Is the theory flawed? I might think so if your you are pushing air across heat sinks and their external temp is higher than ambient. This is kind of where im at with air cooled, fans above blowing down but i try to cross vent to so the hot air isnt blowing into the canopy. Based on fact you are getting condensation on them I don't think that's the case and the airflow might actually help the condensation issue.
One more thing to think about what is the temp difference of the cob closest to inlet and cob closest to outlet? You might be able to balance this if needed / desired by airflow.
A few more things you may have already considereded.....
If the water is just a few degrees (if I recall correctly 4-9 deg F, ask an hvac tech) cooler than the sorrounding material (i.e.heatsink) that would be optimum effeciency. Thermodynamicaly speaking it takes 1 calorie to raise 1gram of water 1 degree C regardless of if the water is hot or cold, so long as it is liquid. So ideally your outlet temp will be very close to your desired operating temp if the system is running optimally. No matter how hard you try you can't break the laws of physics.
@SSGrower ,
@ttystikk
I agree with your understanding of thermal dynamics. The plan was never to blow "hot" air 82-95F on the plants but rather "cool air" (60-70F) on the plants... My question was " Is blowing cool air on the plants going to limit transpiration or increase transpiration? Its seems there is this school of thought that temps in the canopy need to kept higher with LED due to a lack of IR. MY plan has been to run ambient air temp of 80-85F, CO@1200-1400, with a PPFD of 1000-1200. And then blow a nice cool breeze out my lights onto the plants. I'm so excited to fire these babies up! A culmination of 16 years growing.....
I use to get condensation on the unit before I installed a relay to cut power to the dc drivers, leaving the line voltage to the light still energized. this allows me to still harvest power to run the 12v pus's to spin the fans with the lights off. When the light is on, or when the fans are running pushing air across the fins and through the unit, no condensation forms. I could also just cut flow via a solenoided valve, but then I lose cooling at night. I want a day/night temp differential. Water Temp In is ( dependant on dew point) 60-65f. water out is 62-67. Keep in mind however, this is for one light, not a large install...
On my Bitcoin rack that was generating over 180,000btu, 30 ASIC chips that pulled 600w/240v. the temperature differential was only 5F difference between Supply and return of this giant computer.... And mind you, the temp differential never changed, ranging from 65f on the supply side, all the way down to 36f on the supply side.... I actually froze this up during one winter night, at 1.8 gpm with the improper ratio of glycol in it. Was running to lean.... (glycol decreases the efficiency of the pump by increasing the viscosity of the solution)