There is no need to store summer heat for the entire winter, which would necessitate a far larger capacity system.<p>One would only need to store solar thermal energy that is available on any sunny or partly sunny day for night time and cloudy days.<p>Where I live about half of all days produce abundant solar thermal energy even in the depth of winter. Calculating in night time, you end up with about 12.5% of total winter time having abundant free thermal energy.<p>So one would need to build a system of solar thermal collectors about 8 times the size one would need to heat a house on a sunny winter day, and that is not a very big system.<p>Space wise I think it would work for single family residential homes on .25 acre lots if the house was designed for it from the start.
The opposite of saving winter ice for the summer was popular in the 1800s before mechanical refrigeration. Ice can last many months if insulated by sawdust below ground.
Another way is to simply use the ground. Dig trenches, lay in pipe. The ground is cooler than the air in summer, can warmer in winter. I read that using it as a heat exchanger can cut HVAC bills by 30%.
I think this kind of technology has enormous potential to improve human life. Bad weather is a huge, chronic problem that makes almost everyones' life substantially worse. Just the other day my aunt broke her wrist after slipping on a patch of ice.<p>One question though: why do they need a special high-tech material to do this? Why can't they just bubble warm air through cold water in the summer and vice-versa in the winter? Water has very large heat capacity, 400x that of air by volume.
(Wikipedia:) Worldwide production [of sodium hydroxide] in 2004 was approximately 60 million tonnes, while demand was 51 million tonnes.<p>So it might be relatively cheap to acquire the working material.
This reminded me of a similar system that uses the same tech as those hand warmer things that have a chemical that changes state, either absorbing or releasing energy. They also talk about absorbing heat and physically transporting it. The example they have was waste heat from industrial processes being shipped via canal to a district heating system.<p><a href="http://www.sunamp.com/" rel="nofollow">http://www.sunamp.com/</a>
> The heated water generated in the process of condensation is then transferred to a geothermal probe (generally loops of pipes embedded vertically in the ground) for storage and retrieval.<p>That is a neat approach. It works well for solar-heated water. Where winters are very cold and summers hot, one can also have cold-storage loops for summer cooling.<p>I'm not sure about the NaOH thing, however. I get that it enables heat transport. But as scotty79 notes, transporting concentrated NaOH is hazardous. It's already done, of course. But the scale for heat transport would be much greater than as chemical feedstock, I think.
I usually find these types of new green technology to be impractical, and obviously not going anywhere (store energy by dragging a train uphill for example).<p>But this actually looks like it would work!
Is this something that could be used in a dense urban residential setting?<p>Is the reaction extremely volatile? Does this require a high-tech ultra-low-tolerances system, or can it be DIY-ed?<p>I can see having a setup on a condo balcony (esp. if you're facing south / west), with heat exchangers on an otherwise-unused wall, and a few cylinders of NaOH. As long as the kit doesn't blow the wall off the building if it leaks or some such disaster..
There is a better solution already implemented..<p><a href="https://youtu.be/sbX6K7ky9LQ" rel="nofollow">https://youtu.be/sbX6K7ky9LQ</a>