skyking
Well-known member
2000 sq. ft. shop .What kind of a/c to install .
Shop air conditioning ????
- Thread starter skyking
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Charles (in GA)
Well-known member
That steel building in your aviatar? You cannot get an AC large enough to cool it. (well, you could, but I doubt you would want to pay the electric bill, or buy the unit).
Ceiling fans, large floor fans, and lots of cold water and such in the fridge.
Charles
Ceiling fans, large floor fans, and lots of cold water and such in the fridge.
Charles
whatuusay1
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- Jun 15, 2009
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Agreed - to effectively cool the space You'd have to put in insulation on all walls, doors and ceiling - probably spray in for the best seal you can get. Assuming you do that You're probably best bet is going with a traditional A frame airconditioner and blower - mount it up off the ground to keep your floor space. Put a duct along the back wall that empties into your shop. If you dont want to mess with traditional ducts etc. You could get away with a dual zone minisplit (prob 24k BTU each) - space them out on the back wall or either side of your shop. I've had great luck with a 24k unit cooling our 3 car (insulated) garage without issue (easily drops the temp by 20 degrees in 15 minutes).
Keep in mind if you are talking about that large shop in your avatar - opening the door is going to cost you at least an hour of cooling capacity.
I'd spend the cash on insulation first - and then worry about trying to cool it.
Keep in mind if you are talking about that large shop in your avatar - opening the door is going to cost you at least an hour of cooling capacity.
I'd spend the cash on insulation first - and then worry about trying to cool it.
That is my shop/hangar .I just finished it and the entire building and all doors including the 40x12 hangar door has 3" of insulation. I thought maybe there was a trailer house or commercial outside unit that could be used. Would spend 5 or 6 thousand if nescessary. I didnt even put in skylites because I didn't want the heat.
pattenp
Well-known member
If you are only cooling a 2000 square foot room you have a lot of choices. A large window unit would be the most economical. It would be best if you had a professional do heat load calculations for you so you could purchase the correct size unit.
My first question is "What about heat? Natural gas, propane or electrical?"
It makes sense to get a unit that can heat and cool. How about fumes? Are you going to weld, paint or do other shop activities where ventilation is needed?
My first question is "What about heat? Natural gas, propane or electrical?"
It makes sense to get a unit that can heat and cool. How about fumes? Are you going to weld, paint or do other shop activities where ventilation is needed?
A large window unit will take the edge off. There's a 25,000 btu window unit (no window, just a hole in the wall!) in my 3000sf shop. Last weekend it was 100° outside, but it was about 85° inside. It's really too small and runs all the time, but it makes the shop usable.
After posting this thread I wonder If I need to put in a/c .My hangar has 3" of insulation on every inch. My hangar door is 40'x12' plus a 10'x10' on the other side .We have had triple digit temps for a week and with a roll around swamp cooler I have been fine. It has me wondering................
Charles (in GA)
Well-known member
You problem is volume. The building is tall, and open to the roof, and these folks recommending mini-splits and such are not taking into consideration the CUBIC FEET of volume in the building.
I have 3600 sq/ft. However the building has a 16 ft eave, and a 21 ft peak, 66,600 cu ft of volume.
Apparently you done good if the insulation is such that the swamp cooler is doing the trick. I would seriously consider adding ceiling fans to push heat in the winter back to the floor. They might help you in the summer also to stir that swamp cooler air around.
Charles
I have 3600 sq/ft. However the building has a 16 ft eave, and a 21 ft peak, 66,600 cu ft of volume.
Apparently you done good if the insulation is such that the swamp cooler is doing the trick. I would seriously consider adding ceiling fans to push heat in the winter back to the floor. They might help you in the summer also to stir that swamp cooler air around.
Charles
I have a 2000' metal building with 14' ceiling in OKC. Inside the 2,000' is a 200' office and bathroom cooled with a 12,000 btu window unit. There is also a 150' room with CNC equipment cooled with a 18,000 btu terminal package unit (like a hotel room). Shop has radiant barrier and 6" of fiberglass insulation on walls and ceiling. With outside temp. of 109 today I have to do something quickly. My short term plan is to install a 28,500 BTU window unit in one of the man doors. Long term plan is to install a 5 ton wall mount package unit. Entire unit hangs on the outside wall with only two holes cut through the side wall for supply and return ducts.
pseudorealityx
Well-known member
The window A/C is mounted into the EXTERIOR wall of the office space, and not back into the rest of the shop space, right?
Yes, it vents through the exterior wall. That is the reason I used a 12K btu unit. The wall is 9" thick and that is the smallest unit I could find that had the side intake vents at that depth. I have had to replace the office unit once because some a-hole stole the condenser coil. Ruined a $400 unit to get $10 worth of scrap copper.
Skyking,
I was originally looking to put a package unit on the roof but the curb between the unit and the roof concerned me. I found the wall mount and like that option better. The wall unit is more expensive but you don't need the curb and I can do all the work myself. Check out acunitsdirect.com. I am looking at the W60A1-A unit.
