HELP me CHOOSE A NEW A/C please

[inreplyavalon]

Good day to you folks.

I am in the process of upgrading my room from 5400 watts to 9,400 watts.
I currently am using a frigidaire 25,000 btu window unit.

I am running co2.

I am looking to purchase a SPLIT a/c but i live in a wintry, snowy climate and need to make sure this thing will work when it is cold outside.

My research is telling me i will need a 50,000btu setup.

anyone out there ever deal with a situation like this? Any advice?

 

[dunkydunk]

Well, you are beyond the capacity of a mini split as they top at 25-30k btu. Their low end operating temp is around 15 degrees F, but I think they can be made to work lower with the addition of heating jacket or some such thing. You could think about using two mini's to get you to your needed btu's, but you'd probably be best served by a more serious unit, the kind of thing a big restaurant would use to keep their cold room cold all year round. I'm not sure where you would start looking for something like that.

I have two mini splits, for two different rooms, but 15 degrees would be a rare cold snap for where I live.

 

[Securityfirst]

How are you running co2 , what kind of lights do you have any pics?

 

[milehighmedical]

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[Midnight]

Good day to you folks.

I am in the process of upgrading my room from 5400 watts to 9,400 watts.
I currently am using a frigidaire 25,000 btu window unit.

I am running co2.

I am looking to purchase a SPLIT a/c but i live in a wintry, snowy climate and need to make sure this thing will work when it is cold outside.

My research is telling me i will need a 50,000btu setup.

anyone out there ever deal with a situation like this? Any advice?

http://www.frigodesign.ru/sale/sporlan/HeadPressControl_Sporlan.pdf

"The typical method of maintaining normal head pressure in a refrigeration system during periods of low ambient temperature is to
restrict liquid flow from the condenser to the receiver, and at the
same time divert hot gas to the inlet of the receiver. This backs
liquid refrigerant up into the condenser reducing its capacity which
in turn increases the condensing pressure. At the same time the hot
gas raises liquid pressure in the receiver, allowing the system to
operate normally."

 

[inreplyavalon]

Dunky Dunk thanks for the restaurant idea. Do your two units work down to the rare 15 degree day? I suppose i could easily run my lights during the day, but mornings and evening can definitely get COLD round here.

Securityfirst, i am running a sentinel co2 generator. It is a two burner unit and perfect for my 13x13 foot space. It is hooked up to a sentinel controller. The lights are two rows of 3 and 4 1000w. and i am looking to add 4x600w running down the middle aisle, bare bulb.
So its one row 3x 1000 and another row of 4x 1000 these are all horizontal in hoods, and i want to hang 4 600's vertical down the middle. I can swap out some of the horizontal 1000's for 600's in order to keep the temps down if need be.

Milehigh i was looking at the excels. It says they work below 40 degrees, but does not say how far below? Not sure i have a space i could build a closet for the unit. Maybe in my veg room, but having it outside would work best. Stealth noise is not much of an issue as there are not many folks living near me. Though i would be concerned about the temperature outside. I am running a co2 generator.

midnight not sure if your educating me or suggesting something? A bit too technical for my simpleness. Though thanks.

 

[dunkydunk]

Dunky Dunk thanks for the restaurant idea. Do your two units work down to the rare 15 degree day? I suppose i could easily run my lights during the day, but mornings and evening can definitely get COLD round here.

To be honest, I haven't had to find out yet, but if this cold snap we're having now keeps up, I may find out.

Split units rock, they are virtually silent, and perfect for co2 as there is no air exchange outside the room. But you should know straight off, they are a much more involved installation than a window unit. I installed both of mine DIY, and you have to run some heavy wiring back and forth, and I had to buy a vacuum pump to do the refrigerant side, as getting an HVAC guy in was out of the question. Most units come pre-charged with enough refrigerant to fill 25 ft. of line, but after that, they need to be topped up, which is more technical than I was willing to undertake. I was lucky both times and didn't need more than 25 ft of line between the indoor and outdoor unit.

