A thermal battery that uses superheated bricks [video](youtube.com)
youtube.com
A thermal battery that uses superheated bricks [video]
https://www.youtube.com/watch?v=R9XMWHFzPs8
75 comments
But what is the effeciency of such a system?
In the first minute of the video they claim “98% storage efficiency.” Not sure exactly what that means though.
This page gives 1% loss per day: https://rondo.com/how-it-works
But clearly that's energy in -> steam out, not including any losses from converting from steam back to electricity for example. Although clearly they are targetting first processes that require steam as an input.
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Apparently electric heating is 100% efficient from some basic googling. I had no idea this was the case. So maybe the 98% efficiency is not totally bullshit.
No machine has perfect efficiency
The losses are heat. Resistive heating is 100% efficient. Use a heat pump though and you can get to 300%-400% efficiency because you are using the energy to move heat from one place to another instead of turning it into heat.
Referring to COP as efficiency is an intentionally misleading practise pushed by the heat pump industry that makes communication worse for everyone forever if we accept it and doesn't really help anyone.
Refer to it as COP or as moving 3 units of heat for one unit of input.
Refer to it as COP or as moving 3 units of heat for one unit of input.
You’ve got to expound on this a little more because 300-400% efficiency doesn’t make sense.
The comment you're replying to probably meant to say it has a coefficient of performance [1, 2] of 3-4.
[1] https://en.wikipedia.org/wiki/Coefficient_of_performance
[2] https://en.wikipedia.org/wiki/Heat_pump#Performance
[1] https://en.wikipedia.org/wiki/Coefficient_of_performance
[2] https://en.wikipedia.org/wiki/Heat_pump#Performance
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Heat goes in. Heat goes out. It's already thermalized.
You can't kill what is already dead.
The right question is how much heat escapes? This will depend on time, and they seem to be claiming 12 hours effectiveness which would seem to imply half of the heat escapes at max storage somewhere between 3 and 24 hours.
You can't kill what is already dead.
The right question is how much heat escapes? This will depend on time, and they seem to be claiming 12 hours effectiveness which would seem to imply half of the heat escapes at max storage somewhere between 3 and 24 hours.
No, the right question is "what is the efficiency of the system". It already entirely encapsulates the lesser question of how much heat escapes.
That question has no defined answer. It's like asking 'how many cups of water should I drink'. Or 'how much deisel does my bicycle use'.
It depends on both time and how full it is. Possibly also how full it has recently been as well in the case where it is filled unevenly to reduce loss.
Without anything more specific than '1% loss a day' from their marketing copy, it's difficult to say, but probably "about 90% in typical use" if you want to be even more reductive than that rather than encouraging clear communication.
It depends on both time and how full it is. Possibly also how full it has recently been as well in the case where it is filled unevenly to reduce loss.
Without anything more specific than '1% loss a day' from their marketing copy, it's difficult to say, but probably "about 90% in typical use" if you want to be even more reductive than that rather than encouraging clear communication.
Details: bricks can be heated up to 3000 deg (Celsius?). The heat that comes out is only 120 deg Celsius.
It's a heat storage system. Before water is used. Now we can use bricks.
It's a heat storage system. Before water is used. Now we can use bricks.
No, the 120°C is for residential district heating. According to their website, they can heat up air to over 1000°C: https://rondo.com/how-it-works
F, not C. Alumina melts around 2000 C and boils at 2977 C.
1)The system clearly doesn't exist, or we'd see pictures and video of it. Given how simple such a system is, and that they've received tens of millions in financing, why do they not have even a small scale demonstrator?
2)The video is nothing more than a dressed up zoom "interview" with the CEO and some stock video clips. Everything should be assumed to have been written by, or at least thoroughly vetted by, Rondo.
3)For example, the claim is that lithium ion batteries are expensive at grid scale...but the cost of such batteries continues to fall, there's now commercially viable recycling for them, and other technologies such as iron-flow are cheaper, do not require rare-earth metals, and are already in the commercial marketplace. So is pumped hydro, which they also don't address.
