(With the ambient temperature steady at 70°, we were interested to see if any of the coolers would make ice while we were tossing and turning. Three hours later we took the temperature again, then left each cooler to run overnight. After two hours we inserted a gallon of water warmed to exactly 100° F. We took temperatures at the 1-hour and 2-hour marks. We learned in our last test, and confirmed with this one, that an empty cooler will reach its lowest temperature within 2 to 3 hours of being started. The thermometer probe was on a stiff wire, and care was taken to make sure it was suspended in mid-air near the middle of each cooler space. We took decibel readings 12″ from the fan. We used a 12-volt power supply (running at 13.8 volts) to power the units, and took electrical current measurements several times, starting about half an hour after each machine was turned on. We tested each unit under identical inside conditions, with the same indoor-outdoor thermometer. The accompanying chart shows the basic test procedures. In any case, if you go to your local department store to buy one of these coolers, better inspect it before you leave the parking lot. Only the Adler/Barbour unit arrived unscathed, possible because it was hand-delivered from only a couple of miles away. (We repaired it with glue.) The shroud inside the Igloo was completely detached and had to be snapped back in place, and there was also some scuffing or maybe roughness due to a poor mold release in the box lip directly above both handles. The shroud covering the Koolatron’s thermopile and fan motor had a stress crack around its mounting screw. The Coleman had a fist-sized dent in the lid. It was joined by the Igloo Kool Mate 32 (the same as last time), the Koolatron cooler from Canada (same as last time), and the Waeco-Adler/Barbour Tropicool Classic TC-32.Īmazingly, three of the four coolers arrived at our offices slightly damaged. This time we tried the Coleman Powerchill 40-quart model. In our ’96 test, the Coleman Thermo II cooler bested the other three units tried. We’ve included dimensions of the units we tested in the chart on page 18. So if you intend to use one on your boat, you’ll need to think carefully about where you’re going to put it and secure it, especially considering that you’ll need to plug it in to a cigarette lighter adaptor or wire it directly to a circuit breaker. Fourth, they’re stand-alone boxes, and big ones at that. It’s better to think of them as ice-preservers, not ice-makers. If it chillier than that, they can make ice, but very gradually. This means (obviously) that they won’t make ice if it’s warmer than 72 degrees out. Third, they generally cannot cool their innards lower than about 40 degrees below the ambient temperature. Second, they’re not very well insulated, simply because their makers expect that you’ll be supplying ample amounts of power to them. That’ll draw your house battery down fast if you’re not generating power to it. First, they’re quite power-hungry, most needing about 4.5 amps continuously. Of course there are drawbacks to thermoelectric coolers, too. Compare the prices in the accompanying chart to the cost of a new compressor-driven refrigeration system. In most cases you simply reverse the plug connection in order to warm the box.įinally, they’re cheap. It’s also lightweight and portable-a cooler with a thermopile and fan weighs only marginally more than an empty cooler, and of course everything except the power cord is contained in the box itself.īecause the Peltier Effect can work both ways, these coolers can also act as warmers. It’s simple, quiet, and has one moving part-the fan. A Peltier Effect cooler removes heat from its insulated space by driving an electric current through those dissimilar metal partnerships (called thermocouples) set up in a series (called a thermopile), and pulling the warmth away from the thermopile and outside the cooler with a fan. Peltier in 1834.)Īs PS readers know, from having read many an article about compressor-driven refrigeration, making an icebox work is not about adding cold air to the space, but by continually removing heat from it. (In a nutshell, when you send an electrical current through the joint between two dissimilar metals, heat will pass from one metal to the other. The last time we tested thermoelectric coolers, back in December of 1996, we spent a fair amount of space describing the history and science of the Peltier Effect, the process by which these coolers work.
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