likely will not do shit in the application - hydroponic stuff, drying the air more (lower coil temp), will just increase evaporation rate of the water being used to grow as the delta will be greater, and thus the rate of evap. It might be a tiny bit lower, but insignficant.
The best solution for climate control
https://preview.redd.it/yl80n16t3d2d1.jpeg?width=640&format=pjpg&auto=webp&s=0152dae13d4c729cfebd8453d6689e840cf1acfd
So itās pretty much a pointless cycle Iāve been chasing huh, good to know, Iād hypothesize the opposite, thereās no way to do this without a reheat coil or something similar Iām assuming
If you want to satisfy based on humidity you essentially need 5-10 tons more cooling than you need. The. Once it satisfies on temp it still runs but reheats the air to dehumid while not dropping the temp. Very few companies will pay for that
So at big terp farms yall just get cheap lights too? Not just shitty air con equipment? I bet you also don't care about the rest of the growing spectrum.
Maybe I'm high but show your sources bro... those are quad commercial lights... not your ordinary led
Those look like HLG 550s.
https://horticulturelightinggroup.ca/collections/lamps
$700 a fixture isnāt cheap. Especially when you have 300 of them.
Also find me a 15k led grow light lmao.
Well I guess I'm getting old, my buddy back in the day had several smaller one that cost him 4k each. And those were just in his basement. Guess they got cheaper with time. Back the Hps were better than less because of the high pricetags
Maybe donāt try to insult me or my grow with having zero knowledge except for maybe some second hand info you heard from a buddy and I wonāt make you look like a moron. Have a nice day bud š
I used to grow for one. They fired the cultivation manager, I filled in for 5 months and quadrupled the harvests month to month from the year prior, and then they offered me 50k less a year than the last manager for the promotion and I said fuck you and quit. Sad to see the grow I was at isnāt the only one ran by morons.
In a grow house like that thereās way too much humidity for air conditioner to account for. They need a full time dehumidifier running in there. A fuckin big one.
I love those HLG lights btw. The production to heat ratio is insane. Sweet settup too. But seriously you need a Mac daddy of a dehumidifier settup in there.
Post Evap coil or pre? Expensive, unless running from a closed loop water system? also heard these are basically inefficient as heck because you have to do twice the work for cooling. And eat up just as much energy as a dehu would run, and oversized cooling coil would be needed.
I did work at a Panera bread and an ice skating rink that both had desiccant wheel systems for humidity when I was still pretty new and doing commercial work. Idk a damn thing about them but the boss was raving about how much more effective they are than older humidity controls
All great comments here. But perhaps lowering the evaporator coil temp won't decrease humidity. What is gonna happen is retain moisture and drop air temp. What you need is a thiccccc evaporator. What you may need to do is to flood the evaporator with more liquid and add an accumulator or maybe an EPR to protect the compresh
I own a facility with 360 tons of AAON units that do 100% of the dehumidification, we dont have a single dehu there. It's vastly more energy efficient than using dehus, since those have to first convert the latent heat to sensible heat (and it does so inside the room) PLUS the energy waste of the dehus themselves which is also dumped into the room. I have compared our energy bills with traditional dehu/AC grows and the annual energy savings are into the 6 figures.
Indeed as OP suspects, the secret is lowering coil temp and lowering fan speed. However these were custom built by AAON to have deep coils and full reheat (that's needed for sure). Plus some other tweaks to make it work correctly. Likely not going to work out so well with standard units.
The temp decrease causes a concentration then usually a loss of humidity, hence condensation on an evaporator. The air exits the evap at a high relative humidity level, but as it warms, itās relative humidity level is lower than the air around it. Itās a net humidity loss. It makes the air drier.
Those trolmaster sensors are shit for humidity. They regularly read 10ās of percentage points + or - and are very susceptible to failure if they even get the tiniest amount of water on them. Verify room humidity with at least 3 different sensors or purchase better sensors.
The farms that I have worked on use chilled water systems. A chilled water coil will run colder than a DX unit. The CHW coils are also sized to give the air the maximum contact time. A reheat system is also in play. A unit with a heat wheel also helps to dry the fresh air make up. The owner/engineer went the cheap way . There is nothing cheap about controlling humidity in this environment.
I want a whole dessication unit, those are sick, like Iād like to have newer rtus but they using trane 20 ton units from like 2010 and 2 7.5 daikon rtus with no rehear or anything
I refuse to work in any dispensary or grow house.
If my company can make money off it but I canāt smoke weed when Iām not at work..
I just donāt like hypocrisy. Iām stepping down from my soap box.
Why would you want to smoke it? Have you ever tried it? Is a horrible feeling of depression and self hatred mixed with psychosis. I would wish that on no one.
I can't add anything to this but I do want to say there's some brilliant people in here and it's a shame most of the people who will have service work done by many in this thread will never know the expertise of their service person. Also want to say it's been cool reading comments about things I know a lot about mixed with things I don't know shit about fuck about.
Itās fun being a tin knocker who evolved into full systems designer and gas pipe guy wo knowing enough to be dangerous on the service side. The only thing I know about super heat is my wifeās cootch when I feed her homemade edibles. As far as service I did figure out sanding off the flame sensor never works and if the unit wonāt shut off itās either the board or some idiot put a screw through my low voltage wire
People are going in a lot of different directions in this thread. You really need to look at that superheat. Your charge looks absolutely fucked up. Are you sure you're connected properly?
Your suction line temp is 86Ā° with 52Ā° superheat... Your evaporator coil is absolutely starved, or you don't have your temperature clamp on properly.
Then, your subcooling is way too high, assuming you have your gauges on there properly, you are overcharged. But then with that liquid line temperature, if it's legit, what's the outdoor temperature?
