Data Centre Management
Joakim Palmberg is director, segments & applications, SWEP
Solving data centre hunger
Global transitioning to liquid cooling and a demand for more high performing data centres, without compromising on energy efficiency, is more crucial than ever, says Joakim Palmberg
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ata storage has become one of the world’s fastest growing businesses as cloud storage becomes more and more commonplace. According to the latest predictions, the energy usage of data center will double between now and 2030, reaching more than 2 per cent of the total global energy consumption.1 The digital transformation has led to a need for more, faster and efficient data centres and the trend seems to last. At the same time, we are challenged by limited energy resources, galloping prices and global warming. How can we make both ends of the equation to meet? Storing data consumes a great deal of energy and produces a lot of heat, so large-scale data centres need powerful cooling to ensure optimum running of their IT equipment. Cooling systems typically are responsible for around 40 per cent of the power consumed in a typical data centre, with vapour compression chillers commonly utilised. These use a mechanical compressor powered by electricity, steam, or gas turbines. They produce cooling using the “vapour compression” refrigeration cycle.
Maximising efficiency
Maximising capacity and efficiency while adapting to natural or low GWP2 refrigerants is nowadays essential for vapour compression chillers. Intergovernmental bodies worldwide are tightening regulatory frameworks to further restrict the use of synthetic refrigerants such as chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC). The aim
BPHE technology is ideal to use as an intermediate circuit to separate the external glycol loop with the internal server loop. Further, a tight temperature approach is a key feature of SWEP BPHEs and makes it possible to operate despite low temperature differences and utilise ‘free cooling’ for a longer period of the year, regardless of the season. An expedient BPHE provides high turbulent flow, preventing fouling and scaling and the flows keep particles in the fluid in suspension.
Planning ‘white space’
is to replace them with environmentally friendly natural refrigerants as part of the drive to reduce global warming impact. Liquid cooling of servers is the most energy-efficient way to drive the data centre industry forward. This allows optimum energy use in the technology suite, so more power drives the applications on the servers, rather than the cooling systems. SWEP’s wide range of Brazed Plate Heat Exchanger (BPHE) evaporators, condensers, economisers and desuperheaters for chillers combine plate and distribution technology, which also includes dual or single refrigerant circuits solutions. They thereby improve efficiency and reliability, reduce pressure drop and minimise refrigerant charge. Energy can be saved if the ambient temperature can be used to cool the server with the chiller turned off, thereby enabling ‘free cooling’. SWEP
Excess heat obtained from cooling in a data centre can be recovered using BPHEs and supplied directly to a district heating network or nearby buildings
Top tips for data centre energy managers Sustainable energy Use renewable energy, typically wind, solar or nuclear.
Liquid cooling Invest in the most efficient system possible. Air-cooled systems will phase out in the short to medium term.
Efficient chiller system with modern low GWP refrigerants Lower pressure drop in the system leads to reduced pump size and reduced energy consumption. Compact BPHEs mean lower carbon footprint. Free cooling Take advantage of ‘free cooling’, which involves lowering the air temperature in a data centre by utilising naturally cool water instead of mechanical refrigeration. With BPHE from SWEP you have tight temperature approach and can take advantage of free cooling even at small temperature differences (so for a longer period of the year).
Excess heat Data centre excess heat obtained from cooling can be recovered using BPHEs and supplied directly to a district energy network if available. White space and the machine room Optimise your white space by going for compact design. With BPHE the CDU can be smaller and even fit a chassis level CDU.
For cost efficiency, the ‘white space’ in data centres (the area allocated for server cabinets, storage, network gear, racks, air-conditioning units and power-distribution systems) must be planned and used cost-effectively, making compactness of equipment an important factor. The Coolant Distribution Unit (CDU) is usually sited next to the servers, though compact in-rack solutions are also frequently used. Thanks to the BPHE size, both alternatives can be addressed with unparalleled cooling capacity. The BPHE serves as a loop breaker between the media, and the coolant is transferred to the di-electric fluid to cool the servers, with heat transferred in the opposite direction away from the servers. Additionally, SWEP’s 2-Pass flow pattern heat exchangers allow near doubling of thermal performance, within the same footprint. Excess heat from data centres doesn’t have to be wasted. Surplus heat, for example heat from servers or indeed other machines or industrial processes, can be source for various heating applications. Data centre excess heat obtained from cooling can be recovered using BPHEs and supplied directly to a district energy network or nearby buildings. As waste heat is an unwanted by-product from another process it has a very low carbon footprint. Given the expansion of data centres across the world, there is considerable potential for this type of heat recycling, though there is still a way to go to balance the potential costs with the likely environmental benefit.
References
1) https://www.propertyfundsworld. com/2021/07/20/303768/pandemicdriven-data-reliance-fuels-record-datacentre-investments 2) The Global Warming Potential (GWP) of a refrigerant is its global warming impact relative to the impact of the same quantity of carbon dioxide over a 100 year period.
38 | ENERGY IN BUILDINGS & INDUSTRY | JUNE 2022
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