IMPORTANT INFORMATION: Turns out the heat capacity of air is actually 1000kJ/kg K, not 700. I was fooled by Google search which gave the wrong answer. That means the energy we stored was a bit over 8 Wh, which means the energy density was over 900MJ/m3 and the efficiency over 30%, so better than the video shows The salt in my setup is never dried completely. Di- and mono hydrates of calcium chloride melt at 170+ C, which my setup cannot achieve. Therefore the setup only dries to the dihydrate state of calcium chloride, meaning some water is still in there in the "dry" state, even if the drying setup is left to run for an infinite time. I forgot to measure the volume directly. The 32mL was based on the density of CaCl2 hexahydrate (1.7g/mL). In reality, the volume would have been slightly greater due to the air gaps between the grains. I considered it fair to use this "smaller" value though, since likely I could have run the setup for longer without overhydration, and could have started with dryer salt, which would have increased the energy content, so this sort of compensates. Not a very scientific way of thinking of course, but realise this wasn't a scientific experiment, but a demo for a YT video, take the values I measured with a grain of salt and look at actual research for obtaining values :) My camera had some issues which caused some glitches in the video. Your graphics card or monitor is not broken. Thanks for watching!
Given that premise, it would have been better to just explain it using already available data and some slides. Trying to derive the data using terrible methodology became a distraction from the point you were trying to make. You also didn't bring up the efficiency of the process until around ⅔ of the way through the video despite it being a key factor in deciding how valuable a process is. Some channels you might want to check out for different ways of presenting and/or demonstrating something like this are Practical Engineering, Undecided, AvE, Cody's Lab, Minute Physics, The Thought Emporium, and Nile Red. There are many others, but I think that's a decent variety of styles. I think the styles of The Thought Emporium and Nile Red would most fit you, but the others touch on topics it seems you would be interested in and might provide some inspiration for how you would want to produce your content
@@blackoak4978 First of all, I know most of these channels, they're great. So although some things were off, I wouldn't call the method "terrible". The numbers are, as far as I can tell fairly accurate, and match up quite well with what research shows. The biggest problem is the wrong value for the heat capacity of air, but I only discovered that after the video was up. (and what a stupid mistake it was) I felt in general the accuracy of the test doesn't change the conclusion of the video much. If anything, the errors here make TCES seem a bit worse than it is. If it had been 40% energy denser, or less dense, the general point would still be kind of the same: not quite dense enough to be revolutionary, but perhaps better than sensible or latent heat storage. Of course I could have opted for a different way of doing this. For instance, I could have just used existing values, but IMO, that's a bit boring and gets the point across less well. Otherwise, I could have done the demo without measuring values, so that people could have seen it in action, but then used existing data for analysis. That is something I considered doing, and almost did, but I decided against it, because I think doing the measurements on camera adds extra value, because it allows people to think/learn about calculating heat energy in an air flow, etc. It also contained the (IMHO) important lesson not to just blindly trust a power meter (or any measuring equipment for that matter). Basically, although things didn't go perfectly, I think there's stuff in there people can learn from, which includes the mistakes. Finally about the efficiency, first of all it's not quite as critical as it seems. Systems like this are generally charged from "leftovers" such as excess power generation, direct solar heat, or even industrial waste heat. Say your storage system can store 30%, then that means you can recover 30% (a significant part) of the energy that would otherwise not be used at all. 30% is low, but turning a solar panel completely off, or dissipating all heat through some cooling tower is clearly worse, and so even with a low efficiency it can be a significant improvement. This is the reason why I didn't discuss efficiency earlier in the video, because it's not as important as with other energy storage systems. That doesn't take away the fact that efficiency is very important nonetheless. I tried to find information on this, but I could not find a practical test result for the charging efficiency of a salt hydrate system. If you happen to find it, please do send it to me because I'm very much interested in this. This is actually one of the other considerations I used when I decided to test this myself, I wanted an efficiency figure, which I could not find elsewhere. I figured, given my rather simple drying setup, I could at least obtain a worst-case efficiency figure, which is better than nothing. The number I got (25-30%) with a very basic setup, makes me optimistic about what would be possible given a bit more design effort, so I do want to try it again some time soon, with better thermal insulation.
If you place the heat storage inside the environment where the heat will be needed, leaking heat ceases to be much of a problem. ALso look up Zeolite... used in some dishwasher drying cycles already
I guess it depends when you're charging it. If the charging is done when heat is also needed for something then there is indeed no loss. I knew about zeolites, but didn't realise some dishwashers use it haha. It appears they have an energy density disadvantage compared to salt hydrates, but they don't suffer from the same physical degradation which is nice.
@@AKIOTV , yes it's a different mechanism (zeolite vs cc) , some bosch dishwasher have the zeolite system. I may experiment with the CC too. I wonder how corrosive it is. For simple thermal storage inside my space I used a ceramics kiln filled with Basaltic rock... I liked the largish rocks because of the air spaces.. makes it easier to get hot air flow in and out. The Kiln , having a lid is nice. Very cheap high temp solution. If I were in the I.K I would just use some old night storage heaters... but we don't have them here in the USA , at least not cheap used ones. Thought about using low temperature water for heat storage, it takes up more volume and could freeze etc, all systems have pros and cons. The Kiln is very simple if one is safe about the very high temperatures. The nice thing about the Thermal (and electrical)chemical storage systems is they can store and be used way down the line...since they can be activated when needed....For daily (nightime release) the thermal kiln storage will save cycles and need for larger lithium batteries, much cheaper... for "edge cases" (many dark days in a row) Then I will go to my Lifepo4 and or a generator to charge batteries and recover the generator waste heat. Heat pumps as the normal heat source.