As for keeping the unit warm, you could build a shed outside for it, so when it's cold it can keep itself warm, and when it's warm outside you take the walls off so it can keep itself cool. I'm speaking on a seasonal basis, not a daily basis.

I bought my units from 2 different suppliers, and GreenDroplet.com was by far the best, on both price and service.

 

[RedRain]

general rule of thumb is 3000w per ton of cooling

get a heatpump mini split with inverter technology it will work up to -10c or 15f. Thats for a fujitsu 1.5 ton mini split heatpump. When you go to a larger mini split heatpump they work up to 18-20 f. You can install an ICM fan controller to manually adjust the fan speed, but it will void the warranty, but I have seen it done with good results.

You can easily get an air to air split (what a normal home ac outside and air handler/furnace inside) AC to work in -25c weather. You need a crank case heater, which heats the oil in the compressor to avoid moisture mixing with the oil, and to keep the oil warm. A condensor fan switch. On a r22 machine, you only want the fan to come on when the head pressure reaches 220-250 psi. This will allow the condensor coils to heat up and not allow ice build up. On an r410a you set the switch to 350psi. If your unit has 24v safety switches, you need to bypass the low pressure switch for 2 min on startup. When its -25c outside, all the refrigerant will log in the coldest area (condensor coil, outside) and the machine will think its low on refrigerant and not start.

The inverter on mini splits allows the fan to not spin as fast, to regulate the head pressure of the unit. This allows the coils to not freeze up in low temp operations. If you choose to use a mini split, make sure u get a heatpump model with inverter. Also make sure the unit has threaded brass quick connects that are sealed. If you get a unit with flared fittings, you will need a vaccuum pump, vaccuum guage, and HVAC manifold to bring the lines down to at least 500 microns.

They do make water cooled a/c, that have no outdoor unit and uses a closed loop water supply to act as your condensor unit. No added mositure is brought to the room since the water supply is in a closed loop system. They come in 2-6 ton capacity, and work very well.

Do not build a shed or stucture around your unit. The unit sucks in air and evacuates hot air through the fan. You need air flow across your outdoor unit, or you will have issues. Once the air in that box gets too hot, the unit will not be able to drop the head pressure. Not only will it no longer cool, but you are putting excessive stress on the system. The machine creates cold air inside, and produces hot air outside. That heat has to go somewhere!! I have seen people put their condensor unit in a cold garage, but this only works for a few hours before the units cooling capacity starts to drop off and stop cooling all together.

I gave you the proper way to "winterize" a unit. Thats the way professionals do it, and the only way to do it. The people who are giving you this advice, obviously have no understanding of how a A/C sytem works. You cannot put the outdoor portion or the unit inside. Why do u think its called the outdoor unit? LOL. If you are spending all this cash on a unit, and want it to work. Set it up properly!! Sorry I hate to see advice that is given that is completely wrong!! Doing these things like building a shed around your unit will set u up for disaster and compressor failure.

Hope this helps!!

 

[milehighmedical]

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[RedRain]

Red Rain -

You can definitely put the "outdoor" unit inside. It's just that you can't "just put it inside". Whatever enclosure its in will obviously have to ventilated, like I said. How do you think an A/C box on a window A/C works indoors? The heat is ventilated. The A/C is just acting as a sealing barrier so that CO2 can be used. The same amount of heat still has to be ventilated, one way or the other. If you place the unit outside (as it's intended) the ambient air flow outdoors will be enough to cool it, obviously. But that doesn't mean you can't put it indoors if you use the correct CFM.

Don't tell me I'm wrong, when I'm not or that I don't have the understanding of how an A/C works, because I'm not and I do. The method of enclosing and ventilating that portion of an A/C system has been used for many years, and is still used today, and it'll still be used tomorrow. There have been many large commercial build/grows on IC where this was done, successfully.

P.S. - I think you misread my post, and thought I suggested it was enclosed WITHOUT ventilation, which I agree is completely impossible to use in such a configuration. But, I did not in fact suggest anything of the sort.

