Central Air: 2 x 3 Tons or 6 Tons?

[queequeg152]

interesting. where are you going to be getting this hot water? is it supplied by the facility wherein this building will be erected?

i ask because forced air gas furnaces are extreemly simple... the old style80% efficient units are ... cheap ish... and very simple and reliable.
you might even conside buying some old used furnaces... it might sound ghetto, but you could easily hang one from the ceiling on a trapeze for temporary service. alternativly you could mount it on a furniture mover, but these furnaces just are not meant to take abuse.

from the unit you could run fabric duct work along the extent of the room, perforations facing perpendicular.

the fabric duct hangs from a taut steel wire, and can be collapsed into a pile at one end when not in use. additionally the furnace unit could be removed from service during non heating months and stored elsewhere.

i recommend a separate system because this room as i see it in my head, will have a reletivly small heating load... were talking about like 500 sq ft here.
and adding small furnaces to each propsed 3 ton air handler makes 0 sense.
adding one larger furnace to only one of the air handlers makes less sense because the distribution systems are isolated.

since you only need to heat to ... what 55-60 degrees? you could just run perforated fabric duct down the length and get away with it.

fabric duct is not expecially cheap compared to duct board or flex duct... but if you can get over the cost its a wonderful material for temporary use ducting.

 

[Snype]

interesting. where are you going to be getting this hot water? is it supplied by the facility wherein this building will be erected?

i ask because forced air gas furnaces are extreemly simple... the old style80% efficient units are ... cheap ish... and very simple and reliable.
you might even conside buying some old used furnaces... it might sound ghetto, but you could easily hang one from the ceiling on a trapeze for temporary service. alternativly you could mount it on a furniture mover, but these furnaces just are not meant to take abuse.

from the unit you could run fabric duct work along the extent of the room, perforations facing perpendicular.

the fabric duct hangs from a taut steel wire, and can be collapsed into a pile at one end when not in use. additionally the furnace unit could be removed from service during non heating months and stored elsewhere.

i recommend a separate system because this room as i see it in my head, will have a reletivly small heating load... were talking about like 500 sq ft here.
and adding small furnaces to each propsed 3 ton air handler makes 0 sense.
adding one larger furnace to only one of the air handlers makes less sense because the distribution systems are isolated.

since you only need to heat to ... what 55-60 degrees? you could just run perforated fabric duct down the length and get away with it.

fabric duct is not expecially cheap compared to duct board or flex duct... but if you can get over the cost its a wonderful material for temporary use ducting.

I have to install a new heating system in the house. We currently have no heat here. So when I install the forced hot water furnace or boiler (whatever you call it), I'll make a zone for the grow room. I'm not trying to go the duct route for this because it takes up too much room compared to forced hot water.

 

[queequeg152]

interesting. i had pegged this as some sort of industrial ware house setting.

so you are looking to just add water coils to the duct work?

 

[billyboat]

I run 3 quest 205's in an almost identical space to combat night time humidity, they run almost non stop at night and without the ac on, the room easily gets to 80 at night when its cold outside. Remember during night time the humidity spikes tremendously at night, and after week 5 I like to keep that humidity low, especially at night...so those dehuys are working hard...

 

[Snype]

interesting. i had pegged this as some sort of industrial ware house setting.

so you are looking to just add water coils to the duct work?

It's a farm house with a barn that has 3 floors as well. I'm putting in baseboard heat. You know, baseboard heat, forced hot water. Like what's in most houses on the east coast.

 

[Snype]

I run 3 quest 205's in an almost identical space to combat night time humidity, they run almost non stop at night and without the ac on, the room easily gets to 80 at night when its cold outside. Remember during night time the humidity spikes tremendously at night, and after week 5 I like to keep that humidity low, especially at night...so those dehuys are working hard...

Wow! 3 Quest 205's? Sounds ballin'! That'll sure add some heat! The problem is when the plants are small and don't give off so much humidity. That's when I may need some additional heat.

 

[MIMedHead]

I live in MI we have cold ass days

 

[queequeg152]

im ultra jelly. a three story barn? assuming its in decent shape... sounds fantastic.

yes baseboard heaters are an excellent idea... i ha dent thought of that honestly. we dont have much baseboard or old school radiators down south.

 

[queequeg152]

I run 3 quest 205's in an almost identical space to combat night time humidity, they run almost non stop at night and without the ac on, the room easily gets to 80 at night when its cold outside. Remember during night time the humidity spikes tremendously at night, and after week 5 I like to keep that humidity low, especially at night...so those dehuys are working hard...

idk what a quest 205 is, but im assuming its a beefy dehuy.

relative humitdity does increase when air temps drop, but the flux of water vapor should is quite low at night when plants are not transpiring as much, and temps are cooler.

perhaps your grow area is not as well air sealed as it could be.

water vapor flux across things like unpainted drywall surfaces can add up to a great deal of moisture infiltration... however its the acutal air leaks that make up the vast majority of moisture infiltration.

 

[billyboat]

idk what a quest 205 is, but im assuming its a beefy dehuy.

relative humitdity does increase when air temps drop, but the flux of water vapor should is quite low at night when plants are not transpiring as much, and temps are cooler.

perhaps your grow area is not as well air sealed as it could be.

water vapor flux across things like unpainted drywall surfaces can add up to a great deal of moisture infiltration... however its the acutal air leaks that make up the vast majority of moisture infiltration.

