lll throw my input here since I did commercial HVAC and refrigeration for a period of time but got out of it a few years ago.
If your going to go the route of DIY I would not depend on any walls in your house. Build a box pretty much floor, walls and ceiling. Your biggest concern will be insulation. As everyone has suggested foam in between the outer and materials is the typical out there that I have seen in the commercial world.
Now using a ac unit to cool this walk in cooler seems crazy to me. What temperature are you looking to acheive in this walk in cooler? The only thing that concerns me is that an AC unit is meant to cool to a certin point like 60 degrees. A walk in cooler on average is 35-40. Usually a different type of refirgerant is used to acheive this goal. If your AC unit is working to hard to cool you will have problems with it.
To touch on the freezer it needs to be an independent unit from the cooler IMO. Going back to refrigerant theory a different kind is used to acheive this goal.
I havent read to muuh into these DIY cooler and freezers but I have seen some pretty shitty ones while out there while working. Spending a few thousand will problably save you alot of headaches in the long run. A self contained unit would probably be your best bet. Pretty much you put up your box drop the cooling unit on top of the box wire it in and your good to go.
Feel free to shoot me a PM if you want to know anything else.
i like walk in coolers. thats where i spent most of my time in one at a pizzeria that i used to work at. i had a lawn chair in there. nothing beats it on a hot summers day, maybe a beer though. with the design though i wouldnt recomend linolium. it is slippery when cold and wet.
Some updates from another forum, then I will post some responses in here…
This is great. I was looking for some insulation with a high R value. I will look into using a core of foam for the wall and metal sheathing, but I fear that may break the bank, and not be as sturdy. I will have to see.
Vapor barrier I got, do i need it on the inside and the outside though?
We are aiming for a R-Value of 40+ and using materials that are mold inhibiting. Mold in my house is the last thing that I want!!
To keep the coils warmer than freezing, I was thinking about taking a run of heat trace through the drip pan so that the water would not freeze and could drain, as well as pulling “warmer than freezing” air over the coils using fans and some ducting or small heaters only when the unit is running. I can go into further detail if this seems confusing, but do you think that would help keep the unit running? I got this idea from the original thread posted by John Beere.
The fan that I am using to pull in the air is a very solid unit. It is very small and has a flow rate of 100 CFM running at .21 Amps. It is made by Hoffman for industrial environments. I may take the fan from the outside and nix it, and just have a fan moving air from the freezer to the cooler.
I had thought about doing this as well, but allowing the exchanger on the back of the freezer to breathe outside air…
I like the idea, but I would 1000x rather have it as a functional built in freezer within the walk in.
I guess since I only left it like 3’x3’ I will not be losing much space by placing a large freezer in there. Ok, back to the drawing board… Freezer ducted in, and the cooler operating off of an AC unit. I would assume that it will help to keep my freezer from running all of the time having it in such a cold environment.
Cool. Vapor on the warm side. Got it.
I am going to just put a freezer in the cooler. What I will do is build the back of the freezer flush with the outside of the frame, and spray foam the **** out of it where it meets up with the walls. I do not have my design program at my office, but I will make up a new drawing when I get home. I just can’t wait to get out of my current house and get a fresh slate to make a nice brewing area with a bar and “Man Cave” in the basement.
GVH Dan made some good points, and seems to have some experience. One very important thing that hasn’t been mentioned is that you should not have any sides of the freezer common to the walls or floor of your basement. I would recommend an air gap on all sides, except obviously the floor which should be raised. Most industrial walk in freezers actually heat the floor slab to prevent the are beneath the concrete from freezing. If the underside of the floor or wall is allowed to freeze there is a very good chance the concrete will heave. I’ve been in a couple industrial freezers where there are cracks that run the whole length of the freezer (150 feet-ish) and stick up over two feet.
Moisture will always try to go from high vapor pressure to low, which typically means from warm to cold areas. You will have moisture from your cooler getting into the freezer which means defrost should be expected. Almost any refrigerant can be used to get temperatures below 0 F, the challenge is making sure the refrigerant pressures are regulated to get the desired temperatures. Almost any system you buy will have either a thermal expansion valve to regulate this pressure, or a back pressure regulator. Most refrigerations systems use a coil temperature 10 degrees lower that what you’d like to maintain. All home a/c units are regulated to 45 degree refrigerant temperatures or higher to avoid any of the issues associated with freezing.
Most refrigerators take air from the freezer as you mentioned and use it to cool the refrigerator. Two big advantages to this method are that less equipment is required, and you can count on your moisture being collected in the freezer as ice and not in the cooler potentially causing mold. The major drawback is controlling both temperatures with one cooling source. The best way to do it would be to have a fan in the freezer VFD’d or intermittently blowing toward the cooler with a dampered return to the freezer (simple flaps would be okay). I would put this fan toward the top of the wall between the two, and the return as far away as possible from the fan to assure circulation through the cooler.
