dehumidifier and mini split

[queequeg152]

also i forgot to mention this... its probably obivious to you, but increasing the temp in the room will make the dehumidifiers, operate more efficiently. how much more so depends on how warm. i would think lower 80's would see a decent increase in performance... 10% or so.

warm air however can hole more moisture. so perhaps the plants would transpire more?

 

[TheCapn]

also i forgot to mention this... its probably obivious to you, but increasing the temp in the room will make the dehumidifiers, operate more efficiently. how much more so depends on how warm. i would think lower 80's would see a decent increase in performance... 10% or so.

warm air however can hole more moisture. so perhaps the plants would transpire more?

Yes the plants will transpire more when the room is warmer. And they transpire more when the humidity is ideal. I measured the output of the dehu, and it was about 8 gallons. That's about what I would expect. Nothing wrong with that.

But both of you, quee and merkin, said something today that got me researching mini splits and humidity. I will explain in the next post.

 

[TheCapn]

These two things are what got me started researching humidity and mini splits.

From Queeque>>its a variable speed cassette no?

From Merkin:
>>You might want to check the humidity of the air coming out of the mini-split.

I hung my humidistat in front of the output of the mini split (as merkin suggested) and after some time, it read 76%! Later I checked it and it was around 62%, which is about what the room was. Also like merkin suggested, the mini split is over sized for the room.

Remember in my previous post I said, "I have the speed on high right now, in order to help circulate the air."

I read that the way the "dry mode" on a mini split works, is that it slows the fan down to allow more time for the water to accumulate and then drip away. I think what is happening, is water starts to build up and before it has a chance to drip down the hose, the compressor kicks off (because it is over sized and it doesn't take long for it to cool the room) and then that water sitting on the coils is evaporated back into the room. Meanwhile, the fan is on high, accelerating that process.

Just a stoner theory? I lowered the fan speed to the slowest setting. wah-la. The output humidity then read 48%! And this was after only about 20 minutes.

I am going to keep the fan on low for 24 hours and see how it does. Already the room humidity has lowered to around 50%. This is slightly lower than it has ever been able to get it, during lights on.

Does this low fan setting hinder the efficiency of the mini split to cool the room? I'm thinking yes. Does it HELP the efficiency of dehumidifying the room? I'm thinking yes!

But this doesn't change the fact that the revolution performed better, or so it seemed to, and it is a less capacity unit. Because of that, I feel like there is something wrong with the quest. Bottom line, a mini split doesn't "give off" or "create" humidity. It just removes humidity better when the fan speed is slow. So, it "helps" the dehumidifier.

HOWEVER, As quee said, there are other factors here that might determine why the revolution seemed to work better. #1. It puts off a TON of heat, which, makes the room warmer, and the dehu process more efficient, and #2. since it was putting off heat, that made the mini split work harder, which in turn, helps to dehumidify the room.

What do you guys think?

 

[queequeg152]

thats exactly how the dehumidification feature works.

is your minisplit not a variable refrigerant flow model? it should be able to ramp down to 40% or so of its capacity... is it so oversized that it still short cycles?

yes running the fan slower will tend to reduce the total capacity of the system, but not hugely.

 

[TheCapn]

thats exactly how the dehumidification feature works.

is your minisplit not a variable refrigerant flow model? it should be able to ramp down to 40% or so of its capacity... is it so oversized that it still short cycles?

yes running the fan slower will tend to reduce the total capacity of the system, but not hugely.

>>>is your minisplit not a variable refrigerant flow model?

Yes it is, but from everything I read, it won't dehumidify as well as lower capacity unit. The coils are cold or a less amount of time, so water doesn't build up as much. Over the last 48 hours, I have been experimenting with the fan setting. Running it on low, GREATLY helps the dehu do the job.

But with the dehu being oversized, the dehu SHOULD be able to do the job on it's own. I got a replacement dehu yesterday. Just hooked it up this morning so I will let you know how it does.

 

[queequeg152]

>>>is your minisplit not a variable refrigerant flow model?

Yes it is, but from everything I read, it won't dehumidify as well as lower capacity unit. The coils are cold or a less amount of time, so water doesn't build up as much. Over the last 48 hours, I have been experimenting with the fan setting. Running it on low, GREATLY helps the dehu do the job.

