vortex before or after cooltube?

[ithruxix]

You could also do Cooltube -> Fan -> Filter.

The fan will pull the cold air through the cooltube and push air into the filter which is outside of cab.

Ding. This is correct. You can add a scrubber at the beginning of the lineup if you want, but it is not neccessary.

 

[smoke1sun]

Actually Can Filters can be used either way and they tell you that. There is a video somewhere from a trade show where a rep from CanFan says exactly that. Simply take the prefilter and put it over the fan before the air goes into the filter. Any other filters, I dont know but I imagine the same would apply.

I would try to put the filter at the end. By putting the filter first, then pulling, you are prone to any leaks along the way. Any air that is pulled through these leaks will not be filtered.

I have heard over and over that pulling is more efficient than pushing. But I think that is more appropiate to a longer run of multiple lights, not 3 feet in a cabinet. BTW I push air through my hoods so I dont pull up any stank air.

I think this is the video you might be talking about.

http://www.hydrotv.com/showhd1.html

 

[ElGato]

for small cabs where space is a concern it makes no sense to have the filter inside the cab

hence..
reflector/cool tube ->fan ->filter.............nuff said

mj

 

[ithruxix]

With a setup like MtnJ's, there would be no point in putting a filter IN it. Hence, the ease of mounting it outside the cab, constantly giving the plants fresh air, etc.

BTW, elgato your setup is the shit!

 

[yamaha_1fan]

I dont think that anyone would say they dont work , of course they will work ..
the question is 'is there any difference in efficiency?'




One thing that bothers me though is that the fan (which is placed after the first cooltube) is working with hot air. Air expansion due to heat plays a role so I m confused a bit..

Watch the video. I belive the guy says no problem, basically implying no loss of efficiency.

I think you are making it more complicated with the air expansion issue. Tons of growers use their vortexes to pull out hot air, no biggie.

I would pull through both lights, then push through the filter

 

[midwestnug]

if it is carbon filter it does not matter if pulled or pushed as long as air is ran through it. it works both ways, so why waist space putting it in cab? put it on out side and push air out of it. same for use in water, pushed or pulled doesnt matter. by the way all those who pay top $ for that carbon to refill, from hydro store, goto pet store and pick up bulk carbon, for fish tanks filters. its the same carbon. but cheaper. you can even use this to custom make a filter for your cab. save lots of money and you can make it as big as you want. cotton bags used for fish tank filter. you can buy in like box of fifty. just run about 1\4 in carbon, cotton, 1\4in. carbon, cotton, tell desired smell is taken car of, when hooked up. way cheaper then buying them. maybe ill build one and give directions when i got it down pat.

 

[imnotcrazy]

Pushing through a filter? It's less efficient for the same reason Pulling Air is more efficient than pushing it. This is due to the simple fact that friction increases exponentially as it is pressurized/accelerated by a fan. You may not think of the effects of friction on air due to it being such a viscous element/material, but friction does play a role in how air moves.

And as far as filter efficiency pulling VS. pushing the air through it: Pushing the air through should be relatively effective IF you can maintain the SAME VOLUME (CFM) of air across the carbonregardless if pushing/pulling. The Can filters are rated in CFM as well as how well they work due to "Contact time" with the air over the carbon. Meaning if you are pushing the air thru the filter 2x as hard, it will be 1/2 as effective because the carbon didnt have enough time to remove the smell from the air.

Furthermore, I MUST agree with Yamaha1fan, I tend to always have negative pressure @ my carbon filter then have the fan BEFORE the lamp hoods/assemblies. This ensures any exhaust/lamp cooling system always has POSITIVE pressure after the carbon scrubbers. This insures any faulty seals or duct connections that may be leaking: leak back INTO the grow room to ensure that the leak will be scrubbed over by the exhaust system.

 

[l33t]

Pushing through a filter? It's less efficient for the same reason Pulling Air is more efficient than pushing it. This is due to the simple fact that friction increases exponentially as it is pressurized/accelerated by a fan. You may not think of the effects of friction on air due to it being such a viscous element/material, but friction does play a role in how air moves.

