How can variable frequency drives and motors create energy-efficient cooling for data centers?

变频器与电机如何高效冷却数据中心？

Data centers use enormous amounts of energy, especially in cooling the IT equipment housed within their walls.  However, investing in variable frequency drives (VFDs) and energy efficient motors in cooling systems can make a massive contribution to keeping energy consumption under control. We asked Maria Fedorovicheva, Global Product Marketing Manager for HVACR – ABB Motion, to explain how.

数据中心的用电量极大，尤其是冷却数据中心的IT设备。  通过在冷却系统中使用变频器和节能电机可以大量减少能耗。关于这一点，我们采访了ABB运动控制事业部的HVACR全球产品营销经理Maria Fedorovicheva。

Why look for efficiency gains in data center cooling processes?

数据中心冷却过程中的效率提升为何如此重要？

As an integral element of modern computing infrastructures, data centers already use around one percent of the world’s total energy production. Cooling systems, which play a critical role in ensuring the reliability and availability of the facility around the clock, typically consume up to 40 percent of all the energy used by the data center. The other large user is the IT equipment itself. Based on these figures, it is clear that the fans, pumps, and compressors – which form the heart of data center cooling systems – should be one of the first places to look for efficiency gains.

作为现代计算基础设施的一个组成部分，数据中心的用电量占全世界总发电量的大约百分之一。在确保数据中心的持续可靠性和可用性方面，冷却系统发挥着关键作用，但它的用电量通常约占数据中心总用电量的40%。另一个耗电设备是IT设备本身。这些数据表明，能效提升应该从构成数据中心冷却系统核心的风机、泵和压缩机开始。

Are there any regulatory parameters to control energy usage in data centers?

是否有监管参数来控制数据中心的用电量？

One of the most common metrics for energy efficiency has been devised by the industry consortium, Green Grid. This is the power usage effectiveness (PUE) - the ratio defined as the total power entering the data center divided by the power used by its IT equipment. In an ideal world, a data center would have a PUE of 1.

作为行业联盟，绿色网格提出了最常见的能效指标之一：电源使用效率，即进入数据中心的总电量除以IT设备用电量所得比值。在理想状态下，数据中心的PUE应为1。

According to a study performed by the Uptime institute, the PUE levels of data centers have been decreasing over the years, from around 2.6 in 2006 to 1.7 in 2019, although the recent trend, since 2013, is flat. To help drive PUE down further, it is necessary to take actions to increase the efficiency of data centers during their operating life as well as implementing cutting edge technologies in new projects. One solution that can help in decreasing PUE substantially is to adopt VFDs and energy efficient motors for the cooling systems.

根据Uptime Institute开展的一项研究，多年来，数据中心的PUE水平一直呈下降趋势，从2006年的2.6左右下降到2019年的1.7，尽管自2013年以来的近期趋势是平缓的。要使PUE进一步降低，需要采取措施在数据中心运行周期内提高效率，并在新项目中采用尖端技术。在冷却系统中使用变频器和高效电机有助于大幅度降低电源使用效率。

Why VFDs specifically?

为什么选择变频器？

VFDs have proved to be a highly effective energy-saving solution for cooling. Drives enable the speed of electric motors used in cooling applications to be controlled precisely, so that they produce the required flow at any time, resulting in energy savings of up to 35 percent. This is in contrast to running the motor at full speed and controlling the output by throttling and damping. The relationship between motor speed and energy consumption means that even just a moderate reduction in speed can result in a very significant improvement in energy efficiency.

变频器已被证明是一种高效节能的冷却解决方案。变频器可以使冷却系统中的电机转速得到精确控制，使冷却系统在任何时候都能够提供人们所需的温度，从而实现约高达35%的节能。这与电机全速运转，通过节流限制输出的情况完全不同。电机转速与能耗之间的关系意味着，即使只是适度降低转速，也可以显著提高能效。

While data center cooling systems are sized to handle peak loads under the most adverse conditions – from summer heat to component failures – they seldom, if ever, operate at their design loads. Instead, they operate mostly in a lightly loaded state. VFDs provide the flexibility to enable the cooling system to match the varying load profile so that high system efficiency can be maintained even at partial loads.

虽然数据中心冷却系统的规模足以应对极端情况下（包括夏季高温和部件故障）的峰值负载，但它们很少在其设计的负载状态下运行。相反，它们大多在轻载状态下运行。变频器提高了电机的灵活性，使冷却系统能够适应不断变化的负载情况，因此即使在部分负载下也能保持系统的高效运行。

Does motor technology matter as well?

电机技术是否也很重要？

Absolutely. Different motor technologies show a different performance depending on the load. At 25 percent load the efficiency difference between motor technologies can easily be over 10 percent. It therefore makes sense to choose a motor based on its performance in the range where it will be operating most of the time. And in most cases, that range is not the nominal load, but well below it.

当然。不同的电机技术会根据负载表现出不同的性能。当负载为25%时，电机技术之间的效率差异很容易超过10%。因此，根据电机在多数时间的运行负载范围来选择电机是可取的。在大多数情况下，这个范围不是额定负载，而远低于额定负载。

Are there any other considerations regarding cooling process efficiency?

关于冷却过程的效率，是否还有其它考虑？

In fact, the whole system efficiency matters – we can install highly efficient motors to run applications like pumps, fans or compressor with the minimum possible losses and use drives to match the motor speed to demand so that we save energy. But if, say, the design of a fan causes it to create massive aerodynamic losses, the whole system efficiency or wire-to-air efficiency may suffer. That means when considering energy efficiency in data projects, it makes sense to go beyond looking at each element on a component by component basis to evaluate the efficiency of the entire cooling system.

事实上，整个系统的效率很重要——我们可以使用损耗尽可能低的高效电机来拖动泵、风机或压缩机等设备，并利用变频器使电机转速符合需求，从而实现节能。但如果风机设计，使它产生巨大的空气动力损耗，整个系统的能效或电能转化空气动能效率可能会受到影响。这就意味着，在考虑数据项目的能源效率时，必须评估整个冷却系统的能效，而不仅要逐一考虑每一个元器件。

As the server density of data centers continues to increase then so will their heat loads. Future-proofing data center cooling systems means that they must be specified with the scalability to meet future needs. By scalability, we mean that they can be adjusted to suit changing loads, such as when a facility is expanded in size. Again, VFDs developed specifically for heating, ventilation and air conditioning (HVAC) applications as well as motors with high efficiency characteristics- not only at nominal speed but also at part loads - offer an important benefit, as they are designed with flexibility and scalability built in.

随着数据中心中服务器密度不断增加，其热负荷也随之增大。面向未来的数据中心冷却系统必须具有可扩展性，以满足未来的需求。关于可扩展性，是指在数据中心规模扩大时，冷却系统可根据不断变化的负载加以改变。同样，专门为供暖、通风和空调应用而开发的变频器以及高效电机（不仅可以以额定速度运行，还可以在部分负载下运行）带来一个很重要的优势，因为它们的设计具有灵活性和可扩展性。

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