风冷对比液体冷却:
电力电子设备的热管理进步


获取更多信息


过去几十年,电力和能源是电子工业中发展最迅速的两个行业。功率转换、倒置和整流以及蓄电池和燃料电池技术已成为所有行业实现技术增长不可或缺的一部分。

电力电子系统趋于复杂并在更高功率范围下运行,而其尺寸却变得越来越小,使得热量成为系统完成工作的最大限制因素。为处理耗散的能量,必须优化风冷方案并放大尺寸以充分去除多余热量。在一些情况下,尺寸成为强制对流方案的限制因素,在风冷系统的尺寸和重量使该系统难以用于实践的情况下,液体冷却迅速成为最受欢迎的替代方法。

从风冷系统转换为液体冷却方案不能是贸然轻率的决定。在提高热管理以处理较高热负荷时,需要考虑许多因素和可能性。尽管市场趋势表明全液冷系统最终将是用于冷却电力电子设备的行业标准,但在系统改良或升级时,存在许多选择和混合解决方案,可以实现两种方案的益处。如果预算或期限使得直接转换为液体冷却不切实际,那么通过设计改良或引入两相冷却或液体组件优化强制对流方案就是可行的过渡方案。

Engineers have been developing liquid systems that are complimentary to existingair cooled solutions that can be expanded to fully replace the air cooled systemsover time. This is done by focusing on the electronic devices that can gainimmediate benefit with liquid cooling. Utilizing fluid couplings, reliable pumpsystems, and compact heat exchangers, the system removes heat from the air flowto the liquid where it is transferred and managed elsewhere. In other cases,engineers are opting to fully replace their air cooled systems with liquid cooled toimmediately enable higher power outputs and optimize thermal performance.

As you consider the switch to liquid cooling in order to improve the performance of your power electronics devices andfacilities, there are several key determining factors:

• 您对于尺寸、重量和热性能有何要求?

• 您能够进一步优化您的风冷系统吗?

• 风冷系统作为可行的散热方案付诸应用还能够持续多久?

• 液体或体积可用性是否有任何限制?

• 对液体冷却的投资需要花费多长时间才能实现性能和效率的回报?

• 如何实施或设计液体冷却才能融入您的应用?对应用/设施停机时间的影响将会是什么?

• 如何及何时开始?


风扇散热器风冷

风冷的优势


Air cooled systems are significantly less expensive than liquid systems. They do not require regulated or specializedfluids and they are comprised of fewer components that are more economical than components for liquid systems. Asthey have no liquids to leak and less components to break, they also have less modes of failure. In addition to havinghigher reliability and lower cost, air cooled systems are also easier to modify or upgrade.



风冷的局限


In typical applications, air cooling systems are comprised of an extrudedor bonded fin heat sink and often a fan. When reliability is a significantfactor, engineers may forgo a fan and instead opt for passive solutions.

Both natural and forced convection have limitations. Natural convection islimited by the total surface area needed to dissipate heat, thisnecessitates large, heavy solutions that are often impractical.

Forced Convection solutions are limited by pressure drop. Heat sinks withlarge surface areas in feasible volumes create a high amount of airresistance that hinder the amount of flow and therefore heat transfer thata fan can produce. Larger forced convection solutions also require largeror more fans, increasing the amount of noise generated by the solution.

However, the biggest limitation of air cooled solutions is thermal performance. Air does not have the same capacity asliquid to absorb and transfer heat. At a certain threshold, air cooling becomes an insufficient solution and liquid coolingis necessary.

风冷改装和混合解决方案


There are three common methods of improving your air cooled system. The first is to optimize your heat sink design andfan selection. Generating more air flow, optimizing your fin geometry, or increasing your heat sink volume are ways toimprove upon your air cooled solution without introducing additional technologies. The second is to introduce twophase cooling into your design. Heat pipes may be integrated to spread higher power densities or move the heat to anarea where it can be more easily dissipated. The third most common method of increasing the performance of an aircooled solution is to start introducing elements of a liquid system such as a passive thermosiphon.

查看风冷产品页面



液体冷却的功效


Liquid has the capacity to transfer heat up to 4X higher than the capacity of air of the same mass. This enables higherthermal performance in a smaller solution. A liquid cooling system is a hydraulic circuit that typically consists of a coldplate that interfaces with the heat source and device, a pump that circulates the fluidthrough the system, and a heat exchanger that rejects the heat absorbed by the liquidfrom the device. Liquid cold plates have a much smaller working envelope than a heatsink that would be used in air cooling for the same application. Additionally, multiplecold plates can be connected to the same exchanger with minimal impact onperformance. Liquid cooling grants an additional level of control over the coolingsystem because it controls inlet temperature to the cold plate as well as flow rate.

