PDA

View Full Version : Metal Shop Building - Size Needed for unit



Nick_P
06-16-2011, 03:21 PM
Previously, while searching the internet for an answer to what size unit I would need for my shop out back, I erred in my apparent hijacking of a past post that was very similar in nature to what I was looking for. Unlike most Engineering types, redundancy is not something I like, so I jumped in the frying pan. I guess I wrinkled someone’s day by doing so – what I wrote was “ In my endeavor to upgrade my shop space, I happened on to this post. I have 2200 sft. of space with no windows, one entry door and one overhead door. I have R38 in roof (walls are 15' at eave) and R14 in walls. I would like to cool the space. I live in Dallas, TX. Your thoughts.”
So, to that question again: I have a metal shop building. It is 36’x60’x15’ with a small compressor room out back. Presently, I am having more insulation placed in the ceiling for a total of 12” (R38 by my calculations). The walls contain R14.
Now, some questions were fortunately lobbed my way regardless of the admonishment from a member that felt like I was hijacking the post. I submit here for your edification what I feel are the answers to said questions.
1. Only one man door of 3’x7’ size.
2. One Overhead 12’x12’ door – not insulated and it faces East but is sealed when closed.
3. No trees. This is old cotton land and it was completely stripped of them. You want them, plant them and hope for growth.
4. No paint booths, zip zero. However, I could comfortably contain one within the premises.
5. No furnaces. My heat source when required is a propane unit that is so noisy you can’t hear the TV, so I don’t run it much, besides this is Texas ya know.
6. One (1) worker – me with an occasional visit from my bride of 35 years who reluctantly stays to assist at my request. Oh, also a Golden Retriever on occasion will come for a visit.
7. Two refrigerators (beer and snacks to keep me out of the house), One Freezer and a coffee pot that runs all day.
8. One 15 hp. Air Compressor – Mounted in the Compressor room out back but does have a pathway allowing its hot air to encroach to the shop.
9. No radiant barrier in any location.
I have all of the internal walls sheetrocked to 8’. There is a 52” Flat Screen running most all of the time. With the outside temp at 100° F, it is 90° F inside. So, there ya have it, a nice new post of my very own. I look forward to ya’lls thoughts.

TIA yall, and have a Blessed day. :angel::angel::angel:

Shophound
06-16-2011, 04:16 PM
At the top of this page is a link to a progam called HVAC-Calc. You can use it to get a good estimate of what size cooling equipment your shop might need. At least pertaining to the building shell itself and people. If you ever install a paint booth I recommend it NOT draw air from the shop AT ALL. Have a dedicated fresh air intake for it equivalent to what the exhaust hood draws out, and you won't lose a/c from the shop when you're running the paint booth exhaust.

If this is a woodshop, you need to account for dust collection. I recommend you put the dust collector in a separate closet and then provide an air grill between it and the air conditioned space of the shop. You don't want to suck your cool air outdoors every time you run the dust collector.

HAP2
06-16-2011, 07:31 PM
I just installed an old 3.5T, 12 SEER in my 40x60 12' eave metal shop. I have the standard insulation ceiling and walls, insulated 10x16' and 8x9' overhead doors. The system will deliver the standard 20* delta T and does a great job of lowering the humidity. I does however struggle to lower the temp. If I know I want AC on a particular day, I just turn the system on early in the a.m.
One thing you should really consider is a Heat Pump unit. That way you can ditch the propane heater and save save a few $$.
Also, I mounted the cond. unit on the outside wall with a short line set to the AH. I just fitted an oversized filter and a long-throw register on the supply side used, the old mercury thermostat, piped the cond drain to my shop sink to keep things simple.
Just nice to have AC...

basshound71
06-16-2011, 08:20 PM
Kind of depends how cool you want it. Without doing any calcs I would probably say a 7.5 ton

Nick_P
06-16-2011, 11:22 PM
Kind of depends how cool you want it. Without doing any calcs I would probably say a 7.5 ton

While working in it tonight, it was about 90. I would like at least a drop to 80. Certainly, 75 would be grand.

Thanks

dan sw fl
06-17-2011, 08:09 AM
While working in it tonight, it was about 90. I would like at least a drop to 80. Certainly, 75 would be grand.

Thanks

http://www.bardhvac.com/digcat/S3364_TechDoc_CD/TechDoc-PDF/7960-576.pdf

BARD model W30H1

Two 2.5 ton dehumidification Heat pumps
spaced about 30 feet apart on the 60 foot wall.

:whistle:
Outlet at about 9 foot high

NO ducts
NO use of existing floor space
Flexibility of use / program scheduling and t-stat for each "end"

Load is highly dependent on infiltration - thus use of DEHUM mode and
also addressing Outside Air condions of 65' - 75'F.

Somewhat "Free heat " so-to-speak for a very large percentage
of annual Heat needs.

-Shophound- can provide additional guidance on worthiness in a TX climate.

Nick_P
06-17-2011, 08:55 AM
Thanks Dan. Now that is truly a KISS solution. Very nice. These units look like what is used on portable office space on construction sites. My investigation continues. In reviewing the link, I am guessing that winter heat requires an additional heating coil.