Thats a good reply. Friction def plays a role. I m glad someone mentioned it.

Can I ask you one thing then.
If I understand correctly ..Wouldnt it be 'always' more efficient (due to friction) then , in a system where there are no lights/hoods or Filter at all , to pull air and place the fan at the very end of the ducting ???

If yes what happens if we insert hot lights in the equation? Where would be the ideal place to place the fan then? I m possitive that air expansion plays an important role here too..but it of course makes things more complicated..

And as far as filter efficiency pulling VS. pushing the air through it: Pushing the air through should be relatively effective IF you can maintain the SAME VOLUME (CFM) of air across the carbonregardless if pushing/pulling.

I m not sure what you want to say here. Do you mean that pushing air through is not as effective in practice due to the outer surface area of the filter being bigger than the inside cylindrical surface?
Or do you refer to air contraction here ?Meaning as the hot air goes into the filter it loses some of its thermal energy ? I think I got confused a bit, could you please elaborate?

The Can filters are rated in CFM as well as how well they work due to "Contact time" with the air over the carbon. Meaning if you are pushing the air thru the filter 2x as hard, it will be 1/2 as effective because the carbon didnt have enough time to remove the smell from the air.

Furthermore, I MUST agree with Yamaha1fan, I tend to always have negative pressure @ my carbon filter then have the fan BEFORE the lamp hoods/assemblies. This ensures any exhaust/lamp cooling system always has POSITIVE pressure after the carbon scrubbers. This insures any faulty seals or duct connections that may be leaking: leak back INTO the grow room to ensure that the leak will be scrubbed over by the exhaust system.

You mean you have a CF first in the growroom >next is a Fan pushing air through the cool tube > air is directed outside. Right?

 

[Rainman]

I run my setup as fan - light - carbon filter and believe this is the best setup. I dont trust ratios and all the numbers being thrown around so I hooked it up both ways. Pulling the air was ok but I couldnt feel the air flow with my hand at the filter(my scientific test!) so I tried it with the air being pushed. This was noticeably different and produced way better flow to my carbon filter. I also run a second fan to push fresh air in so I have no issues with pressure in the room. Since the build and running of several cycles i know it works better! Think about it! When is it ever easier to pull something than to push it? Basic physics in my eyes. Even with a whole bunch of company data saying something different. Peace!

 

[petemoss]

I've always pulled the air out with a filter-cooltube/hood-fan arrangement. This has worked well for me with a 400 and a 1000 watt hood. Now I'm setting up a 250 watt light and using a small S&P centrifugal fan (4").

On the fan, there is a sticker that says "Not use with heated air in excess of 40C/104 F Thermally Protected." Now I'm hesitant to put the fan after my cooltube sucking out hot air. The fan is a lightweight plastic version made to be very quiet. The hot air may warp the plastic fan blades, so I'm considering a filter-fan-cooltube setup, pushing the air.

First, I'll use a Vortex knockoff (170 cfm) to pull and see how hot the exhaust air is that way (104F is not very hot, I believe). If the air feels close to 100F, I think I'll use the S&P fan to Push air.

 

[cannakid]

bluestar- props on starting this thread, ive looked n looked aswell for the old stuff..

ive been itchen to re-vamp my exhaust system this weekend, as simple as takeing my 6inch canfan (like 420-something..450cfm?) out of my hydro hut mini thats has a 400w galaxy running a MH bulb . -ducted over to a 600w galaxy running a HPS -exhausted out a window via dual hole Portable AC's window peice(i found a spare part, my Ac is a single hose exhaust) the flowering area is just outside the hut and in the same room. i have used the rig in the hydrohut to hold a can filter and have found a spot for the can fan up in the other corner -secured inplace, quite alot of 6 inch dicting was used to make it around the inside of the hut to cool that lamp but a 4inch reducer is needed to get air out of the hydro hut. after that another supersun 2 hood, this one fireing a 600hps -all the heat the goes out the window.

