6 ms·

So, assuming it is cheap and available, that's storage for solar power solved.

by ktizo 14y ago

ChuckMcM 14y ago
Not exactly but its a good start. But some interesting ideas come to mind. Using a conveyor to carry Zeolite to the top of a CSP plant and take the resulting stuff down to the reservevoir where its dumped into steam generators for turbines. If it replaced molten sodium as the working 'fluid' then that would make construction of such plants somewhat less challenging from an engineering perspective. I miss the days when this stuff would show up in the Edmund Scientifics catalog.
- ktizo 14y ago
  Why not exactly? Is basically decent heat storage and transfer with fairly low losses and minimal decay. Silos of these seem perfect for solar. 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.
  - ChuckMcM 14y ago
    Not exactly because it doesn't change the design space of CSP, it just offers up a different heat storage mechanism. 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.
    - ktizo 14y ago
      Was thinking of it more as an urban/industrial thing. 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. ;) http://engineering.ucsb.edu/~yuen/references/ref-2.pdf http://engineering.ucsb.edu/~yuen/references/ref-2.pdf
      - ChuckMcM 14y ago
        No need to sulk :-) there are fun things you can do. So lets say you have this huuuuuge pile of zeolite, you put it in your back yard during the summer and dry it out, then you store it in your shed during the winter and use it to warm the house rather than gas, or wood, or electicity. Many climes are wet during the winter and dry during the summer so this works out well for the adsorbtion requirements, and you don't get the air quality guys on your case for burning wood in the winter time. That is a difference if these things can hold their energy potential for the 9 months between summer and winter.
        ktizo 14y ago
        No need to 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. :)
jerf 14y ago
I'd like to see some energy density numbers in units I can understand before I would jump up and down about this use. (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.)
- ktizo 14y ago
  Fair point. Although the exact energy per volume is a less important measure, given that we know the ballpark, than the energy stored per energy invested, and the maximum storage available when considered as a commodity in the market and resource availability.
- hexagonal 14y ago
  The term of art you're looking for is "specific heat". https://en.wikipedia.org/wiki/Specific_heat 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.
  - quantumstate 14y ago
    The specific heat is the energy needed to raise the temperature per mass. So for water it takes 4.184 joules per gram to raise the temperature by 1 kelvin. So if you heated water to 75 degrees you would have put in about 205 joules per gram. You then have to deal with conductive losses and the efficiency of a heat engine. 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.
Mvandenbergh 14y ago
That rather depends on how hot they get when you add water to them. Unless they get very, very hot indeed you're going to get rubbish thermodynamic efficiency generating electricity with them. I think these will be more useful for storing low temperature heat energy.
tjmc 14y ago
Probably not. It's important to distinguish the storage of heat and power because the efficiency of converting heat into electrical power depends on how big the temperature difference between your heat source and ambient temperature is. 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.
- ktizo 14y ago
  Until I had a proper look at this, for some reason I thought you might be able to crank much higher temperature differentials out of the process. 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.
DeepDuh 14y ago
Let's do some math here, shall we. Oil has an energy density of 45MJ/kg. Water has a specific heat of about 4.2 J per gramm-Celsius. So if ambient=20C and heated water=100C we have 4.2*80 ~= 340 J/gramm => 340kJ/kg. These zeolites are claimed to have 4 times that capacity => 1.3MJ/kg. 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.
anusinha 14y ago
The amount of energy you can store in this type of interaction is not very significant compared to other forms of solar storage. Batteries are one class of storage methods, but what's even better is to use solar energy to split water molecules and store it in molecular hydrogen and oxygen (H2 and O2). These can be recombined in a fuel cell to produce water (with no loss in molecules) and produce electricity. A much, much greater energy density, far greater than any existing battery would be in such devices. 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.
- ktizo 14y ago
  On a similar theme, I really like the work of Dr. Lonnie Johnson, better known for designing the supersoaker, on his weird cross between a heat engine and a fuel-cell that he calls a JTEC; http://www.johnsonems.com/?q=node/2 http://www.johnsonems.com/?q=node/2

So, assuming it is cheap and available, that's storage for solar power solved.

by ktizo 14y ago

So, assuming it is cheap and available, that's storage for solar power solved.

