b1-66er: https://youtu.be/2gWudPtN6z4?si=3hrm3wg7PozSVl5U
b1-67er: Heating the pool thar way is generally the right idea sort of. It's tough to use heat that's at say 180F (probably about as hot as you want server chips to run), because the delta T relatively low. So you have to move a lot of water. And pumping costs energy. What you really want is relatively high temperature heat so that a small amount of pumping energy moves a lot of heat. There are some practical thresholds. Regular buna-N seals will get you to about 200F. CHEAP. Slightly more expensive viton seals will get you to about 450 F. Still very practical. Temperatures above that get trickier, it's expensive to get sealing materials that will survive. But there are solutions. Then there are the solar concentrator guys that are using molten salt as their fluid at around 1000F. They are out of their goddamm minds if you ask me.