I was originally looking to put a package unit on the roof but the curb between the unit and the roof concerned me. I found the wall mount and like that option better. The wall unit is more expensive but you don't need the curb and I can do all the work myself. Check out acunitsdirect.com. I am looking at the W60A1-A unit.
EOC_Jason
Well-known member
What is the eve height of the building? If it was 16' you could *probably* squeak by with a 5-ton unit, which would keep the temp comfortable and humidity low. On really hot days (i.e. 110+) you would have to realize it would probably still be in the 80's in your shop (depending on what kind of heat you are generating inside with machinery or whatever), but still feel a heck of a lot better than outside! Also the unit would be running constantly all day long trying to keep up.
If it's a higher ceiling then you would seriously need a second 5-ton to keep things nice and cool... Or you would have to go to commercial sized units...
If it's a higher ceiling then you would seriously need a second 5-ton to keep things nice and cool... Or you would have to go to commercial sized units...
Not sure on Skykings eve height but mine is 12'. I have also already taken 350 sq' out of the equation with other cooling. If I could get the shop down to 80 and low humidity when the outside temp is 111 I would be very happy.
pseudorealityx
Well-known member
Many packaged units have sidewall discharge options, so they can be mounted on the ground next to the shop and ducted into the building. They you don't need to be as concerned about the penetration into the building vs. going through the roof.
Not a bad option if you've got room outside.
Not a bad option if you've got room outside.
You need to get a "real" heat loss/gain on this building. Not doing so is hoping you can hit the hole on the rolling donut. Once you know what the load is, you can better select your options. I remain a fan of the mini-split heat pumps as they are all inverter controlled, meaning variable speed with attendant efficiency increases. Standard sizing for commercial buildings use the old rule of thumb of 400 sq ft/ton (12kbtu) of cooling. Does your foam increase or decrease that? Only the heat/loss gain program knows for sure.
BadgerBoilerMN
Well-known member
A proper heat load takes into account the volume, exterior surface area, windows doors, insulation and infiltration. Not to mention, orientation, inside and outside design temperatures. Oh yes, the latent, as well as sensible heat are considered. A swamp cooler may work for dry climates.
A mini-split heat pump is nearly always the most economical to operate (window shakers representing the very low end) and how "big" the space is represents just one component of heat load analysis. A properly sized AC unit will be more efficient at removing the latent heat than one that it over-sized.
5 tons, really? Why guess?
A mini-split heat pump is nearly always the most economical to operate (window shakers representing the very low end) and how "big" the space is represents just one component of heat load analysis. A properly sized AC unit will be more efficient at removing the latent heat than one that it over-sized.
5 tons, really? Why guess?
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pseudorealityx
Well-known member
You forgot the internal loads. People, lighting, equipment. 
BadgerBoilerMN
Well-known member
Yes, thank you.
BadgerBoilerMN
Well-known member
I design condition not listed in any of my books but a subject for an ASHRAE white paper perhaps
I design condition not listed in any of my books but a subject for an ASHRAE white paper perhaps
...assuming you are volunteering for hands-on testing?
So....Is an 18500 btu window unit overkill in a 24X30 with 12' ceilings?
Anyone??
As mentioned by BadgerBoilerMN earlier in this thread, there are a great many factors beyond mere room volume that go into A/C sizing. If you want a veracious answer, would need to know design delta T, wall/ceiling R values, infiltration, solar hear gain, etc.
If you want an off the cuff answer, I would say no... 18500 BTU is not likely to be too large. It may even be too small.
If you want an off the cuff answer, I would say no... 18500 BTU is not likely to be too large. It may even be too small.
Design delta T? (Excuse my ignorance) But I have no clue what that is. I'm in the process of building the garage we are going with R38 in the ceiling & R19 in the walls with a complete vapor barrier and sound deadening on the ceiling as my Mom will be living above me and I don't want to disturb her with noise or fumes. Infiltration? Again (clueless)! As for Solar heat gain; I think you mean light from windows & radiant heat from garage doors & things? There will be no windows as I'm mostly below grade (on 3 sides). There will be one door leading to outside & one door to the inside both sealed fire doors (Code). The garage doors will be the best insulated ones I can get. I hope all this gives you a better idea of what I'm doing or at least trying to do and better help answer my question.
Thanks
Jim
pseudorealityx
Well-known member
Delta T is the difference between 2 temperatures. For instance, some people want a garage that's just 'better than nothing', and low 80's is fine, since it's 100+ outside. Others want to be able to keep it cool like a house, mid to low 70's. Obviously you need a larger unit to push the temps down more.
100 - 80 = 20 degree delta T
100 - 75 = 25 degree delta T
Infiltration is how leaky the space is. You want to minimize the drafts, so good weatherproofing around the doors, any windows, etc.
100 - 80 = 20 degree delta T
100 - 75 = 25 degree delta T
Infiltration is how leaky the space is. You want to minimize the drafts, so good weatherproofing around the doors, any windows, etc.
It will have radiant heat in the floor & insulated so good I'm hoping to be able to heat it with a match. Looking to keep it like I keep my house a cool dry 72-74 deg. year round. No excuse not to work on my hot rods then.
Looking to keep it like I keep my house a cool dry 72-74 deg. year round. No excuse not to work on my hot rods then.