i want to just get that hut out of the room and cut alot of fat from the exhaust line, but is it best, in anybodies opinion to have the fan befor or after the 600w or as it is both the 400mh and 600hps (the 400w is on 20 hours of light, the 600w -12 hours light) is it best for the longevity of my canfan to push the so its operating temps stay down, the concept is that after a 600w lamp or a chain of lamps -cooltoobs or super sun2's- the air will be extreamly hot like 100 degrees and up so the fan may have a less favorable opperating condition. lets remember that humidity is reletive, to heat, and humidity could also effect oure fans.. over time, so i may just rig the fan between the fiter and lamps but im up for critisizm

the vegg plants dont need a filter anyway/ smell isnt a problem that much, also the cab has SO MUCH negative pressure cause it holds the fan and filter that are just too dang big for its good. but the 400w is hot enough to need cool air exhaust out the window, thoes lamps run very hot i just cant see anyother way then ducting out a window even if i get it in another room.
their soo hot makes me want to break out my 4 24inch T5 rig and use floros to vegg, its way slower though

 

[hoosierdaddy]

Best way to do this...most efficient use of that...
People...
The efficiency of any of our items is all relative to the application. If the filter area, and air flow, are sufficient to obtain the numbers (numbers that have been accepted as proper air movement) then it matters not a hill of beans in what fashion you use it.

If good enough is good enough, why fret over the fact that you may not be using the equipment to it's fullest potential? The fan may not be placed in the most efficient position, but if the configuration allows the numbers (or any other conditions that exist, including space issues) to be met, then it is golden.

I think many like to see what they type, after reading it coming from someone else. Makes them feel learned. Maybe they are, maybe they aren't...but if naysayers want to boast about efficiencies and such, maybe they should also site the math and science that goes along with their claims. Really teach us something....
Because guess what....in a proper teaching of these issues and the science behind them, are those facts and formulas used to engineer such projects. And again, if those facts and formulas show that there is proper air flow by pushing into an X sized filter set-up, then it is good...and who cares if it would be better if it were pulled through instead? It would only matter if you couldn't meet the numbers with the push-through configuration.

 

[imnotcrazy]

If yes what happens if we insert hot lights in the equation? Where would be the ideal place to place the fan then? I m possitive that air expansion plays an important role here too..but it of course makes things more complicated..



I m not sure what you want to say here. Do you mean that pushing air through is not as effective in practice due to the outer surface area of the filter being bigger than the inside cylindrical surface?
Or do you refer to air contraction here ?Meaning as the hot air goes into the filter it loses some of its thermal energy ? I think I got confused a bit, could you please elaborate?




You mean you have a CF first in the growroom >next is a Fan pushing air through the cool tube > air is directed outside. Right?

Leet: Pushing the sir thru the filter *MAY* mot be as effective if the air velocity/pressure forces the air past the carbon at more than the maximum filter rating. ALL of these filters are rated for a specific CFM AND efficiency of scrubbing based off air contact time with the carbon material. You CAN NOT exceed this rating when utilizing the filter AS INTENDED, with the proper size fan: pulling thru the prefilter into the carbon.

As far as placing fans at the end of a run of ducting, I have come to find placing the fans BETWEEN the filter and hoods allows me TWO benefits:

1) The pressurized air is MUCH more effective at cooling the hot bulbs

2) ANY leaks in my ducting or hoods AFTER the filter have POSITIVE pressure internal to the ducting. These possible leaks, which I may not notice, will then leak back INTO the grow tents/room to be re-scrubbed before being expelled from the exhaust. If I had the fan at the end of the run and had a leak, negative pressure would cause the leak to act as a vacuum, pulling hot stinky air from the grow room BEFORE being able to be scrubbed.

Plus following these "rules" I have in place: also protects the fans from having excessively hot air from being drawn across the fan motor. You MUST remember these fans are "thermally protected" and will shut themselves down when the motor reaches @ 104F or so. Lamps can EASILY generate those kind of temps and shut down your exhaust system inadvertently.

