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 DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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 GRow ROom DEsign - Improvements? 
#320064 - 11/22/09 05:03 PM (15 years, 11 days ago) |
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After a lot of research, I trashed my plans to grow with LEDs and decided on MH/HPS. There are still a few things that have eluded me in my quest for knowledge.
THis is my plan.. 4x4x6.5 ft grow tent with a 1000w MH/HPS convertable ballast for vegging with MH and flowering with HPS. I'm a little confused when it comes to reflectors and cooling. I know I can rig a good exhaust (shouldn't be hard, the tent comes with holes), but I'm unaware how much air should be used to cool the light. My grow friend mentioned how important it is to blow carbon filtered air through the reflector to keep the bulb from exploding...?!?!?!.
If I use a reflector, that is not air cooled, and I rig up a GOOD exhaust sucking all the air from the top of the tent into an attic, is that enough to cool the light or do I need to have ventilation AND a fan on the light?
Are aircooled reflectors worth it or necessary?
Any input would be greatly appreciated.
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81renaissance
Coachella '13 KKOTY
Registered: 04/20/08
Posts: 4,182
Loc: State of Mind 
Last seen: 9 months, 12 days
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Re: GRow ROom DEsign - Improvements? [Re: DJ_avocado]
#320091 - 11/22/09 05:48 PM (15 years, 11 days ago) |
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 Not important to "blow carbon filtered air" at all. That's just silly.
As far as air movement is concerned, you do want an oscillating fan or some other method of moving air around your plants to keep them moving and help them develop strong stems. If you have a good exhaust, and a clear intake then the temps in your tent should be okay.
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"So it goes."
-Kurt Vonnegut
BlueBerry_Swisher said:I want French fries. No, I want a penis French. Thank you. I'm so excited. I can not contain myself. Now I eat chocolate. It is so good. I'm trying to rub it all over myself. And then lick. Now I need a hot shower. The end.
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 Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: GRow ROom DEsign - Improvements? [Re: 81renaissance]
#320171 - 11/22/09 08:31 PM (15 years, 10 days ago) |
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well as far as the air flow is concerned...
if you want the temperature in the tent to never exceed 80 degrees F, you will set that as your exhaust temperature.
Then you can take the temperature of your air outside of the tent, we'll assume 70 degrees F for the inlet temp.
And knowing the humidity the of the exhaust and the outside air will aid in the accuracy of this. But for this I will assume a 5% increase in humidity between the inlet air and the outlet air...just to demonstrate the effect it has.I will use 45% RH inlet and 50% RH outlet for this.
Using a Psychrometic Chart for Air at 1 atmosphere of pressure, you can look up the enthalpy of your inlet and exit conditions.
Inlet enthalpy: 38 KJ/KG of dry air
Outlet enthalpy: 54 KJ/KG of dry air
Using this, you can assume a 1000W input of heat energy to the system from the light, which is equal to 1 KJ/s.
You can then plug these into the equation for heat loss through the air flow, where m = mass flow rate of dry air, and Q equals the heat flow out of the system:
Q = m (54 - 38)
substituting 1 KJ/s for Q, we find that m = .0625 kg dry air/second
from the psychrometric chart at the temp and RH of the exhaust, we find that the specific volume of the exhaust is .864 meters cubed/KG dry air.
and by multiplying m by the specific volume, we then find the volumetric flow rate of the exhaust needs to be .054 meters cubed / second.
This then converts to 114.4 cubic feet per minute, or about 115 CFM minimum.
Obviously, no one should run at the absolute minimum, and differences in inlet and outlet temps and humidity will effect the required flow rate, and this flow rate does not take into account the actual rate of water loss from the plant...so in order to keep the humidity down you may need to run higher flow rates.
If you need anymore help with this method or have questions feel free to ask.
Hope this helps,  
agmotes165
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“The Universe is under no obligation to make sense to you” -NDT
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DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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Re: GRow ROom DEsign - Improvements? [Re: Data]
#320364 - 11/23/09 01:23 AM (15 years, 10 days ago) |
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hmmm...I concur. Thanks! I can't wait to hook it up. 
