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Why extract from the top?

extract fans heat airflow with farty bits

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#81 MDS

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Posted 06 July 2018 - 11:37 AM

:lol: Not seen this for nearly two years :D

 

Yes, let us know how things go Missy & don't forget your camera next time :)


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#82 bigbadbillybob

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Posted 06 July 2018 - 01:03 PM

I have tried both top and bottom extraction fans, and to be honest they both work.

In a 1200w 2.4 by 1.2 tent the difference is...……..

drumroll...………………………….

2 degrees less heat when extracting from the top. 

 

When I say I extracted from the bottom I mean that my filter was sitting on the floor in a vertical fashion so the fan was about 600mm from the floor, but sucking thru the fan which was a t floor level.

My new room has an other alternative. This time I  am extracting from the middle of the room.

I would have liked to have hung my fan from the ceiling, but it was just going to interfere with the lights, no matter where I put it/.

I tried it at floor level, because I had a huge silencer fitted but didn't think it would help temps so ended up removing silencer to put outside the room and lifting the filter so its now 1.4metres from the floor to the bottom of the filter. 

will be interesting to see how it fares.


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#83 Anonymiss

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Posted 06 July 2018 - 03:47 PM

:lol: Not seen this for nearly two years :D

 
I've been studying ;)

post-7-0-02099000-1530892031.jpg

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#84 MDS

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Posted 06 July 2018 - 04:11 PM

 
I've been studying ;)

post-7-0-02099000-1530892031.jpg

 

I see you must be getting good at this :lol:

 

Attached File  6a00d8341c301153ef017c31d172a5970b.jpg   102.19KB   0 downloads
 


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#85 Enzyme303

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Posted 06 July 2018 - 06:27 PM

@Anonymiss

Burning flesh is great for stocking up on carbon :)


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#86 Anonymiss

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Posted 07 July 2018 - 06:08 PM

Funnily enough, @ MDS , I've actually read quite a lot of Lovecraft :)

And if I'm burning flesh, @Enzyme303, then it's probably because it's going to get eaten ;)
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#87 MDS

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Posted 07 July 2018 - 06:30 PM

Funnily enough, @ MDS , I've actually read quite a lot of Lovecraft :)

Not read any of his work (that I can remember)... I'm more of an Asimov fan & others such as Greg Bear, Kim Stanley Robinson, Ken Macleod, Stephen Baxter & of course Arthur C. Clarke ;)


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#88 Anonymiss

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Posted 07 July 2018 - 06:59 PM

post-7-0-62475400-1530873937.jpg

So, I was helping someone set up a new (their first) tent yesterday and after some discussion we decided to break with the usual inlet-at-the-bottom/extract-from-the-top tradition.

The tent is 1 m x 0.5 m x 1.8 m, with a double-socked 8" vent on the top, and one on each end for a cool tube.

There are also three fly-screened passive inlets with covers, and two double-socked cable inlets (one at the top and one at the bottom).

The lighting is a 250 Watt HID.

The fan is a Soler and Palau TD-SILENT 350/125 placed outside and on top of the tent, blowing into a 100 mm carbon filter.

The final plan uses split extraction, drawing air from both the top and bottom of the space, with the inlets coming in through the cool tube vents and then some short lengths of duct to direct it into the space between the lamp and plant.

The extraction ducting comes in through the top vent and then splits using a T-piece, with one leg taking air out of the very top of the tent and the other dropping down to floor level.

Will it work? I don't know, but preliminary testing using garden cane and paper plate 'plants' to disrupt the air flow looks good, with decent temperatures throughout and a small (2°C or so) variation between the top and bottom (of the plant-occupied space, not the entire area - it's obviously hotter above the lamp).

I'll report more when things are up and growing :)

I didn't have a camera available so there's no photos, but I'll try to remember next time

 
Turns out that it's quite difficult to take a decent photo of a reflective silver box filled with shiny white things, but here it is...

post-7-0-89837500-1530988473.jpg

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#89 MDS

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Posted 07 July 2018 - 07:12 PM

Can that bottom extraction point be raised up Missy? I'm assuming that's why you used flexible ducting...

 

Just thinking it might be handy pulling air over the plant as the plant will be directly under the light & the airflow should cool it a tad, while the top extraction point will likely take care of any heat that rises :)

 

Nice idea with the T piece running straight through to the bottom exit point & having the top one off at an angle... Not sure if you thought about it, but that's how I would have done it if I was trying this idea out... So the top one isn't dominant ;)


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#90 Enzyme303

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Posted 07 July 2018 - 08:56 PM

Seems to eliminate the need for a reciprocating fan cool idea :) You could probably regulate air flow rates for the T point and lowers with step down pipe sizing depending on where needed, it also would be handy to look at this on a flir for thermal imaging ,i have heard of thermal imaging apps but may have to buy hardware to use,you could also rent a flir to take a look if inclined .


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