4)The immediate and pretty obvious drawback to their "dynamic insulation" concept: if you stop pumping air through the "battery", the insulation that is rated to only handle 150C is suddenly exposed to thousands of degrees...and now you have a fire, backed by an enormous thermal mass, which is a problem, as firefighting is largely based on using the phase change of water to pull more heat away from a fire than the fire can generate.
5)While this tech sounds nice for industrial processes, it's not anywhere near as practical for domestic heating, where geothermal heat pumps will be more efficient. At its core, this is a system that is fueled by resistive heating, and heat pumps are several times more efficient than resistive heating.
What would be interesting is if they're able to leverage solar radiation directly via solar concentrators. You'd see a roughly four-fold increase in efficiency over solar.
2)The video is nothing more than a dressed up zoom "interview" with the CEO and some stock video clips. Everything should be assumed to have been written by, or at least thoroughly vetted by, Rondo.
3)For example, the claim is that lithium ion batteries are expensive at grid scale...but the cost of such batteries continues to fall, there's now commercially viable recycling for them, and other technologies such as iron-flow are cheaper, do not require rare-earth metals, and are already in the commercial marketplace. So is pumped hydro, which they also don't address.
4)The immediate and pretty obvious drawback to their "dynamic insulation" concept: if you stop pumping air through the "battery", the insulation that is rated to only handle 150C is suddenly exposed to thousands of degrees...and now you have a fire, backed by an enormous thermal mass, which is a problem, as firefighting is largely based on using the phase change of water to pull more heat away from a fire than the fire can generate.
5)While this tech sounds nice for industrial processes, it's not anywhere near as practical for domestic heating, where geothermal heat pumps will be more efficient. At its core, this is a system that is fueled by resistive heating, and heat pumps are several times more efficient than resistive heating.
What would be interesting is if they're able to leverage solar radiation directly via solar concentrators. You'd see a roughly four-fold increase in efficiency over solar.
> The system clearly doesn't exist, or we'd see pictures and video of it.
> While this tech sounds nice for industrial processes, it's not anywhere near as practical for domestic heating, where geothermal heat pumps will be more efficient.
A family member had a heat storage system that used electricity to heat bricks about a decade ago. Worked great for home heating with time-of-day rates (especially with some solar to offset the peak rate daytime). And the purchase cost was very low, unlike any sort of ground source heat pump.
> While this tech sounds nice for industrial processes, it's not anywhere near as practical for domestic heating, where geothermal heat pumps will be more efficient.
A family member had a heat storage system that used electricity to heat bricks about a decade ago. Worked great for home heating with time-of-day rates (especially with some solar to offset the peak rate daytime). And the purchase cost was very low, unlike any sort of ground source heat pump.
> For example, the claim is that lithium ion batteries are expensive at grid scale...but the cost of such batteries continues to fall
The rate at which they have been falling has been diminishing for quite some time, until this year when they are starting to rise (more than inflation).
The idea that past price movements will always continue indefinitely has zero basis in reality.
And yes li-ion batteries are way too expensive for large scale grid usage, even if they did fall at 10% yearly we would be decades away for them to be a satisfactory solution.
The rate at which they have been falling has been diminishing for quite some time, until this year when they are starting to rise (more than inflation).
The idea that past price movements will always continue indefinitely has zero basis in reality.
And yes li-ion batteries are way too expensive for large scale grid usage, even if they did fall at 10% yearly we would be decades away for them to be a satisfactory solution.
> The idea that past price movements will always continue indefinitely has zero basis in reality.
This is true. Any pretend exponential curve is at best a logistic curve near the beginning or middle.
But there are good reasons to think batteries as a whole are in the class of logistic curves near the middleish.
There are lots of chemistries in the 500-1000Wh/kg range with various deal-breakers making them not an option. Chemical reactions go up to about 10,000Wh/kg and some of them as yet undiscovered might resemble 'battery' more than 'fuel cell' or 'magic portable nuclear thingy'.
