Sunamp's thermal battery uses a chemical found in salt-and-vinegar potato chips

Sodium Acetate is an interesting chemical - it’s also effective at improving the hydraulic properties of concrete.

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=sod...

> Sunamp’s thermal battery are three compounds: sodium acetate trihydrate (SAT), a food flavoring used in salt-and-vinegar potato chips; water; and a sprinkling of so-called crystal habit modifiers

In case you didn't want to parse the entire backstory of the company's founding to find out.

I'm a big fan of Sunamp and have one of their heat batteries!

https://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and...

Is it Salt, or is it Vinegar?

Actually it’s something else, maybe these aren’t the crisps you’re looking for.

Surely there’s just three ingredients for salt and vinegar crisps.

I got a bunch of those heating pads from a high pressure salesman who had a booth at the New York State farm show.