Do-It-Yourself Walk-In Cooler

Do-It-Yourself Walk-In Cooler MISCELLANEOUS EQUIPMENT Miscellaneous 33-4-34 Why spend $2,500 or more on an 8 by 8-ft. walk-in cooler when a room air conditioner will do? Until market gardener Ron Khosla developed what he calls the CoolBot, people often used an air conditioner to keep produce fresh, but the units were hard to control. "A room air conditioner can produce enough btu's to cool a room down, but the fins will start to freeze up when you get below 65 degrees," explains Khosla. "A room air conditioner doesn't have the fans and surface area needed, but if you modify it, you void the warranty." With more than 200 customers to supply weekly, plus sales to restaurants, Khosla and his wife Kathryn needed reliability and ease of control. The problem was, as a small farmer, he also needed a low cost system. Commercial grade walk-in coolers were expensive to start with and notoriously expensive to repair. Khosla found out he could make an A/C cooling system work if he constantly monitored it to prevent freeze-up. His challenge was to find an automatic way to do so. The solution was the CoolBot, a micro-controller that constantly monitors the walk-in cooler temperature as well as the A/C unit. It checks for frost or freeze up and adjusts the A/C fan and compressor as needed. "We tried doing it with analog components, but they weren't much cheaper, and they only worked 90 percent of the time," says Khosla. "Of course the one time it would go bad would be when the coolers were full, and we would suffer huge losses. Our micro controller is able to make decisions at a more complex level, and we haven't had any problems since we got it set right for different air conditioners." Installation is easy. Simply plug in the CoolBot to a wall outlet. It takes about as much energy as a cell phone charger. Let the wire labeled room temperature sensor hang freely. Stick the wire labeled frost sensor into the cooling vents of the A/C unit. Attach the third wire to the temperature sensor on the A/C unit with a piece of aluminum foil for thermal connection. Khosla says the $299 CoolBot will cut cooling costs by close to 50 percent compared to a commercial walk-in cooler. He points out that a single visit from a commercial repairman can cost as much as a CoolBot. Khosla keeps costs down by assembling units on his farm. This also gives him complete quality control. "We put the boards together, solder the contacts and assemble the finished product," he says. The CoolBot works with any size, brand and age A/C unit going back to 1970's. Khosla recommends properly insulating a walk-in cooler with at least 4 in. of Styrofoam in walls, ceiling and floor. A/C units also need to be sized to the room for efficient cooling. Contact: FARM SHOW Followup, Ron and Kathryn Khosla, 205 Huguenot Street, New Paltz, N.Y. 12561 (ph 845 810-0033 or toll free 888 871-5723; farm@flyingbeet.com; www.storeitcold.com).

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