分析：蒸发冷却在数据中心是否仍然适用——水耗与能效的权衡

Cooling tower for a data center

Evaporative cooling can use roughly 20,000 to 50,000 gallons of water per day for every 1 MW of IT load, making water consumption a growing concern in data center markets.Getty Images蒸发冷却每 1 MW IT 负载每天大约消耗 20,000 至 50,000 加仑的水，这使水资源消耗成为数据中心市场日益关注的问题。Getty Images

Water use has surged to the top of the list of community concerns around new data center development. In many markets, it now rivals power demand as a flashpoint for residents and local officials evaluating new facilities. Stories about data centers consuming enormous volumes of water circulate widely in neighborhood forums and on social media and have become a common argument against new construction, especially in drought-prone regions.用水问题已跃升为新数据中心开发相关社区关切事项的首位。在许多市场，对于评估新设施的居民和地方官员而言，它如今已成为与电力需求不相上下的争议焦点。关于数据中心消耗巨量水资源的报道在社区论坛和社交媒体上广泛流传，并已成为反对新建项目的常见理由，尤其是在易干旱地区。

The concern is not unfounded. According to a report by Media Analytics Ltd., a data center with a 1 MW IT load using evaporative cooling can consume roughly 20,000 to 50,000 gallons of water per day. At that rate, a 10 MW facility could use 200,000 to 500,000 gallons per day, a 100 MW site could consume 2 million to 5 million gallons per day, and a 1 GW facility could use 20 million to 50 million gallons per day, depending on design and operating conditions.这种担忧并非没有根据。根据 Media Analytics Ltd. 的一份报告，一座 IT 负载为 1 MW 且采用蒸发冷却的数据中心每天大约消耗 20,000 至 50,000 加仑的水。按这一速度，一座 10 MW 的设施每天可能使用 200,000 至 500,000 加仑的水，一座 100 MW 的站点每天可能消耗 200 万至 500 万加仑的水，而一座 1 GW 的设施每天可能使用 2,000 万至 5,000 万加仑的水，具体取决于设计和运行条件。

With numbers like that, the obvious question is: why would any operator still choose evaporative cooling?面对这样的数字，显而易见的问题是：为什么还有运营商会选择蒸发冷却？

The answer is that while evaporative systems are water-intensive, they still offer meaningful advantages in cost and energy performance under the right conditions.答案是，尽管蒸发冷却系统耗水量大，但在合适的条件下，它们在成本和能效方面仍具有切实的优势。

Evaporative cooling remains widely used because it can reject large amounts of heat more efficiently than dry cooling alone. In a typical setup, heat from the data center is transferred to water circulating through a cooling tower or a similar heat-rejection system. As a portion of that water evaporates, it carries heat away, and the remaining water is collected and recirculated. It is the same basic principle the human body uses when sweat evaporates and cools the skin.蒸发冷却之所以仍被广泛使用，是因为它比单纯的干式冷却能更高效地排出大量热量。在典型配置中，数据中心的热量被传递给在冷却塔或类似排热系统中循环的水。随着部分水的蒸发，热量被带走，剩余的水则被收集并重新循环。这与人体通过汗液蒸发为皮肤降温所依据的基本原理相同。

The tradeoff, of course, is water consumption.当然，其代价就是水资源的消耗。

The Tradeoff: Water Savings vs. Energy Efficiency权衡：节水与能效

Matt Green, CEO of HVAC firm Brucker, said one reason open-loop evaporative systems remain in the market is simple: first cost.暖通空调公司 Brucker 的首席执行官 Matt Green 表示，开式循环蒸发冷却系统仍在市场上占有一席之地，其中一个原因很简单：初始成本。

“Now, there are some reasons why open-loop cooling still exists, and it’s really driven in many cases by upfront first cost, so an open cooling tower is going to be less expensive [than a closed-loop system],” he said.“开式循环冷却之所以仍然存在，是有一些原因的，在很多情况下，这实际上是由前期初始成本驱动的，因此开式冷却塔（相比闭式循环系统）会更便宜，”他说。

Green estimates that an open-loop system can cost 60% to 70% less upfront than a closed-loop alternative with comparable heat-dissipation capacity. That difference is largely driven by the amount of copper, aluminum, and other materials required in a dry cooler used in a closed-loop design.Green 估计，在散热能力相当的情况下，开式循环系统的前期成本比闭式循环替代方案低 60% 至 70%。这一差异主要取决于闭式循环设计中干冷器所需的铜、铝及其他材料的用量。

Over the life of the system, however, Green argues that the economics shift. In data centers with long operating hours, he said, closed-loop systems have a lower total lifecycle cost than evaporative cooling systems once water use and ongoing operating expenses are factored in.然而，Green 认为，从系统的整个生命周期来看，经济性会发生转变。他说，对于运行时间较长的数据中心，一旦将用水量和持续运营费用考虑在内，闭式循环系统的全生命周期总成本要低于蒸发冷却系统。

