Here is a link to a discount on a Coolbot, which allows you to use an air conditioner to bring the cooler down to, and maintain, 36-38 degrees. I put one in this year and it works great! Very simple to install.

http://storeitcold.referralrock.com/l/80568C08/

I just happen to have such a cooler in my summer DIY plans. Can you give us some details as to size, thickness of insulation, etc? I'm always happy to see what others have done and how it works.

I'm planning a 6x8' cooler. I haven't planned the details yet but I'll probably use 4" of foam board. It'll be open on top under a metal roof with a good air space, screened off to keep the starlings out.

Mine is a 6x8 also. Since it was built in a new pole barn, the two outside walls are 8 1/2" of layered pink Foamular 150, with a 1/2" Polyiso board with the aluminum facing on the outside walls, facing outward working as a vpor barrier. For the walls inside the building, I used 2x6's with the polyiso on the outside and the foamular 150 on the inside. For the inside, I couldn't decide on a liner and just put 1/2 foamular over everything to close it up tight for the first year. Those walls ended up being 6 1/2" thick, with the Polyiso and the inner 1/2 " liner. The ceiling was built like the walls.

Under the floor is 2" of Foamular 250 with a vapor barrier beneath that.

Every layer of insulation was cut to fit and I caulked the seams of every layer. For the door, I ended up buying a good exterior house door with a foam filled frame. I was going to glue another inch of foamular to the inside of the door but never did. The door is the weak link in the insulation, but it hasn't been an issue.

My research said "do not use fiberglas insulation". The foamular was not cheap, but the cooler works very well. The coolbot took it from 75 to 37 degrees in a short time, like 10 minutes.

When hanging meat, be sure to keep the fan on to keep the air circulating. Some air conditioners allow the fan to cycle on and off in an energy saver mode. Don't do that with meat.

I'm not sure what you mean by "open on top with a good air space". I actually built my ceiling about 18" under the building ceiling so that i could store things on top of it. I think you'll want your ceiling insulated with foamular also.

Go to the Coolbot site, they have plenty of info on construction and also answer questions over the phone. I found them very helpful.

Buy lots of caulk!

By open on top, I meant that there will be a good air space above the insulation. I used to be a roofer and more than once, a search for 'roof leaks' turned out to be insulation tight against the roof with no air space. Moisture would get through the insulation and freeze to the underside of the roof deck. When the sun hit it, it would melt and run down through the insulation and ruin a ceiling. The fix was to somehow get a good air space in there with ventilation to get the moist air out.

Coolbot's website recommends R-40 on all 6 sides. 2" Foamular is R-10 per inch so 2 2" layers should be R-40. Also, leaving a well caulked air space between layers can add another 5 or so R's.

A steel door with a foam core will have an R-value of 5 or less. High efficiency doors are a little hard to find without paying a wad for one. Most will give you a U-factor but that's related to the glass which you don't want in a cooler. Most don't list an R-value. A 2" layer of Foamular glued to the door will increase the R's by about 5x.

About that discount...you can also get a Coolbot from Amazon but you'll pay $50 more for it.

Anyone have any plans in a PDF file.

You dont need plans or dwg. I sketched mine out on mthrfking hardees bag. Actually all you really need is a brain and a tape measure.

Mine is 8x8 with a 9ft ceiling. With a winch in the ceiling. Plans....pffft!!!

I can get mine down to 36f in about 1/2 hour.

18k btu LG with electronic frost sensor. My walls are 6" thick. Ceiling too and my floor has 3" styrofoam down under 3/4" plywood.

Sounds cool

I've considered building one on a utility trailer so I can move it when it's not in use.

I've been wanting to build one as well. Been considering building a permanent one in the garage or making some modular panels that can easily be erected in a small shop out back.

Planning on a 16x12 shop with a loft. It'd be easy to insulate the floor and loft and then have a couple 6' panels that can be zipped up. Stack them up when not in use.

It'd save some space in the garage and make it easy to put in a drain etc....

I believe the 2" foamular is R-10 in total, not per inch. Be sure to verify.

You're right. I was thinking crooked. Coolbot recommends an R value of 25, not 40 so 2 layers of 2" still get you close to their suggestions.

Just finished painting the inside of a 13'x20'x8.5' just a few minutes ago. AC unit and coolbot showed up yesterday. Thanks for posting.

Rock Chuck,

You also mentioned the doors having about an R-5 You are right, most of them do. I searched around a bit and ended up with a Plyco if I remember right. Their model 31 with insulated frame has an R-11 rating. It was over $500 though, but way cheaper than a cooler door...

the lowest priced door I've seen is a plain steel exterior door with a couple layers of foam board glued & screwed on. I've seen them at Home Depot for under $150, prehung.

I have built-in a number of reefer/freezers on yachts. Present thinking is, for the money, Dow blue board insulation is preferred because it does not absorb moisture (which kills insulation performance). Leave no air gaps at joints in insulation. Insulate all surfaces adequately, including doors. And pay special attention to minimize air gaps between doors and door frames. Use D-gaskets at these interfaces to minimise heat gain.

