosion, shorter lifetimes or loss of performance.

Immersion cooling systems include a boiling plate attached to high heat flux devices such as CPU’s and GPU’s that are immersed in a dielectric fluid. These plates include a BEC (boiling enhancement coating) that initiates boiling of the fluid with a small temperature difference. The bubbles that boil up in the fluid bring the heat to the surface and reject the heat from the system when it condenses on a heat exchanger or cooling coil type condenser.

Boyd’s Immersion Cooling Boiler Plates are extremely high performance, differentiated with a boiling enhancement coating (BEC) optimized with high boiling capacity and low temperature rise to ensure component temperatures are maintained below their maximum limits.

Materials: Copper for high heat flux and Aluminum for lower heat flux components.

Two phase solutions offer increased design flexibility and are extremely customizable. It is vital to consider your options when optimizing your solution.

In addition to sintering, wicking options include grooves and screen-mesh options. Grooves are extruded with the tube. Screens or mesh are rolled and inserted into the pipe along the interior wall.

Heat pipes and vapor chambers can be manufactured in a wide range or materials and alloys, although Copper is the most common. Copper is extremely compatible with water and several other fluids, highly conductive, and is easy to manufacture. If additional strength is required, stainless steel or titanium may be selected with the latter the best choice when weight reduction is desired.

Boyd’s decades of innovation expertise, experience, resources and unique approach to integrating multiple technologies into a streamlined product will continue to keep the company on the forefront of innovation and improved manufacturing. If you are ready to improve or retrofit your cooling solutions or are looking to tackle new challenges for the next generation, start by contacting Boyd to learn more about two phase solutions, customizations, and other possibilities for better optimized cooling.