precision cooling hoods using outdoor and indoor air

[smurfin'herb]

hey guys, Ive decided to cool my 7 daystar a/c hoods, instead of using up all that extra juice from the a/c unit to fight ALL the heat from the lights. I figure this will cut down on electric from how often the a/c generator kicks on. Can anyone agree on this concept?

Anyway, I wanna have the ability to pull air from the OUTSIDE (for winter and cool summer nights) AND from the INSIDE (when outside temp is too high/low for cooling lights) INDEPENDANTLY. Idea #1 was that i could get a two way split piece of ductwork, run one end of it outside (with filter attached of course) and one end inside, and then install electric dampers on each end and then somehow connect those to be in sync with a temperature gauge (with hi/low presets) that would be able to tell the temp of the incoming air flow in the ductwork, and if it exceeds the preset temp, then it will close one damper and open the other one. Idea #2 was in that case, if both the outside temp and inside temp were above the preset, it would probly switch back and forth a ton of times, so in your suggestions it would be nice to find a tempurature unit that could just compare and choose the path where the cooler air comes in. The only problem i could see with Idea#2 is that there are no presets, therefore, in the winter it would be pulling as low as 5 degree air thru the hoods..... Is that ok? Sounds like a bad idea but i dont know why it wouldnt work... Will the lights bust or become inefficient? anyone done this before?

So can anyone point me in the right direction for a rig like this? is there somethin out there that does this already?
Comments, suggestions, are appreciated! Rock on!

 

[DIGITALHIPPY]

u need a motorized Y baffel ive seen them b4, sorry no links.
work on a flip flop on/off concept. then u can plug it into a temp sensor with a probe outside so when the incoming air hit higher then [lets say]76 boom! the motor kicks in and the intake is now re-directed to an inside intake... now u need to expell this air outside again or into an attic to max out the energy savings.

7 hoods is a bit much u might need 2 in/out not sure.

 

[smurfin'herb]

SWEET! But if it works like a flip/flop then that means its timed, and it would not be able to automatically choose where the cooler air is coming from. Where would i find a temp gage that is capable of controlling a motorized baffel, so that it could decide where the cooler air is coming from and then send that signal to the baffel to use that ductline? Im not seeing where i could just plug the baffel in to the temp unit......Would i have to wire it up myself, or do they make temp units that hook up to stuff like that? Oh and by the way they are only 600's in the hoods...

 

[nUt_jOb]

smurfin.. the problem is the airflow restriction per hood can take down the output of a can fan fast.. you can string only about 3 lights together in a row IMO before airflow goes down too low. You can put another fan between lights. Your setup would need 2-3 inline can fans in my opinion.

Now, smurfin, what you are talking about is completely doable and if you cant find the Y baffle you can just use two inline electronically closing duct inserts available at smarthome and other sites. There is no controller that I know of that will do exactly what you are suggesting with the flexibility I think you are looking for. One can be pretty reasonably constructed and programmed (under 200 bucks) but if I remember correctly your setup is only for 12mo or less.. so save the cash IMO and just reroute the ducts manually when temperatures are staying low enough. You only have to do it once or twice for your period of time.

No problem with 5 degree temps unless condensation builds up on the incoming ductwork.. then you would just need to insulate them or install insulated ducting from the start.

*edited for bad grammer

 

[smurfin'herb]

thx for the input! At what temp would condensation build up on a 600watt bulb?

 

[Guest]

Nut Job, running 3 pairs of 6" Sun System II hoods with 600W each through an 8" Elicent inline(formerly a10"). The A/C has only been called for twice in the last 3 or so weeks.

Smurfin, check the Grainger.com online catalog for thermostatic controllers for your damper setup. I seem to recall seeing that item there.

tystik

Inline shown at the upper right of the photo is a 10" and has since been changed to an 8".

 

[smurfin'herb]

thx ty. dang that sure is a comprehensive list they have there... could u tell me a more direct way to access what u are describing on that link?

 

[DIGITALHIPPY]

http://www.famcomfg.com/Dampers.htm
this is the type of damper im talking about. you get one thats auto open and one thats auto close.... when power is applied (at timeintervals u want, or in this case temp controlled) they flip, meaning the open closes and the closed opens.....
am i making sence?
ty is right about grainger.com they are good store. tad pricy but nothings cheap. there delivery is great (atleast for me)

*edit
yea u might need 2 or 3 6" fans...im guessing thats nbd though.

 

[nUt_jOb]

Ty,

6 lights with little to no AC.. you must have nice ambient temps.