Not exactly but its a good start. But some interesting ideas come to mind. Using a conveyor to carry Zeolite to the top of a CSP plant and take the resulting stuff down to the reservevoir where its dumped into steam generators for turbines. If it replaced molten sodium as the working 'fluid' then that would make construction of such plants somewhat less challenging from an engineering perspective. I miss the days when this stuff would show up in the Edmund Scientifics catalog.

ktizo 14y ago
Why not exactly? Is basically decent heat storage and transfer with fairly low losses and minimal decay. Silos of these seem perfect for solar. 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.
- ChuckMcM 14y ago
  Not exactly because it doesn't change the design space of CSP, it just offers up a different heat storage mechanism. 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.
  - ktizo 14y ago
    Was thinking of it more as an urban/industrial thing. 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. ;) http://engineering.ucsb.edu/~yuen/references/ref-2.pdf http://engineering.ucsb.edu/~yuen/references/ref-2.pdf
    - ChuckMcM 14y ago
      No need to sulk :-) there are fun things you can do. So lets say you have this huuuuuge pile of zeolite, you put it in your back yard during the summer and dry it out, then you store it in your shed during the winter and use it to warm the house rather than gas, or wood, or electicity. Many climes are wet during the winter and dry during the summer so this works out well for the adsorbtion requirements, and you don't get the air quality guys on your case for burning wood in the winter time. That is a difference if these things can hold their energy potential for the 9 months between summer and winter.
      - ktizo 14y ago
        No need to 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. :)

jerf 14y ago

I'd like to see some energy density numbers in units I can understand before I would jump up and down about this use. (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.)

ktizo 14y ago
Fair point. Although the exact energy per volume is a less important measure, given that we know the ballpark, than the energy stored per energy invested, and the maximum storage available when considered as a commodity in the market and resource availability.
hexagonal 14y ago
The term of art you're looking for is "specific heat". https://en.wikipedia.org/wiki/Specific_heat 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.
- quantumstate 14y ago
  The specific heat is the energy needed to raise the temperature per mass. So for water it takes 4.184 joules per gram to raise the temperature by 1 kelvin. So if you heated water to 75 degrees you would have put in about 205 joules per gram. You then have to deal with conductive losses and the efficiency of a heat engine. 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.

Mvandenbergh 14y ago

That rather depends on how hot they get when you add water to them. Unless they get very, very hot indeed you're going to get rubbish thermodynamic efficiency generating electricity with them. I think these will be more useful for storing low temperature heat energy.

tjmc 14y ago

Probably not. It's important to distinguish the storage of heat and power because the efficiency of converting heat into electrical power depends on how big the temperature difference between your heat source and ambient temperature is. 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.

ktizo 14y ago
Until I had a proper look at this, for some reason I thought you might be able to crank much higher temperature differentials out of the process. 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.

DeepDuh 14y ago

Let's do some math here, shall we. Oil has an energy density of 45MJ/kg. Water has a specific heat of about 4.2 J per gramm-Celsius. So if ambient=20C and heated water=100C we have 4.2*80 ~= 340 J/gramm => 340kJ/kg. These zeolites are claimed to have 4 times that capacity => 1.3MJ/kg. 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.

anusinha 14y ago

The amount of energy you can store in this type of interaction is not very significant compared to other forms of solar storage. Batteries are one class of storage methods, but what's even better is to use solar energy to split water molecules and store it in molecular hydrogen and oxygen (H2 and O2). These can be recombined in a fuel cell to produce water (with no loss in molecules) and produce electricity. A much, much greater energy density, far greater than any existing battery would be in such devices. 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.

ktizo 14y ago
On a similar theme, I really like the work of Dr. Lonnie Johnson, better known for designing the supersoaker, on his weird cross between a heat engine and a fuel-cell that he calls a JTEC; http://www.johnsonems.com/?q=node/2 http://www.johnsonems.com/?q=node/2