Walk In A/C Question

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drost

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OK,

So I'm finally getting ready to build my walk in à la John Beere with the air conditioning unit to cool it.

I have a question, though. Since I live in Iowa, it gets below freezing in the winter. Has anyone used a standard window air conditioner in a cold weather area? I'm worried that the coils will freeze in the winter, and will ruin the a/c unit.

I'm also considering one of the stand-alone a/c units that only need to vent out, but those are about 3X the price.

Thanks for the help,

drost
 
I had a window AC unit at my apartment, it was left in place all winter, I never tried actually running it in the winter, but it was perfectly happy to just sit there. You could try installing some sort of vent that simply let in cold, outside air during the winter that had a servo that would open and close it when needed.

*edit* I live in Minnesota
 
you can get a cover for the ac unit, but its only to keep the cold air out. it wont damage the ac unit but its good to cover it as it keeps junk out of the unit.
 
It won't hurt it. They're made to be left outside year round. You could even use it to circulate air when its not hot enough to run the cooling part of it.
 
Here are a couple things to consider, with high summer humidity any air transfer into the cooler adds to the cooling load by the increased moisture you will condense on the coils. Water vapor travels from the warm area to the cold area so vapor barrier goes on the outside of the cooler structure to prevent moisture buildup and rot in the framing. The lower the air infiltration into the cooler the happier the cooling unit will be. Air conditioners use a flow restriction tube to meter refrigerant with condensor running 80+ degrees F, when condensor temp falls the inside coil temp goes way below freezing as there is not enough refrigerant flow and compressor heats up from lack of refrigerant flow to cool motor. On commercial units the condensor fan is cycled to maintain high side pressure on cold days, you might be able to partially cover outdoor coil to get enough heat buildup to make AC unit work in winter.
 
Many A/C units have a vent position. If you are using an external temperature controller, you could use that position in the winter.

As far as the A/C unit itself & freezing weather, they can handle it.
 
Is the room below-ground? In that case, cooling it should be a moot point.

However, I'd invest in a dual-stage temp controller so you can run a space heater when the temps get too low.
 
Here's an idea: Buy one of those "remote" thermometers (Target, like $20 arent they?) and put the receiver outside/upstairs/wherever is convenient, and the transmitter in the walk-in. (I'm still assuming we're in a basement room. Correct me if I'm wrong.)

Why?

Because then, you can run the 2-stage controller with the heater on and the A/C turned off. Dial the heat-side of it in so that it stops heating a few degrees below where you would normally keep the A/C set to cool it to. Let nature keep it cool, let your space heater keep it from frosting/freezing. Whenever you get a nice, unseasonably warm day (We've all seen 70*F in December at least once, right?), then just keep your eyes on the remote thermometer more than you usually would, and if it starts "threatening" to climb into too-warm temps, go turn the A/C unit on - after all, if it's warm enough outside to throw your temps, it's warm enough to safely run the A/C unit for a day. There should be no harm to your A/C unit as long as the outdoor temp is above about 50*F. I've had a couple of HVAC techs that fixed my parents' system advise that it's beneficial to run the A/C once or twice during the winter. "Keeps things lubricated" or something, I'm sure. Kind of like driving a parked car a couple times a year to keep stuff from crapping out too badly.
 
Is the room below-ground? In that case, cooling it should be a moot point.

However, I'd invest in a dual-stage temp controller so you can run a space heater when the temps get too low.

Thanks everyone for your responses. Sorry, I've been working in the basement for the past couple of days, so haven't logged on to HBT.

Chriso, why would it be a moot point? My basement isn't going to hold refrigerator temps without some cooling.

Thanks,

drost
 
OK Perhaps I should ask a few more questions. Are you keeping it cooled to lager temps or ale temps? I re-read John Beere's thread, I had completely forgotten that he is keeping his at cooold temps, like 35-37F. I was thinking along the lines of 52-62F, cellar temps... good for fermentation and aging alike. With those temps, your and my climate *would* permit a sub-ground room to stay fairly comfortable in the cooler months, without necessarily needing active air conditioning. Striving for mid-30 degree temperatures, though, would be far more difficult.

What about venting the "butt end" of the A/C unit out into the non-cooled portion of the basement, instead of outside? It would heat up the adjacent room slightly (would suck in summer, but be 'free heat' in winter time!) but it would allow you to run it 12 months of the year.

I guess I'm a bit lost without visuals. I'm a very see-it-to-build-it person. What can ya tell me about the space you're working with? What's near it, what's outside of the walls, how big, etc etc etc. A picture could help immensely.

Sorry if I was startin' to drag you down the wrong road! Like I said, the temps make all the difference in the world. I've got a dirt-room cellar that I want to have someone cut a port in the concrete, so that I can put a window A/C unit into to maintain 60*f temps... a far cry from mid-30*F temps. Either way, I'm very interested to keep helping, as it's relevent to my future project too! :D

C
 
I wouldn't think that an AC unit would be able to cool into the 30-40's. Even if it is able to cool to that temperature you'll need to put it on a timer or possibly have the coils heated to prevent it from freezing.

Good luck
John
 
I wouldn't think that an AC unit would be able to cool into the 30-40's. Even if it is able to cool to that temperature you'll need to put it on a timer or possibly have the coils heated to prevent it from freezing.

