Ventilation on HID light

[SmokzAlot]

Staying on topic, the best I can do is show you how I did my system in myGrowRoom. Read the thread and see why and how I did it. I can expand or extend my system at any time with no mods to the original install. Ample foresight and planning allows for growth as well as efficient operations. This equals less maintenance as well. I am all for that. All I need do is add on to what I have. I draw my experience from over 25 years of metal fabrication and industrial ventilation work. I can help you big or small. Is my system prefect? No I too am constrained by budgets, time, location, and so on like everyone else. We strive to make informed decisions that best fit our mode and method of operational awareness.

Sharing the wealth is all....

 

[ilikebike]

Let's K.I.S.S. this...

By drawing air through the light you are also getting the coolest intake possible for max cooling of the light. Like I said the fan generates some heat as well. Why add that load before the light? The turbulence in the light is horrible at best. One must remember as well everything down stream of the fan is pressurized and will leak into the room if there are any voids. Why create more potential problems? Restrictions between the fan and the outside also add to the problem. With the fan outside the room sealing inside is not so important, as it is sucking not blowing. That is what we are trying to accomplish. The only point of sealing inside, would be to pull via the filter only.

Let's make sense of it. Drawing air from the room filter then light, does not add heat load. It is the light that adds the load, hence we want nothing in front of the light that produces heat. The air we are drawing from the room is providing for air exchanges and CO2. Now on the topic of adding CO2 then it would require isolating the light cooling system as a separate system. Then another for air exchange. The second system will need to be on a timer, as well as the CO2 system. You don't want to be exhausting the CO2 when you are trying to feed it.

Lets say you have a thermostat for the fan to kick on when it gets over 85*F. Should you ONLY run the co2 timer at night so the temps stay down and the fan isnt being used and the co2 doesn't get sucked out? I was very confused about this so i went and bought an environmental controller but i would still like to know the proper way to do it with out one.

 

[mikey232]

Don't ever run co2 at night because plants don't use co2 in the dark only during the day so if you run it at night you'll just be wasting it

 

[SmokzAlot]

An optimum time is about an hour after lights on. Give the stoma a chance to open up.

= Wiki =
In botany, a stoma (also stomate; plural stomata) is a pore, found in the leaf and stem epidermis that is used for gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening. The term stoma is also used collectively to refer to an entire stomatal complex, both the pore itself and its accompanying guard cells.[1] Air containing carbon dioxide and oxygen enters the plant through these openings where it is used in photosynthesis and respiration, respectively. Oxygen produced by photosynthesis in the spongy layer cells (parenchyma cells with pectin) of the leaf interior exits through these same openings. Also, water vapor is released into the atmosphere through these pores in a process called transpiration.

How does humidity relate?

Carbon gain and water loss

Carbon dioxide, a key reactant in photosynthesis, is present in the atmosphere at a concentration of about 390 ppm (as of December 2011). Most plants require the stomata to be open during daytime. The problem is that the air spaces in the leaf are saturated with water vapour, which exits the leaf through the stomata (this is known as transpiration). Therefore, plants cannot gain carbon dioxide without simultaneously losing water vapour.
=

 

[mikey232]

No. My system is Filter--> Fan--> Reflector--> Out of tent and into attic. The filter is where it all starts.

Are you thinking the filter is a flow through design? It is not, it is capped on the end so the air only enters through the filter and only goes the direction of the fan flow. Only one duct exits the tent. My fan is a simple 6" 440cfm from ebay

If you can't figure it out with these photos I don't know what else to tell

Wow really the pictures don't matter dude there's nothing to fighter out your running your fan so you get the most heat out of it and the worst CFM. Some people you just can't help there just perfect lol I'm done!!

 

[TorturedSoul]

600 watts of light for ~6.39 square feet of garden space? That's definitely enough to benefit from CO2 supplementation.

With a setup like that, I hope you are running separate ventilation for the light and the room. You won't have the odor to deal with in the hot exhaust from the light. Your carbon filter will last longer because the air (from the grow room) won't be so hot. You'll be able to set the room ventilation on a timer or (better) a temperature switch so that it only runs when needed, which will help you keep any CO2 that you add/generate.

 

[SirGrowAlot]

If you are set up in a closet and you have a hole under the door, when running an outtake fan/filter combo, do you need to have an intake also?
If an intake is required (even with the hole under the door that lets air in) about how much intake is required? the same amount as the fan pulling air out? Less? More?

 

[SmokzAlot]

If you are set up in a closet and you have a hole under the door, when running an outtake fan/filter combo, do you need to have an intake also?
If an intake is required (even with the hole under the door that lets air in) about how much intake is required? the same amount as the fan pulling air out? Less? More?

First lets state you have an intake. It is what we call a passive intake. The question should be is it adequate.

How much do you need? Well you can calculate it if you want. Or guesstimate it as many do in small scale grows. Closets with doors and openings and such is a crude garden of sorts. So as I see it we are looking for a solution of equal caliber. never lesser.... A chain is no stronger than its weakest link.

Anyway let temps be your monitor, to measure if you are moving enough air out. To address the intake lets use a real world approach. When the fan is on does the door have suction as you open or close it? We are looking for negative pressure (suction). Secondly if it is negative we need to see if it is too much. Pay attention to the exhaust at this point. Does it speed up or slow down as you open or close the door? How is the output affected? Find the balance point between temps and negative pressures and fan labor rate to guesstimate the intake. If you measure square inches of your fans opening take about 80% of that for a minimum intake port size in square inches. Just a place to start, individual mileage will vary. Shape don't matter. If you want better than that then calculate the CFMs and such to achieve the next level of environmental control.

K.I.S.S. approach:
At it's simplest form...Buy a fan bigger than you need and put a variable speed on the fan to balance it out.

Example:
Cut an 6" hole for a 6" fan, then a 6" intake hole. Install speed control and turn it on.

The complexity begins when you start adding to the system making it more complex. Like carbon filters, lighting, ducting, and so on. The basics? Air in and air out... Is this optimum? not by a long shot, but it works good and is easy to do. So many choices...

 

[Batcave]

I have a question for the ventilation guys. I buy a new 6" filter every 9 months just to be on the safe side and it is almost time for me to get a new one. I have a friend that has a extra brand new 8" filter rated at 720cfm he offered to sell me for just a few dollars more than I pay for the 6" filters. I have read a few times over the years where people used a larger filter than their fans. Longer filter life, and more surface area so more air flow? What would actually be better a 6" 440cfm filter or the 8" 720cfm filter using a reducer to attach the the 6" 440cfm fan? Any other advantages to using a larger cfm filter than your rated cfm fan?

 

[ilikebike]

makes sense. The bigger filter got bigger holes = more air flow, id say do it, you can get those reducers at home depot/lowes for like 7-8$

 

[SmokzAlot]

Makes complete sense to me. Less labor for the fan means longer life, and longer life from the filter. May also be a noise reduction.