Cold and Dry tent?

[Ca++]

Yep... grew at 10k feet for a few years and LOVE the -50F temps and almost no RH. (Your grow provides more RH than you might think. )

I used a Lux-100 thermostat outlet for years, and quite a while before inkbird came heavy on the scene.

Run your intake ducting around the top of the room a good 10' before exiting. Combining that with a thermostat controlled outlet will keep your room temps perfect. Lots of fresh air and zero worries about freezing your plants.

I do this, but the temperature difference between the exhaust and room is not that great. Along the exhausts run, it cools a few degrees. I want to increase the difference. So less heat leaves. This means bringing in the colder air, straight to the exhaust duct. Boxed away. So by the time that cool air gets out that box, it's close to the temp the air left the tent.

I like these semi-circular supports, that get the air taking a longer route.
I think I can get some alloy 2" mast poles quite cheap. 6 of them might might make a core I can afford to try, for a 4" exhaust system.

I won't fold it back upon itself.

Today I'm making a duct system to reduce the stratification. I have a couple of 4" socks on my tent, one top, one bottom. I'm externally piping them together, using downpipe and a couple of elbows.

The elbows have them nice ridges, for the sock to engage with.
I have this to attach a fan

I will hot glue a 12v blower to it. Then put it in the bottom elbow. The blower will easily get air from the downpipe, and chuck it out at 90 degree's to it. So at the floor, or sideways to take it around the tent with the aid of circulator fans. I could glue the fan straight to the elbow, but I like this modular approach, that offers some adjustment. I can still twist the blower about.

 

[trixP]

I do this, but the temperature difference between the exhaust and room is not that great. Along the exhausts run, it cools a few degrees. I want to increase the difference. So less heat leaves. This means bringing in the colder air, straight to the exhaust duct. Boxed away. So by the time that cool air gets out that box, it's close to the temp the air left the tent.

I like these semi-circular supports, that get the air taking a longer route.
I think I can get some alloy 2" mast poles quite cheap. 6 of them might might make a core I can afford to try, for a 4" exhaust system.

I won't fold it back upon itself.

Today I'm making a duct system to reduce the stratification. I have a couple of 4" socks on my tent, one top, one bottom. I'm externally piping them together, using downpipe and a couple of elbows.

The elbows have them nice ridges, for the sock to engage with.
I have this to attach a fan

I will hot glue a 12v blower to it. Then put it in the bottom elbow. The blower will easily get air from the downpipe, and chuck it out at 90 degree's to it. So at the floor, or sideways to take it around the tent with the aid of circulator fans. I could glue the fan straight to the elbow, but I like this modular approach, that offers some adjustment. I can still twist the blower about.

Jesus Christ that’s crazy engineering

 

[Ca++]

'Shell and Tube' designs are often used with steam, or hot exhaust. It's pretty rugged, and should need few tools to make a free flowing box for our duct.

The fire box vents through the tubes, to the chimney. The shell held the water.
Big one..

I may progress from a cardboard box and single pipe, but the condensation handling is so easy with that single pipe design.

 

[Douglas.Curtis]

I did forget to mention I prefer to use lung rooms... so I do not dump that air straight to the grow area. Ooops

 

[Ca++]

I did forget to mention I prefer to use lung rooms... so I do not dump that air straight to the grow area. Ooops

I see you bought cold in, and keeping it within a duct, ran it some way through the warm room, before it went into a lung room for further heating/treatment.
Do you recall any figures? The main points to touch on would be duct length, and air speed. The heat gain, taken from the temp difference end to end. And the room temp.

What you speak of is quite similar to what I'm planning. I want to bring in cold, and instead of run it through the room, I want to run it along the exhaust. The exhaust being hotter, and full of heat I don't want to leave. It should be better, with the possibility of reducing exhaust heat loss by 90%. Obviously it would be an awesome room that only lost heat via the exhaust, but it is certainly the main point of heat loss, in most peoples expectations. So if we can keep even half the heat that wanted to leave that way, it should be game changing. What I don't know, is just how big my heat recovery apparatus will be. It seems a meter should be good though.

Ultimately we have 30+cm above a tent, where this thing could live in many grows. That is enough to jacket up a 150mm duct. Or follow your thinking, and coil up the rooms inlet pipe, where the most waste heat resides.


I have half fitted my stratification busting re-circ pipe. I was surprised to find the tent socks I used, were tight around the 68mm guttering parts. I think the holes in my tent were 3" for cable runs, not venting. If anyone wants a hard pipe solution for maximising 3" holes, the guttering is as big as I could get through(along with a couple of electrical leads). TBH though, An old vacuum cleaner hose is big enough, if using a 12vdc blower.
I will get pics when it's together. Few more days.