Perhaps more important than even the vapor barrier is an infrared barrier. Aluminized Mylar can do both; shiny side out.

I looked at the Dow board at Lowes. It has the same R-value/inch as the pink OC but costs twice as much. Lowes only has it here in 2x8' pieces, not 4x8, so it has many more gaps to seal. It's tongue and groove, which the OC isn't but good caulking will take care of that.
Anything I end up building will have siding over it so light reflection shouldn't be a problem.

Unless it's metal siding, use an IR barrier.

Neighbor triple insulated wall and ceiling of about a 12 x 12 foot space with a yard sale air conditioner through the wall. Gets it down into the mid 30's.

I almost hate to bring this up - building permits. I realize that most of these coolers are built without one but they're still required and there's always the possibility of it coming back to bite you don't have one. One easy way to avoid that is to make it portable, like build it on a trailer. You don't even need tires, just a frame and an axle to make it look portable.

We put a big LG ac into the smokehouse. Its well insulated.

I have always had the bot on the list to buy, unfortunately we were not thinking walk in cooler at the time and its got R50 fiberglass in the walls, but the inner walls are sealed and painted, so I'm hoping it works out for occasional use...

Tag

having used walk in coolers for most of my life, and that use here in Florida, I just don't believe this product can work as it says.
Maybe if the outside temps are not very high, or if the 'cooler' is built inside an already air conditioned building. Maybe.
Scary to think of using one of these for restaurant use. I don't see how an A/C unit can pull down temps fast enough to insure food safety.

A big window a/c puts out a lot of cold air. The big problem is that when its in a window, there are lots of air leaks, sun comes through the windows, it's trying to cool a large space, and it shuts down before it gets cold. Its amazing that they work as well as they do.
In a small sealed room with LOTS of insulation and when it's allowed to run, yes they can get cold.

A 12k btu unit is made to cool a 200 sq ft or larger room. Here, it's being used to cool a room 1/4 that size and far better insulated.

My cousin has a walk in cooler in Ohio and has been using the coolbot device for several years. Works great.

Not sure how we progressed to restaurant use. I just wanted to share my satisfaction with this product for home/hobby use. After cooling a few deer this past fall, my wife has been using it to store apples. My brother put me on to these. He has had a walk in cooler for about 15 years, The first 10 were with a conventional compressor system that required a visit from the maintenance man every year. He switched to a coolbot and has not had any problems since.

That being said, visit their website, I do see where they can be used for restaurants if the door is not opened more than 6 times per hour. Again, this thread was intended for options at home. Every tool has it's purpose...

When I was in my twenties, I worked for a division of Owens Corning Fiberglass that used to design and build commercial walk ins...we used to use a type of urethane that wouldn't decompose when exposed to fiberglass resins...not sure what it was called, but it was great insulation...I'd think that either styrofoam or urethane panels 3-4" thick with maybe FRP glued on the inside and a thin gauge aluminum outer skin would work good...a window air conditioner for cooling??? Wouldn't it be better and cheaper on electricity to gut an old refrigerator?

Urethane foam absorbs moisture.

Monthly cost to run the AC with the coolbot here in WI has been about $10-$12 per month for the last 3 months (Nov-Jan), based on comparing this years energy use for the last 3 months to last years use.

Here's another idea to chew on.

Some years ago, our apples got ripe during a major hot spell, in the upper 90's. I needed a way to keep 5 or 6 bushels from spoiling until the temps got down to normal. I rigged a large chest freezer as a temporary cooler. The freezer's thermostat wasn't designed to run above freezing so I used a thermostat from a greenhouse that was designed to keep temps down, the reverse of a heater stat. I cut a short extension cord in half and wired the stat in the middle of it. I dropped the stat in the freezer and ran both ends of the cord out under the lid, plugging one end into the wall outlet and the other to the freezer cord. I put some boards under the apple boxes and left air spaces between them the best I could for circulation. I set the stat at 40 and left the freezer's stat at 0. It would turn on the freezer at 42 and it would run until it dropped a few degrees before it shut off.

While freezers aren't designed to work that way, it actually worked very well for short term storage and the cost was only the price of the stat.

QUESTION: Can someone tell me if it would damage the freezer to keep it that way full time? I don't know enough about refrigeration to know if running it at higher temps is hard on the equipment. It would be more efficient to run the cords through the freezer wall rather than under lid which breaks the seal.

It it's big enough for your needs, it will be far simpler and cheaper...assuming that running it warmer than designed won't hurt it. The largest chest freezer you can find will cost much less than building a walk-in with an a/c and a Coolbot.

tag

* Interested in doing one myself !!

Tagged as well. I've done 24yrs commercial meat cutting in my past life and would like to get a couple moose in each fall. This might be the ticket. Pretty warm here in Sept. so a cooler is needed.