Storing heat in a stable compound
 

I thought you guys would find this interesting:

Stable Way to Store the Sun's Heat: Storing Thermal Energy in Chemical Could Lead to Advances in Storage and Portability

This compound goes through a molecular change when it is heated in the sun, storing the heat energy and storing it indefinitely. When a small amount of heat is applied, it reverts back to its original state and gives up its heat. It can get as hot as 200 C. Now they just need to make a similar compound with inexpensive materials.

Very cool idea. It would be great to see this worked into modern use.

That reminds me of those heat packs that you boil. Then when you want heat, you squeeze the "clicker" and the chemical gets hot again. I have no idea how it works, but I it works great.

That is cool - I hadn't heard of it. Here is an explanation. Ohh wikipedia, what would we do without you?

Here is a video that shows how to make your own. I can just imagine it being worked into a hot water storage system. Put a bunch of sodium acetate into sealed bags in your hot water tank, let it heat up during the day and store the heat in a stable chemical form, then trigger the reaction when you needed the heat at night. You would presumably have less latent loss, so I wonder if it would do better than a regular hot water system?