But with the dehu being oversized, the dehu SHOULD be able to do the job on it's own. I got a replacement dehu yesterday. Just hooked it up this morning so I will let you know how it does.

thats true for single stage conventional units... a VRF system should be able to ramp down its capacity and continue to run long duty cycles at a lower capacity.

that is... unless you have a unit so oversized its not able to ramp down low enough.

 

[LightItUpChris]

Hey Capn and queequeg:

That is a great amount of insight to the way the mini-spits are running and helped a lot in the way I look at them. Thanks for that. That small amount of words you wrote goes along way and took a while to figure out.

You are right that in the dark cycle you do not want the ac fan setting on high, bec that just blows more humidity around the room, when it is already inclined to spike (bec the ac condensor is likely not running, bec it has already satisifed). So the fan setting on high just exasterbates the problem by blowing a bunch of highly humid air around.

You either want to set the ac fan setting on Low or to set it on Auto fan setting (if you mini split ac has that function) which i believe that has the capabilty to ramp up and down the fan setting based on the tempature in the the room. I am not talking about the mode setting, that always continues to be set on Cool. I am talking about the fan setting. Which on the mini-split i am using (Midea Brand) has a low, medium, high, and Auto Setting for the fan. Setting it on Auto Fan setting, after reading you post has dramaictaly helped my humditiy issues.

I also have a bunch of 10-12" fans on the wall where the head unit of the ac is mounted. About 5-6 of them. They are mounted to create an air gap between the tops of the colas and the lights. They kick on with the lights and go out when the lights go out. This has helped the ac from keeping any tops from burning.

Also, we run a 4" exahust fan in the room. Sounds stupid i know, but it works. The room is slight passive, with the ac. It is has a rio-stat on it turning it down to a whisper while in flower. And i truly mean a whisper. This helps keep the room a little fresher, than just being 100% closed loop. A little trick, that i believe helps a lot. In my humble opinion.

Thank you for your insight to all who have posted.

Keep up the great work

 

[queequeg152]

Hey Capn and queequeg:

That is a great amount of insight to the way the mini-spits are running and helped a lot in the way I look at them. Thanks for that. That small amount of words you wrote goes along way and took a while to figure out.

You are right that in the dark cycle you do not want the ac fan setting on high, bec that just blows more humidity around the room, when it is already inclined to spike (bec the ac condensor is likely not running, bec it has already satisifed). So the fan setting on high just exasterbates the problem by blowing a bunch of highly humid air around.

You either want to set the ac fan setting on Low or to set it on Auto fan setting (if you mini split ac has that function) which i believe that has the capabilty to ramp up and down the fan setting based on the tempature in the the room. I am not talking about the mode setting, that always continues to be set on Cool. I am talking about the fan setting. Which on the mini-split i am using (Midea Brand) has a low, medium, high, and Auto Setting for the fan. Setting it on Auto Fan setting, after reading you post has dramaictaly helped my humditiy issues.

I also have a bunch of 10-12" fans on the wall where the head unit of the ac is mounted. About 5-6 of them. They are mounted to create an air gap between the tops of the colas and the lights. They kick on with the lights and go out when the lights go out. This has helped the ac from keeping any tops from burning.

Also, we run a 4" exahust fan in the room. Sounds stupid i know, but it works. The room is slight passive, with the ac. It is has a rio-stat on it turning it down to a whisper while in flower. And i truly mean a whisper. This helps keep the room a little fresher, than just being 100% closed loop. A little trick, that i believe helps a lot. In my humble opinion.

Thank you for your insight to all who have posted.

Keep up the great work

sounds like what ever you are doing is working well enough, but in the future id suggest doing a load calc for all of your hvac equipment.

exhausting conditioned air is not crazy per say. alot of newer homes do this to deal with indoor air quality issues... but id suggest you at least investigate buying an economizer unit and sensors to make this activity a bit more intelligent.

when humidity inside > outside- and or temp inside> outside your fan kicks on to bring air inside. that sort of thing.

