500W is quite high load to distribution grid - considering the potential user areas - you may manage to black out the region if many people simultaneously use this + 500W generates a lot of heat also e.g. potential fire safety - if the device is left/forgotten on it's own
. . . so as a trivia from that - a thermal fuse or a relay that'd be auto resetting or user resettable would give you some advance
. . . why a fixed product - do negotiate the social aware folks at the area - the true problems usually need long term involvement
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there's avail all sort of open door / hiking kitchen ware (**broken link removed**) - the advance of what might be that - if you introduce new product at the earthquake tropical storm area the same donation
has to be repeated after 1,2,5,10 years or you only cover the window of product life span
while gas/solar stoves won't generate much difference from firewood (it's about transition from solution A to B the alernatives -- when electrical heater fails it becomes a junk - for gas stoves you can buy another supply , the solar can basically last "forever")
another good convertible is (what you know) vodka - it is desinfectant , anti bacterial , anti microbal , also when ingested an anti viral // although the web lists conflicting options
A v.
B (←i dont see ethanol listed here??) // but from personal experience i've studied that ethanol variated with (
https://en.wikipedia.org/wiki/Hydrogen_cyanide ) namely the
https://en.wikipedia.org/wiki/Sambucus_nigra treats the beast -- also in that case you must educate the folks (i'm not telling it's any easy) about resource management