Brendan Mark, CEO of Capture H2O, a cooling and heating water treatment provider, makes the case from the other side of the ledger. He argues that evaporative cooling retains an important advantage in energy efficiency.Brendan Mark 是冷却与加热水处理供应商 Capture H2O 的首席执行官，他从账本的另一面提出了自己的看法。他认为，蒸发冷却在能源效率方面仍保留着重要优势。

“Water-cooled systems, as opposed to closed-loop air-cooled systems, are about 25% to 40% more efficient from an energy perspective,” he said. “So, there’s a tradeoff. Yes, you are using less water, but you are using more energy.”“与闭式循环风冷系统相比，水冷系统从能源角度来看效率要高出约 25% 到 40%，”他说。“所以这是一种权衡。没错，你的用水量更少了，但能耗却更高了。”

That tension between water and power is central to the debate. A closed-loop system may sharply reduce evaporation, but it typically requires more fan power and can be less effective at rejecting heat during extreme conditions. Evaporative systems, by contrast, can deliver better thermal performance with lower energy use, particularly when ambient conditions favor evaporation.水与电之间的这种矛盾正是争论的核心。闭式循环系统虽然可以大幅减少蒸发，但通常需要更大的风机功率，而且在极端条件下散热效果可能较差。相比之下，蒸发系统能够以更低的能耗提供更好的热性能，特别是在环境条件有利于蒸发的情况下。

Ashlesa Mohapatra, quality manager at ServerLIFT LLC, which makes equipment for moving data center hardware, said operators should evaluate the full design picture before choosing a cooling architecture. That includes the facility’s power profile, capital budget, climate, and long-term operational impacts.ServerLIFT LLC 是一家生产数据中心硬件搬运设备的公司，其质量经理 Ashlesa Mohapatra 表示，运营商在选择冷却架构之前应评估整体设计方案，包括设施的电力状况、资本预算、气候以及长期运营影响。

“You should look at the amount of power that your data center is taking,” Mohapatra said. “You should look at how much money you’re willing to invest in worn-out hardware due to the evaporative systems that you’re installing.”“你应该看看你的数据中心消耗了多少电力，”Mohapatra 说。“你还应该考虑，由于所安装的蒸发系统会导致硬件磨损，你愿意为此投入多少资金。”

Mohapatra also noted that while the cooling water is not in direct contact with IT hardware, water-based systems still introduce maintenance considerations and mechanical wear that should be accounted for in total cost calculations.Mohapatra 还指出，尽管冷却水并不直接接触 IT 硬件，但水基系统仍会带来维护方面的考量和机械磨损，这些都应计入总成本核算之中。

Mohapatra estimates evaporative cooling can use 10% to 35% less electricity during peak summer conditions than closed-loop alternatives, though the exact savings depend on climate and system design. For that reason, she does not treat the choice as absolute. Closed-loop systems are strong on water conservation, but evaporative systems can still make sense when energy efficiency is the higher priority.Mohapatra 估计，在夏季高峰条件下，蒸发冷却的用电量比闭式循环替代方案低 10% 到 35%，不过具体的节省幅度取决于气候和系统设计。正因如此，她并不认为这一选择是绝对的。闭式循环系统在节水方面表现出色，但当能源效率是更重要的优先事项时，蒸发系统仍然有其合理性。

Green is more skeptical. In his opinion, if an operator has the space and can absorb the higher upfront cost, there is little reason not to move to closed-loop systems.Green 则更为怀疑。在他看来，如果运营商有足够的空间，并且能承受较高的前期成本，那就几乎没有理由不转向闭式循环系统。

“If you’ve got the space and you’ve got the additional capital that you can spend upfront to get the return on investment over the life cycle of the product, [non-closed-loop] technology really should not be used in this application,” he said.“如果你有空间，又有可以 upfront 投入的额外资金，以便在产品生命周期内获得投资回报，那么[非闭式循环]技术真的不应该用于这种应用场景，”他说。

He also argues that many companies stick with evaporative technology because it is familiar.他还认为，许多公司坚持使用蒸发技术，是因为对它熟悉。

“A lot of individuals stick with what they know because it’s worked in the past, and they don’t want to absorb a perceived risk of changing technologies on something that’s been proven to work for them,” Green said.“很多人坚持使用自己熟悉的东西，因为它过去一直行之有效，而且他们不想在一项已被证明对自己有效的技术上承担更换技术所带来的感知风险，”Green 说。

Mark, however, defends evaporative technology on performance grounds.然而，Mark 从性能角度为蒸发技术进行了辩护。

“In a closed-loop system, you’re literally blowing air over a set of tubes that has some sort of fluid running through it,” Mark said. “That tube is not going to be able to reject the heat as effectively as evaporative cooling.”“在闭式循环系统中，你实际上是在向一组内部有某种流体流动的管束吹送空气，”Mark 说。“这种管束无法像蒸发冷却那样有效地排热。”