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: GRow ROom DEsign - Improvements? [Re: DJ_avocado]
#320388 - 11/23/09 05:22 AM (15 years, 10 days ago) |
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Ive also heard that replacing the entire volume of your grow room every minute usually works fine...and would probably be a lot easier to calculate haha
peace
agmotes165
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“The Universe is under no obligation to make sense to you” -NDT
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Pilze
Funky Monk
Registered: 10/11/09
Posts: 770
Last seen: 11 years, 5 months
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Re: GRow ROom DEsign - Improvements? [Re: DJ_avocado]
#320413 - 11/23/09 10:49 AM (15 years, 10 days ago) |
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are you talking about those sun huts?
i want to get the 4'x4'x7'
Edited by Pilze (11/23/09 11:07 AM)
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DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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Re: GRow ROom DEsign - Improvements? [Re: Pilze]
#321350 - 11/25/09 01:51 AM (15 years, 8 days ago) |
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Yea thats the one. 4x4x7. I hope I win that...I bid on an inline aircooled fan. I don't know much about where the air is moving or if the aircooling even doubles as exhaust but my main concern is can an aircooled inline light be set up in a 4x4 space??? I already bid on the lights and stuff, the dimensions of the reflector are 18x15x7.5 in. To rig up the cooling looks like it takes more space than I have, does anyone know for sure? Also, if it doubles as exhaust too, that would be great...
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Pilze
Funky Monk
Registered: 10/11/09
Posts: 770
Last seen: 11 years, 5 months
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Re: GRow ROom DEsign - Improvements? [Re: DJ_avocado]
#321411 - 11/25/09 10:15 AM (15 years, 8 days ago) |
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i would get one of those reflectors that has a place to connect the air tubes to blow air through it, so you can put the light closer to the plants. then all i would worry about is air flow on the plants and that wouldnt be too hard.
new air comes in through the bottom, up through the plants, and out the top.
i cant wait to get a sun hunt. i only have a 150 watt HPS right now. its not like thats going to do a hell of a lot, but im going to get what i can from it while i safe up money for a 4-600 watt HPS
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: GRow ROom DEsign - Improvements? [Re: Pilze]
#321415 - 11/25/09 10:27 AM (15 years, 8 days ago) |
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I have 2 of these; http://www.hydrofarm.com/pb_detail.php?itemid=4173
not the highest quality I'm sure, but it's air cooled, sealed glass lens, and was only $90 each.
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Pilze
Funky Monk
Registered: 10/11/09
Posts: 770
Last seen: 11 years, 5 months
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Re: GRow ROom DEsign - Improvements? [Re: Pilze]
#321416 - 11/25/09 10:31 AM (15 years, 8 days ago) |
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ooo thats very nice... thanks for the link. 
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: GRow ROom DEsign - Improvements? [Re: Pilze]
#321418 - 11/25/09 10:35 AM (15 years, 8 days ago) |
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if you're looking for a 600W still I also have a link for a 600W lumatek (VERY nice light) for only $150
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Pilze
Funky Monk
Registered: 10/11/09
Posts: 770
Last seen: 11 years, 5 months
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Re: GRow ROom DEsign - Improvements? [Re: Harry_Ba11sach]
#321654 - 11/25/09 05:13 PM (15 years, 8 days ago) |
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ooo that sounds nice. can i see???
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81renaissance
Coachella '13 KKOTY
Registered: 04/20/08
Posts: 4,182
Loc: State of Mind
Last seen: 9 months, 12 days
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Re: GRow ROom DEsign - Improvements? [Re: Pilze]
#321719 - 11/25/09 09:11 PM (15 years, 7 days ago) |
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Harry: when you were growing with the tent, did you just set up the fan exhaust, and do the passive intake? Are there pictures of your setup somewhere?
My grow space just got a whole lot smaller (as in about 2x2) and I'm trying to figure out the best way to use it. Might be my first ever SCROG grow!
--------------------
"So it goes."
-Kurt Vonnegut
BlueBerry_Swisher said:I want French fries. No, I want a penis French. Thank you. I'm so excited. I can not contain myself. Now I eat chocolate. It is so good. I'm trying to rub it all over myself. And then lick. Now I need a hot shower. The end.