Simple few component mass produced objects made of abundant materials once every ounce of cleverness in production is wrung out tend to cost around $1-10/kg plus their energy cost.
So if we set the upper asymptote at around $1-10/kWh, old technologies are around $1000 per usable kWh and LiFePO4 is around $300/kWh for final products you can actually buy.
It seems reasonable to posit that $20/kWh is achievable before going too far past the inflection point. This is in line with CATL claiming $60/kWh for SIB in the late 2020s, then having costs taper off and settle around $30/kWh in 2040 as the low hanging fruit are all gone. Maybe there'll be a new discovery around then that pushes it down to $1, but it seems unlikely.
This is true. Any pretend exponential curve is at best a logistic curve near the beginning or middle.
But there are good reasons to think batteries as a whole are in the class of logistic curves near the middleish.
There are lots of chemistries in the 500-1000Wh/kg range with various deal-breakers making them not an option. Chemical reactions go up to about 10,000Wh/kg and some of them as yet undiscovered might resemble 'battery' more than 'fuel cell' or 'magic portable nuclear thingy'.
Simple few component mass produced objects made of abundant materials once every ounce of cleverness in production is wrung out tend to cost around $1-10/kg plus their energy cost.
So if we set the upper asymptote at around $1-10/kWh, old technologies are around $1000 per usable kWh and LiFePO4 is around $300/kWh for final products you can actually buy.
It seems reasonable to posit that $20/kWh is achievable before going too far past the inflection point. This is in line with CATL claiming $60/kWh for SIB in the late 2020s, then having costs taper off and settle around $30/kWh in 2040 as the low hanging fruit are all gone. Maybe there'll be a new discovery around then that pushes it down to $1, but it seems unlikely.
It's also not clear how quickly heat can be extracted from the bricks. There were decades of research on energy storage in molten sodium-potassium nitrate because it's a liquid so your output is always very close to the temperature of the salt bath. Clay is not a great heat conductor.
> It's also not clear how quickly heat can be extracted from the bricks.
This is a commonly defined material property [1]. You would simply size your bricks to suit the situation - given same volume, more surface area means faster heat flow.
[1] https://en.wikipedia.org/wiki/Thermal_conductivity
This is a commonly defined material property [1]. You would simply size your bricks to suit the situation - given same volume, more surface area means faster heat flow.
[1] https://en.wikipedia.org/wiki/Thermal_conductivity
Interesting engineering, but a little sad that the presentation needs to talk down other solutions to make this one seem better.
Demand responsive electrical heat is a solid proven tech, it's only going to expand across industrial sectors via innovations like this. I see no need to talk about perceived lithium battery deficiencies. Bill Gates gets mentioned and he seems a repeat offender in this regard.
Demand responsive electrical heat is a solid proven tech, it's only going to expand across industrial sectors via innovations like this. I see no need to talk about perceived lithium battery deficiencies. Bill Gates gets mentioned and he seems a repeat offender in this regard.
Here's a text-based explanation of what this is:
https://rondo.com/how-it-works
https://rondo.com/how-it-works
The swapped labels for solar and wind should be corrected, something I mention because someone from the team will see this comment eventually.
One point in the video talks about that this is novel/interesting because it can handle much higher heat then other thermal storage systems. But at the end of the video it talks about the output being only a bit above 150 degrees. Isn't that completely contradictory? If I want to use this in a steel forge this isn't even remotely close enough.
That's just for district heating, right? They can degrade the heat down to 150 F for that purpose. If they really wanted to, they could extract some power from the high grade heat and produce 150 F waste heat.
Energy is extracted via a heat exchanger. The rate of heat flow in a heat exchanger is proportional to the temperature difference between the hot and cold sides. The closer they are to thermal equilibrium, the slower you can extract energy.
When heating is required, they make much more sense than lithium-ion batteries as they are cheaper, use no critical materials, last longer, and are just as efficient!
What method are they using to extract energy from the bricks that's as efficient as lithium-ion discharging?
