AC, Venting, ideas for a Darkroom Shed?

[morecfm]

I've installed a mini-split heat pump system in an upstairs addition that was previously serviced by a window type air conditioner. Most conventional air conditioners cycle on and off at full capacity to maintain temperature and are rather noisy. The mini split will dial back from maximum capacity and run constantly to maintain temperature. The discharge air velocity can also adjust automatically downward when dialed back from maximum capacity. If we wind up buying the house we're looking at, the auxiliary building has two sections, a 16x12 room and a 16x30 workshop, both wired and with water and sewer. I have that 16x12 room targeted as a darkroom and would put in perhaps a 6000 BTU/hr mini-split for that room only for the reasons above. Perhaps a bathroom type exhaust fan to allow for some air exchange.

[m00dawg]

OOOH yeah I forgot about the constant control that split-ACs can do. Interesting that central HVACs for homes don't do that. That's likely worth the cost and electricity premium since I can keep my darkroom at a more constant temperature and hopefully it impacts the voltage drag less.

[Tin Can]

I'm in far south Illinois.

Air temp 91 and climbing.

Closed up shed at 106, I have a remote temp sensor in there. 2 hours ago it was 90.

Always wire for 2 or 3 times max amp load.

Somehow we always need more.

France just had a 114 day.

Prepare for HOT!

[Leszek Vogt]

If you are near Fry's (electronics) or order online, you can get a nice AC unit, that also has a dehumidifier and fan built-in > $399. I've bought similar and have been using it for years....this thing has a remote, as well. Oh, it's "energy" rated. One of my fave things on this unit, it's being able to move from room to room as needed....and no window necessary....just an opening. Sooo, I can use it in my office, in the bedroom (to cool off for night) or any other area....the wheels help. No doubt it could be adapted and no light would leak into the interior.

There are tons of heaters out there....you can get one (costing less than $30) and it even has a thermostat. I'm totally with Mr Fujicaman, I've also used 12 gauge wire on the entire house & garage, with exception of heavier stuff like cooktop, oven, etc. I've seen fires (first hand) that started in the wall (duh, wire related)....and outside of melting inferno....it's a v. difficult fire to put out....and most times it engulfs the structure.
Anyhoo, a piece of mind was important to me.

By the way, a decent wood shop needs at least 30A service for table saw and 30A for dust collector, not to mention 20A set up for sizable router or planer/jointer.

Agree with giving bit more power than needed....you just might want to make some coffee and those things drain quite a bit of watts .

Les

[jp]

I wired all my outlets in the house with 12g and lights with 14g. Lighting is nothing for load now with LED, CFL and that sort of thing. If you have a big electrical load is will pay for itself quickly in energy efficiency to upsize the wire. At 80% load (minimum wire size for a given load), a certain portion of electricity is wasted heating the wire. Whatever the voltage drop is, it is the wasted energy going into the wire instead of the load. You are allowed to have 3-5% voltage drop, but that's 3-5% waste you don't get back. And bigger wire is good for safety too, though a breaker should trip well before a wire overheats.

[Luis-F-S]

Any reason for something so high that I'm missing? If the shed was for carpentry work, I could see the need for power for saws and other woodworking stuff, but I calculated my power needs so far and it's less than half that:

Enlarger: 100W
Lighting: 2-20W
Fridge: 250W
Fan: 10W
Split-AC: 1200-2750W (2750W looks to be start up power, 1200W continual)
Rotary: 10W

That's 3140W which is around 28A. Using an in-wall AC, it drops down to 2390W / 21A.

Definitely more than just running a Romex 12 gauge cable out there but less than half of 60A. The AC, unsurprisingly, uses the most amount of power by far. I'm actually more worried about voltage sag with it than the actual power requirements, since that could change my exposure times without a line conditioner since I use a ColdLight. Hadn't bothered with messing with that since my next timer may have a lux compensation and I plan to switch to LEDs eventually anyway. I'd have room for two enlargers though so I put 100W since my other enlarger still uses an incandescent.

Without the AC and fridge, I'm only at about 140W - easily enough to run an extension cable out (with a GFCI end) to get started for fall/winter darkrooming or to power from a 12V battery with an inverter probably for an entire darkroom session. Doing so could give me several months to save for the AC and electrical costs.

Do what you want, I've got two 220 V, 60 amp services to my garage which houses the darkroom. It feeds the enlarger 1200 W, print dryer 1800 W, a second enlarger 250 w, a chiller, water heater and various lights, and outlets. Each major component is on its own 20 amp breaker. Also housed are a central air/heat unit, irrigation/backup pump, dry mount press, plate burner, a second washer and dryer, refrigerator and freezer, and a photo studio. Of course, the area is 20' x 40' and two stories, a bit larger than what you're looking at. So if your anticipated load is a minimum of 21A, you should have a 60 amp service.......but you'll figure it out on your own soon enough.

[MusicalPhotog]

Check out my recent post under, “Let’s see your darkroom” discussion. It’s #965 (last page, near the end). I would provide you with a link. But unfortunately, I haven’t mastered that skill yet.

[Tin Can]

You need to learn that skill

Click on the post number in the upper right corner, then copy the entire link above in the header by left click first then right click to copy.

Try that and then you need to make a hot link.

Check out my recent post under, “Let’s see your darkroom” discussion. It’s #965 (last page, near the end). I would provide you with a link. But unfortunately, I haven’t mastered that skill yet.

[m00dawg]

Found It!

Boy it sure is snazzy on the inside! Very nice setup! I actually hadn't though about having the enlarger on more of a mobile table, so that's a thought. I priced out the raw materials earlier today and I'm up to about $1800 for most of the materials (sans air conditioner though) which isn't bad.

[MusicalPhotog]

You need to learn that skill

Click on the post number in the upper right corner, then copy the entire link above in the header by left click first then right click to copy.

Try that and then you need to make a hot link.

That's the piece I was missing! I didn't realize that the post numbers were actually links. Thank you. That is very helpful.