Well do tell ol' mate! We're here to learn.
The way I see it, system design is about about balance. In my mini split and air-cooled HPS trailer, the ac dehumidifies as well as two bigs Sante Fe's. My girls are sweating out 25 gallons of water a day.... Trying to deal with this in my water-cooled set-up became a nightmare of three way control valves, by-pass lines, and micromanaging 2 temps of water. 55-60F as ttystik stated early and 38-42F for dehumidification. Also, you then need to repipe and recover the waste heat from the chiller and only a chiller because you need that hot gas side.
I plan on running free cooling in the winter. Without a heat source (wasted energy) my room would be too cold trying to achieve the amount of dehumidification I need with chilled water or air conditioning. I'm planning on using my trusty old sante fe's to dehumidify with... and my lights to cool the heat from them and remove their LED heat as well. Some of these new dehumidifiers are getting some very efficient numbers. I can then work on balancing flow with outside ambient air temperature by cycling the fan on the radiator and decreasing the speed of the pump. My cooling in the winter should be real nice and I'll blast the chiller for the 4-5 months here.
I've got some drawings on an air cooled dehumidifier that I'm working on as well that run's off 40w and should pull a couple gallons of water a day.
One thing for us all to consider.... Like it's always been ,what works for me, may not work for you. For example, over in montana, water- cooled lights and just a lil burp of fresh air exchange keeps there rooms nice in the winter. They have harsh humidity dips in 20-30's. Using air cooled lights, conventional lights or even LED's or any type of unsealed room had very poor VFD in the winter. not exchange as much air allows you to bump that humidity up a little. Everybody's environments are a little bit different.
And another thing, the thing that first attracted me to Fresca Sol's, maybe water-cooled lights will allow some of us to keep growing herb just a little bit longer without getting busted! FUCK THE POLICE! FUCK YOUR CORRUPT SYSTEM! FUCK HYPOCRISY! These motherfucker's are my sworn enemy! They have harassed me and my friends for way to long. This is one of the many ways I choose to take a stand. Since I was a boy, I've dreamed of growing up to find more ways to fight this system. And I'm happy to report back that I'm winning this battle, not ALL, but most! On we go. OOOPS....Allright.. I'll get off my soapbox.
! An exchange of ideas and information, without any name calling and belittling! Please, keep this discussion going. With my next grow room I would like to implement a smaller scale of what you guys are doing (not 90,000 btus ). Here in Oregon we fight the humidity year round so all this information is quite useful.
Updates! 