What method are they using to extract energy from the bricks that's as efficient as lithium-ion discharging?
This isn't an electricity solution, they are asserting that ~27% of global energy consumption is for industrial heating, which is a more straightforward use case for hot bricks.
edit: I misspoke, 27% of greenhouse gas emissions are asserted to be from industrial heating applications, not 27% of energy use.
edit: I misspoke, 27% of greenhouse gas emissions are asserted to be from industrial heating applications, not 27% of energy use.
Are lithium-ion batteries typically used for industrial heating? That is what these bricks are being compared to. They are even using the terms "charge" and "discharge", and proposing an end to battery storage.
We are going to have lot of intermittent energy production with wind and solar energy. This is a cheap way to convert that to continuous heat for industrial processes, instead of storing it as electricity in expensive batteries.
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...okay ? But how the bricks help ?
Like, there is some merit in say heating up the "heat battery" at peak solar power (or just when grid energy is cheapest) then using that to heat directly but... you're still doing it at 100% efficiency while heat pump does that at 200-300% using nothing but ambient temperature to get that efficiency.
I guess you could use it as a hybrid solution with heat pump for very cold climates that would normally disqualify heat pumps (heat the brick during the day, use heat pump to get the heat back) but even that is kinda meh.
Like, there is some merit in say heating up the "heat battery" at peak solar power (or just when grid energy is cheapest) then using that to heat directly but... you're still doing it at 100% efficiency while heat pump does that at 200-300% using nothing but ambient temperature to get that efficiency.
I guess you could use it as a hybrid solution with heat pump for very cold climates that would normally disqualify heat pumps (heat the brick during the day, use heat pump to get the heat back) but even that is kinda meh.
Renewables open up a huge opportunity for exploiting the fluctuating availability and therefor price of energy.
Thermal storage is one way to execute. Buy solar power when it's cheap at noon and use it for heating at midnight when power is expensive.
Thermal storage is one way to execute. Buy solar power when it's cheap at noon and use it for heating at midnight when power is expensive.
"Renewables open up a huge opportunity for exploiting the fluctuating availability and therefor price of energy."
Actually it is the complete opposite, wind and solar create a huge PROBLEM with its unreliable fluctuating output.
Actually it is the complete opposite, wind and solar create a huge PROBLEM with its unreliable fluctuating output.
It is a way to mitigate the variability of wind and solar power. You can heat the bricks with solar electric during the day and use it at night, or heat them with wind power and use the heat when it isn't windy.
They are talking about "heat" as in "industrial heating", not heating your home. Can heat pumps heat steam up to 1000°C?
In the US 2/3rds of industrial heat demand is at temperature <= 300 C, and various kinds of heat pumps would be very useful for those applications.
Do you happen to have a source/reference for that?
Thanks! That's an excellent link.
I think “where heating is required” is the key caveat.
This is basically going back to the old way of heating homes: When energy is cheap, heat a giant thermal mass. When energy is expensive, leach the heat to other areas where it’s needed.
In the old days this would be a giant brick or clay stove that would heat up during the day (when people are awake to tend the fire) and radiate heat to keep the building warm through the night.
I’m the modern version it’s likely steam pipes heated by the mass that bring the heat to wherever it’s useful (whether that’s an industrial kiln or a home’s radiators). That cycle can be extremely efficient, but you obviously only get heat, not electricity.
It’s probably a good thing to do in some contexts but if I understand it right I’m not sure I’d call it innovative.
This is basically going back to the old way of heating homes: When energy is cheap, heat a giant thermal mass. When energy is expensive, leach the heat to other areas where it’s needed.
In the old days this would be a giant brick or clay stove that would heat up during the day (when people are awake to tend the fire) and radiate heat to keep the building warm through the night.
I’m the modern version it’s likely steam pipes heated by the mass that bring the heat to wherever it’s useful (whether that’s an industrial kiln or a home’s radiators). That cycle can be extremely efficient, but you obviously only get heat, not electricity.
