Zeolite retains heat indefinitely, absorbs 4x more heat than water
extremetech.com
extremetech.com
Zeolite + water <-> Zeolite & water complex + HEAT
The reaction happens at the surface of the zeolite, so the storage capacity is proportional to the surface area of the pellet. If you make the pellet highly porous, this can be proportional to its volume.
In contrast, when you store heat in Zeolite, you are not storing it as kinetic energy, you are driving an endothermic chemical reaction that stores the energy in high-energy chemical bonds. After you are done heating the Zeolite to "charge" it, it will return to the ambient temperature, but it still has (lots of) energy stored in the chemical bonds. This energy does not dissipate in the way that the kinetic energy of a high-temperature substance would. The energy can only be released by reversing the chemical reaction, so it is securely stored. You can then transport the Zeolite at ambient temperature to a location in need of heat, and then add water, which reverses the chemical reaction and releases the heat again.
So it doesn't actually store "heat", it takes in heat (i.e. molecular kinetic) energy and stores it in a different form (chemical bond energy).
Sounds more efficient than teleheating via insulated pipes: http://en.wikipedia.org/wiki/District_heating
http://www.amazon.co.uk/Magic-Gel-Reusable-Hand-Warmer/dp/B0...
I've seen them in person and they're remarkable if you've never encountered them before.
(IANAchemist)
When you heat these and melt them they can stay stable as a saturated liquid until you create a small site for them to start freezing around - they then give off energy when they freeze. The 'clicker' is all that's required to localy concentrate it enough to form a single crystal seed to start the freezing
We use zeolite as a water scavenger in high vacuum systems, it's tremendously good at grabbing onto water BUT because it's so porous and very low thermal conductivity it's a real pain to heat it enough to get all the water out again. We have a heater resistor at the bottom of a small can of this and the top of the pellets a few cm away is cool enough to touch. You might do better with a microwave system but then the inefficiencies are going to hurt.
Why not use one of the many phase change salt solutions that are also used for rechargeable heater packs?
What inefficiencies? A microwave should be more efficient due to it only energizing H2O bonds.
– http://en.wikipedia.org/wiki/Microwave_oven#Heating_efficien...
Parse Error: Unexpected verb "comes" on line 129.
EDIT: upon further research, I find that "adsorption" is actually also a thing, but it appears that here they meant the traditional absorption. Adsorbtion definitely isn't a thing. Also it sounds like a baby trying to say "abortion," which is weird.
What possesses people to give things such similar names? And while we're at it, mathematicians: stop using variables that rhyme. Bs, Cs, Ds, Es, Ps, Zs, it makes my head hurt. Would it kill you to chuck an H or a Q in there? M and N, now thats just purely vindictive. How am I supposed to cope with that?
After writing this comment I think the spelling part of my brain is now fried forever. And to think I've been walking around merrily saying "absorbsion" all these years...
Quote for those not in the know:
-----
<<<"Absorb" refers to a situation where something is taken into a medium, and disappears as a consequence (from?). "Adsorb" refers to a situation where something gets stuck onto (to?) the surface of a medium.
We would use "absorb" for when light is absorbed by a coloured or opaque object, or for when water is soaked into a sponge, or even for when my students manage to "take in" some of what I am telling them. It is an ordinary English word.
"Adsorb" is used for a very specific situation where molecules get stuck onto a surface. It does not occur as a word in ordinary language, outside its scientific meaning. Adsorption is very important, because many chemical reactions can go a lot faster when the reacting molecules are adsorbed at a surface (reactions of hydrogen gas on the surface of nickel, for example), or chemical reactions can be prevented by the presence of a barricading adsorbed layer on the surface (aluminium failing to react with air, for example), or impurities can be removed from a solution by adsorbing them onto a finely divided solid (activated charcoal for decolorizing solutions, or for medicinal use, for example).>>>
Now you can see why my brain was fried trying to type all that correctly. Not only do the phonemes sound the same, the letters are mirror images of each other. I think I now know how dyslexics must feel all the time.
