Overview
Over many decades, Boyd has led innovation of superior heat pipe and two-phase thermal management solutions across many major industries from mobile and consumer electronics to NASA applications and next-generation enterprise and 5G equipment. We’ve observed many misconceptions about heat pipes, how they work, and how to best utilize them in applications while working closely with engineering teams across leading major markets. This article addresses the top 7 most common misconceptions, or “myths”, about heat pipes that we’ve encountered with best practices for heat pipe utilization.
Truth About Designing Applications With Two Phase Cooling
As electronics continue to become more powerful and require more functionality with greater reliability, excess heat remains a significant barrier to the development of better-performing next-generation applications and breakthrough innovation. Every industry, especially Mobile, Medical, Telecommunications, and IoT are developing new products and systems that must be lightweight, multi-functional, and able to manage high heat loads with high reliability. Engineers struggle to effectively handle the heat as consumers demand smaller, thinner, more powerful devices with more options, functionality, and capabilities.
Two-phase cooling is rapidly evolving and gaining more popularity in solving these issues. Heat pipes are especially ideal to spread heat for faster dissipation, light-weighting, higher reliability, and lifetime. But heat pipes most significant benefit is design flexibility and the ability to easily integrate them into thermal systems to vastly improve cooling efficiency and capacity.
For more information on the various two-phase technologies, including heat pipes, vapor chambers, thermosiphons, and immersion cooling, view Boyd’s Guide to Two-Phase Cooling. The addition of heat pipes to your solution or system can vastly improve its thermal performance for more efficient thermal management without adding active components that may be detrimental to application lifetimes, reliability, or accuracy. Active air cooling or liquid cooling can be large or cumbersome. Active air cooling comes with complications such as acoustics, weight, and vibration.
Not all applications have infrastructure that supports liquid cooling systems. Two-phase cooling is being leveraged to extend air cooling system performance, solves acoustic and vibration issues, and leverages existing cooling infrastructure.
Myth #1: If heat pipes break, they will get liquid on my electronics.
Truth: Heat pipes rarely, if ever, break. In the highly unlikely event that one was to break, the extremely small amount of liquid held in the pipe would be fully saturated into its wick and would not be able to drip or leak onto your electronics.
Heat pipes are inherently robust and are a purely passive system that does not have any moving parts to wear down over time. To “break” a well-manufactured heat pipe, you would need to cut the pipe open or put the pipe through an excessive amount of repeated bending or folding.
Heat pipes are charged with a vacuum while being filled ensuring the amount of fluid contained in the pipe is always in vapor form and therefore will not drip.
Their durability, increased reliability, and leak-free nature make heat pipes an ideal solution in markets such as Aerospace, Medical, Consumer Electronics, high-power applications that require high reliability, and where leaks from traditional liquid solutions may be catastrophic.
Through decades of refining manufacturing techniques and engineering specifications, Boyd has developed consistently robust, high-quality heat pipes. Boyd heat pipes are tested in thermal labs utilizing high-temperature testing in accelerated life tests and other exhaustive reliability and performance testing to prove out design, seal, and welding quality.
Myth #2: Heat pipes are heavy
Truth: Heat pipes can remove more weight than they add to an assembly.
Because they are typically made of copper, a heavier material, some believe that integrating heat pipes will add weight to their solution. Boyd engineers often utilize them with other cooling technologies to decrease the weight or volume of an overall solution as experts in heat pipe utilization and integration.
Although they are made of copper, heat pipes are hollow and can decrease the weight of your solution while improving thermal performance in a variety of ways. Heat pipes are often used to transfer heat to a cooler, remote, more open area of a device or assembly with greater access to airflow and space where a fan and lightweight fin structures can be added to decrease the overall size and weight of your cooling solution.
Another common example is replacing a traditional copper spreader or larger heat sink with an aluminum heat sink base featuring embedded heat pipes. The high heat spreading efficiency of heat pipes evenly and rapidly distributes heat across a full heat sink, increasing heat sink efficiency, reducing heat sink size and the amount of material needed, thereby reducing the overall weight and cost of your solution.
Myth #3: Heat pipes only work with the evaporator and condenser on the ends
Truth: Heat pipes function along the entire length of the pipe and will consistently transfer heat from warmer regions to cooler regions regardless of their location along the pipe.
Heat pipes are often designed into thermal management assemblies to transport heat from the heat source at one end to the other end to dissipate safely and efficiently. This utilization is common, but it is not the only way to use heat pipes. Heat pipe wicking structure enables them to work in any orientation and typically runs the full length of the pipe interior. Heat inherently travels from hot to cold and this holds true with heat pipes.
No matter where heat is placed along the pipe, heat will always travel away from the heat source(s) towards the condensation point(s) and back again through the wick. This increases design flexibility and heat pipe use options to enable more innovative and cost-efficient thermal management. One such utilization is embedding heat pipes to spread heat rather than transfer it.
When heat pipes are embedded in the base of a heat sink, the heat condenses along the entire length of the heat pipe rather than a set region. An example of this is integrating heat pipes into air-cooled heat sinks to extend high power performance, mitigating the need for a liquid system when cooling high power IGBTs.
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