But does it work?  Our results were mixed.

CoolIT USB Beverage Chiller A USB powered drink cooler
	Here's the latest imaginative use of the power source present in a computer's USB port. Looking like a coffee mug warmer, the CoolIT USB Beverage Chiller claims to keep your drink cold.

Does your cold beverage get warm because you're drinking it too slowly while working on your computer?  If this is a problem for you, then a beverage cooling device might be just the gadget to add to your desk.

But does the CoolIT Beverage Chiller actually work?  Our testing suggests it is underpowered and only has an appreciable impact on keeping your beverage cold once you've consumed much of it already.

What you get

The CoolIT USB Chiller comes in an easily opened plastic display box.

Inside is the unit itself and a cardboard display piece that doubles as instructions for the unit.  Nothing else is included, and nothing else is needed.

The unit has a permanently connected cord that ends in a regular USB plug, to plug into your choice of USB outlet.  It takes the power it requires to operate from the USB port you plug it into.

The USB cord is about 5' long, giving you plenty of flexibility for where you place the chiller relative to where your USB hub is located.  If that isn't sufficient length, you can always get a regular USB extension cable to add to its length.

Although the packaging makes no mention of this, the manufacturer's website advises there is a one year warranty on the unit.

The CoolIT Chiller - What it is and does

The CoolIT USB Chiller is the opposite of a coffee mug warmer.  It has a metal plate, but instead of the plate being warmed, and you placing a mug of coffee on top; the plate is chilled, onto which you place a can of your favorite beverage.

The metal cooling plate has an anodized blue coating that the manufacturer explains enhances the heat transfer properties of the plate and makes it more durable.  The plate is 2½" in diameter, which is about the same as the maximum external diameter of standard 12 ounce beverage cans.

The unit is very basic in operation.  There is no on/off switch and neither is there any type of indicator light to indicate it is operating; neither is there a thermostat to regulate the degree of cooling.  If the unit is plugged in to a USB port, it starts working, and stays working until you unplug it again.

The unit does not have a traditional type refrigerating unit inside.  Instead, it uses an electronic 'no moving parts' type Peltier Junction to create what is known as a thermoelectric cooler.

Peltier Junction based thermoelectric cooling

A Peltier Junction based thermoelectric cooler is a solid-state unit, similar to a transistor, and has the curious effect of getting hot on one side and cold on the other.  It transfers heat energy from one side of the unit to the other.

Thermoelectric coolers can be small and lightweight, and because they have no moving parts, they are also moderately rugged in functionality.  They can be used in places where regular refrigeration would be too bulky or fragile.

Thermoelectric coolers are also comparatively low powered.  They are good for use when only a small amount of heat transfer is required, but if large amounts of heat transfer are needed, and there is the appropriate space and environment, regular refrigeration systems will be more effective (and also more energy efficient, too).

Note that Peltier devices don't just cool.  What they actually do is transfer heat from one place to another.  So all the heat that is being taken away from the cold side of the device needs to be dissipated on the hot side of the device.  Because the unit's ability to cool is limited by its ability to have the heat dissipated, it is common for these units to have a fan to blow air over a heat sink affixed to the hot side of the Peltier Junction.

Peltier Junctions can also be used to heat, but if you're looking for simple heating, there are easier and more efficient ways of generating heat (ie resistive electrical heating).

If you were to unscrew the base plate of the CoolIT unit, you'd see a simple layout, with the Peltier Junction's cooling side face up to where you place your can.  On the bottom side of the junction is a large finned heat sink, and on the side of the unit is a miniature squirrel cage fan that blows air over the heat sink to transfer the heat away from the unit.

The unit is reasonably quiet in operation.  The fan makes a small amount of noise, and because it is probably on your desktop and close to you, this noise can be noticeable.

The manufacturer says the unit's cold plate is cooled to about 45°F (7°C) and our sample unit quickly dropped to that temperature, and even dropped a little further.

Using the CoolIT USB Chiller

Using the unit is very simple.  Plug it in to a USB port, and it immediately starts operating, and the cold plate quickly feels cold to the touch.

