Portable Solar Micro Chiller




About: Flow happens when you let go.

Dear Instructablers

Every year since I can remember I've headed to a Folk Rock Festival called Fairpot Cropredy Convention and over the three days our beer supply has got progressively warmer, marinading in the tent under the summer heat. for years we've lusted for that cold beer as the sun begins to set.

So this year I took it upon myself to create a micro chiller; something portable with its own power supple and capable of chilling a beer. with most premium lagers demanding a serving temperature of 6 - 9 Degrees Celsius

I thought I'd cracked it with the little thermos flask equipped with a 5V - Peltier and 5V - fold out solar panel; However as always the English summer portrayed us and rain (clouds) stopped play,

But I believe for those off grid and also searching for the holy grail of a cold beer over the hot summer months that this could well be the answer.

So I hope you enjoy building and refining this unit.

And if you enjoy this Instuctable that much as your toasting a cold brew maybe you'll be kind enough to put your hand in your pocket and donate a small amount for my next project.

Step 1: The Shopping List

Step 2: Proof of Concept

Before I starting I created a small proof of concept.

Connecting the Peltier to a striped down USB cable I managed to archive the following temperatures from the cold side of the Peltier.

With the Peltier drawing just over 1 amp and using a A DS18B20 temperature sensor connected to a Raspberry Pi I recorded low temperatures of around 5 degrees Celsius from a non fan assisted heat sink located on the hot side of the Peltier.

You will require a portable power source capable of supplying 5V and 2A .

The next step illustrates the how I've packaged the design.

Step 3: Adapting the Vacuum Food Container

The first step in fabrication consists of adapting a thermos flask to house the Peltier.

This is achieved by using a hole saw to core out a 32mm diameter hole.

Remember the top to the thermos flask and cored hole must be big enough to accommodate the 30mm x 30mm Peltier (+/- 4mm)

After you should have achieved something that resembles picture 3.

Step 4: 3D Printed Structure

4 Parts are required to be 3D printed

You can print them yourself with the STL files attached or out source to a 3D printing service.

Also you can view the files on grabCAD at the following URL: https://grabcad.com/library/solar-micro-chiller-1

(Note: I recommend adding some nut housing's in the BaseFanHousing part)

Step 5: Chiller Assembly Part 1 (Base Fan and Heatsink)

I think the assembly is pretty simple after you have all the parts ready, However somethings can be a bit fiddly to hold and tighten at the same time.

you'll need the following tools

  1. soldering Iron and solder
  2. wire strippers and cutters
  3. Allen keys and screw driver

Please let me know if you need bit from the video explain

Step 6: Assembly Part 2

Unfortunately my bruised and battered Iphone 5 cut the rest of the video off.

But I think the Assembly is quite self explanatory.

I'd start with attaching the fan to the top 3D printed component and insert the zip ties before bolting everything together.

I had to use some plastic spacers to get the correct distance between the heat sink and fan.

The last step in the assemble is to wire the RED, Positive wires to the ( + ) on the power jack and BLACK Negative wires to the ( - ) symbol of the jack.

Step 7: Final Testing

Once assembled you should perform a test! Connect the unit to a USB mains outlet (supplying 5v 2a) (Do not use a computer as the device draws too much current and your PC might crash)

  1. Check everything is wired correctly (Fans should be turning)
  2. Check the Peltier is placed the correct way up! (cold side down and hot side up)
  3. Tighten the screws connected to the springs to clamp the Peltier between the two heat sinks maximising heat distribution.

If all's good insert the cooling unit into the hole cut into the lid and screw lid back onto the thermos flask. (you may wish to glue and seal the cooling unit into position to maximise efficiencies).

When testing the unit I was able to cool the inner camber of the thermos flask to 7 degrees within 45 minutes of the power being turned on.

Some may regard this as the perfect temperature for a premium larger!

Step 8: At the Festival

Once again unfortunately no sun this year meant a true verdict on the unit was not possible.

But the solar array power output does match that required so in theory all should be gravy with the micro cooling unit! I guess I can write a review next year.

Please also tell me if you think things can be improved.

And if you like what you've seen then feel free too help with my next project with a small donation. Please follow the links below.


Peace & Enjoy



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    15 Discussions


    4 months ago

    Hi fellow Toppy, great idea and something I could have used last year. The next revival is in July so I may give something similar a go


    Question 10 months ago

    Is a solar panel like this capable of charging a phone power bank? I am devising a system for lightweight FPV drone flying while backpacking.

    3 answers

    Answer 10 months ago

    Solar Panel has an output of 5 volts & 2 amps. so think so. needs to be in direct sunlight tho.


    Reply 10 months ago

    Direct sunlight wouldn't be an issue, I was planning on draping the solar panel over a backpack all day and then charging a phone battery or two, then using those to power the USB charger for a 1S battery for a drone.


    Reply 10 months ago

    The iMax b6 lipo charger can be made to run off-grid. Use some flexi-solar panels on ur backpack and a mini converter to amp up the charge. Add a couple of capacitors for more omph!!


    10 months ago

    Very cool project! I think I would have put cooling fins of some sort down into the liquid, dont just cool the air. Makes me think about a heat-sink from a liquid cooled CPU and some kind of peristaltic pump. Recirculate the beer up to the cooling unit and back down to the insulated cup. Love your idea though, it really got me thinking.


    10 months ago

    Interesting concept, but highly inefficient.

    1: It's easy to cool air, but using air at the top of the liquid to cool the entire liquid, will take hours.

    2: Once you move the container, water will end up in that fan, either destroying it (shorting) right away, or very quickly (corrosion)

    3: best idea i can come up with, is put a simple heatsink, sealed on the bottom, or side of the liquid. There, you will be cooling the liquid itself, not the air on top of it. No fan, means less power draw, and less things to break. Obviously, you can't do this with a vacuum thermos, and it'll be hard to seal....but at least it's an idea.

    2 replies

    Reply 10 months ago

    Noted and thanks, I had planned just to put the tinny/small can into the cooler unopened!


    Reply 10 months ago

    Ah, well, if the can is cool already, this would at least KEEP it cool!


    10 months ago

    I agree with david.roseman's comment. Find a heat sink from a laptop, it could easily be adapted for this use with the fins immersed in the beer.

    1 reply

    Reply 10 months ago

    I like Duswali’s idea of using a liquid CPU cooling unit and then trying to seal the unit with some kind of gasket! Maybe then a beer can could be dropped and cooled more quickly! Especially if the tinny can be spun in the liquid!


    10 months ago

    This is the perfect culmination of geek and beer enthusiast, I love it.
    Of course, since the design is based on a common CPU heatsink, I can't help but wonder if it could be taken up a couple notches to use liquid cooling; I mean, afterall if it has computer parts, then should it be upgradeable too? :D

    Coiling the cooling tubes through the (ex)vacuum chamber of an insulated container seems simple enough, but making it practical (at least somewhat, anyway) to use and keep clean would be the tricky part. Maybe a little extra solder, or welding, and some gaskets... oh the gears are turning!

    This could be a fun project to tinker with this winter, as I'm inspired by visions of cool refreshing beer long after the cooler loses it's cool, ha.

    Thanks for sharing!!

    1 reply
    Toppy007spark master

    Reply 10 months ago

    Maybe true but I'm a ale drinker so like it just above 7. Peace