@@AKIOTV For the physical degration problem, there is a paper that shows that mixing in a small percentage of hydrophobic silica fume prevents/reduces the physical degregation of the calcuim chloride. Google "furmed silica calcium chloride" and look for the scence direct link, the paper title is: "Exceptionally high energy storage density for seasonal thermochemical energy storage by encapsulation of calcium chloride into hydrophobic nanosilica capsules". I've been searching for a simular reaction that occurs purely in a liquid phase, as liquids are easier to processor and automated. Just starting to read up on mixures of lithium chloride and calcium chloride. The other reaction i've been searching for is one where the drying reaction occurs, around 40-60 dC, so that an energy efficent heatpump can be used. Thankyou for the video, calcium choloride has some amazing energy storage denstity. And i think your conclusion is wrong, calcuium chloride is insanely cheap. Can store on the order of 388 kwh per cubic meter, which is well with the seasonal storage range, and 170 dC isn't hot, everybodies oven can get that hot.
This principle was once used to power small steam locomotives. Steam exhausted from the engine was injected into a mass of strong aqueous sodium hydroxide that surrounded a copper water tube boiler. The vessel containing the solution was vented to atmosphere. The steam condensed within the solution which increased the temperature enough to generate pressurized steam in the boiler to drive the engine. There was no emissions of any kind during operation. The solution was recharged by heating to boil off the water previously absorbed.
Great video! A few reflections: Isn't all, or almost all of energy in form of enthalpy of vaporization of water as long as the calcium chloride don't dissolve in water? I mean, calculating based just on the increased weight should get you much more reliable number than measuring the airflow and temperature difference. That said, 10 grams of water condensing and about 2.5 kJ per gram at that temperature, means 25 kJ, or about 7 Wh, and that makes the corrected just over 8 Wh you calculated very impressively close to correct, and considering the given volume of such bags usually are "theoretical" as in open, and filled to the brim, compensating for that your measurement was kind of spot on. That is, assuming I'm correct about the heat being released from water condensing, and not (at least not much) from dissolving. Especially for buildings that are heated in part to decrease humidity, heating by letting calcium chloride or some other desiccant turn humidity into heat seems like a great solution. Regeneration could be done more efficiently by using a heat pump, which can both provide the heat, and remove the released moisture from the air. If, or how fast solid calcium chloride hydrates release the water when heated depends on temperature and humidity, so "extreme" temperatures aren't required to regenerate it if the humidity is low. I did a similar "experiment" but much simpler, with just small amount of sodium hydroxide in an small open container, without forced airflow. I just measured the temperature, and while I don't remember exactly it remained several degrees above ambient, for several hours. Sodium hydroxide is not as practical as calcium chloride, partly because it's potentially much more dangerous than calcium chloride, and partially because it reacts with CO2 in the air and can't be as easily regenerated as calcium chloride.
The latent heat thing is an interesting one. I have tried to figure out to what extent the energy comes from purely condensation, vs the hydration of the salt, and found it difficult to find a good answer. What I do know is that there's also adsorption (with a d) based systems that condense water onto the surface of a porous medium. In this case, all of the energy is latent heat from the condensation. This is what happens in these zeolite systems that some people have mentioned in these comments. But in a salt hydrate system, as far as I'm aware, there is also energy released from the hydration. I am kind of hoping that someone with more chemistry knowledge can enlighten me on the specifics of this, that would be quite interesting. For the temperature, if you have a very low humidity, you could run it at lower temperatures, but there is still a minimum temperature you'll need. To dehydrate a salt, it needs to be heated past its melting point, so for example, to go from CaCl2 tetrahydrate to CaCl2 dihydrate (which is pretty much what happened in the video) you need to heat past 45C, because that's the melting point of the tetrahydrate. At that point the water comes out and you can evaporate it off. One of the reasons CaCl2 is actually considered not a very optimal medium, is that its higher hydrates melt at low temperatures. For instance the hexahydrate melts at only 30C. That means, if you hydrate past the tetrahydrate, and the reactor is over 30C (which it almost definitely is) you'll end up with a liquid. The tetrahydrate melts at only 45C, which also makes it unsuitable for domestic hot water for showers and stuff (which requires 60C for anti-bacterial reasons). The di- and monohydrates melt at 170+C, so you'd avoid these problems, but you'd also need 170+C to dehydrate, which impractically high.
@@AKIOTV From what I've read, I was under the impression that each CaCl2 hydrate has a humidity equilibrium point, that varies somewhat with temperature, under which it will loose water to the air, even when solid, so now you've forced me to reevaluate what I thought I knew. Anyhow, again, great video!
@AKIOTV For the physical degration problem, there is a paper that shows that mixing in a small percentage of hydrophobic silica fume prevents/reduces the physical degregation of the calcuim chloride. the paper title is: "Exceptionally high energy storage density for seasonal thermochemical energy storage by encapsulation of calcium chloride into hydrophobic nanosilica capsules". I've been searching for a simular reaction that occurs purely in a liquid phase, as liquids are easier to processor and automated. Just starting to read up on mixures of lithium chloride and calcium chloride. The other reaction i've been searching for is one where the drying reaction occurs, around 40-60 dC, so that an energy efficent heatpump can be used. Thankyou for the video, calcium choloride has some amazing energy storage denstity. However i think your conclusion is wrong, calcuium chloride is insanely cheap. Can store on the order of 388 kwh per cubic meter, which is well with the seasonal storage range, and 170 dC isn't hot at all considering that most convection ovens easily reach that temperature.
@@gino_latino No, but there is no need to do that for this test. The humidity affects the power output of the setup (how fast it hydrates), but not the total energy output. With more humid air, the exhaust temperature is higher and it can run for less long, with dryer air it can run for longer and the exhaust temperature is lower. This is probably the reason I was able to run it for longer than expected during this test, the air contained less moisture than during previous tests I did, meaning it ran at lower power and thus could run for longer.
You can use a hygroscopic liquid that heats up when mixed with water. This water can then be evaporated, for example, in a solar heater. Of course, this method is completely unsuitable for use in vehicles, but for heating a house it is an almost ideal heat accumulator.