P.P.S. - inreplyavalon - I understand that you're tight for space, but the enclosure is the best way to control the temperature of your A/C unit, allowing it to function. We have 15F in Colorado frequently, but it'll also drop down to -40F on that rare occasion. So it's totally insane to run a unit outdoors year around. But, since you don't have the space: If you have a functioning setup with your 25,000 btu A/C... I'd just recommend getting another one for now. That'll save you a small fortune on mini-splits, etc.

i was really talking to dunky dunk and posting some good, knowledgeable information, but you aren't 100% correct either

oh really? what makes you think you can safely run an outdoor unit inside?

Unless you own a set of gauges, manifold and have a good understand of what refrigerant you have and how an ac system works, I wouldn't do it.

as i stated do you even know how an a/c system works? You are strangling the A/C and raising the head pressure of a unit. Sure it may work,but you are stressing out the ac and doing it wrong!!! If you had any understanding of how an ac system worked, you would know what i was talking about. Do you acually think that building an enclosure around a condensor is the right way to do it? Your completely wrong!! Raising the head pressure above the max running pressure of r22 or r410 is not going to be good for the compressor or the coil. You have to have control over the condensor fan to not come on until the head pressure is above 200psi or 300psi depending on the refrigerant, allowing the coils to build heat, thus allowing the unit to build pressure and cycle properly. If your compressor is working and that box gets too warm, or your ventilation system cant keep up, you're damaging your ac.

Even if you are venting the hot air from the outdoor unit, its still robbing you of BTU's and lowering the cooling capacity. You would need an area to keep the CFm's of the motor up to allow proper air flow across the condensor coil to bring the refrigerant down to a temperature where it can re-condense into a liquid. I bet you didnt even know that! Why spend all that money on a system and butcher and throw away cooling power? Then you have to worry about when there is not a big load on the ac, and the compressor cant run at its proper pressure, which effects the temperature and the expansion of the refrigerant, which starts to MESS THINGS UP!!!

You are doing it wrong, and passing around misinformation. There may have been people building threads about boxing their outdoor condensing units, but its unsafe and not efficient at all. I have attached a pic of the outdoor condensing unit. The proper way to have your unit running at normal operating pressures, which is safe for the compressor, and the unit will crank out its rated BTU's is to use a crank case heater, and a condensor fan switch.

I guess in your state they half ass things and ghetto up your ac system. I can setup an ac system to run in -25c with the 2 items i mentioned above. The unit will work fine and the system will be running at 100& capacity. Who on earth would go to the trouble of buidling a vented enclosure around their AC to only loose cooling power and greatly shorten the life of their system?? Any HVAC newbie or tool carrying 1 st year apprentice knows that you simply install a control and a compressor heater to winterize a unit. A hillbillie would build an enclosure and vent it. You are trying too hard!

Even if its -50 F, the crank case heater and condenser fan switch will work fine. If you have 24v safety's you need a lowpressure bypass for the first 2 min of startup.

Do you not think people use A/Cs to cool stuff legally in the winter? Maybe a server room? Do you think they build a box around their a/c sytems?? LOL

Good day to you folks.

I am in the process of upgrading my room from 5400 watts to 9,400 watts.
I currently am using a frigidaire 25,000 btu window unit.

I am running co2.

I am looking to purchase a SPLIT a/c but i live in a wintry, snowy climate and need to make sure this thing will work when it is cold outside.

My research is telling me i will need a 50,000btu setup.

anyone out there ever deal with a situation like this? Any advice?

you are correct, a 4 ton would suit you well. go with a 4 ton air to air split, and inquire about a winter kit. do you pay for water? if water is not a problem look into a water cooled ac. no outdoor unit and its a 1 piece system.

there really is no reason why to go with a mini split for that many watts. mini splits lack airflow that an airhandler provides. with a real airhandler, air to air split you will have 1600cfms of cold air blowing out of the indoor unit. a mini split will come no where close to that. you have to generally oversize a mini split, due to poor air flow. the indoor portion of a mini split cant put out the same amount of air.

btw mini splits are available up to 5 tons. They are commonly used on the sides of buildings etc, or when you have no ducting and you want to cool a few rooms. They are commonly called "ductless" splits, I bet you can tell why! You dont need or want a large rooftop ac unit, thats overkill.