 

[Douglas.Curtis]

I see you bought cold in, and keeping it within a duct, ran it some way through the warm room, before it went into a lung room for further heating/treatment.
Do you recall any figures? The main points to touch on would be duct length, and air speed. The heat gain, taken from the temp difference end to end. And the room temp.

8" axial fan, plugged into a Lux-100 temp controlled thermostat set to maintain 66F? My max canopy temps are ideally 69F. So the ducting was along the ceiling of the lung room which contained a 4x4 and 1K hps. It was a 15x15' room, so it didn't take the 8" fan long to cool it off. There was a bit of positive pressure in the room when the fan kicked on, but I didn't care about odor at all so it was vented to the rest of the building under the door. heh Very primitive and effective at the time.

Good luck

 

[Ca++]

8" axial fan, plugged into a Lux-100 temp controlled thermostat set to maintain 66F? My max canopy temps are ideally 69F. So the ducting was along the ceiling of the lung room which contained a 4x4 and 1K hps. It was a 15x15' room, so it didn't take the 8" fan long to cool it off. There was a bit of positive pressure in the room when the fan kicked on, but I didn't care about odor at all so it was vented to the rest of the building under the door. heh Very primitive and effective at the time.

Good luck

Oh I see. It's a bit different to most peoples expectations. No extract on the room. Just blowing in cold from outside, and only when it was too warm for your liking.
Still worth warming that air though, as it meant the fan could run more often, and you didn't have extreme cold slipping along the floor, and out to the house.
You have to start looking at natural drafts I guess, as they become your rooms constant air exchange. One that might ebb n flow.

I like a constant trickle myself, rather than on/off venting. It's a single state to deal with. No big temperature swings like you speak of, and the accompanying co2/rh swings possible. Maybe I'm just fussing over little though. Many types of grow are possible.

 

[Oysters]

My little basement grow room has 2 intakes with 2 exhaust fans. One of the exhausts goes to the duct work shown in the pics. The duct work has control gates (blast gates for woodworking dust control) that allow it to fully exhaust or fully recirculate or a mixture of both. The blast gates allow for pulling air from near the ceiling or near the floor. All goes thru a whole house furnace humidifier into the grow room. In the dead of winter, when the plants are young, it recirculates. The rest of the time the duct work is set for exhaust and the intake pulls air from the ceiling or floor as needed.

The 2nd exhaust fan and intake work normally. Works pretty good.

 

[Ca++]

That's fancy I like that.

I tried this $15 set, thinking it would serve as a re-circ fan.

It's a 9733 (97mm x 33mm impeller housing) and blew like a cheap hairdrier. Not at all what I wanted. The PSU was ramping up n down about 75% at lower speeds, and turned high enough to stabilise, this thing was motoring along with both strong flow, and too much noise. With a choppy feel to the air, indicating the 2amp psu was having to deal with the overload of the 2.7amp fan.
Wish knew before chopping the illegal plug off, to fit a UK one. And glued the fan to my duct adaptor.
Perhaps with a better psu I can rein in it's enthusiasm. At 30w, people are using less to extract from their tent, through a filter.

Back at the drawing board, I have a 7525 0.15a (~1.8w) fan, that gives the breeze of a cheap hand fan almost. These are found in things like desktop humidifiers, which need some pressure to blow through a small spout, but you never really see what it can do, with such a small hole restricting it.

The psu that can't run the 9733 properly, runs this 7530 nicely. It might be doing 10cfm, which while low, offers less cogging past the magnets, than a higher power fan. The 30w was lumpy..

Time to trash my new build, and do a new build. ffs.

 

[Drop That Sound]

Figures we would both be thinking about the same ideas, lol.

 

[Drop That Sound]

I'm about to pickup a couple 50ft rolls of aluminum flashing, to cut up into the square plates for my build, but not sure if I should do a dual cross flow core HRV unit.. with 2 cores working together (or triple!?) Like this:

Or, make some kind of extra intricate counterflow ERV style core. One larger one.

With cross counterflow, you gain least a 10% increase in efficiency, but all the fancy ones have valleys & ridges stamped into the plates to direct and slow the air down, etc.

Not sure if it would be worth doing low tech counter flow with flat plates and strips to act as spacers like I plan on.. The air would stay in the core a little bit longer as opposed to regular cross flow, so maybe a 5% increase?.

Dual crossflow cores would be the most efficient DIY setup, unless you can figure out how to rig up a rotary wheel unit.