Because the coil is the coldest part of the system, most well designed refrigerated warehouses prefer to have a coil running as often as possible, because moisture infiltration is predictably accumulated on the coil instead of on walls or product. This is not what you are looking to do obviously, but using the model of a typical home side-by-side refrigerator should work well.
Most freezers including the one in your kitchen have a hot gas defrost cycle, where high pressure refrigerant is pushed through the evaporator heating the coil surface and melting the ice. This is the most efficient way to ‘thaw’ a coil and can be set up to be automatic or require a button push.
I would put one temperature sensor in the cooler controlling the fan, and the refrigeration bulb (assuming residential type device) in the freezer. That way the freezer always maintains temperature, and the cooler is an indirect load. I would put some insulation, maybe foam board between the two so that the fan controls the cooler temp and you don’t have to worry about over-cooling of the cooler from thermal conduction.
Maybe… But this is not really a everyday home type of thing. I just searched out other DIY projects that were done, like lafengas’s tables and they were in here so i went with here.
You be my guest and move it if you want
I am learning a lot too. This is actually quite insane how much information I am picking up on this subject. I may have to make a career shift after this is all said and done.
Don’t worry about having two moisture barriers. In a refrigerated area where the moisture will always be moving in one direction, it’s not bad to have a skin on the inside and outside. Once you’re done with the framing and foam it might be a good idea to wrap it in plastic then put your outer skin on top.
A standard window type A/C does not have provisions for hot gas defrost or other. This normally includes a separate refrigerant line and a solenoid that would be hard to retrofit later. I would look toward using something designed for use in a freezer.
Blowing warm air over a frozen coil will mean that you are blowing warm air into the space too, and unless you are exhausting the air as it’s going through the coil, the moisture will either condense on the walls or end up back on the coil.
I am still trying to digest your initial post, but you ahve given a wealth of info here.
I am going to not build the freezer out. I am going to place a freezer within the cooler. I will update my drawings later tonight when I get home… my computer crashed, and I had not saved my work. I will start over and actually build this properly in the design program.
The final layout will be a 8’x8’ or 8’x10’ walk in cooler (depending on the space in the new place) with a large reach in freezer in one of the corners of the room. I will be doing testing to see what kind of heat the freezer displaces from the rear before deciding if I want to frame it into the room and displace the heat to the basement.
The AC will still ahve air blowing over it, but it will not be Hot air, it will be “warmer than freezing” air. Basically i will be taking air back from the cooler (the ac is now in the cooler not the freezer) and blowing it over the coil so that it will not freezer up under load.
I would build the freezer into the wall; dumping the heat from the freezer outside the room; no use in wasting both space and heat/electricity on dumping the freezer heat into the walk-in.
One of the guys on the home brew board said that his concern with building it into the room would be the increased chance of heat transfer/leaks at the seam where the freezer is built into the wall. He also mentioned that the air coming out of the back end will not be too hot as it is using cold air already.
I like the built in idea better though. (Built in to the wall, not a built freezer. Even though I really did have my heart set on that ) I think that it will look better and be more efficient.
I don’t think sealing around the freezer will be a big deal. Make the “hole” maybe 1/2" larger than the freezer; then just spray-foam it in. Cover the 1/2" gap/foam with trim. If the freezer fails; then just use a hack-saw and cut it out and replace. I’d make sure you have access to the back of the freezer though for mechanical repairs. Maybe put it on the same wall as the rest of the HVAC stuff so all that can be hidden in a “closet” next to the room.
Almost exactly what I am going to draw up. Shouldn’t the AC unit still pump on the other side to go out to the outside? or should I just vent the utility closet to the outside to dissipate the heat from the freezer and the AC?
The storage room would be ideal as I need somewhere to keep my empty kegs and all of the not in use brewing equipment. FUCK YEAH!!! in two days this has gone from a pipe dream idea to an actual representation that I can easily build in a couple weeks time!!!
Most places build the walk in cooler as an external structure that is actually attached to the main building, but it is actually outside the building on its own. I’m sure this plays to your favor during the winter, as you have a metal box attached to your building that is outside on its own.
The refrigeration units are much larger than any home air conditioning system.
The ones I have seen use form panels for insulation and diamond plate to protect it.
There are at least two large compressors mounted on the roof of the unit, one for fridge, another for freezer.
The freezer is a room inside the fridge and they obviously have a weather tight door between them.
Its a pretty serious project, I probably would not DIY. How close are your neighbors? When I worked at Teds, the people who lived behind it would be pissed at the noise coming from the compressors that would run non stop.
Have you considered what the electric bill would be? Surely you would need at least 2 dedicated 220v lines, not to mention permits, electricians, and wiring it.
) I think that it will look better and be more efficient.