In Focus: The Ocean – A Smart Use Case

About Subsea Cloud: Wet Data Centers?

Subsea Cloud?places data centers subsea and in doing so eliminates the electrically driven cooling. This brings about a reduction in the power consumed (about 40% of the power consumption) and CO2 emission reductions, too.

The Properties of Water

Water possesses a remarkable property that sets it apart from most substances: its ability to absorb heat. This unique characteristic plays a crucial role in maintaining the Earth's climate. In this article, we explore the science behind water's exceptional specific heat capacity and make a case for utilizing this property via subsea data centers.

Submerged data centers, situated in large bodies of water (offshore, ports, rivers and dams), offer an interesting and effective solution for the current power and cooling challenges being tackled by the telecoms industry. By leveraging water's high specific heat capacity, subsea data centers can efficiently absorb and disperse the heat generated by servers. The water acts as a natural heat sink, successfully regulating temperatures without the need for energy-intensive cooling mechanisms.?

Water's Specific Heat Capacity: A Unique Advantage

Specific heat capacity, often referred to as simply "specific heat," is the amount of heat energy required to raise the temperature of a substance by a certain amount. Water possesses an unusually high specific heat capacity compared to most other materials. This means that it can absorb a substantial amount of heat energy without experiencing a significant temperature increase itself. In practical terms, this makes water an efficient heat sink and regulator, making it an ideal candidate for various applications, including data centers.?More on specific heat to follow.

Water vs. Air: A Heat Absorption Comparison

With all of our eyes on government pledges to reduce greenhouse gas emissions, along with cultural shift in what people expect from businesses, we are all trying to find ways to do much more with much less. We can categorize where the work is being done over three scales: microchips; computers; and the data center. A modern GPU or CPU can produce 500 watts or more of heat. Scaling up the heat to model an average data center (tens to hundreds of thousands of servers), it's easy to understand how megawatts of heat are produced that must be disposed of, which in turn requires energy. Clever designs that still utilize air cooling can do it efficiently, but in relative terms, not absolute. A well designed, newer data center can operate with a PUE of around 1.3 compared to 1.6 for a typical data center (according to the Uptime Institute). We can come back to whether PUE is a useful metric another time.

Liquid cooling offers a far more efficient heat transfer with some startups boasting far higher efficiency and lower PUEs than those stated above for air cooled centers. At Subsea Cloud, the fluid we use inside each unit is dual purpose in that it results in an immersion cooled environment (single phase) and it also performs another critical function: it compensates against the sea water, whilst transferring the internal heat out to it.

When comparing water and air, the contrast in their heat absorption capacities becomes evident:

• It takes just over four times the amount of energy to raise the temperature of water as it does the same mass of air.
• Water is also 23 times more efficient in transferring heat than air is.
• Given a specific volume of water flow over a hot component, water has a heat carrying capacity nearly 2500 times that of air.
• There are ways to use water inland (outside of rivers and dams) but they become moot when the water has to be pumped ( as it re-introduces powered cooling mechanism).

In other words, water is capable of absorbing over four times more heat than air for the same temperature change. This makes water an excellent medium for dissipating heat efficiently and preventing overheating in various systems.

Environmental Benefits and Challenges

Submerged data centers not only reduce energy consumption and carbon emissions but also address another critical issue: water scarcity. A large data center consumes anywhere?between one million and five million gallons?of water a day — as much as a town of 10,000 to 50,000 people. Over half of this is estimated to be potable (57%). The demand for drinking?water is increasing at the same time as the supply is under strain due to climate change and pollution. Drinking water is a global and significant concern.

However, where utilizing ocean water for any use case is concerned, careful consideration must be given to the potential impact on aquatic ecosystems and water quality. Deoxidization is already happening and affecting marine life. Climate change is causing the loss of oxygen (deoxygenation) in deep and open ocean areas beyond national jurisdiction. The ocean is taking up heat from the atmosphere, making the water warmer. Warmer water holds less oxygen and is less well mixed. Warmer ocean water is also more buoyant than cooler water. This leads to reduced mixing of oxygenated water near the surface with deeper waters, which naturally contain less oxygen. Warmer water also raises oxygen demand from living organisms.?

Hypoxia often occurs a consequence of nutrient pollution (also known as eutrophication). The causes of nutrient pollution, specifically of nitrogen and phosphorus nutrients, include agricultural runoff, fossil-fuel burning, and wastewater treatment effluent.?

These things are happening without the use of subsea data centers. It’s actually worse in most cases to have in-efficient data centers on land. The comparison here is easy to make and simple to follow:

(1) The ocean is taking up heat from the atmosphere, making the water warmer. It's warming mainly because of human activities. (2) Data centers are the largest consuming asset class in the world and they haven't peaked yet. (3) Removing upwards of 40% of the power they consume and co-locating with renewables is a net benefit to the globe and our targets.

The difference between having a data center on the beach, producing wastewater, consuming 40% more energy (minimum) and producing 40% more CO2 (minimum) has a more negative externalities than consciously placed subsea data centers. This sounds harsh in tone, but it's stated less with contempt and more with awe. Many data centers can barely conform to the newest standards of today, never mind the upcoming standards of the future in an effective, efficient way. As they consume vast amounts of electricity via inefficient power and cooling systems operational costs become a significant concern and many cities cannot handle them (in terms of power, land, water and infrastructure) . But the environmental costs are a far more significant concern. ?

By comparison, the biggest drawback of subsea data centers are only seen and felt by companies that struggle to accept remote troubleshooting of servers or periodic maintenance scheduling (3+ months in most cases).

Conclusion

As the demand for data processing and storage continues to skyrocket, data centers are facing a considerable challenge – managing the heat generated by servers required to handle modern computational tasks. The most traditional data centers rely on power-hungry cooling systems, often consuming massive amounts of electricity to keep temperatures under control. This approach is not only energy-intensive but also contributes significantly to carbon emissions. From an operational perspective, scalability becomes important and hard to do. Inadequate power and cooling infrastructure is limiting their ability to expand effectively, potentially hindering business growth.

Water's remarkable ability to absorb and retain heat makes it a powerful ally in our efforts to create sustainable and energy-efficient solutions. Submerged data centers, harnessing the specific heat capacity of water, present an opportunity to transform the technology landscape. By moving towards this approach, we can address the challenges posed by traditional data centers and pave the way for a greener, more efficient digital future. And, as we continue to explore the potential of water's heat-absorbing properties, the marriage of technology and nature could redefine how we approach modern computing and our ongoing battle to solve the problems we’ve inadvertently created for all species on earth.

Hopefully this short overview of water’s specific heat has made a case for the smart use of water to help us all reach our sustainability goals make stronger choices for the planet.?Or, at the very least, piqued your interest in specific heat and water's potential in our sustainability endeavors.