I’ve been meaning to write this review up, and was prompted to do so by another post today. Disclosure: No financial connection or anything similar.
Introduction
Some of you here have probably heard of the “Galli” method and the “Mighty Kenmore”, the basic idea of which is to “trick” a normal window air conditioning unit into cooling below its typical minimum of 60-64 degrees. It’s easy enough to do with a resistor, a transformer, a bit of soldering and electrical tape, plus some experimentation to get the temperature right. In fact, I did that myself for a couple of years. But after a frozen window AC unit and difficulty keeping the cellar temperature consistently around 55 degrees, I took a flyer on the Coolbot, which is available on this website for $299: http://www.storeitcold.com/ You can read on the site about the genesis for the idea, which was to allow farmers to create cheap cold storage based on the same principle: window AC units are able to cool well below typical comfortable temperatures for a room, and are cheap. In other words, the same reason why some of us are using window units to keep our precious wine at the right temperature.
Setup
The basic idea is the same as the Galli method, but it’s automated and doesn’t require any real effort to set up. Here’s what the unit looks like:
The Coolbot has three wires (each using a minijack). The first is a temperature sensor to determine the ambient temperature, in order to call for cooling at appropriate times. The second wire is taped together with the temperature sensor from the AC unit, and supplies heat to the temperature sensor in order to call for cooling (i.e., the AC thinks all of a sudden the temperature is 90 degrees). The third wire is a temperature sensor that is tucked into the cooling fins inside the front of the AC unit, in order to detect if the fins are starting to frost up. If they are, it overrides the call for cooling so that the AC doesn’t ice up. The Coolbot plugs into a household outlet using a wall-wart transformer.
Here’s a wiring diagram:
The AC unit is set to the lowest setable temperature, with the fan on high or auto. The Coolbot is set to the desired cooling temperature. And away you go . . . (the Coolbot has some adjustments that I haven’t found to be relevant regarding delay for icing and so forth).
Review
I’ve been using the Coolbot since mid-Fall. It was very easy to set up, and can easily be undone if you want to return it (you’ll end up with a slight bend from the fin sensor in the fins, but nothing you’d see with the cover on). The interface is perhaps slightly less user friendly than one gets in this day and age of Nest thermostats and iPhones, etc., but it’s really not that important once you’ve set it, and the instructions are quite clear on how to change the various settings if you want to tinker. The quality of the unit is solid - I don’t think this is a large production device, so it does have a bit of hobbyist/Radio Shack look, but the quality of the bits is great and the fit/finish is excellent. It’s not meant to be a design statement, but rather a functional control unit.
The Coolbot has kept the temperature of my cellar at the setpoint of 55 within +/- .3 for liquid (with bottle probe) and about +/- 1.5 deg for air temperature, regardless of the temperature in the surrounding basement (which fluctuates more with seasons). I have yet to see the AC unit freeze up or have even some frost. I have the fan blowing constantly (as recommended by Coolbot) but the compressor is running only a small portion of the time. I’d prefer it to keep the air temperature a bit more consistent, but it has been within the claimed variation in the instructions and on the website. Of course, air temperature is less important than liquid temperature, so it’s not much of an issue. Ideally, however, one could adjust the acceptable deviation to a lower number.
$299 is a bit pricey, which I think reflects that there’s not a huge market for this and the inventor is trying to recoup what likely took a lot of experimentation and some relatively high costs to get these items fabricated. If you prefer to tinker with the Galli method you can do it for a lot less in parts, some amount of time (your value may differ) and end up with a less attractive look (which may not matter). Or you can buy this and get it all ready for you and spend 5-10 minutes setting it up. Having been not entirely satisfied with my own efforts at the Galli method, I turned to this and am quite happy.