 

[OgreSeeker]

I've been around these forums for over 10 years and I have always ALWAYS been told to pull air not push and that is what has worked best for me. Granted 99% of my grows have been 2k to 8k. I've never grown in a small cab before so maybe pushing the air through the filter works better in a small setup.
How about this...screw the math and screw the science. Hook it up both ways and see what works best for YOUR situation. If your cab is the temp you want and the smell is minimal then no need to over analyze.
I don't think your going to get a straight answer on this cause there are to many opinions involved. It's all about what works best for your application.

 

[Rainman]

Well said Ogre!

 

[hoosierdaddy]

I agree with you Ogre, however it seems you also fell victim to the "I heard it this way" game. Nobody is claiming a better air flow by pushing into the filter...not that I have seen anyway. All that is being claimed is that you can push through them as well as pull. Although there may be a better air flow rating obtained by pulling, pushing is an option, IF it can obtain the numbers you are looking for...which IMO would be to have the air in contact with the filtering medium for at least one full second, and to be able to completely exchange the air in the grow space every 1-5 mins.

I see your stance, and understand what you are saying...but what did you do, hook it up the opposite of what you were told to do just to see if it worked or not? Or, have you just accepted what you were told carte blanche? How would you even know which way is better and why?

They "why" part will give each of us all we really need to know when deciding this issue. Opinions be damned when the correct formulas exist.

 

[Siddartha]

I have a question that seems appropriate to post here.

Say I had a separate sealed chamber, say a sealed rubbermaid, with my scrubber in it. Could I use this separate chamber connected via ducting to the growing chamber, along with the scrubber (inside the separate chamber), connected to the fan, then the cool tube, to eliminate the odor, not take up extra grow space, and pull through the filter?

It's kind of like, pulling the stinky air into the separate chamber and using the scrubber to scrub THAT chamber., then pushing the scrubbed air through the cool tube and out of the system.

 

[OgreSeeker]

I agree with you Ogre, however it seems you also fell victim to the "I heard it this way" game. Nobody is claiming a better air flow by pushing into the filter...not that I have seen anyway. All that is being claimed is that you can push through them as well as pull. Although there may be a better air flow rating obtained by pulling, pushing is an option, IF it can obtain the numbers you are looking for...which IMO would be to have the air in contact with the filtering medium for at least one full second, and to be able to completely exchange the air in the grow space every 1-5 mins.

I see your stance, and understand what you are saying...but what did you do, hook it up the opposite of what you were told to do just to see if it worked or not? Or, have you just accepted what you were told carte blanche? How would you even know which way is better and why?

They "why" part will give each of us all we really need to know when deciding this issue. Opinions be damned when the correct formulas exist.

Besides straight up personal experience, I have learned everything I know from reading forums like this. When 99% of the community agrees on something I tend to go with the crowd and accept what I'm told carte blanche. I often fall victim to the "I heard it this way" game but that's how I learned and that's the reason I am able to pull off 8kw grows consistently without issue.
In my personal situation I have tried pulling and pushing. I used the good ole scientific hand test and it was clear that pulling air worked better for me.
I've given my opinion...that's all it is. I have no numbers to back it up only my personal experience. What are your experiences / opinions on this issue?
What is the correct formula and why?

 

[hoosierdaddy]

I am not questioning which method is more efficient. I am in agreement with the majority of what is best. Thing is, the OP was convinced that they needed to redo their set-up because of the warnings of lesser performance.

I see no need to worry about pushing into a filter that is outside of the cab. The mountain man's cab is a classic example of what can be, and I think we can pretty much see the pudding bowl with that cab. Maybe that cat will show us a back shot of his cab showing his filter...?

 

[BonsaiBud]

I have a filter chamber in my growbox. Now I need to use duct hose instead of rigid metal to connect the filter to the fan.

Mine will go:


upper lamp______>filter chamber->fan suction->then out the top
lower lamp_/

I have the option of exhausting over the lower lamp once I get the Supersun. I will still have to intake unfiltered over the HPS array in the upper box.

I like this second option as it will let me run all ventilation in series.