[No Place for IDC] ④ Visiting NHN Pangyo Data Center

Mega-Apartment Complexes Housing Servers
Up to 30,000 Servers Operated by Financial Firms and Public Institutions
"Unfazed by Power Shortages and Outages Thanks to Own Generators"
Maintaining Temperature and Humidity with Indirect Evaporative Cooling + Energy Savings

Editor's NoteWhen you look up the word 'NIMBY' in the Britannica dictionary, it is noted as an acronym for 'Not In My BackYard.' It refers to collective actions by local residents rejecting the installation of undesirable facilities. Typically, this includes prisons and waste landfills, but Internet Data Centers (IDCs) also struggle to find acceptance due to perceptions that they consume massive amounts of electricity and generate electromagnetic pollution. The demand for IDCs is skyrocketing every year with the rise of artificial intelligence (AI), cloud computing, and the metaverse. Although investments are expanding annually, suitable locations for construction are scarce. Through a nationwide survey of data centers and on-site reports, we examine IDCs and diagnose how to eliminate the NIMBY phenomenon surrounding IDCs, which serve as fundamental infrastructure for future industries.

"We prepare for all possible situations, such as when external power supply is cut off due to lightning strikes, internal facility blackouts, flood disasters, or even when an electric vehicle parked in the parking lot catches fire."

[Asia Economy Reporter Yuri Choi] Park Suhyun, the Data Center Operations Team Leader at NHN Cloud's urban data center 'NCC1' in Pangyo, Gyeonggi Province, confidently spoke about the facility's stability. Just as daily life was halted by the SK C&C Pangyo data center fire affecting email, messenger, and taxi calls, he emphasized that every effort is made to ensure that NCC1, the 'heart' of the digital environment, keeps running continuously.

A data center is a massive apartment complex where servers are gathered. It is a physical space that processes users' internet searches, online shopping, and stores various data. Since even a brief power outage can paralyze its functions, it is equipped not only with servers, computers, and communication devices but also with backup power supplies, security systems, cooling facilities, and fire protection equipment. NCC1, with a total floor area exceeding 13,200 square meters (approximately 4,000 pyeong), spans two basement levels and six above-ground floors.

Fortress-like Security in Core Server Rooms... Sensitive Control of Temperature and Humidity

We headed to the core server room of the data center. This is where NHN's own servers and those of clients such as financial institutions and public agencies are located. The entry process was strict from the start. After signing a security pledge, electronic devices including smartphones were left at the entrance. To prevent static electricity from affecting the facility, shoes had to be removed and slippers worn. For security, card keys and fingerprints were required, and only one person could enter at a time to open each double door sequentially. Servers belonging to financial institutions and public agencies required opening additional locks and cages to gain access.

Inside the server room, up to 3,500 servers were arranged side by side in each of the eight server halls. Green sensors were attached to the upper, middle, and lower parts of the neatly stacked server racks. These sensors monitor whether the temperature and humidity in the server room are consistently maintained. Because even slight changes can sensitively affect server performance, the temperature is kept between 18 and 27 degrees Celsius, and humidity between 20% and 60%.

NHN Cloud Pangyo Data Center Rooftop Air Conditioning Unit
Photo by NHN Cloud

Team Leader Park explained, "The server room separates cold aisles from hot aisles to maximize cooling efficiency by preventing heat recirculation." He added, "Water is sprayed through nozzles from the rooftop air conditioning units, and cooled air is drawn in to dissipate heat."

This indirect evaporative cooling system cools the heat generated by the servers and lowers the Power Usage Effectiveness (PUE). NCC1 manages its PUE below 1.2. The average PUE for data centers in Korea is 1.5, and the closer the figure is to 1, the closer the efficiency is to 100%.

Dual Power Supply via KEPCO Dedicated Lines... Dynamic UPS for Power Outage Preparedness

NHN Cloud Pangyo Data Center Dynamic UPS
Photo by NHN Cloud

Just as important as maintaining temperature and humidity is the continuous supply of power. If the data center is the heart, then power is like oxygen that keeps it beating. The power consumption is considerable. Each server consumes as much electricity as a household in a city, and running and cooling about 30,000 servers consumes 2,400 to 3,000 kilowatt-hours (kWh), resulting in monthly electricity bills in the hundreds of millions of won.

To ensure stable power supply, TCC uses dedicated lines from Korea Electric Power Corporation (KEPCO). Park said, "A dual supply network is established, normally receiving power simultaneously from the East Pangyo and West Pangyo substations. If one side is cut off, the load shifts entirely to the other."

If KEPCO's power supply is blocked, a Dynamic Uninterruptible Power Supply (UPS) activates. Upon entering the UPS room, four massive UPS units the size of village buses caught the eye. The noise was loud, like multiple truck engines running simultaneously, so earplugs were quickly worn. While both static UPS and dynamic UPS supply power during outages, dynamic UPS does not rely on batteries but uses a small generator for self-generation.

Normally, the generator runs on electricity while storing kinetic energy, which is used to provide backup power for 10 seconds during an outage. The diesel engine attached to the dynamic UPS takes about two seconds to reach the appropriate revolutions per minute (RPM), during which emergency power is supplied. The diesel engine runs on diesel fuel stored at the data center and can supply power for over 72 hours. Because it does not use batteries, it has fewer fire hazards than static UPS.

Park emphasized, "Although it has the advantage of not requiring a separate battery room, it is about 5 to 6 times more expensive than the commonly used static UPS." He added, "To prepare for potential fire risks, the diesel engine is equipped with cooling systems and fire detection devices." He also noted that the diesel fuel tanks, stored in reinforced separate spaces, are equipped with leak detection and fire suppression gas systems.

NHN Cloud Pangyo Data Center Integrated Control Room
Photo by NHN Cloud

After touring the server room, UPS room, and power distribution room, we headed to the integrated control room where all these facilities can be monitored at a glance. The wall was filled with monitors displaying every corner of the data center in real-time. The screens showed CCTV footage inside and outside the building, UPS vibration frequencies, diesel tank levels, power consumption, and server room temperature and humidity. Next to the monitoring screens, news videos played to check weather and disaster situations.

Park said, "When an earthquake occurred last month in Goesan, I came to work on the weekend for emergency duty." He added, "If any issues arise, we quickly respond with our own personnel and leverage the accessibility advantage of an urban data center to coordinate with clients."