Cold and Dry tent?

[Ca++]

It's that time of year, where plants everywhere are freezing by cold air intakes. Some growers have even resorted to extracting from the floor.

I was having a think about this

Measuring around my rooms door, I found about 20c at floor level, and 24 at the ceiling. The only place to be getting my tents air from, seems to be the ceiling. This is still air with low RH though, as it entered the home cold, and was then warmed a lot.
The fan pictured, is taking heat from the lights, and moisture lost by the plants, to warm and dampen the air coming in. It may be better not to share the ductwork by using a Tee though. This recirculating fan must overcome negative pressure from the exhaust fan, or air will actually enter at the lights.
If instead, the fan just takes from the top, to the bottom, it's job is very easy. Without the air inlet sharing the ducting. As the exhaust fan would exert pressure equally across the fan.

This seems like the best start. A circulator fan to take from top to bottom, using it's own socks.
Air intakes taken from spare socks, to the roof.

The result, is warmer air from the roof, and some of the warm damper air about to be extracted, being returned under the plants. Where the two air flows can be mixed within the tent. Perhaps having both flow into a 7" fan.

 

[Ca++]

This is a bit more involved than fan and pipe. It's also a cardboard box, and jam jar

I'm showing the perhaps incorrect tent arrangement again, but now, looking at how the air being extracted, can be used to warm the air going in.
The jam jar is to monitor and catch condensation in the hot duct, as it is cooled by the inlet air. If the air entering the box is just room air, the jar will do nothing. If however, your lung room must bring in outside air, then this is probably for you.
If that tent was sending 30c to outside, where it's 5c, then with a long enough box, you could be sending just 5c air outside. Having transferred all the heat to the cold air coming in. Which could reach 30c. The efficiency of these can be so high, as to call it near perfect. To look at an example, a 50,000w condensing gas boiler, can use a pvc flue. In that small box full of flames, the hot air must pass over a colder surface. How cold? It's the returning radiator water. By the time the balanced flue is through a wall, it's not that hot at all. We can transfer some serious heat, in quite a short space.


For me, I'm extracting from the tent to outside. That air must all get in the house somehow, and is a collection of cold drafts everywhere. Just outside air, straight in.
I wish to use this heat exchanger to get fresh air from my loft, which will be a bit warmer than outside. I want to warm this loft air with my extract air. Then I'm going to let this warmed air not into my groom, but into the building. Perhaps on the floor below, using the pipe boxes/risers as ducts. I may not even need a fan, as the house is under negative pressure. It's just a new route for drafts. Along my exhaust duct.

 

[trixP]

I cannot keep my tent 75 without the window open and it’s -10 all day lol, grantee I face the sun and believe me itl heat up my place, intake exhaust both outside, have my intake in front of my heater and also the pipe from the window vs the pipe at the tent are totally different temps.
Also I’m flower running 580watts out of 680 of my full spectrum bars and not currently +80watts uv fr

I’m always battling temps and humidities day by day huge fluctuations in my neck of the woods

 

[trixP]

I see you too batting the smoke effect

I’m still haven’t gotten around to my transfer box like yourself….. I’m deff gona use Wood from an old site

 

[JKD]

Depending on your budget, you can buy a complete unit, or mimic the design.

 

[Ca++]

They are quite compact, using something like a plate heat exchanger.

It's a lot like a car radiator/intercooler. Trying to maximise contact area, in a small space. What they did with a $200 200mm core, I might need 2000mm to achieve with a straight pipe. The question of how much space or money you have, might tip you either way

In the UK, a box like that, with internal fans, might do a 1.2 and cost £400.
Prices should drop as the new homes regs coming, require most builds to have whole house units. This one is just for a bathroom. It's specialist kit today, but just a year or so from mainstream throughout the EU. I have not priced passive one's but I guess £200. A bit more than a cardboard box.

I fully expect home growers to adopt this in the future. Perhaps after building their own, as proof of concept.

-10 outside, window open, 500w, 75 in tent?
That's a serious heater you have, to lift that -23c to +23c
It sounds like you have a duct run through your groom, that is picking up latent heat, in much the same way as my drawing. It would be useful to pick up heat from that exhaust instead. Which I understand needs the de-humidification that brings. To stop the duct steaming outside?
That's quite extreme. I aired the idea as I remembered someone had this issue before. You may need to forget the jam jar though you need permanent drain.

 

[JKD]

They are pricey where I am also. But if you have a small grow in your house you can incorporate it with the house ventilation. Not necessarily optimised for plant growth, but 23 degrees C, 50% humidity, not too bad. Exhaust fan from grow sized for optimal air exchanges for that space. Draws from and discharges to house. Volume of air exchanged for entire house is roughly equivalent.

They’re a balanced system and your grow just becomes part of it. They are designed to work alongside heat pumps/air conditioning. The most efficient ones can retain >90% of the heat from your house while still providing fresh air/turnover. All the wet area etc exhaust vents from your house become intake air for your grow, your discharge goes to all the discharge vents in the living areas etc.

 

[trixP]

They are quite compact, using something like a plate heat exchanger.

