I even remember 5.25 floppy disks :) That was improvement after using tapes :D Yes, I'm that old.

This is very interesting setup, from engineering point of view. However, it is even needed? I mean, I still use for plants the same water from the very beginning and I'm not sure if they use it at all. You could as well store spare canister filled with water inside room and use it, if ever needed. Canister is enough for plants. Tank is overkill for this purpose.

actually i think water temp have no effect on crops. Mine is around 8c if i remember, and i can grow easily.

Interesting idea! You may want to set the rate of flow on the pump rather low initially, so as to not over cool your warm pipe since the equalization with the room temperature via the radiators will be somewhat slow. Then tinker around slowly incrementing it to find a happy-medium circulation rate that will cool the room while still leaving the warm water line warm enough for consumption. I would however, recommend swapping out the second pump (the one on the return; i.e. warm water pipe network to the tank pipe network) with a one-way valve (it's a scroll-wheel option when placing a manual liquid valve (same option available on gas valves)). This will serve two functions: the first is reducing the control of circulation to a single pump rather than two, and secondly it will maintain equal pressures between both the warm pipe network and the cold water tank network, which can be handy considering that pressure correlates to temperature. The one-way valve is essentially a check valve, where flow will occur when the input pressure is greater than the output pressure, but not vice versa. Cheers!

👍👍👍

for a game on Mars probably good, but over time the water will heat up and cooling the room will not be enough. It all seems unnecessarily complicated and inefficient to me. a better solution is a small air conditioner, ie a radiator in a room with gas X in the pipeline and outside passive coolers on the pipeline are enough, all controlled by a simple logic. The water can be left in the furnace and cooled in the atmosphere of Mars or mixed with an ice maker.