Good luck
John

Hi John,

Yep, a window AC unit can keep a space to 30-40...check John Beere's set up: https://www.homebrewtalk.com/showthread.php?t=11440

His is what I'm trying to pattern mine after.

Christo,

The walls are poured concrete on one side all the way up, and poured 1/2 way up and studded the rest of the way. I've studded out the other 2 walls and have a 4'X8' opening.

Thanks everyone!
 
Why not just vent it into your house if it's in your basement?

That's how I did mine. I wired the fan to blow 24/7. It's about a 1/20th HP motor and my electric bill doesn't seem like it went up a penny. I then have the condenser wired to a thermostat and I keep the walk-in at 40 degrees, year round, no problem.

My walk-in is in a "storage" area of a finished basement and simple vents into the room. It's not like it's "exhaust" it's just slightly warmer air whenever the condenser kicks on.... which isn't that often given how well I have it insulated.

Even it is raises the temp in that area of the basement... which it doesn't... I don't care... like I was saying, it's a storage area.

The other reason I wired it the way that I did is that if I get any humidity in the walk-in, the coils will get a tiny bit of frost of them when the condenser is running but the split second the condesser shuts off, the fan running will instantly de-frost the coils.

I keep a plastic cup on the floor under the AC unit to catch the once-in-a-blue-moon drip from the defrosted condensation.

This set-up's been working perfectly for me for well over a year now.

Excuse the messy basement (hey.. I'm busy doing beer-stuff).

You'll see the two PVC pipes coming off the right hand side... those are insulated pipe that carry the lines behind a wall, under my bar and up from the bottom of the tap-box. It's a closed loop and I have a tiny fan that pushes a small amount of air through the pipes to keep the lines chilled (although, I don't even think I need the fan)

Cooler.JPG
 
+1 to this, Cape... That's why I was thinking/mentioned venting inside the house instead of outside. I'm thinking of building a very similar self-standing unit like that since I really don't have any "good" rooms to do a full-out permanent cooler like JB's. Thanks for the pic, that gets my brain a'spinnin!

Ohhh SWMBO is going to resent this. Maybe I can coax her to give me the $350 Home Depot gift card that she's hanging on to. Heh heh heh. I even have a spare A/C unit @ home already. (Heh. I said "unit".)
 
Yeah, this unit has worked out really well for me. It's a weird picture and it looks a lot smaller than it is. It's a 6 x 4 x 6 cooler and I can fit more than I would ever need to in it.

Put it this way, I have six taps on the bar and this hold those six cornies and then, becuase of a huge cookout I was having two weeks ago (see the "how to roast a whole pig" thread) i had my six cornies, a 1/2 keg, 3 1/4 kegs, two more 1/6th kegs, a couple cases of mixed bottles and all sort of food in that thing.... with room to spare.

I gotta put some shelves in it though so I can tuck away select bottles for long periods of time (barleywines, braggots, etc)
 
Cape, thats really cool. I guess mine leaks so much condensation due to venting outside. The brick wall always has water running down it where it vents...
 
Cape, thats really cool. I guess mine leaks so much condensation due to venting outside. The brick wall always has water running down it where it vents...

It shouldn't matter where it vents... it only matters (I believe) how much moisture you're getting inside the cooler... because that's where the condensation is coming from. The moisture in the air consenses on the cold coils inside the cooler, and then drains out the back side.

Did you use a vapor barrier when you built your cooler? I wrapped my entire cooler with really heavy plastic sheeting to make sure it was moisture-proof. I also put heavy duty weather stripping around the door to make sure that sucker was as air tight as possible. ANY air at all that gets into the cooler will bring moisture in with it and water will end up just pouring out of the AC unit.

Like I was saying, I went a bit overboard making mine air-tight and moisture-proof and I still get a tiny bit but nothing too bad at all. I get a few drops here or there and that's probably just from opening the door occasionally.
 
Beautiful set-up.

I obviously went a bit scaled down compared to yours, especially since it's in a spot that no one is ever going to see except me and my wife, but it gets the job done. Mine's primary use is for keeping my kegs and beer lines at temp for the bar but having it the size that it is, we can use ours for all sorts of storage as well.

I think mine ended up running me... probably... $500 at the most. I had the AC unit laying around, my father had the thermostat and then it was just 2x4's, 4x8 sheets of the cheapest plywood I could find and then extruded foam board insulation.
 
Cape,

That's great....I've been told to vent it to the inside in the past, so it's good to see that someone has done it.

I'm planning on a bar right in front of it....do you think the noise from the fan/compressor is too loud to sit by it?

Thanks,

drost
 
Cape,

That's great....I've been told to vent it to the inside in the past, so it's good to see that someone has done it.

I'm planning on a bar right in front of it....do you think the noise from the fan/compressor is too loud to sit by it?

Thanks,

drost

Hmmm... yeah... I kind of do... I wouldn't want to sit right in front of an AC unit. The noise would be a distraction and when the compressor does kick on, it'll blow warm air.

I seriously doubt the warm air will heat up the room at all but at the same time, I don't think you want to be sitting at a bar, enjoying a beer, and get a mini-blast of warm air in your face.
 
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