A USB powered drink cooler
Here's the latest
imaginative use of the power source present in a computer's
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
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 CoolIT Chiller - What it is and
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
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
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
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
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
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
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
How to get maximum benefit from
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
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
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
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.
test with full or half full cans?
cooling results will vary depending on whether the can is full,
half full, or nearly empty.
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
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
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
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
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
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
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
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
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.
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.
This is an interesting
gadget that will appeal to people who've always wanted a Peltier
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'
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20 Jan 2006, last update
28 Nov 2012
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.