you’re suggesting putting the chiller after the cooling tower, but before the condenser right? Which seems like the correct way to play that game.
I don’t think that chiller alone would be up for the task, and I’m not certain OP got that you were suggesting supplementing the cooling tower rather than replacing it.
I suspect ditching the vac entirely, even without adding more heat is the easiest/cheapest way to recover more solvent. if more heat is available, that will speed things up, if it’s not, who cares, they’re no longer loosing most of their solvent to atmosphere.
how does the volume of that water compare to the (tremendous) amount of solvent you’re loosing every run?
you sure you’ve still got water in that pump? (I’ve seen ethanol replace vac oil more times than I can count).
where is the heptane going then?
is that on a controller?