Using the Sea To Cool Your Data Center 194
1sockchuck writes "We haven't yet seen signs of the Google Navy of seagoing data centers that use the ocean for power and cooling. But data center developers are planning to use sea water air conditioning in a new project on the island nation of Mauritius in the Indian Ocean. Cold water from deep-sea currents would be piped ashore to be used in a heat exchanger for the data center facility. A similar system has been used to replace the chillers at Cornell University, which draws cold water from Lake Cayuga. The Cornell system cost $50 million, but has slashed cooling-related energy usage by 86 percent."
Although it uses less electricity, not "green" (Score:5, Informative)
Although this solution is certainly "low power" by no means should it be considered to be entirely green. I work as an engineer on many projects that involve sea water, and when you're using it for a cooling source you typically need to inject some sort of chemical to sterilize the water to keep growths off your heat exchangers (barnacles are sort of a pain in the ass in your exchangers). As a result, using sea water for large scale cooling operations is prohibited in large regions of the United States (specifically the gulf coast) mostly over concerns that the large amounts of warm bleached water will damage the ecosystem. Although, that issue aside, using the ocean as a cooling medium is a great idea, and has been used reliably by power plants for many years.
Warm Water Discharge (Score:2, Informative)
The EPA required some modifications to a similar system for a powerplant in PR a few weeks ago.
http://www.waterworld.com/index/display/article-display/1830526029/s-articles/s-waterworld/s-industrial-water/s-wastewater/s-2009/s-08/s-epa-requires_new_pipe.html [waterworld.com]
Re:interest prospect (Score:5, Informative)
A low carbon stainless steel such as the 316 series should be more than sufficient for any piping. Moving parts such as pumps and impellers would be made of titanium for optimum durability and minimum downtime. Lifetime of the pipes is assured by simply adding a small corrosion allowance to the wall thickness (maybe 1/4"), and checking for corrosion once in a while to make sure its not being destroyed faster than you predict. Although that may sound ridiculous, I promise you it is both fairly common and not that hard. Seawater is the lifeblood of many power plants, and it doesn't take a miracle to handle it.
Re:Environmental impact, anyone? (Score:5, Informative)
The Cornell project was actually incredibly controversial prior to beginning operation for exactly that reason. Studies since have shown that any detrimental effects are negligible, though, so the controversy has died down in recent years. (I was at Cornell when the system went into operation and for a few years afterward)
Old sawmill (Score:1, Informative)
Think they are already doing the sea water cooling thing at the old sawmill in Hamina that Google bought.
http://www.google.com/intl/en/datacenter/hamina/index.html
Most of downtown Toronto is cooled by lakewater (Score:3, Informative)
Re:Environmental impact, anyone? (Score:4, Informative)
Not a subjective judgment in either direction, but for what it's worth, this paper abstract [inist.fr] quantifies the heat imparted to Lake Cayuga as "equivalent to an additional two hours of sunlight each year".
Re:interest prospect (Score:2, Informative)
Most steel ships are painted to prevent corrosion. Paint is a thermal insulator. Coating the inside of your heat transfer pipes with a thermal insulator is like masturbating with sandpaper - it might work, but it doesn't work well.
Aluminum is a great thermal conductor and is saltwater resistant with the 6061 and 6063 alloys. Galvanic corrosive action does occur though, but this can be avoided with careful attention to construction methods and avoiding direct metal to aluminum contact.
Re:Environmental Concerns (Score:5, Informative)
The total mass of the oceans [hypertextbook.com] is about 1.4*10^21 kg. The total mass of the atmosphere [hypertextbook.com] is about 5*10^18 kg. That means the oceans weigh about 300 times as much as the atmosphere.
The heat capacity of water [npl.co.uk] is about 4000 J * kg ^ -1 * K ^ -1. The heat capacity of air [engineeringtoolbox.com] is about 1 kJ * kg ^ -1 * K ^ -1, or about 1000 J * kg ^ -1 * K ^ -1.
So since there's 300 times as much water as there is air, and the heat capacity of water is 4 times larger, heating up the atmosphere by 1200 degree Celsius would take the same amount of energy as heating up the oceans by 1 degree Celsius. This may not prove or disprove your point, I just started thinking about numbers when you said "raising the temperature of a body of water by a few degrees".
