The Mini USB fridge is a great gift for gadget lovers that don’t chug more than two cans of soda every 2 hours.
While not the first USB beverage cooler to hit the market, Dream Cheeky’s USB Fridge is one of the more attractive models to choose from, mostly because it looks like a bona-fide 1950′s refrigerator. As such, not only can it prevent sunlight from warming the aluminum housing of our caffeinated goodness, but the magnetically sealed door can keep the cold air close to the can instead of circulating it with the warm air blown from the back of a laptop. While this probably aids the cooling slightly, I wouldn’t count on it being as effective as the traditional 6-can mini fridges since the walls and door lining aren’t insulated.
Adding to the novelty effect, inside the USB fridge you’ll find a single blue LED to light up the one can interior, the cables to which are stealthily hidden from view in red sheathing. At the base of the interior is a standard cold plate that’s similar to what we’ve seen over a year ago with the USB Beverage Chiller from CoolIT Systems.
The one obvious downside to the enclosure is its inability to house any drinks larger than your standard 12oz can. This means you’re going to have to just keep on fast-chugging your 500mL water bottles, 16oz “tallboy” energy drinks, 24oz “master cylinder” beer cans, 32oz plastic Taco Bell cups and 10oz glass Bawls bottles, unless of course you’re willing to desecrate their sanctity with ice. Ugh. As an alternative coffee drinker that habitually brings in a can of Monster to my day job, this can be quite an issue.
USB Cooling System
Like the CoolIT Chiller and practically all portable refrigeration systems such as those advertised for use in the car, Dream Cheeky’s USB Fridge employs thermoelectric cooling, based on the Peltier effect. In layman’s terms, the Peltier effect is what happens when electrical current is passed through two different metal alloys, causing heat to be transferred from one junction to another, essentially making one side get hot while the other gets cold. While not nearly as powerful or energy efficient as a conventional refrigerator with a compressor, the low cost, size and durability of the thermoelectric cooler has found it a solid niche chilling soft drinks, not to mention cooling our satellites in space.
The effectiveness of the thermoelectric cooler (TEC) is determined by two primary factors: how much electrical current the system is being fed, and how quickly heat can be removed from the hot junction. For the heat removal, an aluminum heatsink (much like what’s probably inside your computer) disperses heat from the hot junction, and is aided by a small 80mm fan that sucks air from the bottom of the USB fridge and blows it over the heatsink and out through the vents on the front and back of the unit.
Current draw is the larger of the two issues, since USB is only spec’ed to provide 500mA of juice at 5 volts. Thankfully most desktops and laptops will provide more amperage than this if necessary, but even then the cooling potential will still be inferior to what larger TEC’s can accomplish with a car’s 12v outlet. And while it didn’t happen to my two systems, there’s always the potential to overload your USB ports, so it’s preferable to play it safe and connect the fridge to a powered USB hub. Contrary to what the manual says, a Mac or PC with 32MB of RAM and 100MB of disk space is not required to power the USB fridge – there’s no data connection whatsoever.
Actual Cooling Performance
Now that you know how thermoelectric coolers are relatively weak when compared to full-fledged refrigerators, it’s safe to drop the bomb: like most Peltier coolers, Dream Cheeky’s USB Fridge isn’t intended for cooling a warm drink. Sure, it’s possible, but it takes well over a day to chill the drink well below ambient temperature. Rather, the USB Fridge is meant to keep cold drinks cold, and my findings support that.
In this little experiment, I recorded the temperature of two cans of Pepsi every 15 minutes for two hours. One can was placed in the cooler with the door left shut, the other was placed on a cardboard coaster with moderate sunlight shining through a nearby window. Temperatures were measured using an infrared thermometer pointed at a piece of masking tape placed on each can (IR thermometers hate shiny surfaces). Since it’s summer time, the ambient temperature was bloody hot around 28ºC (82ºF), and was also monitored throughout the testing with an infrared thermometer, this time pointed at masking tape on the table.
As you can see in the first chart, while temperatures arose for both cans, there was a noticeable difference between the two, although it only became appreciable after 30 minutes where a difference of 4ºC (7.2ºF) was recorded. After one hour and 45 minutes, the gap widened to 6.2ºC (11.2ºF).
Performing the same test on another two 12 oz. cans with exactly 6oz removed from each had some more promising results, due to the fact that the USB fridge had substantially less liquid volume to cool using the same surface area. Here the difference was only 3ºC (5.4ºC) at the 30 minute mark, but after 1h:45 minutes, the gap widened to 6.6ºC (11.9ºF), and later 7.2ºC (13ºF).
So in case you’re wondering at this point, yes, you really can taste the difference between the two cans in both tests. However, if you actually leave an open soda can sitting for two hours, shame on you, it’s getting flat! Saving a full can for a morning break though is where the USB Fridge really shines.
For a functional novelty item, I was left with solid impressions of Dream Cheeky’s USB Fridge. The retro refrigerator appearance complete with a working light is absolutely brilliant, although it strictly limits the USB Fridge to only cooling 12 oz. cans. And while only good for keeping cold drinks cold, the cooling performance was nevertheless appreciated by my tastebuds, despite the strict power limitations. The only other potential downside to the fridge is the price – while competitive with other USB beverage coolers, another measly $20 will afford you 6x the capacity, sans USB.