DIY: Walk-in Cooler (not really auto related...)

Builds
1

I posted this on another site, here is what I posted there. Maybe someone on here has some experience and can help me with some of this. I will also be posting up the build thread of my brewing rig one of these days… It is pretty kick ass!

I am in the process of purchasing a new home, and I have already begun my RIMS system build to be able to produce qty’s of beer. My wife and I are pretty excited to buy a house with a good size basement where we can build a full bar / entertainment room. A big part of this build to me is going to be a walk-in cooler. I have wanted one since I was 18, and now I finally have the means and space to construct one. I priced out purchasing an 8’x8’ but it was upwards of $4,000.

I decided that I should google “DIY walk-in cooler” and to my surprise HBT was the first link that came up. Specifically John Beere’s build. Now that I have read all of that, and all of the other subsequent builds similar to it, I feel that I have a great starting point to work from.

Here is what I have thus far:

  • I will be getting my hands on a 10,000 BTU Air Conditioner to use.

  • The room will be framed with 2x6 pressure treated wood, and will have a floor built the same (maybe 2x4 on the floor… not sure)

  • I live in Buffalo NY where it gets very cold in the winter, so I prototyped, built, and tested a control panel that allows two temp controllers to measure the cooler temperature and the outside temperature. It determines if the cooler needs to be cooled, and if so it will determine if the temperature outside is sufficient to directly pull filtered air, or if it needs to use the AC unit to achieve the desired temperature.

  • I have decided that I do not want just a cooler, but also a freezer built inside the cooler.

  • I want the total interior space to be 8’x8’ or 7’x7’ I will have to look at the space that I have available after we settle on a specific property.

Ok, enough blah blah blah background, here are the questions:

If I place a freezer inside the cooler, I will obviously want the AC to be inside of that space. Should I just place a baffled fan on the freezer wall to blow freezer air into the cooler when the temp control in the cooler demands it? Also if that is the case, and the outside air is cold enough to maintain the cooler and not the freezer, should I just pull outside air into the cooler instead of running the ac? Here is a crappy drawing of what I mean:

http://www.nyspeed.com/forums/../tpgsr/Cooler_Layout.jpg

My biggest concern is the insulation. I can wire a factory to make it automatically, but I have no idea what I am doing with R-Values or what types would be best suited to this application. My boss suggested using the foam sheets nailed to the outside then spray foam to fill between all of the studs then more foam board on the inside (moisture proof stuff). I am not sure if this is the best way to go to achieve a superior R-value. This setup will be in a basement and will have two walls up against the foundation. I will frame out these walls but I am concerned with moisture on my insulation creating mildew.

Any suggestions on how I should approach insulating this thing? Floor, Ceiling and Walls will all have to be taken into account. The actual floor will be tiled or vinyl, most likely tile over a backerboard made for bathrooms. The insulation will have to go under that.

This is all I have for now, I am sure that I will be adding more as this is even more daunting than my RIMS build.

2

I would always run the AC. it will draw any moisture out of the air, just make sure the drain is to someplace out side of the room though.

also, walk-ins typically have that fiberglass type of covering on the walls, I am sure sheets like that glued to the walls (think bath tub surround) will keep any extra moisture at bay off of the interior walls/wood.

3

I plan on using the white sheets as the final layer on the walls. They will be white painted aluminum, and the seams will be sealed with silicone.

Good point on the Moisture in the air, would running a dehumidifier be a good solution to that? I mean, I am trying not to run the AC all of the time, I guess that a dehumidifier is just as bad though. The goal is to get the R-value up high enough so that the BTU loss per hour is very minimal and I will have the AC running very infrequently. The less the AC runs, the less this will cost me per year. I would like to get this to like $20-$30 operating cost per year. (I didn’t get that out of thin air… a guy with a 8’x6’ room metered his usage and noticed a total cost of $24/ year)

4

a dehumidifier would be exactly the same thing (basically) except it doesnt have a fan to move the cold air, just a coil that pulls the moisture out of the surrounding air. I would use a dehumidifier only if its usage is less than the usage+more cold air benefit of the ac unit.

if you are really doing the logistics on this for energy use, will spending 50-100 on a dehumidifier+ its running costs offset what you would save by running the AC a little less? plus cost/hassle of plumbing the drain (and taking up more of your 64 sq feet) for the dehumidifier too, im sure you wont want to remember to drain the reservoir every so often

5

True. My other concern was running the AC with temperatures outside in the 10 deg. range. I will be blowing intermittent warm air over the coils to keep them from freezing up, but I am for some reason thinking that the freezing air outside will cause issues with the unit… Am I wrong?

