The National University of Singapore’s Faculty of Engineering (NUS Engineering), Keppel Data Centres Holdings Pte Ltd (Keppel Data Centres) and Singapore LNG Corporation Pte Ltd (SLNG) have joined forces to develop a novel, energy-efficient and cost-effective cooling technology for data centres. This innovation could further pave the way for more sustainable and compact data centres.

With the rapid expansion of cloud-based services, AI, the Internet of Things and big data analytics, there has been an exponential demand across the globe for data centres in recent years. As the leading data centre hub of Southeast Asia, Singapore accounted for around 50 per cent of the region’s data centre capacity in 2015. Due to the high internal load and the need for consistent cooling and operation in a tightly-controlled environment, data centres are among the major power consumers in the building sector.

In addition, Singapore’s tropical climate imposes a heavy energy burden on cooling in buildings. In 2018, data centres accounted for 7 per cent¹  of the total annual electricity consumption in Singapore.

“About 37 per cent²  of the total energy consumed by data centres is used to cool IT equipment.   Therefore, improving the efficiency of the cooling system can result in significant energy savings and reduce the carbon footprint of data centres. In this project, we aim to demonstrate a novel way of storing cold energy released from the Liquefied Natural Gas (LNG) re-gasification process and using it to cool data centres efficiently,” said Dean’s Chair Associate Professor Praveen Linga, who is from the NUS Department of Chemical and Biomolecular Engineering and the leader of the project team.

A five-member team from NUS Engineering, Keppel Data Centres and SLNG will jointly develop a prototype of a new cooling medium that can achieve two key functions: firstly, to efficiently store and carry cold energy from the Singapore LNG Terminal to the various data centres, and secondly, to be circulated within the cooling loop in each data centre to perform effective cooling.

This novel technology, called Semiclathrate Thermal Energy Carrier System (ScTECS), can potentially enable data centres to improve their power usage effectiveness (PUE) by 20 per cent. The footprint of the cooling infrastructure could also be reduced considerably, saving space and construction costs.

Mr Wong Wai Meng, CEO of Keppel Data Centres, said, “As a leading designer, developer and operator of data centres across Asia Pacific and Europe, Keppel Data Centres continues to innovate so as to offer best-in-class, energy-efficient solutions to our customers. We are pleased to collaborate with NUS and SLNG on how we can make cooling, which is a key aspect of data centre operations, more efficient, and thus contribute to a more sustainable future.”

New generation thermal energy carrier

In conventional chilling technology, a liquid coolant – usually chilled water – is used to cool the air in data centres. Due to the limited thermal capacity of water, large volumes of water are required to supply chilled water in the circulation loop to carry out cooling. Hence, a large infrastructure is required to generate adequate pumping loads to maintain the flow of chilled water in the cooling system.

In this project, the research team will explore the use of semiclathrate hydrates slurries, which are water-based phase-change fluids, as thermal energy carriers to replace chilled water as a cooling medium in the cooling systems used in data centres. The thermal density of the semiclathrate hydrate slurry is two to five times higher compared to chilled water – this significantly reduces the amount of water and power required as well as the size of various equipment and distribution lines.

Assoc Prof Linga explained, “While semiclathrate hydrates have been studied for purposes of gas separation, gas storage as well as thermal energy storage, the challenge lies in the ability to create them efficiently. NUS Engineering researchers will leverage our expertise in hydrate technologies and process engineering to identify a suitable semiclathrate promoter as well as develop a reactor and process design for this novel cooling technology.”

Another innovation that the team intends to pursue is to harness and utilise LNG cold energy from LNG re-gasification terminals and use it to offset the energy demands in data centres. Cold energy generated from LNG re-gasification could be stored in phase change materials and distributed to data centres for cooling purposes. As a start, Keppel Data Centres and SLNG are working together to explore ways to harness and utilise the cold energy from the Singapore LNG Terminal. SLNG will provide key technical inputs and advice related to the LNG cold energy to the team.

SLNG’s CEO, Mr Tan Soo Koong, commented: “SLNG is conscious of and committed to its responsibility to help fight climate change where it can, especially in reducing energy consumption and carbon emissions. We are therefore pleased to be a part of this innovative collaboration with NUS Engineering and Keppel Data Centres. Concurrently, SLNG is also exploring other ways to harness the LNG cold energy from our terminal and be part of the circular economy in Jurong Island.”

The process prototype demonstrating the cooling technology with a capacity of 1 tonne per day will be designed, built and operated for demonstration by 2022 at NUS.

This research project is supported by the National Research Foundation, Prime Minister’s Office, Singapore, under its Green Data Centre Research Programme.