cooltubes hot or cold air? does it matter science

Some guy on here told me air tenp doesnt matter when cooling its to do with humidity etc i duno.
I stil vent in cool air lol.

But wondering on cooltubes does it matter if the air is cool going through it?
Or is it more about the air movement?

I always vent in cool air. But loft being warm i wobdered if i could vent the warm air through the cooltube and 2 birds 1 stone

Heat out loft room
Heat out cooltube

This works of course if the science says the cooling is simply by removal of air and movement.
And not affected by air temp


I always assuned air temp till a dude said the air will all he the same after hitting the bulb in that small tube from radiating temps.....

Short answer: as long as the air is colder than the bulb it will remove heat.

Technically you have two rates of heat removal. The rate of removal of heat from the bulb to the air will be directly proportional to the difference in temperature.

The rate of removal of heat from the air is directly proportional to your fan speed.

Your overall rate is the product of the two. Simply if you have adequate ventilation then the temperature difference between the bulb and air will always be very high so it doesn't matter if the air is warm or cold so long as it's not really really hot. To achieve the same cooling with warmer air you will need a faster airflow obviously.

This is all theoretical, anyone with practical experience.

Edit: yes humidity will affect the rate in the first part (bulb to air) but not the second with one caveat. If you are pumping dry air into a tent, the evaporation/transpiration will cool the area, but this is not applicable to cool tubes.

Edit 2: bulbs radiate very little heat. Heat loss is by conduction to the air (part 1 involving temp differential and humidity, then convection (part 2 airflow)

One other thing to consider is the bulbs operating temperature and its efficiency. Moving air that's too cold may over-cool the bulb. Never allowing it to reach maximum efficiency. This is particularly important when using DE bulbs. They do not like much air movement.

cowboylogic said:

One other thing to consider is the bulbs operating temperature and its efficiency. Moving air that's too cold may over-cool the bulb. Never allowing it to reach maximum efficiency. This is particularly important when using DE bulbs. They do not like much air movement.

Click to expand...

I run 2x 600watt cooltubes. With a 6inch inline fan 430 pushing down them. The pipe does wana move from bottleneck on the light fixtures. But ive fixed it ridgid and tight to reduce this bending.

So i believe i have achieved max airflow through the 6inch cooltubes. I have a filter on to take any shit off the air before the glass.

Im thinking as the air it moves is 23degree room.
The loft is 29degree. So if i drop the filter and use tights to filter crap off the air the flow increases slightly with less restriction and in theory would remove the air in the loft which has a vent into it from a 8inch 20degree room.

So over time this should cool the space down in theory aswel as remove temps on lights
Which then air will drop temps and be less effort for my tent to vent it

cowboylogic said:

Moving air that's too cold may over-cool the bulb. Never allowing it to reach maximum efficiency.

Click to expand...

Wait a minute..... I asked about over-clocking bulbs in another thread, the 10% boost. The consensus was over-clocking is good. Most ballasts are also dimmable.

If cool air can prevent a bulb from reaching maximum efficiency, by extension a person who dims/under-clocks a bulb creates a scenario that the bulb can never reach the temperature for maximum efficiency. Thoughts?

rmax said:

Wait a minute..... I asked about over-clocking bulbs in another thread, the 10% boost. The consensus was over-clocking is good. Most ballasts are also dimmable.

If cool air can prevent a bulb from reaching maximum efficiency, by extension a person who dims/under-clocks a bulb creates a scenario that the bulb can never reach the temperature for maximum efficiency. Thoughts?

Click to expand...

Agreed but if dimming also reducing power the heat required would be lessened to reach max efficiency as a 400 is alot cooler than a 600

2cent said:

Agreed but if dimming also reducing power the heat required would be lessened to reach max efficiency as a 400 is alot cooler than a 600

Click to expand...

I'm just throwing the question out for discussion.

Let's think of a 1000W HPS. The components - arc glass thickness, stems inside the bulb, gases, shell glass thickness, etc - are engineered to provide a certain spectrum at 1000w.

What I would like to know is does dimming/over-clocking into that bulb change the outgo spectrum frequency. Thinking about color spectrum of heat, the bulb spectrum must... but maybe a negligible effect. Over-clocking is only 10%..... but then consider someone losing 10% of their toes, or midpart.. That sounds like a lot.

Below is the graph for the EYE Hortilux Super HPS.

rmax said:

Wait a minute..... I asked about over-clocking bulbs in another thread, the 10% boost. The consensus was over-clocking is good. Most ballasts are also dimmable.

If cool air can prevent a bulb from reaching maximum efficiency, by extension a person who dims/under-clocks a bulb creates a scenario that the bulb can never reach the temperature for maximum efficiency. Thoughts?

Click to expand...

Yes under-driving HID lights reduces the efficiency and spectral output of the bulb

rmax said:

I'm just throwing the question out for discussion.

Let's think of a 1000W HPS. The components - arc glass thickness, stems inside the bulb, gases, shell glass thickness, etc - are engineered to provide a certain spectrum at 1000w.

What I would like to know is does dimming/over-clocking into that bulb change the outgo spectrum frequency. Thinking about color spectrum of heat, the bulb spectrum must... but maybe a negligible effect. Over-clocking is only 10%..... but then consider someone losing 10% of their toes, or midpart.. That sounds like a lot.

Below is the graph for the EYE Hortilux Super HPS.

Click to expand...

Yeah the 10% over-clocking doesn't seem like a real game changer to me. I've never read any studies on how it affect a bulbs output.

I dont know about science, but i used to run air like tent -> filter -> inline fan -> outside tent. Then i switched to much lower powered inline fan that takes air directly outside the tent. They cool so similarly that i dont see any difference in temps, even tho like i mentioned the new inline fan is much lower powered. Ofc it doesent suck the air through filter, which reduces the efficiency of what i had before, but even taking that into consideration the new fan moves less air, but cools the same because air comes outside of tent and not from inside. Outside of tent is normal room temperatures, so its not like im pumping cold air in there now either, just few degrees colder. Altho it might have some effect that my filter output is also now a bit more efficient, because i can run it without less bends.

cowboylogic said:

One other thing to consider is the bulbs operating temperature and its efficiency. Moving air that's too cold may over-cool the bulb. Never allowing it to reach maximum efficiency. This is particularly important when using DE bulbs. They do not like much air movement.

Click to expand...

Regular hps bulbs are in a vacuum so they are uneffected by cold air.DE bulbs are filled with gas.Cold air will cool the reflector and the surface of the bulb faster.It is not required though..Also,it takes very little air movement to cool reflectors.Put your hand on the reflector,is it cool to the touch?Then you have enough airflow.The problem can be the ducting though.If you have alot of ducting in your grow room,the heat will radiate from the ducting back into the grow room before it can be removed.