This has some potential. Someone can build some metal container and leave it to dry entire summer. I am sure that 3-4 months of sun heat will dry the thing. With 10 of these thing each having 1m3 you have all the heat for winter. But, yeah, you need some land, and will probably be costly to do it, but I guess its an option after all.
@@danielmogos8990 It does depend on the temperature though. You need to get the temperature above certain thresholds for drying (I think I mentioned this in some other comment in more detail), and those temps will be higher than the outside air temperature even in very hot climates. If you don't reach the required temperature, you can wait all you want but it won't dry. Therefore you can't just leave it outside to dry, you'll need to use some form of concentrated solar heating. In the simplest form you could focus sunlight on a salt box with some mirrors, but the most commonly available practical solution is to use solar heating panels, which can heat water/glycol to 100+C, which can then be used to heat the salt box and dehydrate the salt. Nonetheless it is indeed feasible to dehydrate a salt with solar heat during summer time.
@AKIOTV Yes, I wanted to mention that. Calcium chloride is not the best salt to use because of high temperature needed for charging. Instead potassium carbonate can be charged at 60 degrees celsius. Closed and black painted metal container can easily reach this temperature during summer months.
I suppose if you let it dry in ambient temperatures it would still store that heat. It would take longer but, it wouldn't use an external power to heat it to dry. Good project!
@@GTN3 You do need an increased temperature, at room temperature it will keep absorbing water until it dissolves in it. You leave this stuff in open air and the next day you'll have a puddle of brine.
I thought about it with zeolite. It would be great using a heat pump generating enough exhaust heat to dry material and then use the energy in winter. When I looked I found a zeolite with an activation temperature of 80C. That’s still to hight for nowadays days heat pumps I guess. But it’s already closer than 170C. I do live in an apartment house so I stopped researching once I saw how many m3 Zeolith I would need. When building a new house one could use the foundation as a storing space for the needed amount. Also one could use exhaust heat from air conditioning and top up the rest of needed energy with PV. Then it could be I thing.
You list it as energy storage, but I think it makes even more sense as a generator itself. You can use the sun to dry it out directly at a much higher efficiency than a solar panel, and then also store it till needed for release. I think it really is both in one.
You have to consider it in terms of comparison. It's not simply about if it can do a job, but if it has characteristics that are better than other alternatives and if it is reasonable to use in scenarios where it provides the most benefit. Yes, you can put it out in the sun, but you can also put a solar panel out in the sun and collect the same amount of energy. In this specific scenario the question then becomes, which of those two options provides the greatest return, or the efficiency of taking a set amount of solar energy, storing it in some medium, then converting the stored energy into useful energy, in this case heat.
@@blackoak4978 My point was that you would collect more of the sun's energy, not the same amount of energy as with a solar panel. I don't know what the efficiency of drying out the salt is with the Sun but it's got to be higher than the abysmal efficiency of a solar panel.
@@chris993361A solar heat collector is more efficient drying salt directly compared to using a PV panel and electric heating. But if yoh already have PV panels, and once in a while have to disable them when there's no demand, then electrically drying salt still makes sense, since it's better than turning the panels off entirely. This more broadly applies to other heat storage too: heating a water heater with solar heat is more efficient than an electric water heater powered by PV, but if you already have PV panels, and at times no purpose for their energy, an electric water heater can be a good idea to install.
One could dry the salt using solar energy (or in general when electricity is cheap -- for load shaving), and reintroduce moisture to produce heat in the evening and morning. In practice, it seems mostly a solution that relies on an abundance of energy available at the wrong time. Due to the shift to renewables, that means it may one day actually be viable.
How much of the energy is actually from the chemical itself, and how much is actually just harvesting the latent heat of the water vapor condensing/solidifying? Low level thermal energy storage like this would seem like something maybe for replacing winter heating requirements from fossil fuels or electric, and recharging during summer when solar energy is in excess. But, during the winter, when the heating would be needed, the cold air would be very dry. Having a tank of water on hand is easy enough, but that's liquid. And if we have to evaporate the water into vapor somehow in order to get all that heat, it won't really be useful.
@@Brainstormer_Industires At very low temperatures, although the power output will decrease due to less moisture, the energy content is the same. So as long as the setup is designed with enough reactor surface area to account for the worst possible humidity conditions in the local environment, you should be fine. For very cold/dry climates, I've seen some prototype solutions that make use of a borehole into ground water acting as a moisture source. Another measure that I think I've seen can be added is a "temperature booster", which basically amounts to an electric humidifier to send maximum moisture into the salt. This can be used to temporary generate very high output power needed for stuff like showers, at the cost of some additional electricity of course. As I've mentioned in a reply to someone else, I'd love to know more about the chemistry on how much is chemical energy vs latent heat etc., since I'm not entirely sure.
Hi. We are taking Thermochemical energy storage using Calcium Hyroxide as our FYP. Can you please help me proposing a small scale design for this purpose? Means what reactors is used? how many pumps? Thermocouples? and everything. Anyone who worked on it before? I'll be thankful
I would need 20 MWh for heating. Let's be optimistic ( global warming ) and use 2MWh. I would need 10 m^3 of CaCl + water That is a lot. Now considering realistic scenario, I would need 100 m^3 of CaCl + 50 m^3 of water ( to use purified water ) + losses and non ideal conditions..... more like 200 m^3 space needed. That is a lot. I made a ist of possible material candidates. After like 20 different compounds, I realized the best choice is probably simple iron powder oxidation and reduction ( realistic space and price requirements )
@@jozsab1 The water doesn't need to be stored though, you can use vapor from the air, or a moisture pit if you have an extremely dry climate. I'm not entirely familiar with iron oxide. Maybe interesting to look at for a video some day.