It’s probably a good thing to do in some contexts but if I understand it right I’m not sure I’d call it innovative.
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And just using a heat pump will have vastly lower total energy usage.
It could be interesting in niches like say have some thermal storage (that say gets recharged at peak solar) for heating water on demand instead of draining battery for that, but that's a lot of extra complexity to save on some more batteries
It could be interesting in niches like say have some thermal storage (that say gets recharged at peak solar) for heating water on demand instead of draining battery for that, but that's a lot of extra complexity to save on some more batteries
No reason not to combine them.
Have a big brick or water thing inside. Heat it while it is sunny with a heat pump.
Hell you could even melt a few tons of sodium acetate during summer and use it for december/january
Have a big brick or water thing inside. Heat it while it is sunny with a heat pump.
Hell you could even melt a few tons of sodium acetate during summer and use it for december/january
I suspect heat pumps are the future for domestic heating, but I’m not sure it’s feasible for industrial uses. Very hard to get a heat pump that can make a 1000* difference between the hot and cold side.
My comment probably shouldn’t have even mentioned home radiators.
My comment probably shouldn’t have even mentioned home radiators.
It's not that heat pumps aren't capable of making a 1000K temperature difference, but with an ambient temperature of around 300K even the theoretical advantage of using a heat pump instead of straight up heating is just ~40%.
It's not nothing, but getting close to the theoretical limit tends to be incredibly annoying when it comes to thermodynamics. Typically it requires doing stuff extremely slowly (so you're always close to thermal equilibrium), which means it's nowhere near fast enough or you need almost perfect insulation etc.
It's not nothing, but getting close to the theoretical limit tends to be incredibly annoying when it comes to thermodynamics. Typically it requires doing stuff extremely slowly (so you're always close to thermal equilibrium), which means it's nowhere near fast enough or you need almost perfect insulation etc.
Why is the ambient temperature important? Isn't it about thermal energy? So wouldn't a heat pump just need to be much larger to work up to 1000 degrees or more?
Say, I have a heatpump that heats up water to 100°C at ambient temperature of 10°C. Couldn't I feed that hot water into another heat pump that heats up water to 200°C and so on?
Say, I have a heatpump that heats up water to 100°C at ambient temperature of 10°C. Couldn't I feed that hot water into another heat pump that heats up water to 200°C and so on?
You could, though the combined setup of two heat pumps is still subject to the theoretical limits of a single heat pump. This particular law holds for any conversion from work into a temperature gradient (or the reverse). Any setup that is more efficient would violate the second law of thermodynamics, which results in a nigh infinite supply of energy.
You can make heat pumps 10x more efficient by using 10x smaller increments of temperature, but then you also need to pump each unit of heat 10 times so in the end it doesn't cost less energy to make a bigger temperature gradient.
You can make heat pumps 10x more efficient by using 10x smaller increments of temperature, but then you also need to pump each unit of heat 10 times so in the end it doesn't cost less energy to make a bigger temperature gradient.
At each 90 degree jump you might, say, put in one unit of work to move two units of heat.
The problem is at step two you have three units of heat, two of which came from ambient heat.
At step three you have 4.5 units of heat, two of which came from ambient heat.
Step five there are 6.75..and so on.
You're expending a lot of energy moving energy you put in so you get diminishing returns.
The theoretical limit is T_hot / T_change (in absolute units like kelvin). If your change is roughly the hot temperature, there's no benefit.
The problem is at step two you have three units of heat, two of which came from ambient heat.
At step three you have 4.5 units of heat, two of which came from ambient heat.
Step five there are 6.75..and so on.
You're expending a lot of energy moving energy you put in so you get diminishing returns.
The theoretical limit is T_hot / T_change (in absolute units like kelvin). If your change is roughly the hot temperature, there's no benefit.
If you have the liquids with the properties to handle that you could.
To make it easier you would have to halve each next heat pump specs, so that the earlier pump can deliver to both the condensor and the evaporator.