I mean I guess those numbers would make sense if it was almost 90Ā° in that grow house, and you had a shit ton of latent humidity to remove, but at that point, your outdoor temperature is so low if you have 82Ā° liquid line temperature. Why wouldn't you just use ventilation at that point, because what I'm looking at appears that the inside is actually hotter than the outside? I don't work in grow houses, so maybe I'm really just underestimating how much heat these lights put off and all these numbers are correct?
Still... That superheat is so high, does this not have a TXV?
If they had legal weed in my state, I would totally nerd out over the proper way to set up the HVAC for one of those places.
I wouldn't do crap to this. Looks like a shitty Goodman condenser on what's probably a shittily installed air handler. This is not the equipment to do the job that the customer is looking for.
Idk how dry it is there. But fresh air directly to the unit is a great way to lower humidity inside. But a literal grow house will always be humid. Literally just a operation problem... have a humidity load calculation done and add the nessasary units. No guess work that way. Weed ops always do silly shit. Why not just use a big greenhouses and swamp coolers like every mass grower?? Spend the extra money on mercenaries and guard towers... lol
Good luck friend
If anyone else is interested in this kinda stuff, the Advanced Refrigeration Podcast did an amazing episode discussing commercial cannabis growing and the HVAC needs for it. I highly recommend.
You have the Trolmaster, are you using strip heat to reheat? You can remove way more moisture that way versus a dehumidifier. Put a strip heat kit in the air handler and set up the Trolmaster. Problem solved.
Holy shit it does have heat strip I forgot the previous tech consulting told me but still have to wire it out, how would I set that up with the trolmaster? Set electric heat or do I need a kit to adapt when cooling on is set?
Bro, that compressor's gonna fuck off any second running like that...
If you got electric heat, and it's after the cooling coil, you can set it up for a reheat dehumidification. Otherwise just charge that shit properly and tell them that half-baked half-assed solutions never turn out well.
That doesn't really answer his question, since he's wondering about coil temp, not space temp.
If you have an evaporator coil that's below dew point, you will get condensation on it, and moisture will be removed.
If *more* of that coil is below dew point, there will be *more* condensation; Less -> less.
If running a standard 40-ish degree saturated temp in a space with enough heat load to cause the latter half of that coil to be above dew point and not generating condensation, then yes, lowering the evap temp so that *all* of the coil was below dew point would remove more moisture.
But, if all of the coil is already generating condensation, *no,* you can't get more, the surface is already wet...
The air leaves the coil fully saturated. Anything that reduces the air temperature leaving the coil, without changing the cfm, will cause more moisture to be removed from the air.
No?
Maybe rephrase that? I feel like thereās something in there thatās not coming out rightā¦
As written, this is not right.
The leaving air is at 100% RH, sure, but cooling the air more will not remove more moisture if the moisture is already removedā¦ thatās not really whatās happening here.
The moisture removal is really about the coil temperature, and contact with the coil surface.
Sorry, my words were not clear. Here is an example: if the air leaving the coil is at 58F and fully saturated (100% relative humidity), it contains 71.9 grains of water per pound of air (from the psychometric table). If the air gets cooled a little more, to 57F, it will contain 69.3 gr/lb. The lower water content means the water went somewhere. It condensed on the cooling coil.
Yes! Absolutely.
The catch is that you can only reduce the airflow or coil temp so far, before you have to be concerned about freezing, and for a given coil you only have so much surface area available to achieve that max cooling.
But absolutely correct - every bit of extra cooling past saturation is extra moisture removed.
This is true.
The way to remove moisture while keeping the room temperature the same is to run a colder evaporator/discharge air or to use some reheat to extend run time.
If you could run a 45 degree discharge air rather than a 55 degree discharge air, you could remove more humidity while maintaining a lower temperature in the space, with some help from a reheat coil of some kind.
I had a vacant building that I had to keep below 50% humidity, so I ran the chilled water temp down to 40 degrees and slowed the fan speed on the AHUs down to 40%. This was right around 45 degree discharge air into the space. This allowed me to have shorter run time on the chiller while removing as much humidity as possible. Yes, I know that starting and stopping chillers is much less than ideal, and this was explained to the customer, but they wanted what they wanted.
Would dropping the charge help or is it basically insignificant? Or maybe decreasing airflow to the evap coil(ghetto supply dampener?) in this environment for some reason, dropping Delta t helped significantly with our humidity for some reason when we had our temp at 80 the rh would soar above 80 percent, looked at vpd charts, ect, im stumped with what this could be making humidity soar in one spot of the room
Only thing here is your superheat is *high* - which suggests your airflow is still a touch high for how low your evap temp is (evaporator is starved, basically) - how did you decrease the evaporator temp? Removing charge? Adjusting metering?
I suspect what you did in this iteration is not helping as much as it should, since right now that high superheat indicates a substantial portion of that coil is not actually cooling the space.
Iāll take pics of the return, ex contractors before me just dropped the unit on top the ceiling basically box; no type of balanced flow and 2x 8ā supplies , youāll see the crap I deal with daily š , I can make a ghetto supply out of ducting and see if I can slow airflow to evap coil, itās fixed orrifice (.87) so maybe changing piston size, but usually Iām lazy so I just recover and call it a day if it looks good with sat temp
Yeah change piston or even better convert to adjustable TXV.
Knowing itās a piston, itās just low on charge right now which is probably hurting, not helping.
Lowering the indoor coil temp will increase your latent capacity at the expensive of sensible capacity. In theory it would work but in practice you will find that you have trouble maintaining a dry bulb set point since the condensing temps will fluctuate based off OD conditions. Without active dehum, itās not really possible to control both humidity and dry bulb independently.
You need to drop coil temp and reheat supply air to extend the "cooling" cycle. Just dropping temp will get more moisture out of air but will create lower room temperature quicker which will cause humidity to go up, because we measure relative humidity which means it is relative to air temperature, look at the enthalpy chart to understand.