液体冷却的潜在风险和权衡


Some have been reticent to adopt liquid cooling because of the additional complexity and the fear of leakage.Complexity often increases the cost of the solution and the amount of maintenance required to keep the systemrunning. However the additional costs are mitigated in that the improved cooling performance will increase the lifetimeand reliability of your device.

Because of its complexity, liquid cooling requires better planning and design to incorporate into your power electronics.Although the cold plate is much smaller than an extrusion or heat sink, the overall solutions tends to occupy morevolume once the heat exchangers, tubes, reservoir, and pumps are all taken into account. Engineers must take all of thisinto account during the initial design phase in order to avoid complications later on. With proper foresight, thecomplexity of the systems can be beneficial as there is more flexibility in system design.

液体冷却方案


AavidHydrosink


The Aavid HydroSink system is a configurable method of combining astandard set of optimized heat exchangers, fans, pumps, valves, reservoirs,fittings, sensors, and control boards with custom cold plates to design thebest possible liquid cooling solution for given requirements.

HydroSinks offer more flexibility in design and installation than standardliquid cooling systems because they are configurable and more easilyadapted to design requirements. Sealing and connecting of the liquid coldplate, control board, and customer machine controls within the enclosureare also customizable.

As Aavid HydroSinks are largely comprised of a set of standard optimizedcomponents, they are more cost effective than traditional custom liquidcooling and their air cooled counterparts.

Currently the Aavid HydroSink is available in two basic compact system sizes, Small and Medium. Actual size of thefinal customer HydroSink system varies by configuration. Sizes are based around fan size and cooling performance.Small operates at a temperature rise 7-20 °C per kW, while the Medium operates at a rise of 3-9°C per kW.

点击获取关于AavidHydroSink™的更多信息

Aavid液冷板


Customized Aavid Liquid Cold Plates are an integral part of the HydroSink system. Aavid offers four distinct, innovativecold plate designs developed to optimize the overall system based on application and requirements. All Aavid cold platesare constructed for worry-free liquid cooling utilizing specialized certification procedures to ensure leak-free, reliablesolutions.

Hi-Contact管式冷板


Hi-Contact™管式冷板
Aavid Hi-Contact tube liquid cold plates feature a high performanceassembly utilizing a continuous tube press fit into an extruded aluminumplate. The patented geometry used in the Aavid Hi-Contact process movesthe fluid closer to the device generating heat, achieving the best thermalperformance from a tube cold plate. To further increase the performance ofAavid's Hi-Contact liquid cold plates, a thermal epoxy is applied to the jointto provide a gap free thermal interface between the tube and the plate. Hi-Contactplates are easy to customize and are available in standard sizes.

浮泡式冷板


Blister technology stamps channels into the base plate, eliminating channelmachining and greatly lowering manufacturing costs. A leak free joint is createdbetween the base and cover plate and the blister channels to allow greaterflexibility to drill mounting holes in the topside of the cold plate without regardfor the location of the liquid channels.

涡流液冷板


Aavid Vortex Liquid Cold Plates are designed to cool extremely high powerapplications. These cold plates were initially developed for applications where ahigh compressive load may be applied such as when cooling SCR type devices.Using patented flow path geometry, both sides of Vortex Liquid Cold Plates areevenly cooled; therefore they can provide equal and consistent performanceacross both surfaces and lend themselves to creating more predictableenvironments.

扩展表面液冷板


Aavid Extended Surface Liquid Cold Plates have increased internal surface areawhich allows for better overall heat transfer. Innovative technologies andmanufacturing processes are used to increase the liquid to plate contact areawithin the liquid cold plate. Their vacuum brazed construction ensures leak freejoints while maintaining high thermal conductivity. Aavid Extended SurfaceLiquid Cold Plates are specially fabricated to improve design flexibility and canbe easily customized for optimized flow paths for application designs.

查看液冷板产品页面



最终思路


The key to effective design for liquid cooling and optimized air cooled systems is to consider your thermal managementas early in the design phase as possible. Aavid offers design, engineering, and testing services that can come in at anyphase and develop the best possible solution based on requirements, constraints, timeline, budget, and any othercritical factors.

With design centers around the world, Aavid can provide any customer the necessary engineering services to design andmanufacture a fully optimized system. Engineers are available at every phase from analyzing if there is a need for liquidcooling or air cooling, to developing an optimized, integrated system, to reliability and validation testing of the entiredevice.

To request a free consultation about your current cooling solutions or for help finding the right thermalsolution for your Power Electronic Applications click here.

获取更多信息



下载技术文献