Cooling a warehouse with no ventilation?

[gettogro]

Ok so I am looking at a warehouse space that is roughly 25x50 14' ceilings. It is going to be tricky for me to make this work. I cant put any condensers outside the building and it has to be stealth from the outside. It looks like my only ventalation is from the gas heater that has what looks like a 4" vent to the roof. This would be my only way to exchange air from the warehouse. How ever I am in a very cold climate and the back 1/2 of the space is underground.

I want to build 2 side by side rooms to run on a flip flop with 6 to 9kw each
air will be constantly circulated between both rooms 1 lights on 1 lights off
Each room will be roughly 10x15 8 ft ceilings
I want to use a 5 ton a/c to cool the bare bulbs
All ballasts chillers exc will be outside the grow space

I want build the sealed rooms inside the warehouse and use the ac condenser to heat the rest of the garage

So the warehouse is 17,500 cu ft
the 2 sealed rooms 2500 cu ft

that leaves 15,000 cu ft for the 5 ton condenser, chillers, ballasts, exc to heat

Will this work? Is there a way to figure out how hot the rest of the warehouse will get?

I believe that gideon is doing something similar and it is working for him, he says his garage gets pretty hot but works great.

Here is the annual climate where im at.

I might be able to get a 200 cfm exhaust fan through the existing gas heater to pull cold air in from cracks in the overhead garage door and blow it out the roof. probably wont be much help at all but with a carbon filter will help keep negative pressure on my unit

Im hoping some cooling experts can help me figure this out.

thanks
g

 

[gettogro]

I was also thinking of using 4 2400btu 13 seer inverter minisplits.

2 in each room. while constantly exchanging the air between the lights on lights off rooms, will help maintain a closer day/night temp.

either this way or a single split 5 ton unit with motorized dampers, however I like the idea of 4 minis..

 

[TrichromeFan]

Are you sure that you can't add one exhaust vent on the roof? Just for equipment cooling? Use outside air for the inlet to the equipment room so there is no smell issue. Just remember that you have to get that heat out of the building somehow. If you are the only roof in the winter that all the snow melts off of, that is not so stealth from the outside. Just a thought.

-TF

 

[squarepusher]

dont think its gunan cut it

 

[Nobodynobody]

Know how you dont want units out side. I highly recommend split type that can have ducting inside. Place the out side unit on the roof. People do it all the time.

Another thing is bringing a roofer in to make a 16" hole

 

[SweetTooth]

Do you have access to a free water source? If you do you could always run a heat exchanger drain to waste.

 

[gettogro]

There is a unit above mine so I cant run ducting through someone else's unit. I am on an end unit but I don't really want a 5 ton condenser on the outside. It would be obvious. no one has ac up here.

I was hoping to just use the heat from the condensers to heat the garage. If the garage temp is 50 degrees, with the a/c's running how hot will it get? 80? 90?

Im sure there is a way to figure it out.

I wish I could plunk them on the roof but I wanted to avoid permits and nosy neighbors.

 

[gettogro]

Do you have access to a free water source? If you do you could always run a heat exchanger drain to waste.

Nope

 

[gettogro]

I used this btu calculator to figure what it takes to heat my garage.

http://www.hearth.com/calc/btucalc.html

I pluged in 25x75x8 to give me 15,000 cu ft, cold climate, with average insulation.

Say I need between 30,000 and 60,000 btus

So with the heat from the condensers of 2 24,000 BTU mini splits running what is the heat output. 48,000 btus? which puts me right in the middle according to the calculator.

Im sure there is some difference for efficiency , But I think im on the right track. maybe

 

[TrichromeFan]

You may have something there with the garage. The only bummer is that it will heat it the most in summer, not winter.

-TF

 

[Nobodynobody]

I feel you brother. I tell my people that ask, Oh it does AC and Heatting, it has to turn on the landlord say. Just make it up and remember You know more then them. For vents. Call it OH its for the Water heater. OH its an attic vent to let the heat out in the summer. Dryer vent. gas heater vent. Bath room shit fan. Kittchin fan above the stove. List can keep going on and on. Start looking at them Strange if they are asking to much. Place them on the spot. Thats is my word of thought. Screw the others. They don't pay for anything to make Life better. I look out my window on a 130f day. just people having a window open...no thank you.....I rather start making fun of the other person. Change the spot light on there house. Control the air wave like we control the air in are rooms!

