'Freeze-thaw battery' stores electricity long-term for seasonal release • Hacker News Board

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#41

Post by SECProto » Tue, Apr 05, 2022, 4:41 PM UTC

mabbo wrote: post #10

phh wrote: post #7

It doesn't sound like the improvement of cost is enough the justify using it only for few cycles a year as the title says rather than every other day. That said, I see nothing in this article saying why it would be limited to seasonal release, I'm guessing it just has a lower self-discharge. The title made me thought of an idea my father had, for which I'm still totally ambivalent: Freeze water in the cellar (speakin…

> Freeze water in the cellar (speaking of like 30m^3) using thermal pomp during winter to heat house and when electricity costs little, and use that ice in summer to cool down the house. Unless I misunderstood, the Toronto Zoo has or had such a system setup for one or more of the food pavilions. What's interesting about this is that the storage grows with the volume (n^3), but the heat/cold loss grows with the surfac…

> On hot, sunny days at the end of the summer, warm up the water stored.

Phase change stores/requires much more energy than simple temperature change. 0°C Ice to 0°C water transition is 334J/g, 0C water to 100C water is ~400J/g (ie 4J/g per degree C), 100C water to 100C steam is 2260J/g.

To store heat from the summer for winter warming (say best case 40C summer temp) you'd be looking at least 3x as much material for heat storage vs ice storage for summer cooling (at say -10C)

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#42

Post by nikanj » Tue, Apr 05, 2022, 4:43 PM UTC

jessriedel wrote: post #34

For more on the general problem of storing thermal (rather than electrical) energy on a seasonal basis see https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag... I was especially surprised to learn that serious attempts at storing heat in soil and rock have been made https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag... https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community which in the winter…

Furthermore, we have a real problem with the soil storing heat: https://citymonitor.ai/transport/londons-tube-has-been-runni...

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#43

Post by treeman79 » Tue, Apr 05, 2022, 5:13 PM UTC

mabbo wrote: post #10

phh wrote: post #7

It doesn't sound like the improvement of cost is enough the justify using it only for few cycles a year as the title says rather than every other day. That said, I see nothing in this article saying why it would be limited to seasonal release, I'm guessing it just has a lower self-discharge. The title made me thought of an idea my father had, for which I'm still totally ambivalent: Freeze water in the cellar (speakin…

> Freeze water in the cellar (speaking of like 30m^3) using thermal pomp during winter to heat house and when electricity costs little, and use that ice in summer to cool down the house. Unless I misunderstood, the Toronto Zoo has or had such a system setup for one or more of the food pavilions. What's interesting about this is that the storage grows with the volume (n^3), but the heat/cold loss grows with the surfac…

How does this compare to hauling ice down from a local mountain lake?

Feels like 0-18th century tech. Doesn’t mean it’s bad though.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#44

Post by projektfu » Tue, Apr 05, 2022, 5:28 PM UTC

pjc50 wrote: post #27

KennyBlanken wrote: post #15

Iron flow batteries already exist commercially, are even more non-toxic/safe, and they don't require heating up (and keeping hot, while using) the battery. https://essinc.com/iron-flow-chemistry/ The utility industry isn't really that interested in storing power for an entire season. Very little ROI compared to a system that allows them to balance minute-to-minute or day/night...or transmission infrastructure improve…

I've never really seen the advantage in going off grid per se , since it increases the amount of wasted capacity in both generation and storage, and running a few wires is cheap enough in urban environments. The most efficient arrangement might be a global grid.

I am not off grid, but the thing that would draw me to it is as an individual sustainability goal. Perhaps it would be more expensive to initially set up and run, but it should be sustainable for 20-40 years. There is the side benefit of reducing the demand on energy to acheive this sustainably. Spending less on technology and energy means working less. In other words, we pay in our own time for the time technology saves us.

To quote Thoreau: 'One says to me, “I wonder that you do not lay up money; you love to travel; you might take the cars and go to Fitchburg to-day and see the country.” But I am wiser than that. I have learned that the swiftest traveller is he that goes afoot. I say to my friend, Suppose we try who will get there first. The distance is thirty miles; the fare ninety cents. That is almost a day’s wages. I remember when wages were sixty cents a day for laborers on this very road. Well, I start now on foot, and get there before night; I have travelled at that rate by the week together. You will in the mean while have earned your fare, and arrive there some time to-morrow, or possibly this evening, if you are lucky enough to get a job in season. Instead of going to Fitchburg, you will be working here the greater part of the day. And so, if the railroad reached round the world, I think that I should keep ahead of you; and as for seeing the country and getting experience of that kind, I should have to cut your acquaintance altogether.' Walden, chapter 1, Economy.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#45

Post by coryrc » Tue, Apr 05, 2022, 5:34 PM UTC

awestroke wrote: post #33

Gasp0de wrote: post #19

This doesn't seem cost efficient at all, my (medium sized) house in Germany consumes about 3000kWh of electricity during winter. This does not include heating, which consumes another 15.000kWh (of heat energy from oil, so around 5000kWh electrical energy with a heat pump). If I were to use this battery I would need to get 3000(8000)kWh of energy storage at 23$ per kWh which would amount to 69000(184000)$. There are b…

You heat you house with oil? I thought Germany was environmentally conscious

It's called "greenwashing". A fair bit of electricity is produced with solar (at a far higher cost than their neighbor's carbon-free electricity) but their gasoline and diesel vehicle manufacturing continues unbounded and their heat primarily comes from fossil fuel.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#46

Post by xvedejas » Tue, Apr 05, 2022, 5:36 PM UTC

SECProto wrote: post #41

mabbo wrote: post #10

Earlier quoted context omitted.

