New ‘mirror’ fabric can cool wearers by nearly 5°C
In Japan they have these portable AC jackets.  I believe they are mainly used by people working on building sites where it gets very hot in summer.  While these are actively cooled rather than passively (as in the article), they seem like a better idea than air conditioning whole rooms.https://wonderfulengineering.com/japanese-invent-a-jacket-wi...
https://www.dailymail.co.uk/sciencetech/article-2016513/Japa...(Sorry can't find any good links - the jackets aren't a fad and seem to be popular with builders)Edit: The company website (Japanese) https://kuchoufuku.com