air conditioning help needed

ebbnflow36

ebbnflow36

Member
O.k., so a minisplit will not work in my application. I need to cool a 12x16 sealed room. I will be air cooling my 4k lights. Not sure why some say that isn't a true sealed room, but that can be a topic for another day. I have read forums and have read many conflicting advice about what size ac I need. I plan on cutting a hole in my room and putting a window ac in. The grow is in a large basement so the ambient temperature outside will fine not to over work the ac. I also read I should get an ac which has a manual switch versus digital, it's 2015 good with that, any suggestions???
 
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deadgro

Well-Known Member
If the room is sealed, a portable would work. If you're exhausting air out with or without a scrubber, I'd go with a window unit. The portable units don't like low (negative) pressure areas. An 8000btu unit should be ok to cool up to 10 or 12F. If it gets much hotter I'd step up to 12000btu.
 
ebbnflow36

ebbnflow36

Member
Really, I originally wanted get a portable, but it seems everyone says they are crap not efficient and are the spawn of Satan lol. I will not be exhausting air from room. I will be scrubbing air with filter on one side of room ducting from filter to opposite side of room for circulation
 
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deadgro

Well-Known Member
ebbnflow36 said:
Really, I originally wanted get a portable, but it seems everyone says they are crap not efficient and are the spawn of Satan lol. I will not be exhausting air from room. I will be scrubbing air with filter on one side of room ducting from filter to opposite side of room for circulation
Click to expand...
Yeah the portables I've used were in non sealed rooms and my research led me to blame the ineffectiveness on low pressure.

The box ac is the way to go. Measure twice, cut once, seal it well with silicone caulk and make sure its supported well.
 
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coloradocoolness

Member
I have a 14k but portable and it really really does not like the negative pressure. I would 100% go with a good,wall unit. You can always build a box around th exhaust out and duct it away if it heats your area up to much. The rear exhaust of a wall mount ac produces a lot of heat that Will,dumb right out side your room. Keep,that in mind.
 
nomofatum

nomofatum

Well-Known Member
I'm no heating expert, but my inner scientist found a simple solution that should be right.

1 W = 3.412142 BTU/hr

Add up every watt you use in that room, convert to BTU, make sure AC unit is say 20% larger, GTG.
 
ebbnflow36

ebbnflow36

Member
I'm sure you got that number from somewhere but it seems way over kill, just doesn't make sense not taking room size into consideration
 
nomofatum

nomofatum

Well-Known Member
From Wiki:
One BTU is approximately:

  • 1.054 to 1.060 kJ (kilojoules)
  • 0.293071 W·h (watt hours)
  • 252 to 253 cal (calories, or "little calories")
  • 0.25 kcal (kilocalories, "large Calories," or "food Calories")
  • 25,031 to 25,160 ft·pdl (foot-poundal)
  • 778 to 782 ft·lbf (foot-pounds-force)
  • 5.40395 (lbf/in2)·ft3

From http://www.rapidtables.com/convert/power/how-watt-to-btu.htm
How to convert watts to BTU/hr
How to convert watts (W) to British Thermal Units per hour (BTU/hr).

One watt is equal to 3.412142 BTU per hour:

1 W = 3.412142 BTU/hr

Watts to BTU/hr conversion formula
The power in BTUIT per hour P(BTU/hr) is equal to 3.412142 times the power in watts P(W):

P(BTU/hr) = 3.412142 · P(W)

Example
Convert 5000W to BTU/hr:

P(BTU/hr) = 3412.142 · 5000W = 17060.71 BTU/hr

That plus the knowledge that every watt of electricity used will turn to heat upon being absorbed, by the plant, wall, floor, ...

That doesn't take into account any natural heat loss that the AC wouldn't need to handle, this is the size you would want if the room is perfectly sealed for both heat and air exchange. Once you try adding in the other variables we probably want a heating/cooling expert.
 
ebbnflow36

ebbnflow36

Member
Mr sunshine you elaborate that I heard that before but wasn't explained, is me walking into the room everyday enough? If to put in exhaust, how do you prevent odor leaks and please don't suggest ona
 
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coloradocoolness

Member
Build a box around the Heat exhaust of your ac, put a 6" adapter 5o to a inline fan and duct to q carbon filter. Or if your not drawing any air from,inside the room smell shouldn't be an issue. Dryer sheets also work well to help mask any extra smell. I,throw a few in my exhaust lines
 
nomofatum

nomofatum

Well-Known Member
Here are your options:
1. Normal System (no CO2) - Intake air from inside your home, climate controlled, approx 68-72f RH under 50, 35 is about ideal. Exhaust air through a carbon filter to outdoors (when it's warmer than 60f outside) or indoors (when you need heat on anyway.) If exhausting indoors you will likely need a dehumidifier except in the middle of winter. When exhausting outdoors it's important to not go overboard, exhausting too fast will cost you on your homes ac bills.

2. Sealed System (with CO2 supplementation) - Air is not exchanged, this would be bad if you do not supplement CO2, the plants will consume and lower the CO2 levels over time in the room. With supplementation you can give higher than normal levels for faster growth/bud development. AC/Humidity control is required in this setup.
 
justugh

justugh

Well-Known Member
ebbnflow36 said:
Can you elaborate on that, don't know why but I got to put in
Words twice
Click to expand...
he is saying u have 4000w know for lighting .......do u have any other things in there adding to the heat

4 x 3.4 =13.6 + 000 13600 btu
u need to put out 13600 atleast for your system

i am sorry portable ac might be rated for 14000 btus but they are weak if u look up the cooling area number compared to a window shaker or tho wall units ......portables are a sheer waste of energy

if u have no choice but to use those .........i would think about combining it with http://www.amazon.com/Hydro-Innovations-904490-Ice-6-Inch/dp/B002JLAC3I/
that with a waterchiller like 1/10 hp in a system of 15 gallons of water running

u use this on the intake for the room ........so the air coming in gets a extra chill making the portable more effective ......
 
justugh

justugh

Well-Known Member
adding a burner too

i am sorry man a 2 ton mini split is the only energy effective choice ......1 system 1 breaker for it

4000w and a burner ............2 3 portables or more
 
ebbnflow36

ebbnflow36

Member
Wish I could have mini split, it's in a 3 decker unless you live in New England you probably don't know what it is, but no one has mini splits outside it look to suspect
 
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