Google's new Finland data center is cooled by seawater

[dividebyzero]

Aren't you talking about thermodynamics ?

A quick look at a definition:

When the temperatures of interest belong to several bodies, the concept also requires that flows of heat between each pair of bodies balance to a zero net flow

and your post:

there is no net heat flow between regions of equal temperature.

I'm also quite interested to find out how :

if the return temperature is similar, the cooling will be minimal, just as in the limit if the temperature is the same, no cooling will be achieved .

Applies to my own (supposed lack) of cooling endeavours, since the article is basically a scaled up standard computer watercooling open model- non refrigerated, albeit with a secondary added coolant source and no recirculation involved.
So, for arguments sake, we use my Z77 rig as example:
Intake and outflow temperature remain constant at +1-2°C Δ over ambient while heat is added to the system.
Now, according to you, the heat exchanger is immaterial...

It doesn't depend on the heat exchanger at all.

...and no cooling is achieved...

no cooling will be achieved .

Despite the fact that water prior to entering the CPU block is at +1-2°C Δ over ambient, at +4°C Δ between CPU block and radiator, and +1°C Δ on exiting the radiator. Based on some quick and dirty calculation based on a conservative 3 litres/min flow rate, 4.18kJ/kgK specific heat for water and the temp delta across the radiator gives a ballpark average of a little over 2250 kJ/h of heat that is adding nothing to water temperature...strange, no?

 

[LinkedKube]

MEANWHILE...AT FOXCONN

 

[LinkedKube]

The water temperature can't be very similar on return, or it isn't going to cool anything?!

It's not a difficult concept, really.

cold seawater in >> water heated by components >> water partially cooled by heat exchanger/radiator (air cooling) >> cold water added to further cool flowing through the cooling loop >> cold water returned to sea

Ever pour a cold drink on an ice cube in the winter. Will you guarantee the end result will be as cold or nearly as cold as the ambient temperture?

 

[LinkedKube]

Aren't you talking about thermodynamics ?

A quick look at a definition:

When the temperatures of interest belong to several bodies, the concept also requires that flows of heat between each pair of bodies balance to a zero net flow

and your post:

there is no net heat flow between regions of equal temperature.

I'm also quite interested to find out how :

if the return temperature is similar, the cooling will be minimal, just as in the limit if the temperature is the same, no cooling will be achieved .

Applies to my own (supposed lack) of cooling endeavours, since the article is basically a scaled up standard computer watercooling open model- non refrigerated, albeit with a secondary added coolant source and no recirculation involved.
So, for arguments sake, we use my Z77 rig as example:
Intake and outflow temperature remain constant at +1-2°C ? over ambient while heat is added to the system.
Now, according to you, the heat exchanger is immaterial...

It doesn't depend on the heat exchanger at all.

...and no cooling is achieved...

no cooling will be achieved .

Despite the fact that water prior to entering the CPU block is at +1-2°C ? over ambient, at +4°C ? between CPU block and radiator, and +1°C ? on exiting the radiator. Based on some quick and dirty calculation based on a conservative 3 litres/min flow rate, 4.18kJ/kgK specific heat for water and the temp delta across the radiator gives a ballpark average of a little over 2250 kJ/h of heat that is adding nothing to water temperature...strange, no?

lmao I didn't even read this post until I noticed it was above the one I just posted.

Your post=coolant savy version of my very simple one.

 

[Zoltan Head]

One more go:- If there is NO difference in temperature between the thing to be cooled and the coolant, I hope it's obvious the cooler won't work, conversely if the coolant is LOTS colder than the object it will cool it very well. Then there is a continuum of situations between these extremes, at the low end of which is "if the return temperature is similar, the cooling will be minimal" mentioned earlier.

 

[dividebyzero]

One more go:- If there is NO difference in temperature between the thing to be cooled and the coolant, I hope it's obvious the cooler won't work

Well, I sincerely doubt that is an issue. The "thing" being cooled...

...is based on Google's containerized data center model. ZDNet estimate for one of these larger data centers is 650,000+ CPU cores per room. Power usage for Google's combined data center op's apparently running in excess of two-and-a-quarter billion kilowatt hours per year. With power usage pretty much equal to heat output, and the fact that the seawater coolant is taken from the Baltic Sea, I'd say it's a given that there's a pretty big temperature difference between the "thing" being cooled and the coolant.

 

[Zoltan Head]

I'd say it's a given that there's a pretty big temperature difference between the "thing" being cooled and the coolant.

Therefore the returning coolant must be warmer than the Sea. QED.

 

[dividebyzero]

Therefore the returning coolant must be warmer than the Sea. QED.

I would sincerely doubt that the difference is anything more than minimal, given that return coolant is already passing through a heat exchanger (in a location not that far removed from the arctic circle), a granite tunnel -a material well known for it's heatsinking ability, and is further diluted by adding further cold water. So you might say that the return water is of a similar temperature to the surrounding body of water. Which is the term used in the original article....so all that your extended posting has revealed is that you know very little about the energy requirement of a server farm, and seemingly less about liquid cooling of computers. QED.

Of course, being the pedant, feel free to search out the enviromental impact study commissioned before work started...you never know the Finnish enviroment ministry might have signed off on Google pouring warm water into the Baltic.

 

[Zoltan Head]

Good, agreement at last. (y)

 

[learninmypc]

I think this is related