Climate and Geography Change the Equation气候与地理改变权衡格局

Mohapatra takes a more situational view. In regions with abundant water supply, evaporative cooling may remain a practical option, particularly if the facility is near a major lake or river and local water availability is not under stress. That does not eliminate political or environmental concerns, but it can make the tradeoff easier to justify from an operational standpoint.Mohapatra 的看法更强调具体情况具体分析。在水资源充足的地区，蒸发冷却可能仍然是一个切实可行的选择，尤其是当设施靠近大型湖泊或河流、且当地供水并不紧张时。这并不能消除政治或环境方面的担忧，但从运营角度来看，可以让这种权衡更容易站得住脚。

Climate also plays a major role. Evaporative systems generally perform better in hot, dry environments than in humid ones. In places such as Arizona, evaporation happens more readily, making the system more effective. In a humid environment such as Orlando, Florida, the air already contains more moisture, so evaporation becomes less efficient and the system has to work harder to achieve the same cooling results.气候也起着重要作用。蒸发冷却系统在炎热干燥的环境中通常比在潮湿环境中表现更好。在亚利桑那州这样的地方，水分更容易蒸发，使系统更加高效。而在佛罗里达州奥兰多这样潮湿的环境中，空气中已经含有较多水分，蒸发效率会降低，系统必须更加费力才能达到相同的冷却效果。

“Evaporative works on the principle that the water actually evaporates,” Mohapatra said. “So, when it’s already humid out there, and there’s a lot of moisture in the air, it takes more energy to pull the water and evaporate it into the atmosphere.”“蒸发的原理就是水真的会蒸发掉，”Mohapatra 说。“所以当外界已经很潮湿、空气中含有大量水分时，就需要更多能量来把水分抽出并蒸发到大气中。”

Where Cooling Strategy Goes Next冷却策略的下一步走向

Green believes open-loop evaporative cooling’s days are numbered. As chipsets get hotter and cooling requirements become more demanding, he expects the market to shift increasingly toward closed-loop cooling systems, such as dry or adiabatic coolers.Green 认为开式循环蒸发冷却的日子已经屈指可数。随着芯片组温度越来越高、冷却要求越来越苛刻，他预计市场将越来越多地转向闭式循环冷却系统，例如干式冷却器或绝热冷却器。

“I think we will, with the new chipsets that we’re seeing, be fundamentally shifted to almost exclusively closed-loop cooling systems,” he said, adding that open-loop systems will gradually disappear.“我认为，随着我们看到的新一代芯片组，我们将从根本上转向几乎完全采用闭式循环冷却系统，”他说，并补充说开式循环系统将逐渐消失。

Mark is less categorical. He believes water-cooled approaches will remain part of the conversation and may become more politically acceptable again as the debate matures and the industry becomes more precise about how, where, and why water is being used.Mark 的态度则没有那么绝对。他认为水冷方案仍将是讨论的一部分，而且随着争论日趋成熟、行业对水如何、在何处以及为何被使用有了更精确的认识，水冷方案可能会重新变得更易为政治层面所接受。

“I think it’ll be more politically acceptable to look at water-cooled systems in the next 12 to 24 months,” Mark said. “But as we know, this space moves really quickly.”“我认为在未来 12 到 24 个月内，重新审视水冷系统在政治上将更容易被接受，”Mark 说。“但正如我们所知，这个领域变化非常快。”

Mohapatra sees a hybrid future rather than a single winner. In that model, evaporative cooling could help facilities manage peak summer demand. In contrast, liquid cooling and other closed-loop systems handle most day-to-day thermal loads more efficiently and in a more compact form.Mohapatra 看到的是一个混合式的未来，而非单一方案胜出。在这种模式下，蒸发冷却可以帮助设施应对夏季高峰需求，而液冷和其他闭式循环系统则以更高的效率和更紧凑的形态承担大部分日常热负载。

“We’re going to have some features of evaporative cooling that will allow us to use it in peak summertime, wherever the data center is,” Mohapatra said. “And then there will be liquid cooling … running through the racks most of the time, but it won’t be bulky. It’ll be really quick and something more compact.”“我们将利用蒸发冷却的某些特性，使我们能够在夏季高峰时段使用它，无论数据中心位于何处，”Mohapatra 说。“然后还会有液冷……大部分时间都在机架中运行，但它不会很庞大。它会非常快，而且更加紧凑。”

「英中对照」分析：蒸发冷却在数据中心是否仍然适用——水耗与能效的权衡

The Tradeoff: Water Savings vs. Energy Efficiency权衡：节水与能效

Climate and Geography Change the Equation气候与地理改变权衡格局

Where Cooling Strategy Goes Next冷却策略的下一步走向