Can I build a walk-in cooler with a Coolbot?
May 16, 2017 9:11 PM   Subscribe

I have a budding (sorry) flower farm, and I need a walk-in cooler. The Coolbot promises I can build a small walk-in cooler for under $2,000, but I am skeptical of this device and it's hard to pin down how well it works. (A lot of the reviews are one-offs, but there are also many good, seemingly legit reviews, and I just can't tell anymore.) Has anybody used this? Could it really work? If so, advice on building cooler?

Commercial walk-ins start at about $3,000, and I'd have to put it in my garage (very painful) or build a separate shed for it (expensive, and probably taxable, since foundation).

The Coolbot claims to take over an air conditioner's brains and make it cool a (smallish) space down to near freezing. I've read comments like "Oh yeah, all the brewers are using them." But then the thread ends.

Let's say it works. A 6x8x6 walk-in cooler would fit in my space (inside a well-ventilated breezeway, with a roof overhead). I hope to build a well-insulated box out of 2x4s, plywood sheathing, and layers of insulation. The company recommends 4 inches of insulation all around; it comes in inch-thick panels that I guess I'd have to glue together around everything basically, with holes for a door and A/C.

Does that sound at all feasible?

I'm posting this here specifically because I think Mefites are pretty skeptical and might be able to reality-check me, or vouch for this concept.
posted by Camofrog to Home & Garden (12 answers total)
I'll have to ask at the local brew pub, but they definitely have a window air conditioner or two poking out of their walk in. I don't know that that's all there is to it, but I don't see anything else poking out at a glance, and it's totally the place's style. Memail me a reminder and I'll ask tomorrow - I'm likely to bump into the owner. I suspect that he'd much rather talk about how he cools his walk in than a lot of topics that he's asked to discuss.

As far as plausibility - a fairly mid-sized window AC can trim 20 or 30f degrees off a barely insulated room that's several times larger than the one that you're proposing without running that high a percentage of the time. The biggest threat I see to it working is that if there's very much humidity at all, it's all going to freeze out on the coils, which are in turn designed to operate in an environment where the ambient temperature is well above freezing. Even so, in a properly humid environment they tend to ice up without much provocation. It's probably not such a problem when the water is all stored neatly in kegs, and you only walk in to change a keg or load inventory occasionally, but I could see flowers posing a whole different set of challenges.
posted by wotsac at 9:39 PM on May 16 [1 favorite]

Look for a used one out of an industrial setting. I think they are called a knock down cooler, knock down walk in refrigerator. Here For example ebay, but there are used dealers. For $200 is your door.
posted by Oyéah at 10:00 PM on May 16

I've seen a 40ft insulated shipping container cooled to ~40F with two window air conditioners. Is your question about the feasibility of cooling power?

Here's a BTU calculator designed for heating. I suspect it would be valid in reverse as well, as in both cases you're just dealing with adding or moving heat.
posted by reeddavid at 10:44 PM on May 16

Wotsac, the Coolbot apparently circumvents (somehow) the icing problem, or tells you how to manage it.

Oyeah, as I said, I don't want to buy a completed unit for several reasons, but thank you.
posted by Camofrog at 11:11 PM on May 16

There's no reason it shouldn't work. There's a heater output for melting ice off the coils.

Make sure to use glue rated for contact with foam board. One of the PL series says "foamboard" on it.
posted by flimflam at 3:03 AM on May 17

Here is the exact video review that you need:

Also his other videos might be relevant to your business.
posted by TomFoolery at 8:58 AM on May 17 [1 favorite]

You can get foam insulation much thicker than 1", this will save you a lot of gluing. And I'd use sprayfoam on all the gaps. I would also use the "staggered stud" method on the walls, this greatly increases the insulation without using more materials.
posted by 445supermag at 1:14 PM on May 17 [1 favorite]

I have one for my cold room! The space is about 12 x 10 x 8 with 4 inches of styrofoam insulation and it serves for veggie storage. Icing hasn't been a problem. Temp stays below 40 unless it's over 100 degrees out. Works good. MeMail me if you have any more questions.
posted by Rust Moranis at 2:09 PM on May 17

Yeah - I didn't confirm that the brewery is specifically using Coolbot, but they're using a coolbot like device, and it works pretty well for them. I certainly have no complaints about the temperature of their beer.
posted by wotsac at 5:29 PM on May 17 [1 favorite]

I appreciate the reassurances! As it turns out, I thought to text another grower whom I sell to, and she has been using a Coolbot for four years without much trouble; she did advise me not to skimp on the foam.

So I grabbed what I needed for the floor today, and with luck it will be running by the time I need it, a week at the outside. I'll try and remember to report back!
posted by Camofrog at 7:53 PM on May 17

My father has a farm. I don't know that he still uses it, but when he first started processing chickens and stuff this is exactly what he used. I wasn't part of the installation so I can't offer much more than: Yes, farmers starting out totally use it.
posted by palindromeisnotapalindrome at 10:54 PM on May 17 [1 favorite]

Follow-up: I built my 6x8 cooler using a 10,000 BTU A/C unit and four inches of foam on all sides, including the floor and ceiling. (It actually needs another two inches on the ceiling when I get to.)

It's almost 90 degrees outside today, and it's 35 degrees in my cooler. It really does work. I have peonies that have been sleeping in there for six days, no problems at all.
posted by Camofrog at 9:00 AM on June 11

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