 

[Asslover]

I have my AC set where I want the temp kept, and my dehu where I want the RH kept, and forget about it. I monitor temp and RH with other devices, and they're always fine. Good luck. -granger

EXACTLY how i do it. I use two 12k btu mini's in a 10x 10 (mounted opposite each other) and two 70pt dehumidifiers.h
I keep the fan setting on the AC's on Low with the flaps going up/down, dehumidifiers set @50%.
I monitor both Veg & Flower room with other devices as well

 

[chegwin]

free CO2 dehu

free CO2 dehu

This dehu makes CO2 as a by product for drying the air... Sounds interesting, has anyone seen anything like this?

http://unbouncepages.com/freeco2dehu/

 

[queequeg152]

This dehu makes CO2 as a by product for drying the air... Sounds interesting, has anyone seen anything like this?

http://unbouncepages.com/freeco2dehu/

bullshit website? where the fuck is the product?

chemical desicant im betting.

 

[LightItUpChris]

Hey queequg,

Thanks for chiming in a bit there and giving me some feed back. Appreciated. I looked into the economizer unit, was pretty interesting. That thing looks pretty cool. But that isn't what i was going for. We are running our rooms at around 2500 ppm of Co2, with gas burning propane generators. So we want to keep our rooms 98% closed loop.

The idea behind the very slight negative pressure on the room with the Rio-stated down exhaust fan was to keep inert gases in the room present. A little Oxygen, and some of the other things naturally occurring in air, that would not otherwise be there. I don't know too much about it because i don't have a ton of science background, but i do know that it helps. Something tells me that the plants need a little more than just Co2 and Oxygen, some of those other gasses that are present in fresh air. This is where the 2-5% passive exhaust for flower cycle comes in (20-30% for vegetative growth cycle). Even with friends that are using 5 ton ac units. They also have noticed a difference. I learned this trick from a friend that was consistently pulling 2 per light on O.G. kush and was pushing for 3 per. light. That was on normal old 1000 watt hps lights. I stood their draw dropped, with notebook in hand. Lol He looked at me and said straight faced, "co2 and air are everything". I am trying to replicate what i saw.

This also made a little sense in our area because outside humidity was often hovering around 20-40 %. So pulling in a very very slight amount, just seemed to help keep things just a little nicer. I am talking about no more than 2-5% negative pressure on the room for flower cycle. No higher, that way you can keep your Co2 levels thru the roof. Put your hand up to where the exhaust is coming out and verify that it is at a whisper.

I would still recommend using a dehumidifier in the room, if you can afford the price of it. But if you are on your first run and can't, just do this and it will likely work. Especially if you hook up a separate 4" exhaust fan that kicks on only during the night cycle when the humidity is inclined to spike, because condenser/compressor is not running on the a/c, because the temperature has already satisfied. Which means it would no longer be dehumidifying much. This fan trick is a cheaper alternative, but kind of a cowboy approach, because if you have extreme cold temperatures outside (ie 20F) and pull that in you may freeze things out. Thought i would throw it out there.

Hope this helps somebody. Smoke one and smile and laugh. I know it sounds funny.

 

[OG Tree Grower]

LightitupChris - I agree semi sealed out produces 100% sealed. I only had one place that was 100% sealed, it had two entrances before the lung room to conceal smell and even then you had to make sure one door was shut before you opened another ect. A real pita. Since then I hold negative pressure like you said, just a whisper and have done a little better with it set up semi sealed.and it's a ton safer smell wise

I also exhaust at night, temps as you mentioned are handled easily with a few heaters In The lung room, the real problem is when it's 80% humidity outside , at that point your better off sealing it up and dehumidifying , so you need one either way. I just don't use it unless I have to.

You said you run 2500 ppm co2? How far away are you running your lights? Food schedule and ppm? What type of system? I'm very interested in this, I could never get co2 to do much for me above 1200ppm, maybe 1500 tops

 

[Shmavis]

Hey queequg,

Thanks for chiming in a bit there and giving me some feed back. Appreciated. I looked into the economizer unit, was pretty interesting. That thing looks pretty cool. But that isn't what i was going for. We are running our rooms at around 2500 ppm of Co2, with gas burning propane generators. So we want to keep our rooms 98% closed loop.