> Freeze water in the cellar (speaking of like 30m^3) using thermal pomp during winter to heat house and when electricity costs little, and use that ice in summer to cool down the house. Unless I misunderstood, the Toronto Zoo has or had such a system setup for one or more of the food pavilions. What's interesting about this is that the storage grows with the volume (n^3), but the heat/cold loss grows with the surfac…

> On hot, sunny days at the end of the summer, warm up the water stored. Phase change stores/requires much more energy than simple temperature change. 0°C Ice to 0°C water transition is 334J/g, 0C water to 100C water is ~400J/g (ie 4J/g per degree C), 100C water to 100C steam is 2260J/g. To store heat from the summer for winter warming (say best case 40C summer temp) you'd be looking at least 3x as much material for…

This is a useful thing: storing energy in a phase change makes it easier to keep the energy stored for a longer period of time compared to if there was no phase change. The difficult part is that steam is much farther from ambient temperatures than ice is (and also that it is far less compact). Newton's law of cooling means that the larger the temperature difference, the faster the heat loss, so steam would require much more insulation than ice would.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#47

Post by sacrosancty » Tue, Apr 05, 2022, 6:12 PM UTC

xvedejas wrote: post #46

SECProto wrote: post #41

Earlier quoted context omitted.

> On hot, sunny days at the end of the summer, warm up the water stored. Phase change stores/requires much more energy than simple temperature change. 0°C Ice to 0°C water transition is 334J/g, 0C water to 100C water is ~400J/g (ie 4J/g per degree C), 100C water to 100C steam is 2260J/g. To store heat from the summer for winter warming (say best case 40C summer temp) you'd be looking at least 3x as much material for…

This is a useful thing: storing energy in a phase change makes it easier to keep the energy stored for a longer period of time compared to if there was no phase change. The difficult part is that steam is much farther from ambient temperatures than ice is (and also that it is far less compact). Newton's law of cooling means that the larger the temperature difference, the faster the heat loss, so steam would require m…

Besides insulation, there's no hope of storing thermal energy as steam because the density is 1000 times lower than ice or water while the specific heat is similar, so the heat capacity per unit volume is about 1000 times lower.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#48

Post by mnahkies » Tue, Apr 05, 2022, 6:25 PM UTC

Haplo wrote: post #13

phh wrote: post #7

It doesn't sound like the improvement of cost is enough the justify using it only for few cycles a year as the title says rather than every other day. That said, I see nothing in this article saying why it would be limited to seasonal release, I'm guessing it just has a lower self-discharge. The title made me thought of an idea my father had, for which I'm still totally ambivalent: Freeze water in the cellar (speakin…

Similar systems are actually being build, but with a bigger scale (like big office buildings). There is no freezing involved, just heating the office space with warm water in the winter (cooling the water to ~10°C) and cooling it in the summer (heating the water to about 40°C).

During the rebuild of Christchurch, NZ they used this technique for a number of buildings, basically pumping out water with one well, then re-injecting it with another as I understand.

Essentially exploits the ground water remaining a constant temperature year around, warmer than the surface in winter and colder in summer

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#49

Post by credit_guy » Tue, Apr 05, 2022, 6:38 PM UTC

Sorry to be a killjoy, but $6/kwh is at least 20x too expensive. In 2021, the average price of electricity in the US was 14 cents/kwh. Assuming you charge with free electricity, your charge-discharge efficiency is 100%, there is no capacity loss over the years, and your cost of capital is zero, you need more than 40 years to break even at that price. All the 4 assumptions above and a few others (zero installation and maintenance cost, zero insurance, zero cost of disposal) are super unrealistic.

Re: 'Freeze-thaw battery' stores electricity long-term for seasonal release

#50

Post by AtlasBarfed » Tue, Apr 05, 2022, 7:10 PM UTC

credit_guy wrote: post #49

Sorry to be a killjoy, but $6/kwh is at least 20x too expensive. In 2021, the average price of electricity in the US was 14 cents/kwh. Assuming you charge with free electricity, your charge-discharge efficiency is 100%, there is no capacity loss over the years, and your cost of capital is zero, you need more than 40 years to break even at that price. All the 4 assumptions above and a few others (zero installation and…

"Exploring the use of Iron" "Limited by Nickel"

"Limited by Nickel": This is just lithium ion battery storage, it is plainly obvious.

"Exploring the use of Iron": using LFP (which will be 200-230 wh/kg in production later this year)

"Added some sulphur": great, but you're wayyyy behind the current state of the art research in Li-S.

That cost is appropriate for maybe a day or two of storage. Months between seasons? That's ridiculous, even if we had a dirt-cheap 200 wh/kg sodium ion battery which COULD probably hit 6$/kg, unlike their unnamed/unspecified techs they are "looking into". Likely it is since every other battery buzzword was notched in this article.

The use case, providing more energy in the summer, is covered with solar + couple day grid storage and existing nuclear or gas turbine for load leveling.

What we need is to install as much wind and solar as possible to immediately eliminate coal, then add storage and more wind/solar as needed to start eating away at gas turbine. Nuclear should stick around for long-term load levelling until batteries become dirt dirt dirt cheap.

This article is so poorly written that it might as well be unintentional FUD.