I wonder if we can use it twice: to charge it you need heat. My smart solar mppt can get above 50 C when the sun shines, and then must be cooled to be no more than 40. So actually the right storage would be something that reacts around 40 degrees, automatically regulating the solar charger. And then at night hopefully you can put it in a hot water bottle for in bed. Of course, we need it to be bigger than this.
@@bloepje 50C is on the low side for calcium chloride, but a different salt might do the job. In general, using waste heat to charge TCES systems is widely considered. For example you could also use waste heat from industrial plants etc. to dry salt at a large scale. Any form of waste heat is usable, so long as the temperature is high enough to (partially) dehydrate the salt that is used.
If you're thinking about performing a similar experiment with zeolite, then keep in mind that it will only heat up if it's completely dry. If you dry it in room temperature, and add water, the exothermic reaction will NOT happen.
@@baraBober I may try zeolite some time. Would be interesting to see the difference. I suspect the same setup would work, although I might add better insulation to the dryer.
Here's what chat GPT has to say about safety of this reaction: When water is added to calcium chloride (CaCl₂), an exothermic reaction occurs, meaning it releases heat. This reaction itself does not produce toxic fumes. Calcium chloride dissolves in water by dissociating into calcium ions (Ca²⁺) and chloride ions (Cl⁻), and the release of heat is due to the hydration of these ions. However, depending on the purity of the calcium chloride, there may be some minor concerns: Impurities: Commercial calcium chloride can contain impurities that might release some gases or vapors. For example, if it contains magnesium chloride or other substances, they might interact with water differently. Aerosols: The heat generated can cause rapid boiling of water, potentially creating steam or fine aerosol particles. While these aerosols are not inherently toxic, breathing them in could irritate your respiratory system, especially if they contain impurities. To stay safe, it's best to perform the reaction in a well-ventilated area, and if you're working with large quantities or unknown purities, wearing a mask or ensuring proper ventilation is a good precaution.
yehhh this way of storage is really good! there will not be much problem about it except for its potential ability to strip national banks down to their last penny in a larger scale
Your error bars are nearly bigger than your signal. You also didn't include the power to run the fan, but given your measurement accuracy it would be below the noise floor and is probably not a major factor anyway. You're also comparing apples to oranges. The lithium-ion batteries are measuring useful electrical energy, whereas you're just measuring energy in the form of heat which is much simpler. You have no way to convert it efficiently to electricity. It's useful only for heat storage, and for that there are just much better and simpler alternatives. Nobody would recommend using a lithium-ion battery as a heat storage device. Bizarre comparison.
@@human_shaped No one would use li-ion batteries to store heat, because they're much too expensive and there are far cheaper effective alternatives. That's pretty much also what I said in the video. Now of course, you can argue that's too obvious to even include them, but I decided to put them in there anyway, for the following reasons: 1) they are a useful benchmark for energy density since a lot of people (at least in my audience) are familiar with their size which helps visualise the kind of energy density we're talking about. 2) although arguably stupid for storing heat, li-ion batteries are pretty much the only available method of storing heat that doesn't lose energy over time. If you wanted to store heat for a long time, sensible heat or pcm storage won't work. The only option that is practically available would be batteries. The fan was running at like 25% speed, it consumed less than a watt of power, I decided to not bother with that haha. It would have been good to mention that in the video.
Nah, Not a viable method. issue is that it will take a lot of energy to boil off the water to make dry again, probably 50 times more heat energy input to boil off the water, than you get back dissolving it in water. The most practical heat storage methods are phase change materials such as wax and Sodium Acetate, but these also have issues. Currently the most practical is just storing heat in water: use a water tank to heat up and then circulating to extract the heat. Water tank can be heated using PV or with solar thermal panels. This is the cheapest & most reliable solution, but is a low thermal density method.
@@guytech7310 EROEI is not as important as effectiveness on a societal level (cost-efficiency in some context), compared to other methods. Is this better than, for example, living off gas (hauled in tanks) using heaters with 20% efficiency? I'd say yes, so this IS viable. Obviously not a universal solution to all our problems, but I can imagine an engineered system of this, coupled with a solar dryer, that's ideal for an off-grid house.
@@besenyeim Its not cost effective either. You waste more money & fuel that it will save. FYI: I heat with Propane, & it costs me about $100/mo in Propane during winter. I have a condensing Boiler with a 80 Gallon Thermal (Water) tank (prevent short cycling. Tank has a 4KW resistive element for solar but I don't have any solar panels yet. Plan is to dump excess solar into the thermal tank. Also planing to add a outdoor wood boiler (I have about 90 acres of wooded land). Using chemical or phase change methods to store heat just isn't practical. Best option for efficient & cost savings is to properly insulate a home to reduce thermal losses (heating & cooling), Last is adding gadgets for thermal storage, solar, etc. The #1 issue with homes is very poor insulation & air leaks.
@@guytech7310 I totally agree about insulation issue. Spending more for a proper layer is the best investment when building a new house. Your plans (solar & wood) are also good. It still seems that, you see thermochemical methods as inferior in general, because they are, in your use-case. But for a few others, it may be the best. Without that explanation of circumstances, your opinion sound authoritative. You clearly did your research, and what you say is true most of the time, but not every time. I'm not trying to change your mind. I just suggest you to express your opinion differently, so you won't discourage others from exploring alternatives (even if they are far from the best). But I feel we are running off the topic of the video.
IMPORTANT INFORMATION:
Turns out the heat capacity of air is actually 1000kJ/kg K, not 700. I was fooled by Google search which gave the wrong answer. That means the energy we stored was a bit over 8 Wh, which means the energy density was over 900MJ/m3 and the efficiency over 30%, so better than the video shows
The salt in my setup is never dried completely. Di- and mono hydrates of calcium chloride melt at 170+ C, which my setup cannot achieve.
Therefore the setup only dries to the dihydrate state of calcium chloride, meaning some water is still in there in the "dry" state, even if the drying setup is left to run for an infinite time.