Do you grow at all?

My Rooms are as sealed tight as can be, walk in cooler tight. Check out my sig, 65k watt show...

I've built built and currently run exactly what the OP is trying to achieve...

 

[queequeg152]

Do you grow at all?

My Rooms are as sealed tight as can be, walk in cooler tight. Check out my sig, 65k watt show...

I've built built and currently run exactly what the OP is trying to achieve...

ive grown indoors if thats what you mean, though certainly not at the scale you folks do.

outside of transplants, i grow outside.

cooler tight is a big claim. i dont suppose you have a blower door/ duct blaster to substantiate that.
you can rent the equipment for like 200 bucks a day if you like.

forgive me if i dont take you at your word with respect to HVAC... but were you not the person a while back claiming that opti climate thing was just a fan coil?

all this being said, thats a shit load of plants. im not suprised you use so much dehumidification now, especially if you are trying to get under 50%

 

[billyboat]

ive grown indoors if thats what you mean, though certainly not at the scale you folks do.

outside of transplants, i grow outside.

cooler tight is a big claim. i dont suppose you have a blower door/ duct blaster to substantiate that.
you can rent the equipment for like 200 bucks a day if you like.

forgive me if i dont take you at your word with respect to HVAC... but were you not the person a while back claiming that opti climate thing was just a fan coil?

all this being said, thats a shit load of plants. im not suprised you use so much dehumidification now, especially if you are trying to get under 50%

Its actually not many plants at all, they are trees.

As in I started using walk in coolers for grow rooms...

The Original Opticlimate's (they have 2 new models since then) were water cooled air handlers and dehuys they still offer this model and its DTW or for recirculating....I have a buddy has runs them like I said with chillers and such...I wasn't familiar that they now have complete ac packages.

I'm not here to argue with you.

 

[queequeg152]

Its actually not many plants at all, they are trees.

As in I started using walk in coolers for grow rooms...

The Original Opticlimate's (they have 2 new models since then) were water cooled air handlers and dehuys they still offer this model and its DTW or for recirculating....I have a buddy has runs them like I said with chillers and such...I wasn't familiar that they now have complete ac packages.

I'm not here to argue with you.

these are walk in freezers? thats quite impressive.

the walk in freezer sandwich insulation panels im aware of.. cost quite alot of money... much more than what it costs to hire a spray foam contractor. quite impressive indeed.

one of these rooms is probably worth more than all my student loan debt.

is your design intent here to make these rooms semi portable? IE rent a flat bed truck and move the whole thing elsewhere?

if the thing was assembled properly with the proper sealing on all of the panel connections... it could very well be incredibly air tight.

 

[r2k]

I don't grow that big, but I have talked to some who have.

If you are growing in cold climates, have you split your space into two rooms? If you grow two rooms that alternate light cycles, you always have half the lights on at any time. You can also pull heat from lighted room into the dark room, so you don't have to worry about cold nights during the winter. You will have half the lights on all the time, so you should be able to heat the rest of the house. The air might be a bit stinky for residential living, so that might not work out as well as you hope.

I am a big believer of running more smaller A/C units rather than fewer big A/C units. It is easy to shut down one or more A/C units as winter comes and you still maintain decent efficiency. In my house, I have found that oversizing A/C and running short cycles is not good for removing humidity. Not the same levels of humidity you will have, but it is a problem. No real good place for a dehumidifier, so we live with it.

-r2k

 

[queequeg152]

I have found that oversizing A/C and running short cycles is not good for removing humidity. Not the same levels of humidity you will have, but it is a problem. No real good place for a dehumidifier, so we live with it.

-r2k

potential derail aside...

im in the same boat to some extent. though not my house...
its a very labor intensive issue to solve, but in case you are interested, id suggest looking into whats involved in retrofit air sealing. if you dont mind crawling around in a hot attic, it can be a very rewarding return on your invested labor.

if you can solve the air infiltration( and verify with a blower door), you can then justify a whole house dehuy like an april air 70h. they are like a grand, but they can make a big difference in these in between months. if you have some airflow over your skin, 76 at less than 50% rh should feel like low 70's at 70% rh.

 

[twist1uc]

I would really suggest checking out water cooled systems. Check out Surna (previously Hydro Innovations).

They have a sizing chart, based on number & wattage of lamps, size of room, co2, dehuey, etc.... Chart is here: http://cdn.shopify.com/s/files/1/0297/6381/files/12082011-CoolingSystemChart.REV.1.1.pdf

Surna's newer site: http://surna.com/climate-control/

 

[queequeg152]

10 grand for a 5 ton system.

nuff said.

 

[queequeg152]

did this snype gentleman die? he is banned, and his tag lists his location as "in heaven"... no clue if this was always the case.

 

[Mikell]

Permabanned maybe. Or he started handing out acid to hitchhikers again and had to close up shop (again). Burn me once, shame on you, burn me twice...

 

[snake11]

over sizing is inefficient. an over sized system will cycle too often, dehumidify poorly, and filter poorly owing to short duty cycles. what do you think all that costs you?

the golden rule for sizing any hvac system is the manual j(for small systems) or similar approximations based on ASHRAE documentation.

Good advice to everyone on the manual j load calcs. This is the right way to do things and will save lots of money in the long run over improperly sized equipment. The company I used to work for would not sell a new system without doing one.