Water versus Air for cold reservoir in thermodynamic cycle

pianoparadise

I am wondering why water is used instead of air for the cold temperature source for a thermo cycle. My guess is the higher specific heat, which means the condenser unit can be smaller, and the mass flow rate less, which reduces the overall cost.

Are there any other reasons to choose water over air?

Mech_Engineer

Water can also have a more stable temperature (especially if it's an ocean or large river). But mainly your guess about the higher specific heat and advantages w.r.t. heat exchangers are correct.

Stanley514

In vehicles water cooling is used to maintain more stable engine temperature than it`s possible with air cooling.This is important for engine efficiency.
Also making radiator separate from engine makes engine itself lighter and more compact and easier to handle and repair.