I forgot to measure the volume directly. The 32mL was based on the density of CaCl2 hexahydrate (1.7g/mL). In reality, the volume would have been slightly greater due to the air gaps between the grains. I considered it fair to use this "smaller" value though, since likely I could have run the setup for longer without overhydration, and could have started with dryer salt, which would have increased the energy content, so this sort of compensates. Not a very scientific way of thinking of course, but realise this wasn't a scientific experiment, but a demo for a YT video, take the values I measured with a grain of salt and look at actual research for obtaining values :)
My camera had some issues which caused some glitches in the video. Your graphics card or monitor is not broken.
Thanks for watching!
Given that premise, it would have been better to just explain it using already available data and some slides. Trying to derive the data using terrible methodology became a distraction from the point you were trying to make. You also didn't bring up the efficiency of the process until around ⅔ of the way through the video despite it being a key factor in deciding how valuable a process is.
Some channels you might want to check out for different ways of presenting and/or demonstrating something like this are Practical Engineering, Undecided, AvE, Cody's Lab, Minute Physics, The Thought Emporium, and Nile Red. There are many others, but I think that's a decent variety of styles.
I think the styles of The Thought Emporium and Nile Red would most fit you, but the others touch on topics it seems you would be interested in and might provide some inspiration for how you would want to produce your content
Oh, also Applied Science
@@blackoak4978 First of all, I know most of these channels, they're great.
So although some things were off, I wouldn't call the method "terrible". The numbers are, as far as I can tell fairly accurate, and match up quite well with what research shows. The biggest problem is the wrong value for the heat capacity of air, but I only discovered that after the video was up. (and what a stupid mistake it was)
I felt in general the accuracy of the test doesn't change the conclusion of the video much. If anything, the errors here make TCES seem a bit worse than it is. If it had been 40% energy denser, or less dense, the general point would still be kind of the same: not quite dense enough to be revolutionary, but perhaps better than sensible or latent heat storage.
Of course I could have opted for a different way of doing this. For instance, I could have just used existing values, but IMO, that's a bit boring and gets the point across less well. Otherwise, I could have done the demo without measuring values, so that people could have seen it in action, but then used existing data for analysis. That is something I considered doing, and almost did, but I decided against it, because I think doing the measurements on camera adds extra value, because it allows people to think/learn about calculating heat energy in an air flow, etc. It also contained the (IMHO) important lesson not to just blindly trust a power meter (or any measuring equipment for that matter). Basically, although things didn't go perfectly, I think there's stuff in there people can learn from, which includes the mistakes.
Finally about the efficiency, first of all it's not quite as critical as it seems. Systems like this are generally charged from "leftovers" such as excess power generation, direct solar heat, or even industrial waste heat. Say your storage system can store 30%, then that means you can recover 30% (a significant part) of the energy that would otherwise not be used at all. 30% is low, but turning a solar panel completely off, or dissipating all heat through some cooling tower is clearly worse, and so even with a low efficiency it can be a significant improvement. This is the reason why I didn't discuss efficiency earlier in the video, because it's not as important as with other energy storage systems.
That doesn't take away the fact that efficiency is very important nonetheless. I tried to find information on this, but I could not find a practical test result for the charging efficiency of a salt hydrate system. If you happen to find it, please do send it to me because I'm very much interested in this. This is actually one of the other considerations I used when I decided to test this myself, I wanted an efficiency figure, which I could not find elsewhere. I figured, given my rather simple drying setup, I could at least obtain a worst-case efficiency figure, which is better than nothing. The number I got (25-30%) with a very basic setup, makes me optimistic about what would be possible given a bit more design effort, so I do want to try it again some time soon, with better thermal insulation.
If you place the heat storage inside the environment where the heat will be needed, leaking heat ceases to be much of a problem. ALso look up Zeolite... used in some dishwasher drying cycles already
I guess it depends when you're charging it. If the charging is done when heat is also needed for something then there is indeed no loss.
I knew about zeolites, but didn't realise some dishwashers use it haha. It appears they have an energy density disadvantage compared to salt hydrates, but they don't suffer from the same physical degradation which is nice.
@@AKIOTV , yes it's a different mechanism (zeolite vs cc) , some bosch dishwasher have the zeolite system. I may experiment with the CC too. I wonder how corrosive it is. For simple thermal storage inside my space I used a ceramics kiln filled with Basaltic rock... I liked the largish rocks because of the air spaces.. makes it easier to get hot air flow in and out. The Kiln , having a lid is nice. Very cheap high temp solution. If I were in the I.K I would just use some old night storage heaters... but we don't have them here in the USA , at least not cheap used ones. Thought about using low temperature water for heat storage, it takes up more volume and could freeze etc, all systems have pros and cons. The Kiln is very simple if one is safe about the very high temperatures. The nice thing about the Thermal (and electrical)chemical storage systems is they can store and be used way down the line...since they can be activated when needed....For daily (nightime release) the thermal kiln storage will save cycles and need for larger lithium batteries, much cheaper... for "edge cases" (many dark days in a row) Then I will go to my Lifepo4 and or a generator to charge batteries and recover the generator waste heat. Heat pumps as the normal heat source.
@@AKIOTV For the physical degration problem, there is a paper that shows that mixing in a small percentage of hydrophobic silica fume prevents/reduces the physical degregation of the calcuim chloride. Google "furmed silica calcium chloride" and look for the scence direct link, the paper title is: "Exceptionally high energy storage density for seasonal thermochemical energy storage by encapsulation of calcium chloride into hydrophobic nanosilica capsules".
I've been searching for a simular reaction that occurs purely in a liquid phase, as liquids are easier to processor and automated. Just starting to read up on mixures of lithium chloride and calcium chloride. The other reaction i've been searching for is one where the drying reaction occurs, around 40-60 dC, so that an energy efficent heatpump can be used.