You can then simply place anything on the cold plate and allow it variously to cool down or to stay cool.  Or, at least, that is the theory of the unit.

How to get maximum benefit from the unit

The unit provides only a very small amount of cooling.  While not an accurate comparison, it is revealing to note this unit provides probably 3 - 4W of cooling, compared to a coffee mug warmer which typically provides about 25W of heating.

To get the best cooling effect, you should use a container with a good conducting metal bottom, and which has a flat bottom making close contact with the entire cooling surface.  A metal mug would be ideal.

Unfortunately, most beverage cans have a concave shape to their bottom, with only a rim around the edge that will directly sit on the cooler.  This reduces the effectiveness of the cooling.

As confirmed by testing, the smaller the amount of liquid being cooled, the more effective the unit is.

You'll get very much better results if you put your can in an insulating can jacket cooler with the bottom cut off it.  By insulating the sides of the can, you cut down on most of the heat transfer into the can, making it much easier for the CoolIT to keep the can cold.

Testing the Unit

We tested the unit four different ways.  We tried it twice to see how well it would keep an already cooled beverage cold, and we tried it once to see if it would cool down a beverage at close to room temperature.

Power Issues

A point of concern was that the unit is rated at drawing 1.2 Amps of current from the 5 Volt power source built in to a USB port.  The USB specification anticipates a normal maximum current draw of 0.5 A, and regular ports in a desktop or laptop computer are usually designed so they variously either will allow for a maximum of about 0.5 A per port, or sometimes, a maximum of 0.5 A to be shared between all ports on the hub.

External powered hubs will often allow for more than 0.5 A to be taken from each port.

If you're connecting this unit to a battery powered laptop, it will of course reduce the battery life, but not by a great deal.  A typical laptop has maybe 50 - 90 Watt hours of battery power, and this unit draws about 5 - 6 Watts.  So if your laptop normally gives you three hours of battery life, at a power usage rate of 25 W, adding this unit would reduce its life down to 2½ hours.

We did note that on our Dell laptop, the unit drew less current than on the other two USB power sources (0.8 A instead of 1.0 A or 1.2 A).  This is good, although it also means the unit is providing less cooling capacity.

Should we test with full or half full cans?

The cooling results will vary depending on whether the can is full, half full, or nearly empty.

The less beverage in the can, the greater the cooling effect - this is due to the amount of surface area of the liquid that is close to the cooling plate compared to the remaining amount of surface area which is absorbing heat rather than being cooled, and the changing proportion between the volume of the liquid and its surface area.

We decided to first test with full cans, so as to see results in the most challenging scenario, then repeat with half full cans to give a best case result as well.

Real world results

Test 1 - lower power, warmer beverage

Our first testing was using a port from a recent model desktop computer.  The port was rated at 0.5 A, and with the unit connected, it was taking about 1.0 A of power from the computer in total.  Although this is twice the specified capacity, the computer didn't seem to suffer any ill effects, and we ran the unit for over 24 hours in this configuration without any fuses blowing or anything else going wrong.

However, in such a case you'd probably want to limit the use of other power hungry devices on the same hub.

We took two cans of Coca Cola, pre-cooled, from the fridge.  We opened them both, and placed one on the Chiller's cold plate and the other on the desk nearby.  The liquid in both cans were tested for temperature using two temperature probes, which were placed first in one can and then in the other, with the resulting temperature readouts being averaged if there was any discrepancy between them.

When testing the temperature of the liquid, we would stir the liquid so as to make the temperature uniform.  Our feeling was that the act of picking up the can from the desk, and moving a straw around or tipping the can up to drink straight from it, would similarly mix up the liquid, and this way we were getting an average temperature of the overall liquid, rather than possibly introducing errors by testing only the bottom of the liquid (colder) or the top of the liquid (warmer).

The testing environment was at room temperature - ie, about 70°F.

At the start of the testing, the liquid in both cans was at 50°F.

After 15 minutes, the liquid in both cans had warmed up to 53° in both cans.  The CoolIT Chiller had made no difference.

