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Google's Liquid Cooling

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399 points giuliomagnifico | 10 comments | | HN request time: 0.001s | source | bottom
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BoppreH ◴[] No.45017675[source]
I see frequent mentions of AI wasting water. Is this one such setup, perhaps with the CDU using the facility's water supply for evaporative cooling?
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bri3d ◴[] No.45017805[source]
The CDU is inside the datacenter and strictly liquid to liquid exchange. It transfers heat from the rack block's coolant to the facility coolant. The facility then provides outdoor heat exchange for the facility coolant, which is sometimes accomplished using open-loop evaporative cooling (spraying down the cooling towers). All datacenters have some form of facility cooling, whether there's a CDU and local water cooling or not, so it's not particularly relevant.

The whole AI-water conversation is sort of tiring, since water just moves to more or less efficient parts or locations in the water cycle - I think a "total runtime energy consumption" metric would be much more useful if it were possible to accurately price in water-related externalities (ie - is a massive amount of energy spent moving water because a datacenter evaporates it? or is it no big deal?). And the whole thing really just shows how inefficient and inaccurately priced the market for water is, especially in the US where water rights, price, and the actual utility of water in a given location are often shockingly uncorrelated.

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1. bjackman ◴[] No.45019506[source]
Even without AI the whole water conservation topic is kinda silly.

The margin at which it makes sense to save water varies wildly by location, but the cultural dominance of the western USA infiltrates everything.

Here in Zürich, my office briefly installed water saving taps. This is a city of less than half a million where the government maintains 1,200 fountains that spew drinkable water 24/7. But someone at the California HQ said saving water is important and someone at the Swiss subsidiary said yes sir we'll look into it right away sir.

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2. acyou ◴[] No.45021140[source]
It's on the same level as people using incandescent light bulbs. Well we clear 160k Euros after taxes and have public medical care, and electricity is 10c/kWh here, so why does it matter what bulbs we use?

We live in an area surrounded by grass fed cows, so what does it matter if we throw away 3/4 of our steak?

Without regard to how plentiful resources are in our particular area, being needlessly wasteful is in bad taste more than anything. It's a lack of appreciation of the value of what we have.

For water specifically - it is generally speaking the most valuable resource available, we just don't appreciate it because we happen to have a lot of it.

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3. MindSpunk ◴[] No.45022396[source]
While I'm not saying waste when things are plentiful in general is okay, I think water is a unique case that can be treated differently.

Comparing to energy costs isn't the same because using the energy for the incandescent bulb consumes that energy permanently. The gas/coal/fuel can't be un-burned. Although solar changes this as the marginal cost of that energy is free.

Comparing to food is similar. Once the food is wasted it is gone.

Water is typically not destroyed, it's just moved around in the water cycle. Water consumption in a region is dictated by the throughput the water cycle replenishes the reservoirs you're pulling from. "Waste" with water is highly geographic, and it's pretty reasonable to take exception to California projecting their problems to geographic regions that they aren't important.

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4. mschuster91 ◴[] No.45025232[source]
> For water specifically - it is generally speaking the most valuable resource available, we just don't appreciate it because we happen to have a lot of it.

And for water specifically, the second order effects from "water saving" programs can be actually negative. Not enough water means that sewers don't work properly any more, leading from events of stink to helping fatbergs grow [1].

To make it worse, the "obvious" idea of scaling down sewer mains doesn't work either because the sewers are (at least in Europe) also used as storm drains, so if you'd scale down the sewers you'd get streets flooded.

[1] https://www.wiwo.de/technologie/blockierte-kanalisation-die-...

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5. fennecfoxy ◴[] No.45027365{3}[source]
It still takes energy, chemicals and therefore pollution to clean water once it's been turned into greywater.
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6. lazide ◴[] No.45028179{3}[source]
Also, water is not readibly fungible as it’s not generally economic to ship large distances. So either you have it, or you dont.

If you do have it, often you have more than you can store or use effectively (the rest just runs off).

If you have a lot of water, then going to a bunch of effort saving it is indeed silly.

If you don’t have a lot of water, then it is indeed essential.

7. ignaloidas ◴[] No.45029067{4}[source]
Sun is continuously running a very nice distillation cycle the size of the world that makes fairly clean water just fall out of the sky. It's only a question of where does it fall, and how much. If you want it even cleaner, wait a couple centuries for it to filter down underground, and get it from there - besides maybe a bit high mineral contents, that can easily be removed, it's essentially free, clean water. The only question is how much it's replenished in the area you're taking it from.

There's plenty of areas where there's more rainfall, than there is outflow/evaporation, with water continuously replenishing deep groundwater. "Saving water" in such areas is of little concern besides the basic, economic one of well maintenance - each one can only pull so much, and more usage means more wells, and more upkeep.

8. bjackman ◴[] No.45030257[source]
It's nothing like either of those things because both of those things have harms to other people and those harms scale linearly with the amount of consumption. Wasting steak isn't problematic because you run out of cows it's problematic because of the climate impact of raising them.

Saying that saving water is "about respect" or something is idiotic. Saving water is about ensuring there's enough water to go around. This is something you need to do in places where water is scarce and not where it isn't. And if you waste time and energy on saving water you are ultimately making the world poorer.

Obviously I'm simplifying things by talking in absolutes here, but what I said above about "the margin at which it makes sense" gets at the truth of the matter. Installing water-saving taps in Zürich is almost certainly a net harm to the environment.

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9. acyou ◴[] No.45035326{3}[source]
This is one of those cases where we fly by and don't think much about it because we live in a plentiful environment. The more detailed we get, the more we realize that everything has a cost, and wasting water is not free as in beer. Have we also considered the disposal costs of wastewater?

I used to live in a place where water was infinite. Fast forward 20 years, now it's not anymore, the fish bearing watersheds ultimately bear the price, but everyone is still unmetered and there isn't low flow anything. If you piss away precious resources for no good reason and claim it's not wasteful, shame on you.

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10. bjackman ◴[] No.45036208{4}[source]
Yes, I have considered the disposal costs of wastewater! Yes, I still think importing hundreds of stainless steel widgets from China and then having a plumber spend who knows how many hours installing them is almost certainly a net negative. If you piss away precious resources doing that then shame on you.