Thankyou for the video, calcium choloride has some amazing energy storage denstity. And i think your conclusion is wrong, calcuium chloride is insanely cheap. Can store on the order of 388 kwh per cubic meter, which is well with the seasonal storage range, and 170 dC isn't hot, everybodies oven can get that hot.
This principle was once used to power small steam locomotives. Steam exhausted from the engine was injected into a mass of strong aqueous sodium hydroxide that surrounded a copper water tube boiler. The vessel containing the solution was vented to atmosphere. The steam condensed within the solution which increased the temperature enough to generate pressurized steam in the boiler to drive the engine. There was no emissions of any kind during operation. The solution was recharged by heating to boil off the water previously absorbed.
@@MarcosBuenijo-i8w That's something I'd not heard of before. Pretty clever.
That's a really interesting way to store energy. Nicely explained as always!
Very interesting. Have you thought about using solar ovens in some sort of panel form to dry out the material?
Interesting as always, nicely simplified 👍👍
Great video!
A few reflections: Isn't all, or almost all of energy in form of enthalpy of vaporization of water as long as the calcium chloride don't dissolve in water? I mean, calculating based just on the increased weight should get you much more reliable number than measuring the airflow and temperature difference. That said, 10 grams of water condensing and about 2.5 kJ per gram at that temperature, means 25 kJ, or about 7 Wh, and that makes the corrected just over 8 Wh you calculated very impressively close to correct, and considering the given volume of such bags usually are "theoretical" as in open, and filled to the brim, compensating for that your measurement was kind of spot on. That is, assuming I'm correct about the heat being released from water condensing, and not (at least not much) from dissolving.
Especially for buildings that are heated in part to decrease humidity, heating by letting calcium chloride or some other desiccant turn humidity into heat seems like a great solution.
Regeneration could be done more efficiently by using a heat pump, which can both provide the heat, and remove the released moisture from the air.
If, or how fast solid calcium chloride hydrates release the water when heated depends on temperature and humidity, so "extreme" temperatures aren't required to regenerate it if the humidity is low.
I did a similar "experiment" but much simpler, with just small amount of sodium hydroxide in an small open container, without forced airflow. I just measured the temperature, and while I don't remember exactly it remained several degrees above ambient, for several hours. Sodium hydroxide is not as practical as calcium chloride, partly because it's potentially much more dangerous than calcium chloride, and partially because it reacts with CO2 in the air and can't be as easily regenerated as calcium chloride.
The latent heat thing is an interesting one. I have tried to figure out to what extent the energy comes from purely condensation, vs the hydration of the salt, and found it difficult to find a good answer. What I do know is that there's also adsorption (with a d) based systems that condense water onto the surface of a porous medium. In this case, all of the energy is latent heat from the condensation. This is what happens in these zeolite systems that some people have mentioned in these comments. But in a salt hydrate system, as far as I'm aware, there is also energy released from the hydration. I am kind of hoping that someone with more chemistry knowledge can enlighten me on the specifics of this, that would be quite interesting.
For the temperature, if you have a very low humidity, you could run it at lower temperatures, but there is still a minimum temperature you'll need. To dehydrate a salt, it needs to be heated past its melting point, so for example, to go from CaCl2 tetrahydrate to CaCl2 dihydrate (which is pretty much what happened in the video) you need to heat past 45C, because that's the melting point of the tetrahydrate. At that point the water comes out and you can evaporate it off.
One of the reasons CaCl2 is actually considered not a very optimal medium, is that its higher hydrates melt at low temperatures. For instance the hexahydrate melts at only 30C. That means, if you hydrate past the tetrahydrate, and the reactor is over 30C (which it almost definitely is) you'll end up with a liquid. The tetrahydrate melts at only 45C, which also makes it unsuitable for domestic hot water for showers and stuff (which requires 60C for anti-bacterial reasons). The di- and monohydrates melt at 170+C, so you'd avoid these problems, but you'd also need 170+C to dehydrate, which impractically high.
@@AKIOTV From what I've read, I was under the impression that each CaCl2 hydrate has a humidity equilibrium point, that varies somewhat with temperature, under which it will loose water to the air, even when solid, so now you've forced me to reevaluate what I thought I knew.
Anyhow, again, great video!
@AKIOTV For the physical degration problem, there is a paper that shows that mixing in a small percentage of hydrophobic silica fume prevents/reduces the physical degregation of the calcuim chloride. the paper title is: "Exceptionally high energy storage density for seasonal thermochemical energy storage by encapsulation of calcium chloride into hydrophobic nanosilica capsules".
I've been searching for a simular reaction that occurs purely in a liquid phase, as liquids are easier to processor and automated. Just starting to read up on mixures of lithium chloride and calcium chloride. The other reaction i've been searching for is one where the drying reaction occurs, around 40-60 dC, so that an energy efficent heatpump can be used.
Thankyou for the video, calcium choloride has some amazing energy storage denstity. However i think your conclusion is wrong, calcuium chloride is insanely cheap. Can store on the order of 388 kwh per cubic meter, which is well with the seasonal storage range, and 170 dC isn't hot at all considering that most convection ovens easily reach that temperature.
DId you check the humidity of the air?
@@gino_latino No, but there is no need to do that for this test. The humidity affects the power output of the setup (how fast it hydrates), but not the total energy output. With more humid air, the exhaust temperature is higher and it can run for less long, with dryer air it can run for longer and the exhaust temperature is lower.
This is probably the reason I was able to run it for longer than expected during this test, the air contained less moisture than during previous tests I did, meaning it ran at lower power and thus could run for longer.
You can use a hygroscopic liquid that heats up when mixed with water.
This water can then be evaporated, for example, in a solar heater.
Of course, this method is completely unsuitable for use in vehicles, but for heating a house it is an almost ideal heat accumulator.
Are there such liquids?
This has some potential. Someone can build some metal container and leave it to dry entire summer. I am sure that 3-4 months of sun heat will dry the thing.