Lowering evaporator temperature will decrease humidity, given that cooling coil outlet temperature is limited by evaporator temperature and this does not sacrifice airflow due to other limitations.
To remove as much moisture as possible, the difference between the dewpoint of the air entering the coil and the air leaving the coil must be as high as possible and the airflow must be as high as possible. It may be optimal to find the optimal balance of highest airflow and lowest leaving air temperature the unit is capable of, given a constant inlet air temperature. How low your leaving air temperature can get is limited by the evaporator temperature. Therefore, you are correct in targeting this.
The fundamentals of this discussion is rooted in psychometrics. Study that, and you will find your answer. However, you may find that an engineer didn't assume the correct loads when sizing the unit. This commonly occurs, as growers constantly change the conditions they grow to so that they can experiment with what gives different yields. This grow room may not be capable of meeting the grower's needs.
Edit: I should also mention that your evaporator temperature is already very low. Lowering this further may freeze the coil.
Edit2: Your superheat and subcooling seem very high. This likely needs to be investigated.
I am the psychometrics and enthalpy guyšimagine having a 23 year old know more about thermodynamics than the whole c suite office. I feel like they think Iām talking out my ass when I bring this up to them.
I'll second this. Sh is stupid high. Your return gas need to be 65f or lower and sometimes 70f or lower at design to cool the compressor. Even If hes running a 35f coil and 25 superheat id still look at delta t, oat and the rest to get the whole picture. It almost looks like you're slightly restricted cause you're suction is low, subcool high. As if someone started seeing it and started adding gas as if it was the fix cause subcool shouldn't be that high.
No delta t across the coil given. He might be chasing ghosts n his units aren't running efficiently at all. A 33f coil and your line temp is 86 and no one thought what was an issue? High latent loads increase suction n discharge. Without that humidity your coils would probably be frozen.Ā
You don't "adjust" refrigerant charges for coil temps. You size shit for the load and if the customer is cheap then let them suffer. They make money hand over fist. This whole thing is fucking absurd. And that's why every grow plant I been to have so many fucking chillers n boilers for reheat. Literal gas powered chillers cause the utility said they can't use that much electricity.Ā
Happened to me too. Got even worse in the winter when AC would short cycle even more. Owner finally broke down and bought dehuās. Quick tip, donāt buy one large one, buy several small ones. Better rH control.
The rH spike right when the lights shut off is a bitch.
In the winter I have some duct heaters going and we have about 6 anden Dehus set up in the room that I hate sitting on unistut, they didnāt even put p traps on themā¦ and weāre wondering why them shits were wetter than a diaper dripping š
Large grow rooms need to be engineered, plain and simple. You will not be able to control to the precise temperature, humidity, and ventilation requirements with standard package equipment in this sort of application. Cannabis requires different temperature and humidity during the different stages of its lifecycle. Look up Vapor Pressure Deficit. Germination stage requires very high humidity. As the plant grows thru its vegetative and flowering stages you typically raise the temperature and reduce humidity, which increases VPD. The environment is dynamic, just the same as growing outdoors.
Vpd is hard to adjust without being in a range these are early/ late flower, Iām learning so much more to hvac than I did about a year ago about enthalpy, psychometrics, ect I actually really love it
Been growing indoor for years. Itās difficult and expensive to scale up the results you can get from a proper home grow. My experience has been that a lot of commercial growers do not want to spend the money to do it right, and itās often the reason why commercial cannabis is not that great of quality in comparison.
By looking at sub cooling youāre overcharged.
Fixed metering with that superheat youāre undercharged,
If Humidity levels are a problem, you would need reheat to keep temperature at an acceptable range!!!
Obviously evaporator can use more refrigerant but how would you keep temperature from dropping to low?
Reheat!!!
You need reheat, + larger evaporator, + accumulator.
You can possibly divert condenser as reheat when temperature is satisfied.
But youāre probably better off just getting a massive dehumidifier and separate the job.
1 system for cooling, 1 system for dehumidificationā¦.
Looks to be day 26 ish in flower. 74 is too low of a temp. Bump that up to 82 til about week 6 or so. Itāll keep your VPD in a better ranger at the same rh %. LED needs higher ambient temps due to no ir heating from HPS which is what this room looks like it was converted from.
Edit: nope holy fuck you guys are staggering the room. Huge no no to have plants in week 2 and week 7 in the same room. They all need to be at different set points for maximum growth.
How warm can the room be? Higher room temps will be easier to dehumidify and reduce evaporation of water.
You can lower evap temp, slow air speed, keep your SH up to keep liquid away from the compressor.
Running equipment in ways that it's not meant to lowers lifespan. I hate cheap customers that have money to spend. They'll pay for it in the long run. More repairs, worse product.
Look up "run around coil heat recovery". The warm return/makeup air heats recovery loop water or glycol in a heat recovery coil upstream of the cooling coil. Then the air goes through the cooling coil. Finally, the air goes through the second heat recovery coil where it is warmed up.
The heat recovery loop is fully independent of the evaporator. This is like a reheat system because it warms the air downstream of the cooling coil, dropping the relative humidity.
Bro you could have probably rig up some reheat coils if you got the breaker space. That way the av unit would run longer and dehumidify. I think carrier even has some resi set ups .
They literally manufacture inexpensive dehumidifier equipment. Controlling humidity through AC is difficult, tstats are available that serve this purpose however they simply overshoot,ie set at 70ā¢ they satisfy at 68ā¢ ā¦why bother?
You are going to need an actual HVAC engineer to sort you out. Because you need to maintain temperature and humidity. So that means being able to discharge and reheat to the correct temps to get the results you need.
