Data Centers

TeraCool pairs a data center with an LNG terminal to conserve energy

Liquified natural gas (LNG) facilities need heat to convert LNG back into a vapor, and data centers need cooling. So, is it that strange to pair the two?

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FIgure A: Schematic of how the TeraCool process works.
Image: TeraCool

What does a data center and a liquified natural gas (LNG) receiving terminal have in common? Possibly a lot if TeraCool, a Cambridge, MA company, has anything to say about it. According to this IEEE Spectrum report by Martin LaMonica, TeraCool wants to create a symbiotic relationship between the two disparate industries.

Why is natural gas a liquid in the first place?

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Image: Geology.com
Natural gas cannot be used in a liquid state, so why bother liquefying it?

Natural gas is converted into LNG when it's not possible to transport the fuel through pipelines — across oceans for example. Specialized ships similar to the one at the left are used instead.

Since space is a premium on ships, the first thought might be to compress the gas, but transporting a compressed, volatile gas is not exactly safe. That brings us to liquefying. As a liquid, 600 times more volume of natural gas takes up the same space in a ship, making transportation of natural gas economical.

The liquefaction process

Liquefaction happens when natural gas is cooled below -259 degrees F (-161 degrees C) — its boiling point. If you are wondering about the economics of keeping LNG that cold during a long ocean voyage, it is unnecessary. Through auto-refrigeration, the LNG needs no additional cooling as long as the liquid remains at the correct pressure.

After the LNG carrier reaches its destination, and unloads the cargo, the next step is to elevate the LNG to near-ambient temperature using a closed-loop vaporization process. Then the now vaporous natural gas can be stored on-site or pumped through the provider's distribution network to customers.

So one can see that although natural gas is an efficient fuel, much of that efficiency may be lost if natural gas has to be transported in a liquid form.

Why a data center?

TeraCool's idea is to save the energy required to convert LNG back into its vapor state. The company's suggestion: use waste heat from a nearby data center as the heat source in the vaporization process. The schematic in Figure A shows how the TeraCool process works.

Bob Shatten, president of TeraCool, during a presentation to the Uptime Institute says the technology is based on the concept of industrial ecology. A California company, DeepWater Desal, proposes colocating a desalination plant near a data center for a near-identical reason: moving cold sea water through the data center first to cool the data center, then sending the now warm sea water to the desalination plant where the higher temperature enables the desalination process.

Notice Figure A includes the capability to produce electricity. The expansion of the refrigerant is enough to power a turbine-generator — gaining more efficiency.

Proposed capabilities

In his presentation, Shatten also mentions TeraCool analyzed what cooling and electrical capacity the TeraCool process would give: "For a 90-megawatt data center with a 30-megawatt cooling requirement (1.3 to 1.6 PUE), the TeraCool system could provide all the cooling plus roughly 11 megawatts of the total-energy requirement of the facility."

Shatten and TeraCool also estimate the data center-LNG facility duo would eliminate 550,000 tons of greenhouse gas each year.

But will they come?

TeraCool has an uphill battle. First, there is the perceived safety concern. As a former volunteer firefighter, I have experienced, first hand, a Boiling Liquid Expanding Vapor Explosion (BLEVE). Even with every precaution in place, data center operators may consider it too much of a risk.

Next, in the US, there is a limited number of LNG receiving terminals (Figure B). The California Energy Commission report claims there are less than 100 terminals worldwide — testing investors' aversion to weak ROIs.

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Figure B: The locations of LNG receiving terminals in the US.

The IEEE report agrees that it may be a tough sell: "The biggest challenge for TeraCool's energy-saving system is simply finding a company willing to give such a new technology a try. Also, data-center operators may balk at colocating at an LNG facility, which could pose more risk than, say, building a data center in a rural location near farms. (TeraCool notes there hasn't been a major accident at an LNG terminal in the history of the industry.)"

Audacious Idea Award winner

Earlier, I mentioned that Shatten and other TeraCool project members presented before the Uptime Institute. The results of his efforts: TeraCool was awarded the Uptime Institute's Audacious Idea Award in 2013. Referencing the award: "Uptime Institute grants Green Enterprise IT (GEIT) Awards to projects, ideas, and products that significantly improve energy productivity and resource use in IT."

Disclaimer: Martin LaMonica is a former Senior Editor at CNET, a sister site of TechRepublic.

About Michael Kassner

Information is my field...Writing is my passion...Coupling the two is my mission.

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