With 10 of these thing each having 1m3 you have all the heat for winter.
But, yeah, you need some land, and will probably be costly to do it, but I guess its an option after all.
@@danielmogos8990 It does depend on the temperature though. You need to get the temperature above certain thresholds for drying (I think I mentioned this in some other comment in more detail), and those temps will be higher than the outside air temperature even in very hot climates. If you don't reach the required temperature, you can wait all you want but it won't dry.
Therefore you can't just leave it outside to dry, you'll need to use some form of concentrated solar heating. In the simplest form you could focus sunlight on a salt box with some mirrors, but the most commonly available practical solution is to use solar heating panels, which can heat water/glycol to 100+C, which can then be used to heat the salt box and dehydrate the salt.
Nonetheless it is indeed feasible to dehydrate a salt with solar heat during summer time.
@AKIOTV Yes, I wanted to mention that. Calcium chloride is not the best salt to use because of high temperature needed for charging. Instead potassium carbonate can be charged at 60 degrees celsius. Closed and black painted metal container can easily reach this temperature during summer months.
I suppose if you let it dry in ambient temperatures it would still store that heat. It would take longer but, it wouldn't use an external power to heat it to dry. Good project!
@@GTN3 You do need an increased temperature, at room temperature it will keep absorbing water until it dissolves in it. You leave this stuff in open air and the next day you'll have a puddle of brine.
I thought about it with zeolite. It would be great using a heat pump generating enough exhaust heat to dry material and then use the energy in winter. When I looked I found a zeolite with an activation temperature of 80C. That’s still to hight for nowadays days heat pumps I guess. But it’s already closer than 170C. I do live in an apartment house so I stopped researching once I saw how many m3 Zeolith I would need. When building a new house one could use the foundation as a storing space for the needed amount. Also one could use exhaust heat from air conditioning and top up the rest of needed energy with PV. Then it could be I thing.
You list it as energy storage, but I think it makes even more sense as a generator itself. You can use the sun to dry it out directly at a much higher efficiency than a solar panel, and then also store it till needed for release. I think it really is both in one.
@@chris993361 You could charge something like this very well with solar heat. Industrial waste heat is another interesting option.
You have to consider it in terms of comparison. It's not simply about if it can do a job, but if it has characteristics that are better than other alternatives and if it is reasonable to use in scenarios where it provides the most benefit.
Yes, you can put it out in the sun, but you can also put a solar panel out in the sun and collect the same amount of energy. In this specific scenario the question then becomes, which of those two options provides the greatest return, or the efficiency of taking a set amount of solar energy, storing it in some medium, then converting the stored energy into useful energy, in this case heat.
@@blackoak4978 My point was that you would collect more of the sun's energy, not the same amount of energy as with a solar panel. I don't know what the efficiency of drying out the salt is with the Sun but it's got to be higher than the abysmal efficiency of a solar panel.
@@chris993361A solar heat collector is more efficient drying salt directly compared to using a PV panel and electric heating. But if yoh already have PV panels, and once in a while have to disable them when there's no demand, then electrically drying salt still makes sense, since it's better than turning the panels off entirely.
This more broadly applies to other heat storage too: heating a water heater with solar heat is more efficient than an electric water heater powered by PV, but if you already have PV panels, and at times no purpose for their energy, an electric water heater can be a good idea to install.
Good one.
One could dry the salt using solar energy (or in general when electricity is cheap -- for load shaving), and reintroduce moisture to produce heat in the evening and morning. In practice, it seems mostly a solution that relies on an abundance of energy available at the wrong time. Due to the shift to renewables, that means it may one day actually be viable.
Nothing beats british accent...!!! That´s a baby Roger Moore right there...!!! great results too...!!!
haha
How much of the energy is actually from the chemical itself, and how much is actually just harvesting the latent heat of the water vapor condensing/solidifying?
Low level thermal energy storage like this would seem like something maybe for replacing winter heating requirements from fossil fuels or electric, and recharging during summer when solar energy is in excess. But, during the winter, when the heating would be needed, the cold air would be very dry. Having a tank of water on hand is easy enough, but that's liquid. And if we have to evaporate the water into vapor somehow in order to get all that heat, it won't really be useful.
@@Brainstormer_Industires At very low temperatures, although the power output will decrease due to less moisture, the energy content is the same. So as long as the setup is designed with enough reactor surface area to account for the worst possible humidity conditions in the local environment, you should be fine. For very cold/dry climates, I've seen some prototype solutions that make use of a borehole into ground water acting as a moisture source.
Another measure that I think I've seen can be added is a "temperature booster", which basically amounts to an electric humidifier to send maximum moisture into the salt. This can be used to temporary generate very high output power needed for stuff like showers, at the cost of some additional electricity of course.
As I've mentioned in a reply to someone else, I'd love to know more about the chemistry on how much is chemical energy vs latent heat etc., since I'm not entirely sure.
Hi. We are taking Thermochemical energy storage using Calcium Hyroxide as our FYP. Can you please help me proposing a small scale design for this purpose? Means what reactors is used? how many pumps? Thermocouples? and everything. Anyone who worked on it before? I'll be thankful
Besides the method I used in the video, I've tried no other methods or reactions, so I also don't know the best ways to implement them.
I would need 20 MWh for heating. Let's be optimistic ( global warming ) and use 2MWh. I would need 10 m^3 of CaCl + water That is a lot. Now considering realistic scenario, I would need 100 m^3 of CaCl + 50 m^3 of water ( to use purified water ) + losses and non ideal conditions..... more like 200 m^3 space needed. That is a lot. I made a ist of possible material candidates. After like 20 different compounds, I realized the best choice is probably simple iron powder oxidation and reduction ( realistic space and price requirements )
@@jozsab1 The water doesn't need to be stored though, you can use vapor from the air, or a moisture pit if you have an extremely dry climate.
