Marc writes: << we could score higher on the Martian intelligence test by universally adopting saner basis vectors for the control space in the first place--namely temperature and total water volume, rather than hot-volume and cold-volume.

...

I find having separate hot-flux and cold-flux adjusters easier to use than the hardware I've seen based on overall temperature and overall flux. This is especially true for adusting temperature. Perhaps it's a little like when you want to quietly close a door (which normally makes a loud noise when being closed), so you pull it against your foot while the foot pushes it closed gently. --Dan