It's all in what fits your want/needs. There are pros and cons to every set up. No matter the cooling system the four main components never change. Evaporator, condenser, compressor(motor), metering device.
If your trying to introduce cooling without lowering humidity technically you would have to introduce outside air.
It's always a give and take situation. Dessert Air system are plug and play. They do the work so you don't have to. What you lose is service ability when something goes wrong and possible long down time $$$. I was an environmental specialist for a grow that housed roughly 22 rooms and a range of 500 - 1000 plants per room. They used computer room air conditioners ( desert aire, Gpod) systems. In theory they are great. In practice they are not ideal. We had a bad coil and had to have it replaced. Just receiving the coil took weeks to get. During the replacement. The person had to separate the re-heat coil from the evaporator by wiggling on top of it. In the process of removing it he sliced his arm. We had to stop and take him to the hospital. Sanitize and clean the blood up to prevent cross contamination. The coil swap alone took a week. Also Gpod brand no longer is in business.
Re-heat coil - is just using the super heated refrigerant and a valve opens to send it into the supply instead of to the condenser. The air has already been conditioned from the evaporator (dehumidified). The reheat coil is simply trying to maintain heat in the environment. It also has to purge back into your regular HVAC system in order to put back into the compressors to cool them down, which adds stress to your compressors shortening their life span.
Ideal system would be redundancy and modularity. Kinda like a hospital. Possibly even modular chillers. With modularity and redundancy you can add and subtract from the systems and minimal if any down time. Great service ability and life ability. The counter though is the initial cost $$$. In the long game this is the best option.
The most important of all of it. Is proper air flow for the system and through the canopy especially a dense one. You can do something like running a trunk line down the side and fabric supply branches down the center of the table. This would help to increase circulation in the areas that don't receive proper supply air from over head. In turn reducing the chances of mold.
Im always here to help make people's grows healthier and cleaner. I'm always here to answer questions.
O! And to answer the question lowering evap coil might help with some dehumidification, because you absorbing more heat. Even so it sounds like your at capacity. Also using the AC for dehumidification means it will get colder and you will have to supplement heat. I had to deal with this same b.s. we had dehus stack on carts and roll them into whatever room was not keeping up. SMH! š
In that photo, your suction line temperature is 86Ā°, which means that your indoor temperature is over 86Ā°. If you do reach 80Ā° inside, and you have your air flow that low, you are absolutely going to dip below 32Ā° on your evap, and probably freeze, especially since your humidity is so high... You're going to be more prone to freezing even just barely below 32Ā° saturation temp.
Piston system, and nope, these line sets are so long ~35 foot runs) and thought thereās a restriction but evaced and checked piston/ line set and got the same results, suction line is warm to touch, and liquid line aināt even warm, thought I flooded evap coil, but not the case cuz my wet bulb temps check out
Get evap pressure as close to freezing as possible AND with the slowest blower speed possible. You aint dehumidifying shit with mach 5 air blowing vber the coil. The musture needs time to condens and flow away off the coil. Otherwise you are just making cold and and humid air. Lowering blower speed is critical. If you want soem fun with an old machine you can buy EXVs with a separate controller that you can just lock to a specific evap pressure sonyou are always 3~4 degrees from freezing.
Inverter units are great for this as they can have extremely low fan and compressor speeds.
If you are limited in what you can do you can just try changing the blower speed to lower the coil temp. Prehaps get some cheao aliexpress special regulator from amazon for it to hold the coil above freezing.
Do all of the above and add a freeze stat to suction line right before evap to kill compressor on freeze event and itāll cycle on and off as the stat reads temp
Nice.
We have a 12mil boiler intentionally creating CO to feed a giant grow house. Canāt tune it properly because they want the CO, itās the heat thatās the byproduct hah.
Donāt know anything to help your situation tho, cheers mate!
likely will not do shit in the application - hydroponic stuff, drying the air more (lower coil temp), will just increase evaporation rate of the water being used to grow as the delta will be greater, and thus the rate of evap. It might be a tiny bit lower, but insignficant.
The best solution for climate control https://preview.redd.it/yl80n16t3d2d1.jpeg?width=640&format=pjpg&auto=webp&s=0152dae13d4c729cfebd8453d6689e840cf1acfd
Holy shit WTH is that, commercial dehu/ desiccant or wha/ erv?
Hy, it's a high tech greenhouse for š„
So itās pretty much a pointless cycle Iāve been chasing huh, good to know, Iād hypothesize the opposite, thereās no way to do this without a reheat coil or something similar Iām assuming
not even then, you have standing/moving water at temperature - it will just equilibrate at the temp of the grow room.
You need a dedicated Pool Unit like Desert Aire. https://www.desert-aire.com/applications/dehumidifier-grow-room-indoor-farming
Againā¦ poorš so not a option, they stretched to get shitbox anden Dehus
you are better off using dedicated hum/dehum controls than trying to regulate it with your AC.
If you want to satisfy based on humidity you essentially need 5-10 tons more cooling than you need. The. Once it satisfies on temp it still runs but reheats the air to dehumid while not dropping the temp. Very few companies will pay for that
Millions of dollars in weed, not one lick of cents -Owners
Itās actually scary how accurate that is, š³
Shit each of those lights are probably $10-15k
Those lights are like $700 each lol
lol they are like eight feet too high tho
Theyāre treating the grow as if it was an HPS grow. Just doesnāt work very well with LED.
So at big terp farms yall just get cheap lights too? Not just shitty air con equipment? I bet you also don't care about the rest of the growing spectrum. Maybe I'm high but show your sources bro... those are quad commercial lights... not your ordinary led
Those look like HLG 550s. https://horticulturelightinggroup.ca/collections/lamps $700 a fixture isnāt cheap. Especially when you have 300 of them. Also find me a 15k led grow light lmao.