The software that I am using to design this is super cool… Chief Architect

http://www.nyspeed.com/tpgsr/3d.jpg

6

my thoughts would be that the AC unit would have a thermostat to sense if it needed to turn the compressor on; if its cold enough to put out the desired temperature it doesnt need to run the compressor, just the fan.

and that rendering is sweet, but it looks mighty cramped.

7

I guess that I can rewire the ac unit to my controllers… Fan or fan/compressor, that would be just as easy as wiring my own fan in the window.

The grain bins are not going to be that big, that was just what the software had readily available to throw in the space. Either way, I want it cramped. I am not going to throw a party in there, I am trying to make it perfectly functional space. There will be 5 kegs total, stacked in a pyramid shape 3 bottom, 2 top. I will also be able to remove one of the grain bins if I need more room. Still need to figure out in my full scale model if I want the freezer larger or smaller.

8

I would frame it with 2x6s and then use R30 fiberglass. Fiberglass has the highest R rating per inch. Then, on the inside I would use the foil-backed foam board. I think I’d use the “shower” vynil sheets to finish the interior walls.

That’s a very cool concept though for the cooling system. I can’t wait to see progress.

9

Just a quick word of advice…if you’re only doing it yourself to save money, you’ll likely find out that will end up costing you more by the time you factor everything in that you didn’t think of at first.

DIYing for self satisfaction is a different story though.

My biggest concern with a DIY build on a freezer/cooler would be moisture control. Not the humidity, but long term leaks that get past the walls and floor and now into your furnished basement.

10

There is a local company that installs cooler/freezer insulation for a living…
A guy from my six sigma class worked there, but I can not for the life of me remember the name. I’ll bet you could track them down, and get info/quote… then DIY?

11

For Insulation, I’d suggest the spray-in stuff that one of the guys here used in his upper bedroom he did. That way it will seal up any/all air paths and block any leaks as well as providing a great thermal barrier.

Edit: As another thought; everyone is saying use R-30. I like that idea, but would add something else to that. I’d use the 1/2" blue/silver foal insulation on the inside of the “outside” wall, then spray-foam around it to seal it to the outer wall. Then use the R-30 fiberglass on-top of that; then a vapor-barrier; then your inner-wall. That would probably be your cheapest and most “Sealed” way to do it.

12

A few things…

  1. I thought air was the enemy with grain storage, not temperature? If so your fresh air cooling is probably going to be a bad idea. You might be better off investing in a decent vacuum sealer and just storing the grain in an unrefrigerated section of your basement.

  2. I’m pretty sure any window AC unit you buy is going to ice up if you try to run it in the winter. The way they are designed to just drip the water they pull from the air will likely build up ice in a hurry when it’s < 20 degrees outside.

  3. I second the idea of 2x6 with R30 fiberglass.

  4. I would put both your AC and outside air intakes inside the freezer. Then your two temp controllers can work to keep both areas the proper temp by always pulling the coldest air in through the freezer.

  5. You’ll probably need more than just a fan to separate the freezer and fridge sections. I think a fan alone will leak too much air and you’ll find that your fridge section turns into a freezer. An servo activated baffle door would solve this issue.

  6. Like Lafengas said, the 4k for the pre-made one will probably end up being cheaper and better.

13

also, I rescind what I said about the dehumidifier. I wasnt thinking the air conditioner would be in a separate ‘room’ away from the refrigerated section. maybe one is needed to keep that section at a desired humidity. the humidity in the freezer room wont be a problem really because its frozen.

and idk if you can get a pre-made unit with separate freezing and refrigeration sections. maybe a pre-built one with a hole cut in the side for a full-size stand up freezer to be glued/sealed into place? (you cant have it just inside the cooler because the coils on the back need fresh air circulation to release the heat it pulls from inside the freezer.)

14

Make the walls out if thicker metal, and seal them up so you can pull a vacuum. :smiley:
Then you only have to worry about conductive heat losses.