It’s actually starting to perk up on the industrial side as well!
https://norwegianscitechnews.com/2021/04/developing-the-worl...
https://norwegianscitechnews.com/2021/04/developing-the-worl...
> producing temperatures of up to 180 degrees celcius
That's a bit short of the 1000°C that Rondo's system promises, so these approaches are useful for very different applications.
That's a bit short of the 1000°C that Rondo's system promises, so these approaches are useful for very different applications.
If using heat pump - can you have an additional container to store pressurised refrigerant? Or that only works for cooling?
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Trying to understand what a “heat echo chamber” is. Maybe the thermal mass is enclosed in a metal box?
Means infrared radiation is reflecting multiple times inside the walls of the structure, analogous to an echo chamber. (I think).
Since it's a very high temperature device, much of the heat transfer going on is through thermal radiation.
Since it's a very high temperature device, much of the heat transfer going on is through thermal radiation.
Is it economical for anything besides heating?
It's probably most economical for industrial processes that need super-heated steam or air. For space heating, a heat pump is so much more efficient than a resistance heater that it would be hard to beat.
Probably not but I live in a country with cold winters where it would be quite useful. It would probably also be useful to industry where high heat is needed for various manufacturing processes. The video mentions this.
It's just the resistive heating tho. Sure, it might allow you to buy the electricity to produce heat at lower rate but it fundamentally does not change the amount of energy you need to consume (well, increases it for losses).
Ideally you would want to use heat pumps which can produce up to 4 times as much heat as resistive heaters with the same amount of electricity.
Another option might be concentrated solar power.
Another option might be concentrated solar power.
It decreases the necessity of other types of batteries for this application, which is a substantial amount of energy consumed in the world.
Better to have some hot bricks being used for heating i the industries, even with lower efficiency, than having to supply the same thermal energy by storing it as electricity in some chemical battery.
Multipronged approaches are the only way for humans to become more energy-efficient.
Better to have some hot bricks being used for heating i the industries, even with lower efficiency, than having to supply the same thermal energy by storing it as electricity in some chemical battery.
Multipronged approaches are the only way for humans to become more energy-efficient.
heating uses the vast majority of domestic (and dare I say often industrial) energy consumption. so it matters, even if it's not for electric generation. A lot of rooftop solar systems go direct to water heating, being more efficient than rouoting that through electrics. (ideally, you want both)
The title is clickbait.
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This is nothing new, residential heaters have been using the same principle for ages: https://en.m.wikipedia.org/wiki/Storage_heater
The novel thing about this design is that it relies on infrared radiation to avoid hot spots in the bricks and increase the rate it can charge.
And the car was "nothing new" because horses have been pulling carriages for ages.
The innovation of their technology is in how they solve the problem. Watch the video.
The innovation of their technology is in how they solve the problem. Watch the video.
I did watch the video. The founder interviewed said much the same thing: this is not novel tech, they're combining existing (proven) tech in a new way.
Which is great! I didn't say it wasn't. But the title and first half of the video,and half of the comments here, make it sound like it's a replacement for electrical batteries, which it isn't.
For example, video compares this to gravitational storage (pumping water back up for hydro plants) which makes no sense, as you don't get electricity back out of this.
So, yes, clever use of tech. The video is fanboyism to the 11th and instead of allowing the tech to stand on it's own two feet, goes very close to actually be misinformative.
Which is great! I didn't say it wasn't. But the title and first half of the video,and half of the comments here, make it sound like it's a replacement for electrical batteries, which it isn't.
For example, video compares this to gravitational storage (pumping water back up for hydro plants) which makes no sense, as you don't get electricity back out of this.
So, yes, clever use of tech. The video is fanboyism to the 11th and instead of allowing the tech to stand on it's own two feet, goes very close to actually be misinformative.
Electricity is used to heat up bricks. Bricks store heat for very long durations. Bricks transfer heat to other systems for industrial heating such as boiling chemicals or steam ironing clothes.
This replaces the fossil fuels used for industrial heat.