 

[Midnight]

midnight not sure if your educating me or suggesting something? A bit too technical for my simpleness. Though thanks.

The example I showed explains how to run he ac in the winter.

 

[dunkydunk]

I think you misread my post, and thought I suggested it was enclosed WITHOUT ventilation, which I agree is completely impossible to use in such a configuration. But, I did not in fact suggest anything of the sort.

Nor did I intend to suggest anything of the sort.

InReplyAvalon -- What RedRain has posted is what I meant by 'a more serious unit,' and he's right, even if he is being a jerk about it.

 

[RedRain]

I just hate seeing half assed, potentially dangerous information.

I am just trying to pass on knowlegeable, and safe information.

its not a more serious unit, its the right way and the only way to run an ac in the winter. other methods are foolish and risky,not to mention that you lose cooling capacity and stress the unit.

 

[mg75]

ThermoPlus is what professional BC growers use.

 

[RedRain]

^^ thermoplus makes a great unit!! water cooled ac's are the bees knees!!! no outdoor unit, super stealthy.

no linesets, and you can dolly it into a shop if it breaks down for servicing!!

 

[milehighmedical]

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[Dr. Buddington]

I have seen two 5 tons split AC's used in a warehouse setting with the outside heat exchangers INSIDE the warehouse. The warehouse had huge blowers that would activate through a thermostat in winter and just run 24/7 in summer month.
Excel Air also says that you can put your outdoor unit inside a building and run a huge duct with a booster fan from the fan on the outdoor unit leading to the outside for exhaust. You need to use something like 1000CFM per ton of cooling.

 

[inreplyavalon]

^^ thermoplus makes a great unit!! water cooled ac's are the bees knees!!! no outdoor unit, super stealthy.

no linesets, and you can dolly it into a shop if it breaks down for servicing!!

I read the specs on these. Could they use 5+ gallons of water a minute? Thats insane if I read it correctly.

 

[RedRain]

It's just that the method I mentioned works for me and many others. So you can huff and puff about all your HVAC knowledge and experience all day long... but it doesn't change the fact that my shit works.

The main reason I put the A/C entirely inside is to be a bit more discreet. The house already has it's own big A/C unit outside. I can't be putting another big one next to it, or hanging a bunch out the windows. Having control over the temperatures of the enclosure is just an additional benefit I enjoy.

So, I'm sorry if I suggested something that you think is totally unreasonable to suggest to another grower. But thank god my plants don't give a shit what you "know" about HVAC.

i was trying to help. you might think it works and whatever, but you are hurting your ac and running it at a higher head pressure than it was desinged for, but you dont seem to care. Theres doing it the right way, and doing it the wrong way. Jsut cause you and your friends have been doing it for years doesnt make it right. Dont tell me that my years of school, tickets, courses and many hours of work dont mean anything. You cant take some helpful advice because it goes against what you and your butcher friends do. Go ahead and run your ac into the ground. See if I care. I am passing on the knowledge that I have gathered and learned. Maybe do some reading and learn about how an ac system works before u flap your gums about what you did, not what you know!

Do whatever u want, dont take my advice!! I am in the trade so I am trying to help some people out with knowledgeable safe advice.

If you want to half ass hill billie it follow this chump, or do some research and educate yourself and you will see what I am telling you is correct. I see and hear this so much, well I have been doing it for 20 years. Yea you have been doing it wrong or half assed. You must take your car to get serviced and tell the mechanic how to do his job too right?

I will definitely interject when I see someone offering poor advice that will surely damage and stress my A/C unit, which is the heart and most expensive part of a show!!

I read the specs on these. Could they use 5+ gallons of water a minute? Thats insane if I read it correctly.

ya that sounds right for a 5 ton thermoplus......in BC they are quite common....i know some people that run 2X 5 ton thermoplus and pay for their water...