The idea behind the very slight negative pressure on the room with the Rio-stated down exhaust fan was to keep inert gases in the room present. A little Oxygen, and some of the other things naturally occurring in air, that would not otherwise be there. I don't know too much about it because i don't have a ton of science background, but i do know that it helps. Something tells me that the plants need a little more than just Co2 and Oxygen, some of those other gasses that are present in fresh air. This is where the 2-5% passive exhaust for flower cycle comes in (20-30% for vegetative growth cycle). Even with friends that are using 5 ton ac units. They also have noticed a difference. I learned this trick from a friend that was consistently pulling 2 per light on O.G. kush and was pushing for 3 per. light. That was on normal old 1000 watt hps lights. I stood their draw dropped, with notebook in hand. Lol He looked at me and said straight faced, "co2 and air are everything". I am trying to replicate what i saw.

This also made a little sense in our area because outside humidity was often hovering around 20-40 %. So pulling in a very very slight amount, just seemed to help keep things just a little nicer. I am talking about no more than 2-5% negative pressure on the room for flower cycle. No higher, that way you can keep your Co2 levels thru the roof. Put your hand up to where the exhaust is coming out and verify that it is at a whisper.

I would still recommend using a dehumidifier in the room, if you can afford the price of it. But if you are on your first run and can't, just do this and it will likely work. Especially if you hook up a separate 4" exhaust fan that kicks on only during the night cycle when the humidity is inclined to spike, because condenser/compressor is not running on the a/c, because the temperature has already satisfied. Which means it would no longer be dehumidifying much. This fan trick is a cheaper alternative, but kind of a cowboy approach, because if you have extreme cold temperatures outside (ie 20F) and pull that in you may freeze things out. Thought i would throw it out there.

Hope this helps somebody. Smoke one and smile and laugh. I know it sounds funny.

Are you scrubbing the air in the room? Or is your dialed-down exhaust running through a carbon filter?

 

[queequeg152]

Hey queequg,

Thanks for chiming in a bit there and giving me some feed back. Appreciated. I looked into the economizer unit, was pretty interesting. That thing looks pretty cool. But that isn't what i was going for. We are running our rooms at around 2500 ppm of Co2, with gas burning propane generators. So we want to keep our rooms 98% closed loop.

The idea behind the very slight negative pressure on the room with the Rio-stated down exhaust fan was to keep inert gases in the room present. A little Oxygen, and some of the other things naturally occurring in air, that would not otherwise be there. I don't know too much about it because i don't have a ton of science background, but i do know that it helps. Something tells me that the plants need a little more than just Co2 and Oxygen, some of those other gasses that are present in fresh air. This is where the 2-5% passive exhaust for flower cycle comes in (20-30% for vegetative growth cycle). Even with friends that are using 5 ton ac units. They also have noticed a difference. I learned this trick from a friend that was consistently pulling 2 per light on O.G. kush and was pushing for 3 per. light. That was on normal old 1000 watt hps lights. I stood their draw dropped, with notebook in hand. Lol He looked at me and said straight faced, "co2 and air are everything". I am trying to replicate what i saw.

This also made a little sense in our area because outside humidity was often hovering around 20-40 %. So pulling in a very very slight amount, just seemed to help keep things just a little nicer. I am talking about no more than 2-5% negative pressure on the room for flower cycle. No higher, that way you can keep your Co2 levels thru the roof. Put your hand up to where the exhaust is coming out and verify that it is at a whisper.

I would still recommend using a dehumidifier in the room, if you can afford the price of it. But if you are on your first run and can't, just do this and it will likely work. Especially if you hook up a separate 4" exhaust fan that kicks on only during the night cycle when the humidity is inclined to spike, because condenser/compressor is not running on the a/c, because the temperature has already satisfied. Which means it would no longer be dehumidifying much. This fan trick is a cheaper alternative, but kind of a cowboy approach, because if you have extreme cold temperatures outside (ie 20F) and pull that in you may freeze things out. Thought i would throw it out there.

Hope this helps somebody. Smoke one and smile and laugh. I know it sounds funny.

could be ethylene from decomposition or bad combustion. are you using combustion to get co2? the co2 enriched greenhouses that propigate roses and other expensive flowers usually take measures to eliminate the ethylene because it has a deleterious effect on growth. some plants are far more sensitive to ethylene than others as well. you might place some toms in and around your co2 generator with control toms elsewhere far away. it should be pretty obvious if there is an appreciable amount of ethylene in the air from your co2 generator.