To quote an old joke:
Child at school:
"Water, Electricity & a Physics Teacher - This should be GOOD !"
Pure water is non-conductive, the more impurities, the more it conducts.
I've not come accross pure water...
But High Voltages will take the easiest route....
It's nice it theory, but I think that by the time you've fitted a pump, a header tank, piping, a radator, cooling devices (I've seen them for CPU on computers) sorted out leak prevension and/or detection...
with a water cooled Computer, if you get a leak, it's all low voltages (Except the PSU), and you have to replace a motherboard and/or CPU - cost £200/£300 ish.
with a projector, if you get a leak.... Ouch - High voltages in the wrong place - Bang goes all the video processing boards at £200++ each...
Cold water on a hot tube - thermal shock - crack - Hissssss... one new tube later - £400++ each...
also I have seen reviews of water cooling devices for PC that had problems, there were dissimilar metals used in them... and you got rust & blockages after less than 1 year...(It killed the CPU - by letting it get too hot, and was the cause of a minor leak)
I think a hush box or a sutable fan mod or louder surround sound system to mask it...
I have seen an experiment on the web, where they got hold of a modern chemical, water like, but non-conductive designed for pumping across computer boards to cool them - it was expensive, and I don't know what the breakdown voltage was... so it may be unsutable for high voltages...
also CRT are designed for use in air, you place them in a liquid and the pressure on them will increase - and could cause them to crack.
Anyway - Have fun... (I'm the one watching from a bomb proof bunker!)
