That's what i was thinking as far as the ballast btu/heat subject.....didnt sound correct...but as far as the hybrid system we're talking about, maybe his way is the best...
[using the 1 icebox to "cool" + re-ciculate air, not vented, (best if using CO2) and use another icebox with it's own fan attached outside the tent to act as an A/C for surrounding room which all can be ran off the same chiller, lines, manifold,pump ect......that way you can cool everything in your tent and cool everything else outside the tent...(ie; ballast, ambient temp of room, and chiller, if the chiller is in the same room, of course]
Because as you mentioned, there will still be heat leftover in the room, (tent) if you have a isolated air cooled pathway just to remove the bulb heat. There will still be heat from intake fan, exhaust fan, lamp cords, fan cords, and dehumidifier, (which I will have in tent, I may vent that heat from it out the tent via the 4" opening on bottom of tent?...going for 35%-45% margin during flowering!
I should be able to accomplish that with the initial cool air from the icebox & dehunidifier going..) BTW, I will be using 2 8" Iceboxes, 8" reflector, (either Radiant 8 or 8" Cool Sun XL) and 2 8" TD-200 S&P inline fans, (538CFM)(Using this type because they make less noise than most fans out there! LOW SONES!) with 1 1000hps and 1000 lumintek ballast, 25 gal res., (with some insulated material around it) 1/6hp submersible pump, and a 1/2hp water chiller, {JUST DONT KNOW WHICH ONE OR WHAT BRAND TO GET BESIDES THOSE "ChillKings"<<EXPENSIVE MAN!!
Ps: I was gonna go with a 2 light system,(which would require 2 ballast, 2 reflectors, 3 fans, 3 Iceboxes,[1 icebox per reflector, 1 fan per reflector,] ect) but because the damm chillers are so expensive I have to dial down my system for now...Although it would make sense to by a bigger hp chiller now as I can upgrade lights and more Iceboxes in the future, BUT DAMM, HAVE YOU SEEN THE PRICE FOR THOSE ChillKings!!????
The folks at hydro innovations had an article in a recent issue of "The Indoor Gardener Magazine" (sorry but they don't have online edition that I can find so no link) that made me think that the author has a slight misunderstanding of thermodynamics. When talking about their upcoming product, a water cooled ballast fitting, they claim that 1000w ballasts produce 3500 BTU and this is not correct. A 1000w lighting system (ballast/bulb) creates that much heat, not the ballast. I like to look at every component of a light setup as being a source of heat. The power cord, ballast, lamp cord, and bulb all produce heat.
When I look at the company's youtube videos for their air cooled products (the heat shields) it seems that they always are exhausting air from within the room to the outside and not using an isolated path for the air which is cooling the lights.
So, which one is better? To me, that depends upon the efficacy of the air cooling system. If we measure efficiency by BTUs/watt then it's a question of how many BTUs from the light can we remove using the power of the fan in the isolated air cooling pathway vs. how much does it cost to run a chiller and remove the heat of the light using water.
Certainly, in a hybrid system like we are talking about there will still be heat from the light in the room as (we all know) fans can't get rid of every BTU using an isolated air cooled pathway. So, there will still be a need for some sort of cooling inside of the room. This is the delta in cost. How much does it cost to run the chiller to just cool the leftover heat + the air cooled light vs. cooling all of the heat from the light.
This is the way I see it anyways. I could be wrong.