If this works as advertised, the commercial applications will be impressive. https://newatlas.com/cct-silicon-energy-battery-thermal-energy-storage/59098/ "World's first working thermal battery" promises cheap, eco-friendly, grid-scalable energy storage South Australia has recently put the world's biggest lithium battery into operation – but perhaps it should've waited. A local startup says it's built the world's first working thermal battery, a device with a lifetime of at least 20 years that can store six times more energy than lithium-ion batteries per volume, for 60-80 percent of the price.
Just for grins: If we assume they mean something on the order of 20 ft long and 4 feet high, and 3 feet wide, as suggested by the photo, then we are talking about 240 cubit feet at 1.2 MW-Hrs. Considering water: 240 cubic feet is about 6800 Kg. At 4.2 KJ per Kg-Degrees C, we get 28.5 MJ per degree C. And 1.2-MW Hrs is 1 MJ per second for one hour. One hour is 3600 seconds. So we end up with 3600 MJ / [28.5 MJ/degree C] = 126 degrees C. The reason for this exercise is to see how it compares to the energy stored in hot water. When I was playing with an energy storage system for my home, I found that hot water has a very large energy storage capacity compared to alternatives. In our case, we would use the hot water directly. It didn't need to be converted back to electricity. So it made perfect sense. So if you take the same volume occupied by this battery, fill it with water, and heat the water by about 120-130 degrees C, you would have the same amount of stored energy. Of course the difference being that is would be very inefficient to convert that heat back to electrical energy. But it again confirms what I found. When all you need is the heat, hot water is a great energy storage option for limited periods of time.
There are also some serious efficiency losses, because it is converting electricity into heat (that first part is 100% efficient), and then that heat has to be converted back into electricity. But sure, if cost is no object for creating renewable energy sources then I suppose it would work. The best steam engines have efficiencies of 50%. Smaller steam turbines, like the ones that would likely be used for these things are only 40%. That will mean you are going to need double the amount of solar panels or wind turbines. Theoretically, if you could design a solar power station that could put the heat directly into storage, you could do away with the efficiency loss, but there would be very big engineering obstacles to overcome (will not discuss it here).
I don't know the functional low absolute temp, but they cite the high temp as 1400 degrees C, or 1673 K. If we assume the low absolute is ambient, so say 298 Kelvin, we get a maximum Carnot efficiency of 83%.
I wouldn't rule out passive solar heating as a use for this kind of mass. It can moderate interior temperatures throughout a 24 hour period, soaking heat in the sun and emitting it to interior space during the night. It's probably not appropriate for all environments, but no solution has to work in all environments. Waterwall concepts can tend to take space, but they don't depend on converting from or to electricity.
Of course not. Passive solar works at far lower temps. I'm not denigrating the various ideas here. Using a mass, such as water, to store heat is something to investigate. In fact, I think you pointed out that converting heat to electricity is not the only choice.
It's much more difficult to convert heat to useful energy when the heat source is only right at the boiling point of water. For a steam turbine, that's not all that hot.
I would agree with that. I don't know of any good methods of converting WARM water to electricity. That vanadium redox direction cited by Bowerbird sounds like it could be promising for massive storage. Looking at wiki, there are several experimental plants being constructed.
Exactly....simply super insulating a home and putting windows on the appropriate side with electrically controlled blinds, can heat a home down to 30F in sunlight. A friend owned a solar house building firm and built them for years. They aren’t cheap, but the payback is amazing. We used some of the concepts in our house more then twenty years ago. We heat our house and heat our water on one fillup of heating oil in two 275 gallon tanks. Our total consumption has never exceeded 450 gallons. We average 100 plus inches of snow a year and live near the Canadian border....so it’s cold. The thick walls with wide window sills make great areas for decorations too...little hidden advantages. Btw, it pays in many ways to insulate the interior walls between rooms too. The last thing you need to do is heat the interior of the walls while waiting for the house to warm up. Also, house shell cost depends upon the linear length of the foundation. Therefore , you maximize your heating efficiency , minimize your cost in building too by building a square house vs a rectangle. Put a deck on and it stretches out the house visually. Cheap heating and building costs can go hand in hand. You also minimize Hall ways which are heat wasting and maximize the efficient heating additional floors. We had wood back up and the wood just rooted for lack of use. It just wasn’t worth the effort throw obviously, you can still save a lot. Wood was just the back heat. One small stove in the lower floor easily heats the whole house... One neighbor copied the technique and put one gas space heater on his lower floor and it heats the entire 2500 plus sq foot house.
Amen. I think it could be shown that conservation is the cheapest and most green form of energy we have. Serious insulation is a great example.
