[nagisa]

I did not say otherwise :) My point is that with a ground-source the cooling can be “passive” – you don’t actually need to turn on anything but a circulation pump or two once in a while.

The downside of course is that its not going to make your already +40°C room into a flu-inducing +18°C one. Its more of a tool to offset a 2°C, maybe 4°C in extreme cases indoor temperature rise. Which is likely more than plenty for many airtight & insulated houses.

And indeed, managing humidity is hard. If this sounds at all interesting to the reader, definitely research whether this is applicable in your situation/area at all.