Grounds power?

Water is cooled with a chiller, and pumped to FCU (fan coil units, basically a heat exchanger with a fan). The FCU blows air through its coil as the cooled liquid is pumped through the coil, the water absorbs heat, cooling the air. The heat then returns via the chilled water system to the chiller to be cooled again and go back out.

The chiller is a mechanical system using refrigerants to cool the liquid. The other output of the chiller is heated water, which then typically goes to a cooling tower (basically another heat exchanger) water flows through the tower as a fan pulls ambient outdoor air, which removes heat from that portion to go back and cool the chiller.

True on the single conductor. The splice would also need to be in a box. Cable of appropriate type wouldn’t necessitate conduit.

Not all jurisdictions require conduit.

Wire size can be increased in size to account for voltage drop.

Decreasing wire size from its corresponding breaker is a fire risk. The wire is not rated for the higher current and will heat up (think of the small wires in a toaster).

This is typically acceptable as a means to account for voltage drop. Check to see if the charger accepts the larger size (many do). Then you can double check with the inspector so they’re aware of the charger does not accept the larger size. Your #8, per NEC, are properly covered by the 40A breaker.