

Heating houses with 'nerd power' - coob
http://www.bbc.co.uk/news/magazine-32816775

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shalmanese
So I looked into doing this on a personal level a while back and did some back
of the envelope calculations and it was hard to square the economics of it.

Two factors made it really difficult:

1\. All computation is done in DC. Even if you assume all other prices fall to
0, the AC->DC conversion cost on a per watt basis makes it hard to compete
with cheap heaters which can operate on pure AC. Just power supplies capable
of powering 1000W of computation costs a lot more than a 1000W heater, even
used. You need to get the economics exactly right to make this scheme
profitable and the factors are so sensitive to shifts that it's hard to plan
for the capex.

2\. There's a noise/convenience/space tradeoff that's hard to square. Ideally,
you want the heat to be close to the users but the noise to be far away. It's
hard to make electronics perform well above 100C as opposed to resistive
elements that work fine up to 1000C. That means either moving air quickly
(noise) or moving it over a large area (space). Neither of these are ideal.

It's possible for these two factors to be overcome but they're sizable and
makes me uncertain whether it'll ever be possible to scale this as a viable
business vs a cool idea that gets trotted out in trend blogs once every few
months.

~~~
jacquesm
The whole trick about any kind of 'co-generation' is that you get something
you need (computation) _and_ something that you can use that would otherwise
go to waste (heat).

The only time that scheme does not work is if you don't need the heat.

~~~
shalmanese
Right, but the profit from co-generation from 100W of computation has to be at
least greater than (cost of generating 100W of DC) - (cost of providing 100W
of pure heat).

I was looking at it in the context of bitcoin mining at the time but it's
remarkably hard to find computational tasks that both generate good $/FLOP
returns and are stable and scalable which is what a scheme like this needs.

~~~
tinco
I'm a bit confused, don't the losses of an AC->DC converter go into heat as
well? Why is that less efficient than a cheap AC heater? Is the energy lost in
some other way or is the heat generated by the converter not usable?

~~~
jacquesm
You're not confused at all. The computational device is a 100% efficient space
heater _and_ at the same time does something other than just heat space.

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frobozz
I'd rather see this kind of thing heating water, which could then be used
either for space heating or directly as hot water (in both cases, as input to
a conventional boiler, rather than being expected to provide all the heat
itself). In places with large seasonal temperature variations, one typically
still wants hot water for washing, etc. even when space heating would be
undesirable.

To combat seasonal demand, last-mile, and access control issues, I would
actually want to see this set up either as a district heating scheme* (e.g. in
the large buildings built for mechanical telephone exchanges); or to heat
water for municipal or club swimming pools.

* [https://en.wikipedia.org/wiki/District_heating](https://en.wikipedia.org/wiki/District_heating)

~~~
txdv
Some ex soviet countries have city central heating systems. I am from Vilnius,
Lithuania, we had that in our old flat. Maybe it might be a good idea to
create data centers around there?

The only unsolved (as in _I_ don't have an idea) problem is, what do we do
with all the heated water in summer?

~~~
Retric
New York also has centeral heating for several buildings.

~~~
sanswork
Toronto has Enwave which does district heating with steam. The same company
also does cooling by piping in cold water from the bottom of Lake Ontario.

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netfire
This seems like an interesting, but inefficient solution. (What do you do
during the summer when heat isn't needed? How much more do these units cost
over a regular computer at a data center? Who is paying for the electricity
and bandwidth for these machines?)

Is there some sort of complementary process that could use the heat generated
by the data center at the site itself? (energy production, manufacturing, etc)

~~~
IkmoIkmo
Yeah that's much more interesting. There's a limited need to do these things
locally. Not just data centres btw, factories, too, actually mainly.

But that requires heat pipes throughout cities, basically next to your
electricity, internet, water & sewage, you now want additional heat pipes
running through every home. That requires huge infrastructure investments,
which makes sense for new real estate, but is probably not worth it for
existing homes.

Lower hanging fruit is actually other factories. The infrastructure to connect
these two is much more trivial in scale, as well as in execution (laying a
pipe in sandy industrial land isn't as big a deal as under paved residential
areas). For non-factory buildings like swimming pools, this works great, too.
So in the Netherlands for example there's one milk factory which heats and
cleanses swimming pool water. (the pool was built with this in mind though,
not retrofitted). And one large elderly home is heated by waste heat from a
sewage cleaning facility. Another entire industrial area of factories is
supplied with the heat from a waste burning facility. All of this is much
easier than tackling homes, for now.