Sorry to add extra "fry" you your brain, but it appears they really did mean "adsorbtion" -> http://en.wikipedia.org/wiki/Zeolite
Which makes a lot of the science understandable. I can't help thinking that by saying "OMG hard science, so here is a massively dumbed down version" they actually made crucial parts of the theory incomprehensible :)
Case in point being; adsorbtion explains later comments about why surface area is important.
I had a linear algebra teacher who was (I think) from Ukraine. Roughly all letters rhymed when he said them, and "a", "e", "i" were homophones.
Ad = To. Ab = From. That's Latin. People that invented it are long dead, so we have nobody to insult when we can't tell abductor from adductor.
This paper presents some of the experimental evaluations of a prototype solar refrigerator, based on an intermittent thermodynamic cycle of adsorption, using water as refrigerant and the mineral zeolite as adsorber. This system uses a mobile adsorber, which is regenerated out of the refrigeration cycle and no condenser is applied, because the solar regeneration is made in the ambient air For the regeneration, a SK14 solar cooker is considered. The cold chamber, with a capacity of 44 liters, is aimed for food and vaccine conservation. The objective is to analyze the advantages and disadvantages of the eventual use of this refrigerator in rural regions of Peru, where no electricity is available. On the bases of the results obtained, a new prototype of refrigerator for rural regions is designed, based on the same thermodynamic cycle, but including changes in design and operation.
http://fc.uni.edu.pe/mhorn/ISES2003%20(solar%20refrigeration...
During the day, solar energy is used to drive water out of the zeolite. The dry zeolite is exposed to water under low-pressure causing the water to evaporate and be adsorbed into the zeolite. The evaporative cooling can be used to refrigerate food without electricity.
A German company with various zeolite refrigeration applications:
Edit: I just found another german company using heat for cooling, this one is using zeolite: http://invensor.com/en/technology/zeolite.htm
What are the physics behind that, because it sounds like it violates the laws of thermodynamics.
(I'm not saying you're wrong so much as saying I can't provide evidence you're right, and I'm hoping someone else can. Or at least tell us what exactly "the heat storage capability of water" is such that something can have 4 times as much. Please hold wild-assed guesses, please, I can compute the energy difference between two temperatures of water for a given volume as well as the next guy, but what temperatures, or is that even the right question? I'm looking for someone who knows.)
https://en.wikipedia.org/wiki/Specific_heat
The relevant number for water at 25C is 4.184 joules per gram. But this isn't a strict apples to apples comparison: if you heat and cool zeolite in a vacuum chamber, it'll have a pathetic specific heat. (Like perlite, another foamed mineral, which has a specific heat of something like 0.1) That's because there's a chemical reaction taking place, not pure dumb-matter heating or cooling.
Meanwhile, the energy density of a lithium ion battery is 720 joules per gram, and the energy density of gasoline is 47,200 joules per gram. This does not "solve" energy storage, in any way, shape, or form.
It's 4.184 joules per gram Kelvin. Meaning it stores that much energy for each dress of heat you add to it. If you take water from near freezing to boiling that's 100 degrees of storage - meaning 418.4 joules per gram - which is much more reasonable.
And there is no reason you have to stop at boiling. Storing something at 500 degrees is not impractical, so assuming starting at 20 degrees (room temperature) you can store over 2000 joules per gram. And there are plenty of materials that can handle even higher temperatures.
I'm sure there's an answer, because I'm sure the journalist got that number from somewhere, but I lack the connections to know where to begin finding this information.
This is not directly comparable to the energy density of gasoline or a lithium ion battery which use chemical reactions to store the energy. So you can turn almost 100% of the energy in a lithium ion battery into useful work but if you put the equivalent number of joules into heating an object you wouldn't get close unless you have a handy 0 kelvin object.
1. you can never win
2. you can only break even on a very cold day
3. it never gets that cold
I miss the days when this stuff would show up in the Edmund Scientifics catalog.
Admittedly the big question, if you were going to rely on it, is whether there is enough zeolite globally to scale to the terawatt-hour range.
