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They should've used lasagna. You could be in a tundra heating it over a fire and, as long as you get it sufficiently and consistently hot, it'll still burn your mouth 20minutes later.

It uses phase change (solid to liquid) to store heat at about 200 kJ/kg. Compare this to heating water in a boiler from 10c to 60c - stores 209 kJ/kg.

So we already have an effective way to store heat which can work for decades without servicing and is also cheap to produce (in terms of money and energy consumption).

Perhaps I am missing something; this product already exists as the Sunamp Thermino.

https://sunamp.com/en-gb/hot-water-solutions-thermino-range/

> But storing the heat they produce has not been possible

Many heat pumps are installed with a large insulated buffer of water (for ex. 300L), which stores heat pretty well?

And homes that use underfloor heating in concrete can store heat pretty well too. Many people use that to heat up the home when energy is cheap and disable the heat pump when it is expensive.

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climates they make your house work that much harder to keep the space warm.

The most optimistic hope is that the government mandate will force enough demand that manufacturers can enjoy some economies of scale and actually try to compete on price. I don't think this will happen anytime soon.

This is similar to nighthawkinlight's videos on phase change materials. It was very cool to see how his Ziploc bags of homemade goo helped regulate temperature.

I was interested to learn about cold district heating recently, which is basically a municipal scale geothermal system.

https://en.wikipedia.org/wiki/Cold_district_heating

I would love to see a bus-sized version for year-long temperature moderation. Like, drop house heat into it during the summer so it can re-heat the house over the winter, and pull all the heat out of it by Spring so that it can cool the house over the summer.

Bus sized because that amount of thermal mass is bound to take up a lot of space, but capable of being buried so that it doesn’t actually take up property space.

Not many numbers in there. I would be interested in some measure of energy and effect per volume, e.g how many kWh of heat are we talking about at e.g 1 liter, and how fast (kW) can it produce it?

I wonder if this can store any heat or just heat pump heat. If it can store any heat, it would help a lot to further reduce heating costs in our modern energy efficient house.

Sometimes, in the winter, we get too much solar forcing, so if we don’t heat all, it can be 85F in the day in the house, but 60-65 at night. (We open the windows during the day, and don’t always close them at exactly the right time at night.)

The article omits some critical details:

It says this is both a "heat pump" and also "storage" AND says that it will run when electricity is cheap or plentiful. Thus:

1: Where does it pump the heat from? (Or is this not really a "heat pump" and instead is using resistive heating?)

2: How long does it store heat? Is this something that will store heat on a 24-48 hour basis, or will this store heat during the spring / fall when longer days mean extra power from residential solar, and then use the heat in the winter?

3: Is the unit itself "warm" when storing heat? Or is the heat stored in a purely chemical way and needs to run through a catalyst or similar to get it back?

4: Can this be scaled up for general domestic heating?

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Just an FYI: There are plenty of schemes with resistive electric water tanks to store heat when power is cheap.

An 85% round-trip efficiency and 4X smaller volume sound great, but how does the installed cost compare to just oversizing a hot water tank or running the heat pump harder during off-peak hours?

the idea is theoreticaly good, but as it depends on sealing incompatable materials apart, there will be problems, and issues with disposing of failed units.Dry sand works as thermal storage without any issues, and only needs more space, competition will be stiff.Water also works, and ordinary off the floor systems can be used with no modifications. The only advantage the system will have is in places where space constraints combine with the desire for fancy solutions and ecobabble.

Related, TIL the US is effectively banning residential electric resistance water heaters in 2029, with heat pump water heaters being the only type that can meet the new standards. Users will see a 2-3x in cost difference and a 3 to 8 year payback on savings.

I'm interested in storing cold, not heat

Storing cold during the night is probably more efficient

I thought about making ice blocks with a freezer on my balcony, probably not a good idea

With the adoption of sodium batteries, I wouldn’t be surprised if solar panel + sodium battery would outperform this system by a lot.

Where I live we need a way to store and distribute cold as needed.

Private equity / Wall St. megacorps want to sell you complex systems that are fragile, unaffordable by the 99%, have short warranty periods, wear out quickly, require cloud logins and proprietary maintenance parts, and are mandated by law.

GFL buying a simple resistive-heated clothes dryer, furnace, or tanked/tankless water heater in 2030.

So it's a large version of those rechargeable hand-warmers?

Starting to get more optimistic about our energy future. Things seem to be tracking pretty good

Stones has the ability to store heat and keep cool.

What's all this fuzz about ?