Questions about my setup

Pedro Mello

Pedro Mello

Well-Known Member
Hi guys, first of all, thank you, I'm having a lot of help here on the forum.

I'm setting up a grow space that has something like 190x120x240cm where I intend to build two pipe supported tents with about 80x95x200cm.
The light will be 6 vero29 3500K B on a HLG 480w driver, each side.

I'm willing to have an inline fan pulling the hot air from the top where it'll go down in a duct to the exit, and the new air will come through two quite big passive
air intakes. The two passive entrances of air have aproximately the double of the exit area.

My doubts are:

1. How intense should be my fan? The one i thought have two speeds 220m³/hr or 280m³/hr
2. There is some formula to calculate the passive intake area?
3. Should I use a carbon filter before or after the exhaustor, maybe both? and this is enough to handle the smell?
4. What is a good distance from lights to the top bud (cannopy, right?)

Thank you
Jah bless
 
SchmoeJoe

SchmoeJoe

Well-Known Member
You've got a few questions so in order if appearance;

1/2) your fans air flow rating should be chosen to give a specific /air exchange rate/. Multiply your tents heightXdepthXwidth to get your total cubic air volume. Divide this number by a particular fans cfm rating to find what /air exchange rate/ this will give you (I'd do a seperate search on calculating your /air exchange rate/ since it's a fairly detailed thing itself.

3) Fans are much more efficient when creating negative pressure by pulling air instead of pushing so definitely run a filter before the fan and not after. You can use a clamp or a short piece of ducting and duct tape to seal the connection between fan and filter this way but the other way with massive positive pressure you're likely to have leaks in the ducting you can't do anything about.

4) The best distance for you're lights will depend on the light. I'm not at all familiar with your set up so I can't safely say.
 
Last edited:
Bigz2277

Bigz2277

Well-Known Member
SchmoeJoe said:
You've got a few questions so in order if appearance;

1/2) your fans air flow rating should chosen to give a specific /air exchange rate/. Multiply your tents heightXdepthXwidth to get your total cubic air volume. Divide this number by a particular fans cfm rating to find what /air exchange rate/ this will give you (I'd do a seperate search on calculating your /air exchange rate/ since it's a fairly detailed thing itself.

3) Fans are much more efficient when creating negative pressure by pulling air instead of pushing so definitely run a filter before the fan and not after. You can use a clamp or a short piece of ducting and duct tape to seal the connection between fan and filter this way but the other way with massive positive pressure you're likely to have leaks in the ducting you can't do anything about.

4) The best distance for you're lights will depend on the light. I'm not at all familiar with your set up so I can't safely say.
Click to expand...
i cannot add more. very well said. give us some more info
 
Pedro Mello

Pedro Mello

Well-Known Member
SchmoeJoe said:
You've got a few questions so in order if appearance;

1/2) your fans air flow rating should be chosen to give a specific /air exchange rate/. Multiply your tents heightXdepthXwidth to get your total cubic air volume. Divide this number by a particular fans cfm rating to find what /air exchange rate/ this will give you (I'd do a seperate search on calculating your /air exchange rate/ since it's a fairly detailed thing itself.

3) Fans are much more efficient when creating negative pressure by pulling air instead of pushing so definitely run a filter before the fan and not after. You can use a clamp or a short piece of ducting and duct tape to seal the connection between fan and filter this way but the other way with massive positive pressure you're likely to have leaks in the ducting you can't do anything about.

4) The best distance for you're lights will depend on the light. I'm not at all familiar with your set up so I can't safely say.
Click to expand...

Thank you, man. I saw your answer only today but helped me a lot!
 
Pedro Mello

Pedro Mello

Well-Known Member
SchmoeJoe said:
You've got a few questions so in order if appearance;

1/2) your fans air flow rating should be chosen to give a specific /air exchange rate/. Multiply your tents heightXdepthXwidth to get your total cubic air volume. Divide this number by a particular fans cfm rating to find what /air exchange rate/ this will give you (I'd do a seperate search on calculating your /air exchange rate/ since it's a fairly detailed thing itself.

3) Fans are much more efficient when creating negative pressure by pulling air instead of pushing so definitely run a filter before the fan and not after. You can use a clamp or a short piece of ducting and duct tape to seal the connection between fan and filter this way but the other way with massive positive pressure you're likely to have leaks in the ducting you can't do anything about.

4) The best distance for you're lights will depend on the light. I'm not at all familiar with your set up so I can't safely say.
Click to expand...

now I'm calculating the dimensions of an aluminium passive heatsink for my setup.
After some study I got that my cobs working with aprox 80w ea would generate 20% of heat at the worst case temperature.
Then I made:

0,2*(80)=16 heat watts

and sized the dimensions of the heatsink.

I've reached that a 8'' x 8'' heatsink would handle each cob.

Is it make any sense?
Thank you.
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Pedro Mello said:
now I'm calculating the dimensions of an aluminium passive heatsink for my setup.
After some study I got that my cobs working with aprox 80w ea would generate 20% of heat at the worst case temperature.
Then I made:

0,2*(80)=16 heat watts

and sized the dimensions of the heatsink.

I've reached that a 8'' x 8'' heatsink would handle each cob.

Is it make any sense?
Thank you.
Click to expand...
I haven't done the research myself so I can't really comment on the math but it does make sense.
 
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