Kate and I (Ron Khosla) started Huguenot Street Farm in New Paltz, NY in 1999, a 250 family CSA with additional sales to several restaurants and two grocery stores.
As small farmers, we learned the value of money the hard way, literally pulling it a few cents at a time from the ground. So the idea of spending $3,500 for even a used walk-in cooler wasn't appealing. I'm completely a "do-it-yourself" person, so I also didn't want to be reliant on a repairman who charged $80 an hour to install and then repair a normal walk-in cooler compressor every time something happened --which is exactly what I saw happening to neighboring friend-farmers.
I got the idea to make an air conditioner function as a cooler from the USDA! They came up with a plan where you hardwire a high amperage timer onto the compressor and add "heat tape" to the fins of the air conditioner to keep it from freezing up. I excitedly did it!
It was way better than nothing, and we were grateful for it. But it's just not "great". You can't set the temperature (it's just a timer based system), so you guess based on ambient temperature. It gets colder, but not as much as you'd like. High-amp timers are surprisingly expensive, and you have to be okay with getting deep into the guts of a your a/c in a way that will not cause a fire while you sleep! No matter how good a job you do, you are dramatically voiding the warranty (5 years on new Energy Star Air conditioners!)
The worst part is that since it's not a "smart" system, changes in the amount of food being stored, door openings, outside temperature/humidity could cause the front fins to freeze into a solid block of ice while we slept! The next morning we'd walk into a warm cooler with smelly yellow broccoli. Depressing, and expensive in terms of lost sales.
We fiddled with the USDA system for 2 seasons. I loved thinking about the money we were saving on a "real" cooler (on the days it worked well) and I especially loved hearing our friends complain about cost/slow response time from their compressor repairmen! *I* was in control! But Kathryn, representing the more practical side of the family, wasn't so impressed with my control.
We couldn't get it as cold as we should, so the "fresh" veggies we were giving out looked older than the grocery store produce from California. And it was dependent on outside-temperatures, so, the hotter it was outside, the worse looking our produce was. PLUS we had multiple (infrequent but very expensive) complete overnight freeze-up failures each season which meant lost revenue and lost-time picking through gross produce. By the end of the second year it was clear that our losses were greater than the cost of a "real" walk-in cooler.
We planted extra vegetables and made sure to harvest closer to the last minute to account for losses. We wasted water, electricity and LOTS of time "hydro cooling" veggies with our well water. And we got in a habit of making multiple trips a day up to the cooler because we could never trust that it might not be freezing up. (Okay, I can't really complain about the last part on 95F days, but it did interfere with field work, especially when it WAS frozen up, which meant a long defrost cycle).
But I couldn't give up, and the reason was that every time I STAYED in the cooler (NOT to avoid work as Kate claimed, but rather to, um, constructively investigate the conditions that caused freeze-ups and to manually control the compressor!) I could get the air conditioner down to 35F with NO TROUBLE!!! The problem was that when I left it back on the timer and heat tape system, it would (unpredictably) freeze up well above 45F!
The obvious solution was that I needed to substitute an electronic "brain" for what I was doing manually in the cooler! My old college room-mate Timothy was a Cornell engineer with a high-tech job and a really soft heart. We spent the next season going back and forth making just that! Today's CoolBot is a micro-controller brain with multiple sensors attached to it that automatically make the decisions I figured out sitting in the cooler (when Kate was out working the fields).
Okay, that last statement was completely unnecessarily added by Kathryn. I would like to note that NOW I have plenty of time to work in the fields, because our cooler works perfectly EVERY SINGLE DAY!
So that's the end of our story! From our veggie farm, we've sold over 25,000 of these since 2006 to all corners of the world! So COOL! :-)