Re:interest prospect (Score:3, Informative)
The 6000 series alloys are also extremely expensive compared to steel and more importantly difficult to weld, even compared to stainless.
Re:interest prospect (Score:5, Informative)
A low carbon stainless steel such as the 316 series should be more than sufficient for any piping.
Stainless steel is prone to pitting corrosion when exposed to water containing chlorides. 316 series stainless steel is significantly corroded by concentrations of chlorides above 1000ppm (ref [hghouston.com]). Standard sea water at 3.5% salinity has a chloride concentration of about 20000ppm (ref [seafriends.org.nz]).
Stainless steel works rather like aluminium when it comes to preventing corrosion; the surface oxidises very rapidly to form a passive coating, protecting the bulk of the metal from oxygen. In water, this only works if (a) the water contains enough oxygen to passivate the metal, and (b) the water won't then dissolve the coating as soon as it forms. In particular, this means that stainless steel is not suitable for things like marine bolts, because under the bolt head the water will quickly lose all its oxygen and you'll get corrosion. It also means you have to be very careful in sea water as the salts can strip off the chromium oxy passive layer.
316 stainless is considered 'marine grade', but only just. In particular, it's unsuitable for warm sea water, as this makes the water vastly more corrosive. So you probably don't want to use it for coolant pipes.
And I haven't even mentioned electrolytic corrosion yet. Sea water is one of the most corrosive environments on the planet, and dealing with corrosion is one of the biggest problems when working with it.
Re:interest prospect (Score:5, Informative)
Re:interest prospect (Score:3, Informative)
Hogtown has done this for years (Score:1, Informative)
Hogtown (Toronto, Canada) has done this for about 10 years. Not just datacenters, but downtown office buildings and hi-rises. A giant pipe (about 1 meter in diamenter) sucks water about 30 km/h in, and runs it through the buildings, keeping them cool in the summer. The reduction in cooling costs is about as others have described. There was a significant amount of research done do determine environmental and ecological impact prior to doing this. In the end, they noted the temperature of the water overall goes up about 1-2 degrees, but the mean water temperature does not increase year-on-year.
Re:not a thermal insulator and heat tax (Score:3, Informative)
Cayuga Lake is hard to talk about as just one ecosystem, because it has such a strange set of features... It is (like all of the Finger Lakes) a collection of water in the bottom of a glacial valley. Unlike many such lakes, however, Cayuga lake is VERY deep in places (over 400 feet deep), and there are (if I recall correctly) springs or caves or something like that at the bottom in the really deep parts. That being said, it also has a decent sized shallow shelf, and a bunch of small bays and swamps where various creeks discharge. It's the shelf-like area at the south end where the cooling intake and outlet pipes are.
Much of the difficulty assessing whether the heat being pumped into the lake was going to have any negative impact or not had to do with the constant protesting by massive numbers of hysterical but scientifically illiterate hippies (if you've lived in Ithaca for a decade or more, you know who I am talking about). As sad as it is, because anything Cornell released or published was decried as bunk if it didn't damn the project, it didn't seem to matter any more what (if any) case they made to the community as a whole, so there wasn't much effort after some point to communicate anything clearly about this project. I don't blame them, it must have been like trying to piss out the sun getting those damn hippies to shut up long enough to have any sort of rational discussion.
In any case, I doubt it has done nearly the harm that the late '70s and early '80s did when the city essentially pumped any excess sewage right into the lake with minimal if any treatment. In any case, I think a heat tax would be a good idea, but only if it were absolutely universally applied (Apply it to residential, commercial, public sector, and industrial waste-heat and in some sort of a meaningful and constant form (X cents per Y million Joules)).
Re:not a thermal insulator and heat tax (Score:3, Informative)
Oh god no, not another tax in Ithaca....I remember having to buy tax stickers that you applied to EACH trash bag you put out at the curb (and you had BETTER make sure there were absolutely zero recyclables in the bag or the trash people would shred the sticker and the bag leaving trash everywhere on your front lawn for you to deal with). Talk about a PITA...
But you're right, the hippies up there make even the most left-wing liberals look centrist...