Data center providers in Japan, KDDI and NTT Data, are exploring liquid immersion technology to significantly reduce the energy wasted on cooling server hardware.
KDDI’s recent field tests have achieved an impressive 94% reduction in electricity consumption for temperature control compared to traditional air cooling systems. Masato Kato, an expert at KDDI’s solutions business, explained that while IT equipment is often thought to be the major power consumer, about half of the overall power consumed by data centers is used for cooling.
KDDI’s tested cooling system involves submerging servers in oil, allowing the heat to be conducted into the oil, which is then transferred to cooling water and released into the outside air. The use of circulating pumps ensures efficient heat transfer, and the oil’s insulating properties protect against potential short-circuits.
To address the pressing issue of energy conservation, KDDI conducted a preliminary demonstration of the liquid cooling system in Taiwan in 2020, followed by pilot tests of container-type immersion systems.
In collaboration with Mitsubishi Heavy Industries and NEC Networks & System Integration, a large-scale test was launched at the Oyama Network Center in April 2022. KDDI aims to commercially offer immersion systems as early as this fiscal year.
Similarly, in spring 2022, NTT Data tested a two-phase immersion system that achieved cooling energy savings of up to 97% by converting the liquid coolant into vapor.
NTT Data is now preparing to test a single-phase system, similar to KDDI’s approach, with plans for practical implementation within this fiscal year.
NTT Communications also introduced an immersion system at an NTT group data center facility in India in January and plans to test the cooling technology in Japan soon.
Despite the widespread use of liquid cooling in high-performance computing, its adoption has been limited in Japan due to a lack of familiarity and experience. However, as data centers increasingly use high-performance equipment and virtual technologies that generate more heat, existing air conditioning systems are unable to meet the growing demands.
Data centers in Japan have been leveraging renewable energy to minimize their carbon footprint, but the limited availability of domestic renewable energy sources poses challenges. To achieve carbon neutrality, a prominent data center operator, Marunouchi Direct, has powered all its data centers exclusively with renewable energy, utilizing non-fossil fuel energy certificates and the feed-in tariff (FIT) system to track energy sources.
The exploration of liquid immersion cooling systems by KDDI and NTT Data showcases their commitment to reducing power consumption and addressing the challenges of heat generation and energy conservation in data centers.
Faced with pressure to reduce carbon emissions across the supply chain, companies are turning to liquid cooling systems to slash power consumption. Global immersion cooling market is projected to grow at an average rate of 26% per year, as reported by market research firm ReportLinker. However, the costs of installing cooling pipes and other construction expenses present challenges.
Apart from Japan, in a city like Hong Kong, liquid cooling is an essential option that should be embraced as the industry standard. As a warm island city with limited space, relying solely on air cooling is not a sustainable solution, especially as the number and density of data centers continue to grow.
The construction of cooling towers can only accommodate a certain capacity, and the increasing energy costs pose a significant burden for many operators. Therefore, liquid cooling presents itself as an inevitable choice for the efficient and long-term operation of data centers in Hong Kong.