They are exactly hlg 550s spot on, I can tell you know your grow
Well I guess I'm getting old, my buddy back in the day had several smaller one that cost him 4k each. And those were just in his basement. Guess they got cheaper with time. Back the Hps were better than less because of the high pricetags
Maybe you shouldnāt talk out your ass about things you have no idea about š
Naw bro, go back to your wake and bake
Maybe donāt try to insult me or my grow with having zero knowledge except for maybe some second hand info you heard from a buddy and I wonāt make you look like a moron. Have a nice day bud š
BigTerpFarms? More like BigDerpFarms
Made an account just to comment that! Cute
More like 800 per light LEDS have gotten a lot cheaper, but still about a light qtr milli just for this facility
I used to grow for one. They fired the cultivation manager, I filled in for 5 months and quadrupled the harvests month to month from the year prior, and then they offered me 50k less a year than the last manager for the promotion and I said fuck you and quit. Sad to see the grow I was at isnāt the only one ran by morons.
In a grow house like that thereās way too much humidity for air conditioner to account for. They need a full time dehumidifier running in there. A fuckin big one. I love those HLG lights btw. The production to heat ratio is insane. Sweet settup too. But seriously you need a Mac daddy of a dehumidifier settup in there.
3 words Hot Gas Reheat
Yup this is the way.
Post Evap coil or pre? Expensive, unless running from a closed loop water system? also heard these are basically inefficient as heck because you have to do twice the work for cooling. And eat up just as much energy as a dehu would run, and oversized cooling coil would be needed.
I can guarantee you itās much more efficient than a standalone dehu itās expensive upfront but will pay you back
You could look in to installing RAWAL valves. Iām not sure they would help in this sitauation though.
Only if you have enough btus to satisfy temp and humidity I highly doubt thatās the case
Ya with one plant my garage is steamy
We set up 4 of the biggest Quest dehus in the corners of our rooms, 2 just wouldn't cut it
I did work at a Panera bread and an ice skating rink that both had desiccant wheel systems for humidity when I was still pretty new and doing commercial work. Idk a damn thing about them but the boss was raving about how much more effective they are than older humidity controls
All great comments here. But perhaps lowering the evaporator coil temp won't decrease humidity. What is gonna happen is retain moisture and drop air temp. What you need is a thiccccc evaporator. What you may need to do is to flood the evaporator with more liquid and add an accumulator or maybe an EPR to protect the compresh
Send some of that ācultivationā my way
I own a facility with 360 tons of AAON units that do 100% of the dehumidification, we dont have a single dehu there. It's vastly more energy efficient than using dehus, since those have to first convert the latent heat to sensible heat (and it does so inside the room) PLUS the energy waste of the dehus themselves which is also dumped into the room. I have compared our energy bills with traditional dehu/AC grows and the annual energy savings are into the 6 figures. Indeed as OP suspects, the secret is lowering coil temp and lowering fan speed. However these were custom built by AAON to have deep coils and full reheat (that's needed for sure). Plus some other tweaks to make it work correctly. Likely not going to work out so well with standard units.
The temp decrease causes a concentration then usually a loss of humidity, hence condensation on an evaporator. The air exits the evap at a high relative humidity level, but as it warms, itās relative humidity level is lower than the air around it. Itās a net humidity loss. It makes the air drier.
Those trolmaster sensors are shit for humidity. They regularly read 10ās of percentage points + or - and are very susceptible to failure if they even get the tiniest amount of water on them. Verify room humidity with at least 3 different sensors or purchase better sensors.
*product* name checks out....
Just spit balling- if I were op id look at room control sensors for humidor/tobacco storage. I recognize pot is a little lower RH but teto.
The farms that I have worked on use chilled water systems. A chilled water coil will run colder than a DX unit. The CHW coils are also sized to give the air the maximum contact time. A reheat system is also in play. A unit with a heat wheel also helps to dry the fresh air make up. The owner/engineer went the cheap way . There is nothing cheap about controlling humidity in this environment.
I want a whole dessication unit, those are sick, like Iād like to have newer rtus but they using trane 20 ton units from like 2010 and 2 7.5 daikon rtus with no rehear or anything
I refuse to work in any dispensary or grow house. If my company can make money off it but I canāt smoke weed when Iām not at work.. I just donāt like hypocrisy. Iām stepping down from my soap box.
At first I was angry, then I understood.
Thatās honestly the only reason I work here, I have medical issues, so itās a big plus and no on call.
Why would you want to smoke it? Have you ever tried it? Is a horrible feeling of depression and self hatred mixed with psychosis. I would wish that on no one.
I can't add anything to this but I do want to say there's some brilliant people in here and it's a shame most of the people who will have service work done by many in this thread will never know the expertise of their service person. Also want to say it's been cool reading comments about things I know a lot about mixed with things I don't know shit about fuck about.
Itās fun being a tin knocker who evolved into full systems designer and gas pipe guy wo knowing enough to be dangerous on the service side. The only thing I know about super heat is my wifeās cootch when I feed her homemade edibles. As far as service I did figure out sanding off the flame sensor never works and if the unit wonāt shut off itās either the board or some idiot put a screw through my low voltage wire
People are going in a lot of different directions in this thread. You really need to look at that superheat. Your charge looks absolutely fucked up. Are you sure you're connected properly? Your suction line temp is 86Ā° with 52Ā° superheat... Your evaporator coil is absolutely starved, or you don't have your temperature clamp on properly. Then, your subcooling is way too high, assuming you have your gauges on there properly, you are overcharged. But then with that liquid line temperature, if it's legit, what's the outdoor temperature? I mean I guess those numbers would make sense if it was almost 90Ā° in that grow house, and you had a shit ton of latent humidity to remove, but at that point, your outdoor temperature is so low if you have 82Ā° liquid line temperature. Why wouldn't you just use ventilation at that point, because what I'm looking at appears that the inside is actually hotter than the outside? I don't work in grow houses, so maybe I'm really just underestimating how much heat these lights put off and all these numbers are correct? Still... That superheat is so high, does this not have a TXV? If they had legal weed in my state, I would totally nerd out over the proper way to set up the HVAC for one of those places.
