# Google opens tiny window onto Baltic Sea-cooled data center

Google has released a video showing off the sea water–based cooling system used by its new data center on the southern coast of Finland. Due to go live later this year, the company's Hamina, Finland, data center was built on the site of a former paper mill – how's that for a metaphor? – and as previously revealed, the facility …

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#### Hamina, hamina!

Oh god. I've said it.

#### Sounds like "hammam".

All that hot water, why not first have a giant jacuzzi/spa centre for employees and neighbours?

#### Power saving idea...

Why not build a stirling engine based generation facility with the sea water at the cold end and the data centre cooling water at the hot end. Free electricity! (Pat. pending)

#### Efficiency <= (1 - T-cold/T-hot)

One of the problems with fitting a Stirling engine into the cooling path is that really annoying 'no free lunch' aspect of thermodynamics. Any real heat engine will be less efficient than the limit given by Carnot's theorem. And for small temperature differences this low efficiency means it takes a lot of machinery to get just a little output.

http://en.wikipedia.org/wiki/Carnot_heat_engine

A second problem is that it will be the 'hot end' of the heat engine that is cooling the electronics. In addition to the temperature drop across the engine from the conversion of heat flow into mechanical energy, the heat has to be coupled both into and out from the engine, rather than going straight into the coolant.

So either the kit will have to be run at higher temperature than it would without the heat engine or the thermal coupling will have to be very much improved; both of which are costly.

Given the rule-of-thumb that the lifetime of electronics is halved for every ten degrees C increase in temperature, it pays to optimise cooling rather than to try to capture and re-use the heat.

See, e.g., http://ixbtlabs.com/articles/storagereliability/

I don't have the time or easy access to the data to do the sums, but I'd guess that the energy gained from running a heat pump could well be less than the energy used to make it and provide additional thermal coupling and to replace the electronics more frequently, even before considering the financial cost. Investment in Gen IV technology looks to me to be better use of the capital that would be required.

#### Thanks for that Mr P!

See the flames as I crash and burn...

#### Wind power

I think was an error in the article in Computer Sweden, wistful thinking perhaps, bye some greenish reporter.

(a fart in Sahara).

#### It's a start

Not using new energy to pump out waste heat is one thing.

How about a combined data center/district heating scheme, thereby putting the waste heat to good use? Like the swimming pool heated by a crematorium...

#### How populous is the district?

I would be surprised if they didn't use some waste heat for baseload heating of the buildings there. For 'district heating', it would depend on how many people and potential 'customer' buildings there are in that area. Is the old mill in an isolated place or on the edge of a teeming metropolis?

#### «Is the old mill in an isolated place

or on the edge of a teeming metropolis?» Depends, Frank, on what exactly you mean by «on the edge of», but Sankt-Peterburg, with a population of about 5 millions, lies within a hundred kilometres or so. However, while the site's proximity to Sankt-Peterburg may very well have played a role in Google's decision to locate there, somehow I doubt they're thinking of piping hot water to the city (but with Google, one never knows !)....

Henri

#### A typo surely?

'According to Data Center Knowledge, the pipe that streams the water from the gulf is about 7.5 miles below the surface of the Baltic Sea and connects to granite tunnels running to the data center.'

I don't think so. 7.5 miles is a smidgeon over 12km. Even at the lousy geothermal gradient found in the Baltic, the bottom of the well would be at over 100C.

The deepest point of the Baltic is only 450m below sea level, the deepest point in the oceans (the Challenger Deep) is 10911m. If the reporters had got it right, Google would be within a gnat's whisker of taking the record from the Kola superdeep borehole which is a stupendous 12.3km deep.

#### Easy To See...

*

...pipes 7.5 miles long, not deep. You want nice clean water for your paper factory.

*i recall a similar system for cooling beer.

#### Swimming pool and the lobster effect

The problem is that you have umpteen megawatts of power coming out of your data centre at 40-50C you cool this with sea water at 2-3C.

Once the water you have heated gets to the output temperature of your data centre then you don't have any cooling anymore.

You can use a heat pump to boost the output temperature of the waste heat so you can use it to generate much hotter water. But boiling kids in the local swimming pool is the sort of publicity that even Google would have difficulty putting a positive spin on.

Or you could have a bunch of chillers to then cool the swimming pool to keep it habitable - but that rather ruins the whole point of the sea water system.

They probably do divert some of the heat to heat the rest of the building and, being Finland, probably a sauna or two.

#### In Finland you can sell your excess heat...

Remember, this is in Finland, where heating is needed more often than cooling, and a big problem with air conditioning is preventing heat loss in winter! So they can probably feed any extra heat to the communal central heating system (and get money from it!). Only in summer it'd be a problem at all.