I'm not entirely familiar with iron oxide. Maybe interesting to look at for a video some day.
I wonder if we can use it twice: to charge it you need heat. My smart solar mppt can get above 50 C when the sun shines, and then must be cooled to be no more than 40.
So actually the right storage would be something that reacts around 40 degrees, automatically regulating the solar charger.
And then at night hopefully you can put it in a hot water bottle for in bed. Of course, we need it to be bigger than this.
@@bloepje 50C is on the low side for calcium chloride, but a different salt might do the job.
In general, using waste heat to charge TCES systems is widely considered. For example you could also use waste heat from industrial plants etc. to dry salt at a large scale. Any form of waste heat is usable, so long as the temperature is high enough to (partially) dehydrate the salt that is used.
If you're thinking about performing a similar experiment with zeolite, then keep in mind that it will only heat up if it's completely dry. If you dry it in room temperature, and add water, the exothermic reaction will NOT happen.
@@baraBober I may try zeolite some time. Would be interesting to see the difference. I suspect the same setup would work, although I might add better insulation to the dryer.
Here's what chat GPT has to say about safety of this reaction:
When water is added to calcium chloride (CaCl₂), an exothermic reaction occurs, meaning it releases heat. This reaction itself does not produce toxic fumes. Calcium chloride dissolves in water by dissociating into calcium ions (Ca²⁺) and chloride ions (Cl⁻), and the release of heat is due to the hydration of these ions.
However, depending on the purity of the calcium chloride, there may be some minor concerns:
Impurities: Commercial calcium chloride can contain impurities that might release some gases or vapors. For example, if it contains magnesium chloride or other substances, they might interact with water differently.
Aerosols: The heat generated can cause rapid boiling of water, potentially creating steam or fine aerosol particles. While these aerosols are not inherently toxic, breathing them in could irritate your respiratory system, especially if they contain impurities.
To stay safe, it's best to perform the reaction in a well-ventilated area, and if you're working with large quantities or unknown purities, wearing a mask or ensuring proper ventilation is a good precaution.
Similarly, Quick lime + water = slaked lime + heat
yehhh this way of storage is really good! there will not be much problem about it except for its potential ability to strip national banks down to their last penny in a larger scale
0:30 "Dear god..."
Your error bars are nearly bigger than your signal. You also didn't include the power to run the fan, but given your measurement accuracy it would be below the noise floor and is probably not a major factor anyway. You're also comparing apples to oranges. The lithium-ion batteries are measuring useful electrical energy, whereas you're just measuring energy in the form of heat which is much simpler. You have no way to convert it efficiently to electricity. It's useful only for heat storage, and for that there are just much better and simpler alternatives. Nobody would recommend using a lithium-ion battery as a heat storage device. Bizarre comparison.
@@human_shaped No one would use li-ion batteries to store heat, because they're much too expensive and there are far cheaper effective alternatives. That's pretty much also what I said in the video. Now of course, you can argue that's too obvious to even include them, but I decided to put them in there anyway, for the following reasons:
1) they are a useful benchmark for energy density since a lot of people (at least in my audience) are familiar with their size which helps visualise the kind of energy density we're talking about.
2) although arguably stupid for storing heat, li-ion batteries are pretty much the only available method of storing heat that doesn't lose energy over time. If you wanted to store heat for a long time, sensible heat or pcm storage won't work. The only option that is practically available would be batteries.
The fan was running at like 25% speed, it consumed less than a watt of power, I decided to not bother with that haha. It would have been good to mention that in the video.
Nah, Not a viable method. issue is that it will take a lot of energy to boil off the water to make dry again, probably 50 times more heat energy input to boil off the water, than you get back dissolving it in water.
The most practical heat storage methods are phase change materials such as wax and Sodium Acetate, but these also have issues.
Currently the most practical is just storing heat in water: use a water tank to heat up and then circulating to extract the heat. Water tank can be heated using PV or with solar thermal panels. This is the cheapest & most reliable solution, but is a low thermal density method.
But the purpose was not to demonstrate the free energy device 😂 You store heat right, which means you use that big thing from the sky for charging.
@@danielmogos8990 No, still very low EROEI. Its like trying to power a 25W bulb with a 1MW generator. I provided better options in my earlier comment
@@guytech7310 EROEI is not as important as effectiveness on a societal level (cost-efficiency in some context), compared to other methods. Is this better than, for example, living off gas (hauled in tanks) using heaters with 20% efficiency? I'd say yes, so this IS viable. Obviously not a universal solution to all our problems, but I can imagine an engineered system of this, coupled with a solar dryer, that's ideal for an off-grid house.
@@besenyeim Its not cost effective either. You waste more money & fuel that it will save.
FYI: I heat with Propane, & it costs me about $100/mo in Propane during winter. I have a condensing Boiler with a 80 Gallon Thermal (Water) tank (prevent short cycling. Tank has a 4KW resistive element for solar but I don't have any solar panels yet. Plan is to dump excess solar into the thermal tank. Also planing to add a outdoor wood boiler (I have about 90 acres of wooded land). Using chemical or phase change methods to store heat just isn't practical.
Best option for efficient & cost savings is to properly insulate a home to reduce thermal losses (heating & cooling), Last is adding gadgets for thermal storage, solar, etc. The #1 issue with homes is very poor insulation & air leaks.
@@guytech7310 I totally agree about insulation issue. Spending more for a proper layer is the best investment when building a new house.
Your plans (solar & wood) are also good.
It still seems that, you see thermochemical methods as inferior in general, because they are, in your use-case. But for a few others, it may be the best.
Without that explanation of circumstances, your opinion sound authoritative. You clearly did your research, and what you say is true most of the time, but not every time.
I'm not trying to change your mind. I just suggest you to express your opinion differently, so you won't discourage others from exploring alternatives (even if they are far from the best).
But I feel we are running off the topic of the video.