For his setup.. 7 lights to be cooled by 76 degree ambient air.. do you agree more than one fan would probably be recommended? At least a pusher and a puller? Right?

smurfin- at no temp would condensation ever form on your multi hundred degree HPS bulb.. condensation happens when warm air is around a cool object (like my beer mug). It doesn't form on a surface that is hotter than the ambient air. Does that make sense?

 

[smurfin'herb]

perfect sense, so if i had 5 degree air cooling my hoods, then that would mean i could put them wayyyy closer to the plants right? and also probly able to add 2 or 3 more lights in winter since i wont be using electric from the a/c!
oh and by the way, whats the better way to cool hoods? pushing air from the beginning or pulling it from the end?

 

[yamaha_1fan]

I dont think you need more than one can fan. You just need to size everything appropiately.

There have been a few posts showing how lights should be cooled. Seems most agree on a trunk system. Basically a big intake, 10-12" with 6" ducting going to the lights then going back to 10/12" ducting to leave. Basically the air never goes through 2 hoods like in an inline system.

I push air through my hoods, but most agree that pulling is more efficient. But no smell can come out the exhaust as I am pushing air through and out the the cracks in the hoods. Pulling air will pull some stink.

I think manually switching where you get air from is probably the easiest, cheapest and most reliable option

 

[nUt_jOb]

yamaha has a good point.. if you want to do it with one big fan then only put a couple of lights in a row between joining them from intake to exhaust headers. Also less bends = better air flow and that matters a good bit in a larger system.

I am pretty sure that pushing is better than pulling, in just about any air system. Atmospheric pressure is not that great so most air systems minimize inlet ducting. Take for example the central AC in a home, the blower sits right after the air filter and the outlet of the blower pushes the air down to all the vents / registers in the home. You could always start with just a pusher and add a puller if necessary.

Here is a good picture of how NOT to run light ducting...




smurfin - With that many lights in a sealed room you will be using AC in the winter too.. dont forget the dehumidifiers that add another 5-10k btu. Also, lights should always be run at an OPTIMAL distance from the plants, if your cooling system cant handle that then it needs upgrading. Low inlet temps to me just mean lower electric bills. You could add a light or two but for only doing it for 12 months it doesnt make much sense.. just hurry up and get started before that 12 months ticks away to 11, 10, 9 ... exc.

 

[Guest]

Nut Job---YES, the blower in a Central HVAC system does push, Keyword : Central. The Furnace and Cooling Coils are usually combined as a unit, with the condenser located outside. The ducting to each room are sized according to the CFM needs for each area therefore, in residential applications, it need not be pulled as that would require inlines near each register.

When you look at the HVAC system you will also note the Cold Air Return grill, at or near floor level. When the Furnace blower kicks on it "sucks" air from each room and pushes it through the loop again via ducting. So it sucks and pushes simultaneously.

Nut Job, here in the Pacific Northwest we are experiencing a very cool Spring, and outside air temps are providing the grow with cool air for the hoods and cooling for the Clone room as well Veg and Flower rooms. The A/C will no doubt be used in the weeks/months ahead, providing "Global Warming" warms this F#@*^+G place up ab bit.

tystik

 

[smurfin'herb]

I dont think you need more than one can fan. You just need to size everything appropiately.

There have been a few posts showing how lights should be cooled. Seems most agree on a trunk system. Basically a big intake, 10-12" with 6" ducting going to the lights then going back to 10/12" ducting to leave. Basically the air never goes through 2 hoods like in an inline system.

I push air through my hoods, but most agree that pulling is more efficient. But no smell can come out the exhaust as I am pushing air through and out the the cracks in the hoods. Pulling air will pull some stink.

I think manually switching where you get air from is probably the easiest, cheapest and most reliable option

could you make a diagram of this trunk system? im not understanding..
im actually thinking bout runnin 8 lights in two rows of 4 with a 8 intake on the front of each row and then 1 8 in. outtake at the end of the rows where the ducting will come together via Y duct piece. does that sound good?

 

[Guest]

thx ty. dang that sure is a comprehensive list they have there... could u tell me a more direct way to access what u are describing on that link?

Go back to the Grainger online catalog, go to "Product Index" or use the search engine. Keyword: "DAMPERS", check the sub sections for MOTORIZED as well as BACK DRAFT types in addition to CONTROLS. Lots of reading there for you.