It's a lot like a car radiator/intercooler. Trying to maximise contact area, in a small space. What they did with a $200 200mm core, I might need 2000mm to achieve with a straight pipe. The question of how much space or money you have, might tip you either way

In the UK, a box like that, with internal fans, might do a 1.2 and cost £400.
Prices should drop as the new homes regs coming, require most builds to have whole house units. This one is just for a bathroom. It's specialist kit today, but just a year or so from mainstream throughout the EU. I have not priced passive one's but I guess £200. A bit more than a cardboard box.

I fully expect home growers to adopt this in the future. Perhaps after building their own, as proof of concept.

-10 outside, window open, 500w, 75 in tent?
That's a serious heater you have, to lift that -23c to +23c
It sounds like you have a duct run through your groom, that is picking up latent heat, in much the same way as my drawing. It would be useful to pick up heat from that exhaust instead. Which I understand needs the de-humidification that brings. To stop the duct steaming outside?
That's quite extreme. I aired the idea as I remembered someone had this issue before. You may need to forget the jam jar though you need permanent drain.

Yes I was having issues with my veg set up, 77-78 65-70%

Other -20 my flwr set up was fine, both my intake n exhaust pipes are the same length and they run for a while 2x25ft in kinda a c shape to make my living space still liveable

I got a big tv n a ps5 heating the same room and a kitchen not far away needless to say normally this set up woulda been in my room…. 19-21 20-28%

Remember the floor ???? Upstairs was leaking though the concrete passage for the plumbing thought the wall in the bathroom under my floor

So normally flower I. That room, Gona finish off as is and make sure no more silly floor black magic

 

[Douglas.Curtis]

Ahhhh... the season for higher quality cannabis. When you get 70F as your max canopy temp, and keep the RH bottomed out, you're duplicating high altitude conditions. (It's not the higher UV )

 

[troutman]

Running cooler is better than running hotter so enjoy it.
Come Summer, you probably wish for cooler temps.

 

[Hiddenjems]

Ahhhh... the season for higher quality cannabis. When you get 70F as your max canopy temp, and keep the RH bottomed out, you're duplicating high altitude conditions. (It's not the higher UV )

I live in a constant battle between yield and quality with temps and humidity. A little warmer and I get larger harvests, a little cooler, and I get more smell and taste.

I can control all of it 100%, so it’s an internal battle. lol.

 

[Douglas.Curtis]

I live in a constant battle between yield and quality with temps and humidity. A little warmer and I get larger harvests, a little cooler, and I get more smell and taste.

I can control all of it 100%, so it’s an internal battle. lol.

Lower yield, yet you need so much less it nearly evens out. Yield and public ignorance is why you don't find it commercially. I'd definitely pay extra at retail for it.

 

[trixP]

Running cooler is better than running hotter so enjoy it.
Come Summer, you probably wish for cooler temps.

Yes but if he’s pulling in negative air temp and his piping is short he can freeze the plants over
Night

One of the reasons I kept my tent far from
The window/ outside wall

We can go
0 to -40c
Here. It’s winter and the other night I had 91 rh outside.

I live in a constant battle between yield and quality with temps and humidity. A little warmer and I get larger harvests, a little cooler, and I get more smell and taste.

I can control all of it 100%, so it’s an internal battle. lol.

constant battle here 0/-40 50-96rh

Plus I’m in a small place

 

[Creeperpark]

That is why I love adding HPS for the Wintertime. I can heat a grow with the extra 400 HPS light added to my LED garden. I love using Combo lighting to raise my flowering plants. The plants love the cool nights and warm days. I run a heater during veg but not in flowering. It fools the plants into growing like it's Fall heading into Winter. It seems like the cool nights speed the plants up with pretty colors and sweet smells.

 

[Hiddenjems]

That is why I love adding HPS for the Wintertime. I can heat a grow with the extra 400 HPS light added to my LED garden. I love using Combo lighting to raise my flowering plants. The plants love the cool nights and warm days. I run a heater during veg but not in flowering. It fools the plants into growing like it's Fall heading into Winter. It seems like the cool nights speed the plants up and with pretty colors.

6 or 7 1000w hps will heat a regular sized house in the winter.

 

[trixP]

6 or 7 1000w hps will heat a regular sized house in the winter.

Lol that’s wild

 

[Creeperpark]

I don't know if anyone else warms the water up before using it, but I always do in Winter. I always bring the nutrient water to at least 70 degrees or 21 c before adding to my pots no matter what the garden temp is... The plants love it and seem to have no lag time.

 

[trixP]

I don't know if anyone else warms the water up before using it, but I always do in Winter. I always bring the nutrient water to at least 70 degrees or 21 c before adding to my pots no matter what the garden temp is... The plants love it and seem to have no lag time.

I always heat my water in my sink 68-70 my go to

 

[Douglas.Curtis]

Yes but if he’s pulling in negative air temp and his piping is short he can freeze the plants over
Night

One of the reasons I kept my tent far from
The window/ outside wall

We can go
0 to -40c
Here. It’s winter and the other night I had 91 rh outside.

constant battle here 0/-40 50-96rh

Plus I’m in a small place

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.

 

[trixP]

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.

Interesting technique