To put it differently, if heat storage was the only problem with CSP, and there is already a heat storage solution available (liquid salt) then Zeolite isn't solving a known 'problem'.
You don't need 'indefinite' heat storage for CSP, you really only need a couple of days worth, and we have that already.
It might be interesting to look at the total economic cost of heating these things up in one place, transporting them, and then generating power there. However the heat capacity, even at 4x that of water, means that you've a constant stream of train cars dumping 'charged' pellets into your power plant. While another constant stream is carrying 'spent' pellets back to be recharged. Not to mention that for all of this to work you need to adsorb water so you end up effectively pumping water in the return path. In a CSP setup without a lot of water (say in the desert) this means you need some sort of vapor recovery mechanism to minimize the loss of water.
Makes sense if you have to do power storage with this technology to do a lot of it at the street level if you can, rather than on the power generation site, as it gives you multiple redundancy and you have to supply cities with water anyway.
So when you have excess electrical power you dry pellets.
When you want power you give them water vapour which then gives you heat, which can give you motive power from heat engines, and from that electricity from induction generators.
All three of which are needed in a typical urban environment, so you are not having to convert all the way back to electric for a large percentage of the power used.
Now I know that this is not by any stretch the most thermodynamically efficient arrangement, but I suspect that it could be a relatively cheap and very robust approach that could store a hell of a lot of energy in a widely distributed network.
[edit] looked into this a bit, and the temperature rise you tend to be able to achieve from adsorption in zeolite is not going to be enough to do anything much more than direct heating, from what I can find. On reflection, that should have been fairly obvious. Sulk. ;)
I know, but I want there to be cool things that solve everything. And anyways, sometimes I enjoy sulking.
Now excuse me while I go gather a huuuuuge pile of zeolite. :)
The easiest way to understand this is the formula for Carnot efficiency: 1-(Ambient temp/Heat temp) which is the maximum theoretical efficiency that can be extracted from a heat engine to do useful work (eg. produce electrical power)
So I don't know how fast this Zeolite releases heat, but let's say it does so gradually so that your working fluid only ever gets to 90 degrees C or 363K. The maximum Carnot efficiency on a 20 degree C (293K) day would be 1-(293/363) or around 19%. And that's the theoretical max - a practical engine would be much lower.
So if the Zeolite can release its heat fairly quickly at a much higher temp it could be useful for power generation, but basically it's more likely to be useful for releasing low level heat again when it's needed.
Still, I prefer finding out that I am dreaming and being wildly optimistic, than to never bother dreaming or being wildly optimistic in the first place.
Now we have yet another effect: The mass density of these zeolite balls is probably WAY below that of oil. Let's be generous and say it's a factor of 2. That means we would need 70 times the shipping volume of oil tankers to replace oil as our primary energy source. House tanks would need 70 times the volume. Car tanks would need 70 times the volume. Let's put it another way: For every liter of oil you use to transport them, you would need more than 70 liters of these transported JUST TO BREAK EVEN. I therefore heavily question whether this is useful even for the applications they claim. If anything they would have to be used very locally, not much more than the range we have today with isolated water pipers for transporting heat.
So yeah. These funny balls might be interesting for SOME applications, but they're far from being efficient enough for mass adoption.
Water-Splitting using natural sunlight is a difficult problem and many research groups at top institutions are working on it. The best known group in this field is Prof. Daniel Nocera at MIT. His research is being commercialized by the company Sun Catalytix and there are plenty of YouTube videos of him speaking and explaining his research. There are other research groups as well. The vision for the future is a distributed electrical grid. Each home or building would have a reactor on top that would contain a water-splitting catalyst producing hydrogen and oxygen gas, which can be stored indefinitely under pressure and then released into a fuel-cell device that would recombine to form water (that can be placed into the reactor) and electricity (for consumption). This would be an efficient way to capture much more of the sun's energy than current photovoltaics and is an entirely closed cycle.
http://www.igb.fraunhofer.de/en/press-media/press-releases/2...
http://www.igb.fraunhofer.de/en/competences/physical-process...