A data center is a building optimized to operate IT infrastructure systems such as servers and N/W computing equipment. It is a place not only prepared for disasters and accidents related to electricity, air conditioning, and fire, but it also provides services around the clock with the most stable environment.
What we hear lately is that these data centers also need eco-friendly technologies. Let’s see why they need to think more about the environment.
As data centers provide services around the clock, they spend a tremendous amount of electricity. This is why data centers need eco-friendly technology.
Inside data centers, there are extremely large computers which thousands of people can use at the same time instead of the little PCs we usually see. These computers require a huge amount of energy.
Data centers also have cooling equipment for all the heat coming out of each server, and this also uses a lot of energy, almost as much energy as the servers themselves require. A large data center actually uses about the same amount of energy as 10,000 households.
How much energy does each part of the data center need, though? The entire amount of electricity the building gets is about 20,000kW, and the usable energy from this is about 13,000kW. The amount which IT infrastructure requires is about half of this (6,500kW) and the power needed for cooling is about 5,500kW.
About 1,000kW is for the communal area such as offices. The annual expenditure of 13,000kW costs about $11 million, which is quite a lot of money. This is why data centers are sometimes compared to an elephant living on electricity. Such a metaphor shows that the cost for data centers is considered quite burdensome to many companies.
The actual situation is quite different, though, because most companies share these data centers. If they were to have their own data center they would have to run more computing and cooling equipment for themselves, and this would in turn increase costs dramatically. This is why many companies share large data centers: to reduce the power consumption by optimizing resources and integrating management.
Using water power, wind power, and solar power for additional energy as well as utilizing the deep water from a nearby river so the cooling equipment can use less power are some of the other efforts made to cut costs. These methods, however, do not tend to be very effective.
Solar power and wind power especially require lots of space and investment, and their break-even point is also as long as 40 years. So far the best way to reduce data center expenses is to improve exterior air conditioning systems for energy conservation and to optimize cooling strategies.
Data centers for global corporations have been working on reducing their energy expenditure for years. Google, Facebook, and Microsoft are known for cutting their power consumption.
The most well-known eco-friendly technology used by multiple global companies to reduce energy consumption is ‘exterior air conditioning’ which cools down the temperature in the computing rooms with the cold wind from outside the building.
- Exterior Air Conditioning
This is the method which cools the server rooms by using the cold wind from outside, where the air is below 13℃ and mixing it with the heat inside so the temperature can stay at the desired level.
Let’s take a look at this system in detail. The average temperature in which all computing equipment can stably run is about 22 to 25℃. When the exterior temperature goes lower than 20℃, they use the air from the outside to lower the interior temperature. Exterior air conditioning only needs fans instead of coolers, so it uses a lot less energy.
For example, a 20R/T thermo-hygrostat uses an average of 22kW/h. If it gets replaced with the exterior air conditioning system it will only take 5kW/h for fans and save 17kW/h.
When thinking about large data centers with 100 thermo-hygrostats, the difference becomes 1,700kW/h and 14,892,000kW annually. This means a data center can save about $1.5 million each year by changing their air conditioning system.
Global corporations have been using these air conditioning technologies for years, and this trend is now spreading to large data centers in Korea. Data centers for global companies are mostly in the north so that the exterior temperature can stay under 25℃ even in summer and the system can save energy all year round. On the other hand, Korea has warm seasons and can utilize this system for only about 5 to 6 months a year.
LG CNS is putting lots of effort into solving the energy crisis caused by increased energy consumption and finding ways to lower the cost for electricity.
After much consideration, they came up with a new idea on how to improve the exterior air conditioning system at their data center. After a year and a half of designing and running mock-up tests, they finally created the new ‘built-up exterior air conditioning system’ at Busan Global Cloud Data Center.
The system consists of three different operation modes as follows.
- Exterior air mode: When the outdoor temperature is between 13 and 20℃, the system turns off cooling equipment and brings in exterior air
- Mixing mode: When the temperature is below 13℃, the system mixes the exterior air with the warm indoor air heated by the computing equipment to keep the temperature at the right level.
- Circulation mode: When the exterior temperature is above 20℃, the system blocks the exterior air and uses cooling equipment instead.
The built-up exterior air conditioning system is similar to Facebook’s, but it is different in that they extended the time it can use the exterior air from 5-6 months up to 8 months. Supposing that the data center has 100 thermal-hygrostats they can save 1,700kW per hour for those extra 3 months they can use the exterior air. This means the system can save 3,733,200 kW and $380,000 more than the other exterior air conditioning system.
It also has a wind tunnel like a chimney in order to maximize the air circulation effect. This helps to get the warm air from inside the computing rooms outside quicker.
This eco-friendly technology has been recognized by Uptime Institute, an organization which evaluates and certifies global data centers, by winning the most prestigious prize from the Brill Awards in May of 2014. The Brill Awards is the most respected program run by Uptime Institute, a data center certification organization known to have strict standards. In June, Jong Wan Kim, the director at LG CNS data center published an article on Uptime Institute Journal (vol. 5) about the data center in Busan. (Link: https://journal.uptimeinstitute.com/lg-cns-deploys-custom-cooling-approach-in-korean-data-centers/)
LG CNS also obtained the highest level of A+++, with the best power efficiency index of PUE 1.39 from the green data certification program in December of 2014.
Adding eco-friendly technology to a data center which was built a long time ago is not an easy job. This is because it has to keep running the air conditioning equipment while switching the entire system. It takes complicated techniques as they have to prevent situations where the temperature at certain parts of the room can skyrocket due to a tiny change in the air circulation.
LG CNS applied its own technology to their built-up air conditioning system, and adopted this system to replace the existing small scale exterior air conditioning system for their first data center in Incheon which was built in 1992.
Fortunately, construction wasn’t too difficult because they were already using a similar system. The construction to switch the system took 6 months and the built-up system ran for about a year. The new system could use the exterior air for about 7 months, saving 250kW per hour compared to the old air conditioning system.
Today we learned about why data centers need eco-friendly technologies and how these technologies were applied in reality. As I mentioned earlier, LG CNS is always working to develop and spread new technologies for optimal operational effect and eco-friendly energy use. I look forward to seeing what they have to offer in the future.
Written by Junho Park, deputy head at LG CNS Infrastructure Service Department