Corporations are striving to make their data centers more energy efficient and reduce their environmental impact. But not always the colder the better.
Studies show that equipment can function normally at a temperature of 27ºC. At the same time, energy savings will be 4-5% for each increased degree.
Therefore, companies are not only trying to find new technologies for cooling, sometimes quite extreme, but also are engaged in the improvement of equipment and premises. Today we will talk about which solutions are becoming more popular, and which are the exception to the general rules.
/ PublicDomainPictures / George Hodan / PD
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Not all the water that cools
Many data centers today choose to cool water, which is considered to be
more efficient than air tenfold, especially for “hot spots”. In addition, modern systems eliminate the possibility of leakage and damage to equipment. However, data centers today are becoming more and more "green", and the high consumption of water turns into a disadvantage.
In the United States alone, in 2014, 626 billion liters of water were
used , including water for cooling and for producing the electricity necessary for the operation of data centers. Therefore, in addition to the PUE indicator for data centers, the water efficiency indicator (
WUE ) is becoming increasingly popular.
One solution is to use
refrigerants to cool water, which in this case can circulate without loss. Another option is to use special liquids instead of water. For example,
GreenDEF liquid, which is made from mineral oil, can reduce the energy consumption of a data center by 30-40%.
But mineral oils have certain
disadvantages : they pollute the environment and are highly flammable. Therefore, many prefer to use dielectric fluids, which also involve direct contact between the refrigerant and the microcircuits.
One of these 3M production fluids is used for two-phase immersion cooling. Read more about it
here . At the annual international conference SC16, some new
solutions were presented, for example, immersion cooling from LiquidMips, which, among other things, eliminates the problem of possible damage to optical connections.
And our, and your
But not all data centers are ready to immediately
switch to liquid cooling. Therefore, today, as an intermediate option, hybrid systems are quite popular, in which cooling with liquid and air is combined. But it is not clear how such systems contribute to cost savings, since they require twice the amount of equipment.
Nevertheless, new solutions are emerging in this area: CoolIT together with STULZ introduced
the Chip-to-Atmosphere modular
system , which allows the use of liquid cooling for the hottest components, and air cooling for everything else.
What is natural is not ugly
More and more corporations are opting for natural cooling in an attempt to reduce their environmental impact. Surely everyone has heard of the Google data center in Finland, which is cooled by sea water.
Water is delivered to the data center through a tunnel that has existed there since the days of the paper mill, which used to be in place of the data center. But salt water
is corrosive, so it is necessary to use glass-fiber-reinforced pipes and titanium plates in the heat exchangers, as well as to install additional filtration.
Facebook faced a similar problem during the construction of a new data center in Ireland, where cool sea
air with high salt content is used for cooling. Therefore, air must pass through additional filters before it enters the data center itself.
According to a
study conducted by Rutgers University, the frequency of equipment failures in data centers with natural cooling without controlling humidity levels in a humid climate is 107-260% higher. Despite the possible difficulties in Ireland, there is a
large number of data centers of various corporations that use “free cooling” and are energy efficient.
/ Flickr / Shawn O'Neil / CC-BY
Paru, where I want
In combination with natural air cooling, it is advantageous to use evaporation cooling, since in this case the amount of electricity consumed can be significantly reduced. But the method chosen depends on the temperature and humidity of the incoming air. So, direct cooling by evaporation is
possible at a higher temperature and not very humid air. Great
benefits from such systems can be obtained precisely in dry climates with high temperatures. But in a cold climate there is no need for them.
For indirect cooling, the temperature and humidity of the air outside should be higher than the inside. The air itself does not become more humid. If the climate is not quite suitable for such systems, experts advise resorting to a
hybrid cooling scheme and apply evaporation cooling only in certain weather conditions, for example, in summer. And, of course, we must not forget about the need to remove excess moisture from the air.
And the data center is floating
We have already written about how the
underground data centers are arranged, but today there are also underwater ones. The first such data center is
a Microsoft
project called Natick. The tests were successful and the company has already patented its invention. Now the development of the second generation Natick, which will be much larger.
The main advantage is that the data center practically does not require maintenance and constant human
presence . But all the elements are in separate capsules, which, if necessary, can be removed or replaced.
Such data centers are suitable for coastal regions, and savings can also be due to the lack of need to occupy territory on the ground. The data center receives energy from the movement of the waves, and is cooled by ocean water. In this case, the location at a sufficiently large depth or even at the bottom protects against the effects of strong waves. But while the design of waterproof modules is 10-20% more expensive than ground modular data centers, and there is no need to talk about mass production.
And the company Nautilus Data Technologies is conducting tests of a
floating data center, which, according to the company, will be 50% more energy efficient than its land based counterparts. Such development, undoubtedly, will help save water resources, since water from a reservoir is used for cooling, which, after performing its function, comes back. According to experts, the temperature difference is so small that it can not seriously affect the overall temperature of the reservoir and the life of its inhabitants.
But fully such a data center can only function in the port. And additional costs will be needed, as the water must pass through a purification and filtration system. And if you place a floating data center in the seaport, you will need special materials to avoid corrosion, which also does not contribute to cheaper construction.
Intelligence on guard cold
In addition to the well-known
example of Google, artificial intelligence systems are now used by other companies. For example, Vertiv, the former Emerson Network Power, thanks to
the Liebert iCOM-S temperature monitoring
system, Vertiv was able to eliminate the re-entry of cold air into the system before fulfilling its intended purpose of cooling equipment.
In water cooling systems, the auto tune function balances the fan speed, water temperature and flow rate. There are other companies that use artificial intelligence systems in data centers mainly to improve their energy efficiency. For example, start-up
Coolan and
Romonet .
Today, companies are trying not only to reduce the cost of cooling, but also to minimize the impact of data centers on the environment. And sometimes it’s very difficult to choose a single technology and even a place for building a data center. The Government of Sweden
offers special parks to host data centers, which are located within Stockholm to use the heat generated by data centers to heat nearby houses.
The state has reduced taxes on electricity by 97% (for data centers) and is ready to buy the generated heat. In another scenario, data parks may provide free cooling systems to their residents. Therefore, it is possible that the offer of “cooling-as-a-service” from Sweden will eliminate the headache of many companies and allow them not to think at all about which cooling technology to choose.
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