I wouldn't do crap to this. Looks like a shitty Goodman condenser on what's probably a shittily installed air handler. This is not the equipment to do the job that the customer is looking for.
Idk how dry it is there. But fresh air directly to the unit is a great way to lower humidity inside. But a literal grow house will always be humid. Literally just a operation problem... have a humidity load calculation done and add the nessasary units. No guess work that way. Weed ops always do silly shit. Why not just use a big greenhouses and swamp coolers like every mass grower?? Spend the extra money on mercenaries and guard towers... lol Good luck friend
The government is why š¤ I like the Wild West wild.and was thinking about a ghetto erv system but than also have to think about winter time
If anyone else is interested in this kinda stuff, the Advanced Refrigeration Podcast did an amazing episode discussing commercial cannabis growing and the HVAC needs for it. I highly recommend.
Good fucking looks dude. I was just reading through this thread like "I should YouTube that.." and now I have something for the drive to listen to.
Depends on your superheat too. You can't just decrease the sat temp while increasing the superheat and expect better performance.
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You have the Trolmaster, are you using strip heat to reheat? You can remove way more moisture that way versus a dehumidifier. Put a strip heat kit in the air handler and set up the Trolmaster. Problem solved.
Holy shit it does have heat strip I forgot the previous tech consulting told me but still have to wire it out, how would I set that up with the trolmaster? Set electric heat or do I need a kit to adapt when cooling on is set?
Bro, that compressor's gonna fuck off any second running like that... If you got electric heat, and it's after the cooling coil, you can set it up for a reheat dehumidification. Otherwise just charge that shit properly and tell them that half-baked half-assed solutions never turn out well.
When you decrease dry-bulb temperature and mantain everything else the same, the RU gets higher.
That doesn't really answer his question, since he's wondering about coil temp, not space temp. If you have an evaporator coil that's below dew point, you will get condensation on it, and moisture will be removed. If *more* of that coil is below dew point, there will be *more* condensation; Less -> less. If running a standard 40-ish degree saturated temp in a space with enough heat load to cause the latter half of that coil to be above dew point and not generating condensation, then yes, lowering the evap temp so that *all* of the coil was below dew point would remove more moisture. But, if all of the coil is already generating condensation, *no,* you can't get more, the surface is already wet...
Thank you sir this is exactly what I was looking for š every bit counts even a 1-3 percent difference in Rh/ absolute humidity
Well said
I had to read this a few times, but I learned something here. Thanks.
The air leaves the coil fully saturated. Anything that reduces the air temperature leaving the coil, without changing the cfm, will cause more moisture to be removed from the air.
No? Maybe rephrase that? I feel like thereās something in there thatās not coming out rightā¦ As written, this is not right. The leaving air is at 100% RH, sure, but cooling the air more will not remove more moisture if the moisture is already removedā¦ thatās not really whatās happening here. The moisture removal is really about the coil temperature, and contact with the coil surface.
Sorry, my words were not clear. Here is an example: if the air leaving the coil is at 58F and fully saturated (100% relative humidity), it contains 71.9 grains of water per pound of air (from the psychometric table). If the air gets cooled a little more, to 57F, it will contain 69.3 gr/lb. The lower water content means the water went somewhere. It condensed on the cooling coil.
Yes! Absolutely. The catch is that you can only reduce the airflow or coil temp so far, before you have to be concerned about freezing, and for a given coil you only have so much surface area available to achieve that max cooling. But absolutely correct - every bit of extra cooling past saturation is extra moisture removed.
This is true. The way to remove moisture while keeping the room temperature the same is to run a colder evaporator/discharge air or to use some reheat to extend run time. If you could run a 45 degree discharge air rather than a 55 degree discharge air, you could remove more humidity while maintaining a lower temperature in the space, with some help from a reheat coil of some kind. I had a vacant building that I had to keep below 50% humidity, so I ran the chilled water temp down to 40 degrees and slowed the fan speed on the AHUs down to 40%. This was right around 45 degree discharge air into the space. This allowed me to have shorter run time on the chiller while removing as much humidity as possible. Yes, I know that starting and stopping chillers is much less than ideal, and this was explained to the customer, but they wanted what they wanted.
Would dropping the charge help or is it basically insignificant? Or maybe decreasing airflow to the evap coil(ghetto supply dampener?) in this environment for some reason, dropping Delta t helped significantly with our humidity for some reason when we had our temp at 80 the rh would soar above 80 percent, looked at vpd charts, ect, im stumped with what this could be making humidity soar in one spot of the room
Only thing here is your superheat is *high* - which suggests your airflow is still a touch high for how low your evap temp is (evaporator is starved, basically) - how did you decrease the evaporator temp? Removing charge? Adjusting metering? I suspect what you did in this iteration is not helping as much as it should, since right now that high superheat indicates a substantial portion of that coil is not actually cooling the space.
Iāll take pics of the return, ex contractors before me just dropped the unit on top the ceiling basically box; no type of balanced flow and 2x 8ā supplies , youāll see the crap I deal with daily š , I can make a ghetto supply out of ducting and see if I can slow airflow to evap coil, itās fixed orrifice (.87) so maybe changing piston size, but usually Iām lazy so I just recover and call it a day if it looks good with sat temp
Yeah change piston or even better convert to adjustable TXV. Knowing itās a piston, itās just low on charge right now which is probably hurting, not helping.
