Who knows how effective this would be?!
You get a bit more light at lower Tj. from the COB's but on the other hand there a pumps and fans needed to keep water temps down... If you manage to make the profits higher than the sum of the additional consumers, then it would be profitable.
Mabye with a big passive radiator and only a additional pump..
I've seen a 650w gaming PC passively cooled with a big converted oil radiator for room-heating. He removes the heating element and insert a 240l pump instead. There is a youtube video but I don't have the link.
There are also other big passive PC cooling radiators like this one below.
The Alphacool Cape Cora HF442 + HF642 are scaleable to nearly every cooling capacity up tp 650w and more with really good ∆T for a passive radiator and this modell is from 2013...
You can connect a 442 and a 642 together to get a 1042 radiator or add another 442 for a 1442 unit.
Only limiting factor is flow and pressure but with a good pump I see no reason for a fail.
There are also vids on youtube about this radiators.