You will need a thermostat that will shut off the inline intake fan, which will allow the damper to CLOSE by its weight & design. Suggested OFF setting of 75F. Your A/C would be 5 degrees higher, and come ON at 80F.

The inline/damper thermostat would be Located Outside at the opening of the FRESH AIR intake, as you want to measure outside temps. When outside temps drop again to below 75F the inline will turn on, the airflow will open the damper, and begin cooling, at which time the A/C will sense the drop to below 75F and automatically turn off. Many thermostats can be set for a temperature operating range, for instance, on at 80F and off at 76F. How you set it is up to your own judgment.

My grow incorporates a Fuzzy Logic controller to accomplish this task. When outside FA and internal temps exceeds the preset temp then the AC comes on, drops the temps and in turn shuts off the FA intake fan.

It has been a long long long day, today and yesterday, harvesting and trimming, and I hope my tired old butt has provided you a clear solution for your situation.

tystik

 

[DIGITALHIPPY]

Nut Job---YES, the blower in a Central HVAC system does push, Keyword : Central. The Furnace and Cooling Coils are usually combined as a unit, with the condenser located outside. The ducting to each room are sized according to the CFM needs for each area therefore, in residential applications, it need not be pulled as that would require inlines near each register.

When you look at the HVAC system you will also note the Cold Air Return grill, at or near floor level. When the Furnace blower kicks on it "sucks" air from each room and pushes it through the loop again via ducting. So it sucks and pushes simultaneously.

Nut Job, here in the Pacific Northwest we are experiencing a very cool Spring, and outside air temps are providing the grow with cool air for the hoods and cooling for the Clone room as well Veg and Flower rooms. The A/C will no doubt be used in the weeks/months ahead, providing "Global Warming" warms this F#@*^+G place up ab bit.

tystik

you make a good point about the suck/push of a central a/c.

i also like how optimistic your view of global warming is.
when my house here in cali is under 300feet of water ill buy some oceanfront in arizona with you and embrace the heatwaves our a/c's will no doubtidly have to suffer.


i look at my night time flowering as my little way to be as "green" as possible.

(the night-time juice is mostly nuclear/wind/thermal/hydro, the demand is lower so they turn off the coal, and oil pp's.)

 

[yamaha_1fan]

I dont think you need more than one can fan. You just need to size everything appropiately.

There have been a few posts showing how lights should be cooled. Seems most agree on a trunk system. Basically a big intake, 10-12" with 6" ducting going to the lights then going back to 10/12" ducting to leave. Basically the air never goes through 2 hoods like in an inline system.

I push air through my hoods, but most agree that pulling is more efficient. But no smell can come out the exhaust as I am pushing air through and out the the cracks in the hoods. Pulling air will pull some stink.

I think manually switching where you get air from is probably the easiest, cheapest and most reliable option

I meant to say ONE CAN FILTER not fan. You may need 2 fans to push/pull.

I have seen some diagrams on here, just do a search. I dont have one handy.

 

[Guest]

I meant to say ONE CAN FILTER not fan. You may need 2 fans to push/pull.

I have seen some diagrams on here, just do a search. I dont have one handy.

6 x 600W, hoods in pairs, ducted in pairs, not singularly. 10" rigid ducting for manifolds. Recommend he use 12" rigid with a 10" inline, yes a 10". With a large manifold duct system there is less resistance to impede airflow.

At the center of the photo is an (galvanized) intake manifold with 3 saddle taps supplying incoming air to hoods in pairs.

At the right side of the photo is an (black) exhaust manifold with 3 saddle taps exhausting the 3 pairs of hoods. Pulling air through one hood, to the next hood and OUT with 600's does not pose a problem. With 1000's I would definitely duct individually.

tystik

 

[Budweiser13]

Ty-Stik if you could do a how to on a system like this it would help some of us HVAC challenged and would be greatly appreciated. I know you pull your cool air from under the house what if your house is on a concrete slab with no space under it what would be the next best place to pull and exhaust. I am thinking the attic would be a good place to exhaust the heat I am just not sure about a stealth place to pull cool air from. I will be setting up a 4000 watt room so you say I should not connect 2 1000 watters in line that they should each be separate. Your knowledge is gold when it comes to this kind of stuff. I think there is a lot of growers who are using air cooled hoods but dont know how to set them up correctly...........

 

[smurfin'herb]

i agree with budweiser, i have no idea what a large manifold duct is, or rigid ducting, or even a saddle tap. im confused with this terminology. and i cant tell whats goin on in that pic, a diagram would be awesome!!