 

[Chillville]

Well that is a little tricky for sure. First thing that I would bring up is that a 5 ton is a little heavy 6k watts per room. Your compressor cycle time may be too short. If you were only using 6k per room I would recommend a 3 ton and if you were doing 9k watts per room I would recommend a 4 ton. If using a traditional a/c system mounting the condensers inside the warehouse area simply won't work properly. Without outside air exchange the warehouse would heat up more and more every hour. With a 24 hr light cycle there would never be an opporitunity to cool down. If using 6k watts at a time you would be putting about 2 tons of heat per hour in the leftover space from the condenser alone, then 1 ton for the ballasts...with 9k watts you are looking at almost 5 tons of heat including the ballast. This is per hour and the heat will build quickly and will decrease the a/c efficiency, the warmer it gets the more BTU's you lose.

A simple solution is a water-cooled a/c or a water-cooled chiller system. You can hook up municipal water and run it to the water-cooled unit drain to waste. They are designed to only use water while the compressor is running and usually use about 3-5 GPM. An idea to save water is to use the extra space in your warehouse put in a large reservoir for the water-cooled unit. Circulate the water from the water-cooled unit back and forth from the reservoir. Once the reservoir gets too hot to use anymore (about 100 degrees) switch to a standard drain to waste until the res cools back down and then start using it again. The heat will dissipate in the warehouse area but will do it over a couple of days instead. You could even put some heat exchangers with fans inside the warehouse to keep it warm while cooling your water at the same time. The fans can be setup on heating thermostats so you could keep the warehouse the exact temperature you want.

I would recommend a water-chiller system because you can actually setup 2 air handlers on one chiller, no need for dampners etc. Each room would have its own temperature control and humidity control this way.

What about a veg room, did I miss something?

 

[gettogro]

Thanks for the replies

Well I guess it just wont work.

I dont have access to running water.

I really dont want to put an ac compressor in plain view, maybe I can put it in a small vented house or something. I would love to put the condensor on the roof of the above unit, but I would have to bring in a crane or something on a sunday morning to get it up there.

Also keeping everything self contained I could avoid getting permits for the HVAC and do it all myself.

I was looking to purchase the unit in a warehouse condo type development. The owner would carry the note and once I owned it I could do anything I wanted in there. I just dont want the neighbors to know what was up, and a 4 ton ac compressor would stand out big time. If I invest 40k in building it and then I cant grow there for some reason I would be fuct. The owner was cool I just am not sure about the neighbor complain to the association about the A/C.

Then again I could just pull the permits and do it the right way and ask permission from the board to put it the A/C. After all im only going to grow 12 plants.

Ill have another chat with the owner/developer tomorrow

 

[CannabisJohn]

I used this btu calculator to figure what it takes to heat my garage.

http://www.hearth.com/calc/btucalc.html

I pluged in 25x75x8 to give me 15,000 cu ft, cold climate, with average insulation.

Say I need between 30,000 and 60,000 btus

So with the heat from the condensers of 2 24,000 BTU mini splits running what is the heat output. 48,000 btus? which puts me right in the middle according to the calculator.

Im sure there is some difference for efficiency , But I think im on the right track. maybe

Actually for each 12k of cooling the condenser ejects 15k of heat. So 48k of units eject 60k or so. I have seen a 2 car garage on a 65F day be at 95F with only 2 tons in it.

 

[Chillville]

Actually for each 12k of cooling the condenser ejects 15k of heat. So 48k of units eject 60k or so. I have seen a 2 car garage on a 65F day be at 95F with only 2 tons in it.

Hey John, I knew that the condenser put out more heat than it was removing from the air handler but I didn't know how much, I will keep this in my back pocket. Thanks

 

[Chillville]

GG, I would reconsider that spot if you have no running water. I'm assuming that means that you don't have a drain either. That alone is going to make it hard to garden, you will be bringing in lots of water for that amount of lighting...that shit will get old quick. You could always keep a large res and have water delivered once a month.

I think to keep things low key I would go with the 6k watt setup and use the 3 ton a/c system, they are really small and light too. You could rent a scissor lift to put the unit on the roof instead of hiring a crane. You could be in and out pretty quickly with some planning, maybe 30 mins or less from unloading and loading of the lift. Just run your refrigeration lines down the 4" heater vent tube down to the air handler. ChillKing just came out with a/c's that are plug and play, precharged units with quick disconnects that you don't need a license to install. Essentially being able to do this project all yourself. If my neighbors were to ever ask about my chiller my story is that I have a server room with lots of computers and they have to stay cool. If they want to see I would tell them the servers stored medical records so I couldn't let them in. Seems plausible but I've never been asked.

Make sure to get a compressor heater for your a/c with those outdoor temps.

 

[gettogro]

GG, I would reconsider that spot if you have no running water. I'm assuming that means that you don't have a drain either. That alone is going to make it hard to garden, you will be bringing in lots of water for that amount of lighting...that shit will get old quick. You could always keep a large res and have water delivered once a month.