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: GRow ROom DEsign - Improvements? [Re: 81renaissance]
#321758 - 11/26/09 12:34 AM (15 years, 7 days ago) |
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yep, I had a 95cfm squirrel cage fan that I had sealed on the exhaust, and then I left only one of the 2 velcro windows open and one of the weird little drawstring sleeves on the opposite side for maximum passive intake.
I found that that arrangement actually created enough wind inside the tent that I didn't even need another fan inside. the passive intake facilitated evapostranspiration, it was magnificent
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DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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Re: GRow ROom DEsign - Improvements? [Re: Harry_Ba11sach]
#321925 - 11/26/09 12:51 PM (15 years, 7 days ago) |
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So if I'm running a 1000w in a 4x4x7 tent, is a 6in vortex fan, (449cfm) and a small oscillating fan, just for a breeze,good enough passive intake? How about with a carbon filter?
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: GRow ROom DEsign - Improvements? [Re: DJ_avocado]
#322014 - 11/26/09 02:56 PM (15 years, 7 days ago) |
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lol dude you have 112 cubic feet. 449cfm is HUGE overkill, but I'm sure it'll only make the buds nicer. it's not so much overkill that'll it'll be bad, it's just about 5 times more than the minimum
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DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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Re: GRow ROom DEsign - Improvements? [Re: Harry_Ba11sach]
#322022 - 11/26/09 03:15 PM (15 years, 7 days ago) |
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I was kind of thinkin for overkill. I figured it would keep everything way cool and ventilated. How bout if i put the fan on a timer? maybe every other 5mins or something? Has that ever been done before or is it better to keep it on?
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81renaissance
Coachella '13 KKOTY
Registered: 04/20/08
Posts: 4,182
Loc: State of Mind
Last seen: 9 months, 12 days
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Re: GRow ROom DEsign - Improvements? [Re: Harry_Ba11sach]
#322231 - 11/27/09 10:44 AM (15 years, 6 days ago) |
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Quote:
Harry_Ba11sach said:
yep, I had a 95cfm squirrel cage fan that I had sealed on the exhaust, and then I left only one of the 2 velcro windows open and one of the weird little drawstring sleeves on the opposite side for maximum passive intake.
I found that that arrangement actually created enough wind inside the tent that I didn't even need another fan inside. the passive intake facilitated evapostranspiration, it was magnificent
In the 2x2 how many plants did you have going?
I can't recall if you had a grow log...link if so?
good to hear that you were able to create enough air movement with just the passive.
To clarify then, you didn't duct/air cool your light; temps were controlled by the exhaust fan+passive intake.
Do you think its wise to max out the wattage inside the tent at 600 or could she handle a 1000w setup if you had a higher CFM fan?
--------------------
"So it goes."
-Kurt Vonnegut
BlueBerry_Swisher said:I want French fries. No, I want a penis French. Thank you. I'm so excited. I can not contain myself. Now I eat chocolate. It is so good. I'm trying to rub it all over myself. And then lick. Now I need a hot shower. The end.
|
DJ_avocado
myco-botanist
Registered: 11/21/09
Posts: 147
Last seen: 12 years, 8 months
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Re: GRow ROom DEsign - Improvements? [Re: 81renaissance]
#322308 - 11/27/09 02:47 PM (15 years, 6 days ago) |
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These are my final plans. My only concern is the position of the carbon filter and the length of ducting used. There is also going to be an oscillating fan not shown in the pic.1) Will the 449cfm Vortex fan work well enough for passive ventilation and light cooling despite the sharp bends in the duct and its length into the attic? I want to place the fan in the attic to reduce noise, my room is next to the front door. Should it be inside the tent?2) Noise reduction ideas? I was going to stuff foam or something into my windows but was wondering if anyone had any tips to muffle noise without sealing the room and probably making it real hot.3) Is the carbon filter ok there, over the light?
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: GRow ROom DEsign - Improvements? [Re: 81renaissance]
#322326 - 11/27/09 03:44 PM (15 years, 6 days ago) |
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holy shit man, 600W? I ran it with 250W of CFL's and 2 plants, and 3 more in solo cups (barely even count as plants in there)
I suppose you can try it, but that's a pretty frickin' insane amount of light for only 4 square feet
this is the only grow I did in it
http://www.growery.org/forums/showflat.php/Number/251624/fpart/1/vc/1
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