#### Hope they remembered the jellyfish!

These lovely creatures just love to party around inlet pipes..

Coat: Mines the one with the plane ticket to Helsinki and barrel of jellyfish sperm

#### Sod the jelly it is the baltic we are talking about

It is a lovely swamp which is mistakenly named a sea. It has everything - unexploded torpedoes and mines from two world wars, stocks of buried chemical weapons which the Nazis never used and most importantly lots and lots of lovely gas-hydrate to bring that all up if it is warmed up properly.

There are a few places around the world where any f*** with the seabed, dumping warm water and other similar abuse should be prohibited by law. Baltic is one of them, Black is the other and the rift valley lakes of death (the ones with CO2 dissolved in the bottom layer) happily close the formation.

Yes I know - it will take a few million years for one Google datacenter to warm the sea. Camel. Straw. Back. Nuff said.

#### Not in the Gulf of Finland

Fortunately for Google, jellyfishes are not so common in the Baltic, and even less so near the eastern end of the Gulf of Finland, where Hamina is located. I believe the reason is the very low salinity of the seawater there, compared to other seas. The jellyfishes have not adapted to that.

#### @MacroRodent

Thanks for the comment, but haven't jellyfish began to me a big issue in Baltic during recent years?

Maybe not in the eastern part as you say, but if Google starts warming up the waters there they might...

I think we'll be seeing Google Ads on how nutritious Finnish jellyfish really is, with a bit of soy sauce and lime :-)

Now that you mention it, I remember I had heard of that, but not any more in recent years. I think it was bit of a false alarm. They haven't become a problem, at least not in Finnish waters. Low salinity, I guess. Jellyfish want saltier seawater than we have here. Of course they might adapt eventually...

#### Interesting but not really that efficient

Given the climate they are in there is no reason for this data centre to need water cooling at all, they could have used air to air heat exchangers all year and stayed within narrower control ranges than other Google sites.

Chiller energy consumption in this sort of site would be < 10% of the IT power anyway, most of the energy is going to be in the pumps and fans.

Ugh.

#### Minimising Environmental Impact Is Only 'Local'

Mixing the waste heat water with some cooler 'tempering water' from the gulf, before discharge, will only minimise the thermal impact in the local discharge area. It will have no effect on the thermal impact on the gulf as a whole. They are still dumping a given amount of total heat energy into the gulf. However, kudos to them for making the effort to not stew local lobsters, etc.

I would assume that they and various Finnish researchers have calculated the thermal impact for various running scenarios and come to the conclusion that it will not be harmful to the gulf's natural inhabitants.

#### No lobsters to stew here (and they would have been nuked already anyway)

There aren't any in the Gulf of Finland. Actually not other edible crustaceans either.

About the thermal impact, it is probably much less than that of the existing nuclear power plant at Loviisa, which actually isn't far from Hamina. It, too, dumps its waste heat to the sea. Maybe between the two, they will make the cold sea here nicer to swim in...

#### I'm sure they will find something else

Even if they are boiling any lobsters, I'm sure the anti-everything brigade will find something else to scream about. People tried this at Cornell University about 10 years ago and the green-meenies were up in arms about warming up the finger lakes. Didn't matter how many calculations showed the heat input to be negligible in contrast to the diurnal changes (let alone seasonal), it was "the end of the world".

Personally, I think they will use more energy pumping the various streams of water around than they would have done with chillers.

And a 7.5 mile pipe out into the sea is probably right - to get deep enough to avoid most of the surface level sea life (including possible jelly-fish). That is probably the original tunnel from the paper mill which would have been discharging some nasty smelling stuff previously. Even been close to a working paper mill?

#### Pity they'll have to hand the keys to Microsoft....

...after President Balmer completes his annexation of Finland. ;-)

#### How similar?

"We return it a temperature that is much more similar to the inlet temperature, so we minimize any environmental impact in that area"

Obviously not that similar or they would just recycle the same water rather than getting any more.

#### Air to air doesn't work

Not in the "open the windows" sense, anyway; the humidity is wrong.

You can, however, pump the cooling water from your CRACs outside and back in again to get clean and humidity controlled "free air" cooling; you just use the chillers (without their refrigerant circuit switched on) as big water-air heat exchangers when the outside air is cold enough. Works in the UK when it's a bit frosty, provided you have externally-located chillers, and most people do it, but it's probably not sufficient for Google power densities. I suspect they're something more than the usual 750 or 1500W/sq.m.