> One end of the building will
> be over 100km from the sea,
Well, that part's easy. You put the non-citizen service workers on that end, you didn't think MBS was planning to provide them with AC, did you? :-)
Talk about a disincentive to show up to work before sunrise and leave after dark.
> Also wouldn't this be like
> the elevator problem in tall
> buildings?
No, the vertical pipes in the building will branch off from the horizontal pipes running along it, the vertical height is trivial by comparison.
> The first few kilometers of the
> line will need to have pipes
> sized for the cooling water of
> the 165km behind it eating up
> interior volume.
Firstly you'd bury the pipe, if it's at a depth of just 10 meters the average soil temperature at depth really helps, even before insulating it.
Secondly, by having it run in a loop you'd drastically reduce the energy to pump it. It'll take no more energy to pump water up 10m or 1km, as long as your outlet pipe is also at the same depth.
> passing it through a heat
> exchanger [...] be more energy
> efficient than a AC?
The whole thing is obviously ridiculous, but cost-benefit analysis doesn't really enter into what's ultimately an ego project enacted by royal degree.
I was just pointing out that once you're willing to invest the sort of money Saudi Arabia has in upfront costs, there's no reason the end result (no matter how ridiculously expensive) can't be sustainable and passively cooled.