I think to keep things low key I would go with the 6k watt setup and use the 3 ton a/c system, they are really small and light too. You could rent a scissor lift to put the unit on the roof instead of hiring a crane. You could be in and out pretty quickly with some planning, maybe 30 mins or less from unloading and loading of the lift. Just run your refrigeration lines down the 4" heater vent tube down to the air handler. ChillKing just came out with a/c's that are plug and play, precharged units with quick disconnects that you don't need a license to install. Essentially being able to do this project all yourself. If my neighbors were to ever ask about my chiller my story is that I have a server room with lots of computers and they have to stay cool. If they want to see I would tell them the servers stored medical records so I couldn't let them in. Seems plausible but I've never been asked.

Make sure to get a compressor heater for your a/c with those outdoor temps.

There is a 3" pvc pipe that I have access to in my unit that is the drain run off for the roof that goes to the sewer. There is also a common area bathroom where I can run a hose from to fill up my tanks as needed. 2 6 plant of my diy UC's would use around 100 gallons a week give or take.

I just got an email back from the seller and he says I can put the a/c where ever I wanted. Thanks for the tips on the sizzor lift and the compressor warmer. last winter my minisplits quit working on night when it was like -20 but fired back up the next day. luckily just the air from the cool tubes was enough.

I will be having my race cars and all my tools there in the front 1/2 of the shop. I build custom turbo kits, roll cages, and custom fiberglass body parts. I need that large "heat pump" to maintain temps to properly cure the fiberglass in the winter. I might just be paranoid nobody would probably even notice or even care anyways.

If I can get it on the roof how about the snow build up around the unit. Is there any precautions to take? We got 500+ inches of snow last year. Or will the condenser coil just melt the snow around the unit to give it the air flow it needs?

Glad we got this new forum, you guys are a big help. I am pretty determined to make this happen. Once I get new lines pulled from the meter, there is only a 60A service in there right now, it will be balls to the wall. I want to have the rooms up and running in 30 days.:rasta:

 

[Chillville]

Ahhh I see, that makes more sense. That's really convienent to have the 3" drain pipe in there at least. Also great excuse for having the "heat pump" running in the winter. Since you build turbo's then your room is probably going to be badass. Please post some pics later if you don't mind.

I wanted to explain why a/c's without heaters stop working in winter in case it helps anyone reading. Your minisplits probably didn't turn on because of the low pressure switch that monitors freon. It was actually cold enough to make the freon contract lowering the overall pressure in the system enough to keep it from running. The compressor heater helps keep the pressures up and the most important thing that it does is to keep the oil inside the compressor fluid, this extends the life of it and can keep from cratering if the oil is too thick. Everyone should be using a compressor heater if using it in below freezing conditions!

If the a/c is running then I don't think you need to worry about the snow. I'm from the south so snow isn't a problem for me. Hopefully someone can chime in from up north that can tell us for sure whether or not it would be a problem.

 

[CannabisJohn]

Hey John, I knew that the condenser put out more heat than it was removing from the air handler but I didn't know how much, I will keep this in my back pocket. Thanks

That is reason why chillers normally require 2.3 gpm/ton on chilled water and normally about 3 gpm/ton on condenser water side. This assumes 10F delta T on both sides.

 

[CannabisJohn]

There is a 3" pvc pipe that I have access to in my unit that is the drain run off for the roof that goes to the sewer. There is also a common area bathroom where I can run a hose from to fill up my tanks as needed. 2 6 plant of my diy UC's would use around 100 gallons a week give or take.

I just got an email back from the seller and he says I can put the a/c where ever I wanted. Thanks for the tips on the sizzor lift and the compressor warmer. last winter my minisplits quit working on night when it was like -20 but fired back up the next day. luckily just the air from the cool tubes was enough.

I will be having my race cars and all my tools there in the front 1/2 of the shop. I build custom turbo kits, roll cages, and custom fiberglass body parts. I need that large "heat pump" to maintain temps to properly cure the fiberglass in the winter. I might just be paranoid nobody would probably even notice or even care anyways.

If I can get it on the roof how about the snow build up around the unit. Is there any precautions to take? We got 500+ inches of snow last year. Or will the condenser coil just melt the snow around the unit to give it the air flow it needs?

Glad we got this new forum, you guys are a big help. I am pretty determined to make this happen. Once I get new lines pulled from the meter, there is only a 60A service in there right now, it will be balls to the wall. I want to have the rooms up and running in 30 days.:rasta:

Most a/c units will not cool below 0F outside. The main reason is that the differential pressure within system will not be high enough to properly flow refrigerant. There are some manufacturers who make units that can cool lower for computer room applications. They are very expensive. If you need more info let me know. I would install an a/c unit for warm days and use outside air when temps get below 40F or so. Install the condenser above snow line if possible. Follow the manufactures requirements.