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Thread: OT: Shop AC

  1. #1
    Join Date
    Mar 2004
    Location
    SE, Michigan
    Posts
    2,056

    Post OT: Shop AC

    It's not off topic, but it is.

    I'll start trolling for answers now, before summer hits.

    I need to install AC in the shop. It's given...the amount of work I am accomplishing now just amazes me, simply because I keep the shop heated to 60 F all the time (corn is cheap).

    Problem is, I'm not at a perm location, so I dont want a perm installation. What I would like to do is fit the evaporator coil to the existing furnace blower (not the corn stove) and install an external compressor.

    I know you can get the units quite cheap (under a grand)...my question is, can I install it myself.

    It sounds like a dumb question, however I have all the tools. I have a vac pump, manifold gauges, nitrogen, etc...I've just never done it. Watched it done plenty, just never actually did it, so dont know the proper steps. I mean, I know it's vac system out, purge with nitrogen, vac out again, fill with freon, but that's about all I know.

    Getting the freon and the compressor is not difficult, just have to make a couple calls.

    Oh, the reason I want to install it is simple...I dont want a permanent installation. When I move, I plan to take my compressor and evaporator coil with me. No point in spending that money only to spend it again a year later.

    -Jacob

    [This message has been edited by snowman (edited 01-21-2006).]

  2. #2

    Post

    Does your shop have any windows? You could try a window unit.
    When in doubt, doubt your doubt.
    www.metalillness.com

  3. #3
    Join Date
    Feb 2004
    Posts
    304

    Post

    Perhaps a Ptac (packaged terminal AC unit)unit is a better product for your situation. It's like a hotel unit.

    Here is a link to Carriers version of these units: http://www.customerservice.carrier.c...TI1434,00.html

    Almost all manufacturers make a Ptac unit. I have a split heat pump system in my shop.

    Just as I did not start threading and chambering gun barrels without help I wouldn't advise messing about with an AC unit unless you have someone to help.

    You could install the AC on your air handler and raise the selling price accordingly when you leave.

    James

  4. #4
    Join Date
    Mar 2004
    Location
    SE, Michigan
    Posts
    2,056

    Post

    A window unit wont work in my garage...at least not well. 900 square feet of uninsulated drafty workspace. It would take probably 20000 BTU's to cool it down. The garage is actually my father in laws...so I could care less about the resale value. He wont move out until he dies, and he wouldn't use the AC if it was 110 degrees...grew up on a farm without AC, doesn't feel like he needs it.

    It's sorta like my corn stove...it'll get lifted up and put on a trailer. He doesn't work out there in the winter, if he does it's for a couple hours at a time, and the natural gas heater works, it's just expensive to run.

    It wont be cheap to keep it cool, but damn it will be worth it.

    -Jacob

  5. #5

    Post


    I'm going to install a 12K BTU window unit in my shop. The summer heat in my garage is not very comfortable but if I can drop the temp 5-10 deg and reduce some of the moisture on those humid days then it will probably make a big difference. I think its usually around 80 in the shop durring the summer. Usually it's the humidity that bothers me.. We'll see.

    -Adrian
    When in doubt, doubt your doubt.
    www.metalillness.com

  6. #6

    Post

    Condensing units typically come precharged with enough refrigerant for 30'of lines. Not a difficult job to install. Bend lines in a long radius being careful not to kink. Purge with nitrogen before brazing. Leak test before evacuation/releasing refrigerant. Federal law requires 13 seer units now so prices will be higher. Sheet metal work and wiring will be more difficult than installing refrigerant lines. Size unit for about 400 sq ft of floor space per ton cooling.Check furnace blower for adequate air flow capacity(400 cfm/ton).Look for 18-22 deg.F delta T across evap. coil.Suction press. needs to be above 60 psig to prevent coil freezing for R-22. Discharge between 160 and 250 depending on outside air temp.Check compressor for proper volts and amps. Full load amps are usually for design temp of 95 ambient.Make sure thermostat cycles unit.You're done.

  7. #7
    Join Date
    Oct 2002
    Location
    Russellville, AR
    Posts
    750

    Post

    Check a Graingers catalog for packaged units. Entire unit sets outside, run inlet and outlet ducts through a wall or window. Can get units up to several tons. A two ton unit should be plenty.

  8. #8
    Join Date
    Nov 2002
    Posts
    1,669

    Post

    The refridgerant won't be as easy to aquire as you would think. It's quite regulated and only licensed and certified technicians are supposed to be able to buy it. There are also rich rewards for people to rat you out if you release anything more than a deminimus amount of freon.

    I understand that there other refridgerants that work well like propane, but there is that additional hazard in a shop if there was a leak. Ammonia is another that could be used and you sure would notice it if it leaked.

    Last summer I thought about using a "mister" system on the roof but didn't get round'tuit. I would have set it to just barely wet the roof every few minutes. The constant evaporation should have a big effect here in Utah. In Florida it would probably wouldn't work.

  9. #9

    Post

    Wouldn't a misting system rust your tools?

    I have a similar situation, but the temperature swing won't let a heat pump do much here. At least Albuquerque has dry air... I could use a swamp cooler, but am concerned about rust. Normal home distribution pipes for swamp cooler units really take a hit here.

    I am watching closely to see if anyone comes up with a great solution... as I am not too proud to steal good ideas when they come along.

  10. #10
    Join Date
    Nov 2002
    Posts
    1,669

    Post

    The idea with the misting system would be on the roof and so virtually all the moisture would rise. There would probably be minimal increase of humidity inside. Utah and New Mexico are pretty dry states (in more ways than one.) It should work pretty well.

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