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rlpb
I've always found it interesting that electric radiators are 100% efficient
but if you treat a computer as a radiator then you get the same 100%
efficiency but extra computations done on top.

~~~
erikb
Was that a joke? Both points are wrong. Electric radiators aren't 100%
efficient, can't be. e.g., some of the transformed energy will be light (the
metal gets red when it starts to get hot).

And of course if you use a computer then X% will go into the computation. The
reason why it might be cost efficient for you is because the server guy thinks
he has the same costs for electricity no matter if the server is in the data
center or in your home, and therefore pay your bills for the server heater.

~~~
gus_massa
Part of the energy can get transformed into light (mostly infrared) or sound,
but unless it goes out by the window, all that energy will bounce until it's
absorbed by a the walls and furniture. It's very easy to get 100% electricity
to heat conversion if you have not windows.

You get also 100% conversion with a normal lamp or a sound system (unless they
are very close to a window). You get all the heating, and the light or music
for free.

~~~
erikb
I investigated further into that. The confusion arrised from unclear wording
in my memory, I guess. You are right electricity to heat is 100%. The
inefficiency of electric heat radiators is in the electricity production being
inefficient compared to burning the same resources for heat directly.

------
pol0nium
Related : [http://www.qarnot-computing.com/](http://www.qarnot-computing.com/)

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vanderZwan
Sounds like a good idea, although it appears to still use convection heating,
which is the least sustainable form of heating. Low Tech magazine has some
relevant articles related to the topic[0][1].

Anyway, back when I still used desktop computers I always made sure they were
placed in such a way that they doubled as a heater for my feet. Now that I
think of it, it probably would have combined quite nicely with a kotatsu-style
set-up[2].

[0] [http://www.lowtechmagazine.com/2015/02/heating-people-not-
sp...](http://www.lowtechmagazine.com/2015/02/heating-people-not-spaces.html)

[1] [http://www.lowtechmagazine.com/2015/03/local-
heating.html](http://www.lowtechmagazine.com/2015/03/local-heating.html)

[2]
[http://en.wikipedia.org/wiki/Kotatsu](http://en.wikipedia.org/wiki/Kotatsu)

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ZipGreen
There are a team of folks in NYC working on combined heat and computation as
well – Project Exergy ([http://projectexergy.com/](http://projectexergy.com/))

Seems like the model is something that will become more familiar in the
future.

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sdoering
We do have some startups in Germany, that do that kind of thing already. So
their story seems likely to be PR BS to me.

I was asking myself the question, if I would trust my data to be stored around
the country in different private homes. And as a user of a heating solution, I
would ask myself, how secure their business model is. If i switch from gas to
server based heating, I would have to be sure, that 5 years from now, I would
not have to shoulder the costs of switching back (one provider lets you have
free heating for the costs of switching from gas/oil to server based).

So as interesting, as I find these ideas, as a homeowner, I would not want to
have to switch heating during midwinter because the cloud provider goes down
the drain.

~~~
erikb
Why would you replace your old heating system? I would think of that as an
additional heat source that enables you to save some resources from your
general heating system.

Think of it as the solar water heater on a house's roof. It doesn't always
works but when it works it helps you save some money on other options.

~~~
sdoering
Well the ones I found in Germany need you to change the system, as they do not
provide heat directly in the rooms, as in the OP, but have a central system
(server rack) that heats the whole house/flat and docks onto the existing
piping.

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richardbrevig
> To prevent the server stacks overheating, tech companies spend vast sums on
> cooling technology - more than a third of a data centre's hefty energy bill
> may go on air conditioning.

Data center cooling isn't necessary. I saw a presentation by Christian Belady,
the general manager of Data Center Services for Microsoft's Global Foundation
Services (GFS) group, where he spoke about how they don't cool their data
centers anymore. He tested the theory by putting a bunch of racks outside in a
tent to see that they wouldn't overheat.

~~~
DanBC
You need to cool the bits where the humans are.

~~~
richardbrevig
Agreed, and that's what he said, the cooling was for humans, not the servers.
I think their current plans are open where they let air in from outside.

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herendin
It would be very interesting to compare this to Bitcoin mining, on a dollars
per watt chart.

At first, I thought it would be simple, but soon realized there are many, many
factors involved

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teamonkey
It doesn't go in to detail about how it's free to use. Presumably as well as a
fibre optic cable it needs to be plugged into the grid, so do you need to
invoice them for power costs at the end of each month?

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cosmolev
"user needs heat but the internet is down and the radiator has nothing to work
on, it starts performing dummy equations" \- even bitcoin mining is greener
than this

~~~
msellout
Yes, that's an unlikely scenario. As you say, they can mine bitcoin.