15

saved me from typing out what was on my mind.

16

I am doing it for both reasons. I have read and followed several builds of walk in coolers as DIY and all of them came in right around $1000 dollars. Mine will probably be more based on the fact that I am attempting to place a freezer into the space. I am not too worried if I go over budget, but I really do not want to buy a commercial solution if I can build something comparable myself. I like building things. I will also be sealing up all joints and using adhesive where possible instead of nails. That will help keep the two environments safe. There will be a few areas where conduit has to pass through the walls and I will be sealing those areas up with foam. I have to look into the best means of sealing everything because a leak into my finished basement would be devastating. I would cry if I had to throw out furniture due to mildew.

My boss suggested the spray in foam, but there are lots of different types. That is what I was looking for from here is what type would be the best to use. Open cell, closed cell etc… I was looking at getting something like this to use: http://www.fomofoam.com/HVAC.htm

  1. Air and temperature. They will be in sealed bags inside of the plastic containers. If I am pulling air from the outside directly with fans, it will make it’s way through several filters before entering the cooler. I will probably have filters on the AC box as well to keep the air good. I mean we are dealing with food.

  2. The icing up is a concern, and one solution that has been proven effective on other builds is to place a couple small fans blowing “warmer than freezing” air back over the coils to keep them from freezing up. I was also mentioned that this is running so infrequently after it is cooled inside that you can monitor it over the first cool down, and then not really have to worry about it freezing as it is not running long enough to build up much condensation. I will do some more research on this, as it may be a big sticking point.

  3. Isn’t R30 fiberglass really really thick? like thicker than 6"??

  4. My concern is that if it is cold enough outside to keep the cooler cold, and not the freezer I will be wasting my energy running the AC to chill the freezer as the cooler is pulling it’s air.

  5. Everything will be baffled. I just put the fans in there for the concept, but the air will only go in one direction.

  6. Better oh yeah, but I really do not need something that is overpriced for my uses. Industrial coolers are expensive as they are built for continual traffic. Mine will hardly ever see traffic and will not need to have the insane cooling power of the commercial units. If I can get my insulation to the same level as a commercial unit then I have nothing to worry about.

When I worked in a kitchen, we had a massive cooler and the freezer was built in to one of the corners. I can not use that cooler as a design example because it had three 2 fan cooling units in the cooler section and one large 3 fan in the freezer section.

I would think that I could run a line from the dehumidifier to the same drain that the ac line is going to be run to. For clarification on the freezing of the drain line on the AC, the pan and the drain line will be wrapped with a heat trace wire up to the point where it goes through the insulation and into the external drain.

Keep the feedback coming, This is getting me thinking a lot! Seems that this project is going to be quite the undertaking… I wonder how long this will take to build out and get working 100%

17

you could check out Welsh Restaurant supply, which is here in binghamton. They get used stuff all the time, and pretty good stuff too.

Check them out: http://www.equipment123store.com/walk-in-parts-prod.html

18

The spray-foam link you send is going to cost some serious $$ though.

The more I think about it, the more I suggest the other method I suggested. R-30 is made for 2x6 walls. I think you’ll get very similar results with the Foam-Board/Spray-Foam/Fiberglass/Vapor-Barrier method and it’ll be a LOT cheaper.

19

The other guys that did it use Aluminum bubble vapor barrier / Fiberglass / moisture rated FoamBoard and used glues to hold everything together. Some nails, but a lot of ashesive.

Here is a build thread where he makes a lot of mistakes as he goes, but with the help of others he still gets the project done and quite nicely.

20

Fiberglass, blankets and batts 3.33 per inch 3.33*6=19.98 R-20 for the walls.

Urethane foam 5.3per inch 5.3*6= 31.8 r-32 for the walls.

The spray in insulation is more expencive, but if you are going to keep your cooler 36-40° all the time the little bit more $ you pay for insulation will totally pay off in the long run. (prolly “short run”)
http://www.sizes.com/units/rvalue.htm

Another option.
the R-value per inch of Johns Manville’s AP Foil Faced foam sheathing product?

6.5/inch. Polyisocyanurate foam has the highest R-value per inch of any residential insulation.

6.5*6=39 you could be up close to a R-40.

Good luck on your build it sounds REALLY “cool” waka waka waka!