DIY Supermaterial Could Save You From Heatstroke: Salt based PCMs ( www.youtube.com )
A simple mix of two cheap salts, Sodium Sulfate and Table Salt (Sodium Chloride) dissolved in boiling water can create a really useful Phase Change Material that has a melting point of 18c (65f) which allows it to be recharged back into it's cooling state simply by putting it in a basement and can then be used as a cooling...