After 30 minutes, the liquid in the can on the CoolIT had increased to 55° and the liquid in the other can had increased to 56°.  The CoolIT was making a very slight difference.

After 45 minutes, the liquid in the cooled can was still at almost 56°, which the liquid in the other can had increased to 57°.  The CoolIT unit had allowed the temperature to increase almost 6°, compared to a 7° increase in the regular can.

After 60 minutes, the liquid in the cooled can was at 57° and the liquid in the other can was at 58°.

We did continue the test to the 75 minute point, where the cooled can was still at 57° and the regular can had increased to 60°, but our feeling is that the typical period of time a can of drink would be open and unconsumed is probably in the 15 minutes to 45 minutes time frame.  Much longer than that and the beverage will be flat and stale, and unappealing no matter what temperature it is at.

Test 2 - more power, cooler beverage

For the second test, we connected the CoolIT unit to an external powered USB hub, and this increased its current draw up to 1.2 A.  Of this power, 1.05 A was being used by the Peltier Junction (the other 0.15 A was for the fan), up from 0.85 A in the first test; an almost 20% increase in cooling power, so we expected the unit to perform more impressively.

We also started off with cooler cans of soda.  Most domestic fridges have temperatures in the 35° - 40° range, and depending on how long a can of soda is in the fridge before you take it out, you'd normally expect the temperature of the soda to be close to the ambient temperature in the fridge.

A colder can of beverage would also tend to warm up more quickly when removed from the fridge, due to there being a greater temperature differential between itself and the air around it.

All other test procedures were the same.

At the start of this second test both cans of soda were at 43° F.

After 15 minutes, both cans had the same temperature, 46°.

After 30 minutes, both cans had the same temperature, 49°.

After 45 minutes, the cooled can was at 50°and the normal can was at 51°.

After 60 minutes, the cooled can was at 51° and the normal can was at 53°.

Test 3 - more power, half full can of beverage

When discussing the first two test results with CoolIT, they pointed out that a typical usage scenario will have less than a full can of drink sitting on the desk.  And because a less than full can of drink can be cooled more easily than a full can, it seemed fair to repeat the testing a third time, using the powered USB port for maximum power and a half full can of drink.

All other test procedures were the same.

At the start of the third test, both cans of soda were at a moderately warm 54°.

After 15 minutes, the can on the CoolIT was still at 54° while the other can had increased to 56°.

After 30 minutes, the CoolIT can had increased to 55° and the other can had increased to 58°.

After 45 minutes, the CoolIT can was still at 55° and the other can had increased to 61°.

After 60 minutes, the CoolIT can was still at 55° while the other can had increased to 63°.

Test 4 - cooling a room temperature beverage

Although CoolIT don't claim the unit is capable of cooling down a beverage from room temperature, we were curious to see what would happen, and so placed a full can of warm Coke on the unit and kept a second can alongside.  We left the can on the unit for 4½ hours and then tested both.  The can on the cooler was at 66° F and the can alongside was at 72°; in other words, the cooling effect was negligable.

Test Conclusions

The less soda in the can, the more effective the CoolIT chiller is at keeping the contents cool.  When the can is full, the unit is of little use.  But as the can goes down to half full and less, the unit becomes increasingly effective.

In a way, it could be said this functionality mirrors how you drink a beverage.  You get it out of the fridge, and it is already cold, and you start drinking it.  Then, as time goes by, the amount of drink remaining gets less, while the CoolIT's ability to cool a drink that would otherwise be increasingly warming gets greater.

The CoolIT chiller has no appreciable cooling effect on a room temperature can of soda.

Summary

This is an interesting gadget that will appeal to people who've always wanted a Peltier Junction device.

At $39.99 from the manufacturer and various other sources, it is not too expensive, making it an affordable item to own or give to the gadget geek in your life.  With no moving parts (except for an unstressed fan) it should be reliable as well as simple to use.

But as a practical unit for ordinary people, it is absolutely not an essential 'must have' item.

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Originally published 20 Jan 2006, last update 21 Jul 2020

You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.