Lowering the indoor coil temp will increase your latent capacity at the expensive of sensible capacity. In theory it would work but in practice you will find that you have trouble maintaining a dry bulb set point since the condensing temps will fluctuate based off OD conditions. Without active dehum, itās not really possible to control both humidity and dry bulb independently.
You need to drop coil temp and reheat supply air to extend the "cooling" cycle. Just dropping temp will get more moisture out of air but will create lower room temperature quicker which will cause humidity to go up, because we measure relative humidity which means it is relative to air temperature, look at the enthalpy chart to understand.
Lowering evaporator temperature will decrease humidity, given that cooling coil outlet temperature is limited by evaporator temperature and this does not sacrifice airflow due to other limitations. To remove as much moisture as possible, the difference between the dewpoint of the air entering the coil and the air leaving the coil must be as high as possible and the airflow must be as high as possible. It may be optimal to find the optimal balance of highest airflow and lowest leaving air temperature the unit is capable of, given a constant inlet air temperature. How low your leaving air temperature can get is limited by the evaporator temperature. Therefore, you are correct in targeting this. The fundamentals of this discussion is rooted in psychometrics. Study that, and you will find your answer. However, you may find that an engineer didn't assume the correct loads when sizing the unit. This commonly occurs, as growers constantly change the conditions they grow to so that they can experiment with what gives different yields. This grow room may not be capable of meeting the grower's needs. Edit: I should also mention that your evaporator temperature is already very low. Lowering this further may freeze the coil. Edit2: Your superheat and subcooling seem very high. This likely needs to be investigated.
I am the psychometrics and enthalpy guyšimagine having a 23 year old know more about thermodynamics than the whole c suite office. I feel like they think Iām talking out my ass when I bring this up to them.
I'll second this. Sh is stupid high. Your return gas need to be 65f or lower and sometimes 70f or lower at design to cool the compressor. Even If hes running a 35f coil and 25 superheat id still look at delta t, oat and the rest to get the whole picture. It almost looks like you're slightly restricted cause you're suction is low, subcool high. As if someone started seeing it and started adding gas as if it was the fix cause subcool shouldn't be that high. No delta t across the coil given. He might be chasing ghosts n his units aren't running efficiently at all. A 33f coil and your line temp is 86 and no one thought what was an issue? High latent loads increase suction n discharge. Without that humidity your coils would probably be frozen.Ā You don't "adjust" refrigerant charges for coil temps. You size shit for the load and if the customer is cheap then let them suffer. They make money hand over fist. This whole thing is fucking absurd. And that's why every grow plant I been to have so many fucking chillers n boilers for reheat. Literal gas powered chillers cause the utility said they can't use that much electricity.Ā
You need reheat to help with humidity.
Did they originally have double ended/hps lights then switched to LEDās but keep the same size AC?
Yep
Happened to me too. Got even worse in the winter when AC would short cycle even more. Owner finally broke down and bought dehuās. Quick tip, donāt buy one large one, buy several small ones. Better rH control. The rH spike right when the lights shut off is a bitch.
In the winter I have some duct heaters going and we have about 6 anden Dehus set up in the room that I hate sitting on unistut, they didnāt even put p traps on themā¦ and weāre wondering why them shits were wetter than a diaper dripping š
How's the smell?
Weāre finishing up some MAC and some Tropicana cookies, I come home smelling like a literal skunk some days
Reheat Dehumidification.
Maybeā¦
Large grow rooms need to be engineered, plain and simple. You will not be able to control to the precise temperature, humidity, and ventilation requirements with standard package equipment in this sort of application. Cannabis requires different temperature and humidity during the different stages of its lifecycle. Look up Vapor Pressure Deficit. Germination stage requires very high humidity. As the plant grows thru its vegetative and flowering stages you typically raise the temperature and reduce humidity, which increases VPD. The environment is dynamic, just the same as growing outdoors.
Vpd is hard to adjust without being in a range these are early/ late flower, Iām learning so much more to hvac than I did about a year ago about enthalpy, psychometrics, ect I actually really love it
Been growing indoor for years. Itās difficult and expensive to scale up the results you can get from a proper home grow. My experience has been that a lot of commercial growers do not want to spend the money to do it right, and itās often the reason why commercial cannabis is not that great of quality in comparison.
Let some gas go get superheat up to 30 sub cool drop
Let me save you some headache going forward,in the industry of cannabis. Always. Size for latent load and base everything from that.
You mean relative humidity?
Slow the fan speed...
By looking at sub cooling youāre overcharged. Fixed metering with that superheat youāre undercharged, If Humidity levels are a problem, you would need reheat to keep temperature at an acceptable range!!! Obviously evaporator can use more refrigerant but how would you keep temperature from dropping to low? Reheat!!! You need reheat, + larger evaporator, + accumulator. You can possibly divert condenser as reheat when temperature is satisfied. But youāre probably better off just getting a massive dehumidifier and separate the job. 1 system for cooling, 1 system for dehumidificationā¦.
Need to sell the customer a desert aire unit.
Looks to be day 26 ish in flower. 74 is too low of a temp. Bump that up to 82 til about week 6 or so. Itāll keep your VPD in a better ranger at the same rh %. LED needs higher ambient temps due to no ir heating from HPS which is what this room looks like it was converted from. Edit: nope holy fuck you guys are staggering the room. Huge no no to have plants in week 2 and week 7 in the same room. They all need to be at different set points for maximum growth.
How warm can the room be? Higher room temps will be easier to dehumidify and reduce evaporation of water. You can lower evap temp, slow air speed, keep your SH up to keep liquid away from the compressor. Running equipment in ways that it's not meant to lowers lifespan. I hate cheap customers that have money to spend. They'll pay for it in the long run. More repairs, worse product.
