Introduction: 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:

(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