Optimal airflow question

How long u guys think it should take to clean out the complete volume of your growspace once?

Once every 2 minutes?
Once every minute?
Twice a minute seems a bit excessive, but that's what people in shops are telling me.
(probably just trying to upsell, imo.)


I'm roughly at 1.5 minutes and I'm feeling pretty confident I'm good here.

Whadda u think?

kind regards, sh0

Ask 10 people and get 10 different answeres.

Why should there be a specific number???
How do you measure it?

I'm not concerened about exchange rate. I set my fan control to desired temperature and humidity.

For grow rooms a lot of people say it can be even once every 5 minutes. But big rooms have more space for grow lights to dissipate heat. In small, medium grow tents heat accumulates faster so at least every minute is better to keep temperatures low. Of course intake temperature, space air circulation etc takes account in equation...

CFM of the fan divided by the square footage of the tent = how many times air will exchange per minute at full power.
Adding a carbon filter will lower the exchange rate. Filters still being used from previous grows may pull even less air.

024matters said:

For grow rooms a lot of people say it can be even once every 5 minutes. But big rooms have more space for grow lights to dissipate heat. In small, medium grow tents heat accumulates faster so at least every minute is better to keep temperatures low. Of course intake temperature, space air circulation etc takes account in equation...

Click to expand...

Really ... ? I think if you would have issues with the humidity then...

edit btw: I forgot, you guys like to do everything with a computer + machine. I don't.

HydroKid239 said:

CFM of the fan divided by the square footage of the tent = how many times air will exchange per minute at full power.
Adding a carbon filter will lower the exchange rate. Filters still being used from previous grows may pull even less air.

Click to expand...

This would be true about 1 foot tall tents. You need to incorporate height aswell to get the actual volume and air renewal speed

It all depends on the ppm of co2 in the source air and how fast it gets depleted in the grow tent. Temp and humidity also come into it but they can be controlled by other means

Rocket Soul said:

This would be true about 1 foot tall tents. You need to incorporate height aswell to get the actual volume and air renewal speed

Click to expand...

Thanks for catching that. Should have been more specific instead of saying sqft.

L x W x H of a 4x4x7 tent = 112.
AC infinity T6 @ 402 CFM = Renew air 3.59 x per minute without filter.

HydroKid239 said:

Thanks for catching that. Should have been more specific instead of saying sqft.

L x W x H of a 4x4x7 tent = 112.
AC infinity T6 @ 402 CFM = Renew air 3.59 x per minute without filter.

Click to expand...

Just say volume.

3 factors , all different requirements.

Co2 replenishment- that's a whole set of equations in itself.

Heat removal

RH

At the end of the day, without being fancy , if you take care of the heat the co2 will be fine and the humidity shouldn't be far off.
For your average environment anyway.

If you work it from worst case , summer ambient temps .

Those grow shop calculations don't take into account the most important thing..
Ambient temps. Because if your starting point is 75f itl take more air exchange to stay at 80f than it will if your starting point is 68f ..

coreywebster said:

3 factors , all different requirements.

Co2 replenishment- that's a whole set of equations in itself.

Heat removal

RH

At the end of the day, without being fancy , if you take care of the heat the co2 will be fine and the humidity shouldn't be far off.
For your average environment anyway.

If you work it from worst case , summer ambient temps .

Those grow shop calculations don't take into account the most important thing..
Ambient temps. Because if your starting point is 75f itl take more air exchange to stay at 80f than it will if your starting point is 68f ..

Click to expand...

Like he said.

Basic fundamentals of physics and thermology will most surely save a lot of money and noise. One might end up with diy- solutions easier when realizing how effortless it can be to move unpressurized air with a relative heat difference to its surroundings at indoors/small spacing.

Jylhavuori said:

Like he said.

Basic fundamentals of physics and thermology will most surely save a lot of money and noise. One might end up with diy- solutions easier when realizing how effortless it can be to move unpressurized air with a relative heat difference to its surroundings at indoors/small spacing.

Click to expand...

AKA convection. Thermology is the use of infrared imaging for health evaluation.

1212ham said:

AKA convection. Thermology is the use of infrared imaging for health evaluation.

Click to expand...

Thanks for the correction

Edit

In Finnish, thermology equals to thermodynamics, scientifically. It's derived from english so I'm a bit confused.

1212ham said:

AKA convection. Thermology is the use of infrared imaging for health evaluation.

Click to expand...

Noun

thermology (uncountable)

1 The scientific study of heat
2 imaging of the body by means of infrared radiation

Jylhavuori said:

Noun

thermology (uncountable)

1 The scientific study of heat
2 imaging of the body by means of infrared radiation

Click to expand...

My error, I searched thermology rather than thermology definition.

Error good. More total info presented

Information is always polynomial!