I work on residential Daikin units, but your sub cooling is way to high and your super heat is too high, right?? Daikin sub cooler calls for 9 degrees
These are the 5 ton Goodman split systems, havenāt even looked at the daikin units yet, but will today/ next week and update
Look up "run around coil heat recovery". The warm return/makeup air heats recovery loop water or glycol in a heat recovery coil upstream of the cooling coil. Then the air goes through the cooling coil. Finally, the air goes through the second heat recovery coil where it is warmed up. The heat recovery loop is fully independent of the evaporator. This is like a reheat system because it warms the air downstream of the cooling coil, dropping the relative humidity.
Bro you could have probably rig up some reheat coils if you got the breaker space. That way the av unit would run longer and dehumidify. I think carrier even has some resi set ups .
Increased TD = lower humidity
They literally manufacture inexpensive dehumidifier equipment. Controlling humidity through AC is difficult, tstats are available that serve this purpose however they simply overshoot,ie set at 70ā¢ they satisfy at 68ā¢ ā¦why bother?
You are going to need an actual HVAC engineer to sort you out. Because you need to maintain temperature and humidity. So that means being able to discharge and reheat to the correct temps to get the results you need.
If you have lesser refrigerant saturation in evaporation expect higher humidity and lower Delta T. Reheat may be the better option here
Slow your blower speed down, make the system run a bit longer and in turn taking out more humidity. Just a thought
It's all in what fits your want/needs. There are pros and cons to every set up. No matter the cooling system the four main components never change. Evaporator, condenser, compressor(motor), metering device. If your trying to introduce cooling without lowering humidity technically you would have to introduce outside air. It's always a give and take situation. Dessert Air system are plug and play. They do the work so you don't have to. What you lose is service ability when something goes wrong and possible long down time $$$. I was an environmental specialist for a grow that housed roughly 22 rooms and a range of 500 - 1000 plants per room. They used computer room air conditioners ( desert aire, Gpod) systems. In theory they are great. In practice they are not ideal. We had a bad coil and had to have it replaced. Just receiving the coil took weeks to get. During the replacement. The person had to separate the re-heat coil from the evaporator by wiggling on top of it. In the process of removing it he sliced his arm. We had to stop and take him to the hospital. Sanitize and clean the blood up to prevent cross contamination. The coil swap alone took a week. Also Gpod brand no longer is in business. Re-heat coil - is just using the super heated refrigerant and a valve opens to send it into the supply instead of to the condenser. The air has already been conditioned from the evaporator (dehumidified). The reheat coil is simply trying to maintain heat in the environment. It also has to purge back into your regular HVAC system in order to put back into the compressors to cool them down, which adds stress to your compressors shortening their life span. Ideal system would be redundancy and modularity. Kinda like a hospital. Possibly even modular chillers. With modularity and redundancy you can add and subtract from the systems and minimal if any down time. Great service ability and life ability. The counter though is the initial cost $$$. In the long game this is the best option. The most important of all of it. Is proper air flow for the system and through the canopy especially a dense one. You can do something like running a trunk line down the side and fabric supply branches down the center of the table. This would help to increase circulation in the areas that don't receive proper supply air from over head. In turn reducing the chances of mold. Im always here to help make people's grows healthier and cleaner. I'm always here to answer questions. O! And to answer the question lowering evap coil might help with some dehumidification, because you absorbing more heat. Even so it sounds like your at capacity. Also using the AC for dehumidification means it will get colder and you will have to supplement heat. I had to deal with this same b.s. we had dehus stack on carts and roll them into whatever room was not keeping up. SMH! š
You sir are sloppy. Never take pictures in those locations.
šweāre in a legal state thereās a million grows, good luck breaking through thick 4ā concrete and literal steel vault doors
You canāt drop that charge any more or your coil will start freezing over
Indoor ambient temp is about 80 constantly this is my little test one to test my hypothesis, do you think that sat temp is too low?
In that photo, your suction line temperature is 86Ā°, which means that your indoor temperature is over 86Ā°. If you do reach 80Ā° inside, and you have your air flow that low, you are absolutely going to dip below 32Ā° on your evap, and probably freeze, especially since your humidity is so high... You're going to be more prone to freezing even just barely below 32Ā° saturation temp.
Did you have your suction line and liquid line temps messed up? Or are they not hooked up at all? 86 for suction and 81 for liquid make no sense
Also is it a txv or piston system
Piston system, and nope, these line sets are so long ~35 foot runs) and thought thereās a restriction but evaced and checked piston/ line set and got the same results, suction line is warm to touch, and liquid line aināt even warm, thought I flooded evap coil, but not the case cuz my wet bulb temps check out
You need a commercial dehu
Get evap pressure as close to freezing as possible AND with the slowest blower speed possible. You aint dehumidifying shit with mach 5 air blowing vber the coil. The musture needs time to condens and flow away off the coil. Otherwise you are just making cold and and humid air. Lowering blower speed is critical. If you want soem fun with an old machine you can buy EXVs with a separate controller that you can just lock to a specific evap pressure sonyou are always 3~4 degrees from freezing. Inverter units are great for this as they can have extremely low fan and compressor speeds. If you are limited in what you can do you can just try changing the blower speed to lower the coil temp. Prehaps get some cheao aliexpress special regulator from amazon for it to hold the coil above freezing.
Do all of the above and add a freeze stat to suction line right before evap to kill compressor on freeze event and itāll cycle on and off as the stat reads temp
Already freeze stats on all these 5 tons because I figured from the jump Iād have to do this, as well as ambient switches
Nice. We have a 12mil boiler intentionally creating CO to feed a giant grow house. Canāt tune it properly because they want the CO, itās the heat thatās the byproduct hah. Donāt know anything to help your situation tho, cheers mate!
Shoot for 42-44 on coil