Battery Powered Peltier Portable Air Conditioner

Just an introduction

Hi there, whenever you read this instructable, you are searching for something to cool yourself down right?

As I am new to instructable, I am going to post what I have invented these years. Hope they are not out dated when I post them here.

In the summer of 2014, I made myself an advanced version of the portable air-conditioner with Peltier Unit, here is the steps to make yourself a portable air-conditioner that is small enough to put inside your bag and powered by Lithium ion Battery, with the design sketch posted above.

There are lots of designs on the market. One of the most common way is to use ice or water to cool air. But it is not efficient as the ice may run out soon. And the water evaporating method of cooling just didn't work in Hong Kong as the humidity here is always high. Then, why don't we use a Peltier?

In this project, I will supply Peltier module with only 3.7V which varies accounting to the time and the temperature difference. This is still an experimental project which may not be as good as your imagination.

Please be reminded that the risk and money cost of this project is quite high, think twice before you really want to follow this instractable and start making your own portable air conditioner.

This is a big project, I used nearly a few hundred Hong Kong Dollar (or about $60 USD) to buy all those parts, you can see on the picture above. I listed part of the materials I used, you may need more than the items listed below, just add whatever you want if it is necessary.

1. 2 x 12V 5015 Fan

2. 2 x X258 1# Heat Sink 60*45mm

3. 2 x TP4096 Lithium ion Battery Charging circuit

4. 2 x TEC1706, or 12V6A Peltier module

5. 2 x XL6009 DC to DC converter

Some thermal paste, wires, glue and so on

Peltier Cooler Take up a high current and voltage (ie 12V 6A). Battery choice is very important in this project. For me, I used 7 x 454261 Lithium ion battery (each with 3.7V 1100mAh) to match the shape of the casing. I recommend using a lithium ion battery with a higher capacity (eg 3766125 with 3.7V 4500mAh each) if you don't need to match your casing design. Otherwise, it will be a painful job to wire 9 battery together to the control circuit and the Charging circuit.

If you are recovering old batteries, make sure that the battery contains a protection circuit.

If you are using more than one battery and connect them in series, make sure that they are in the same capacity

P.S: The white stuffs at the back of the picture are gloves for fingers that makes me easier to handle the thermal paste. You can buy them if you need.

The Peltier Unit and the two heat sink is the Cooling Core of this portable air conditioner. Follow the steps below to make the core.

1. Connect the 3.7V lithium ion battery to the Peltier for less than 2s. Feel which side is hot and which side is cold. Mark them as HOT and COLD with marker.

2. Put thermal paste on the Hot Side of the first Peltier and place the cold side of the second Peltier onto the hot side of the first Peltier.

3.Place the Heat Sink on both the Hot Side of the 2nd Peltier and the cold side of the 1st Peltier.

4. Use a plastic tie to hold the two Peltier and two Heat Sink together. Mark the Heat Sinks as HOT and COLD.

5. Grab the two 12v DC Fan, Stick it onto the Unit as the picture show above.

6. Use a cardboard or plastic sheet, Block the other end of the heat Sinks.

It is important to check if all things fit together well. If not, the Peltier may burnt or the Lithium ion Battery may over heat due to high current draw.

Glue all things together with AB glue or AA glue, never use Hot glue as it may melt during operation.

As the core may vibrate when operating, you need to give it a check after the glue dries. The simplest way is to shake it with your hand, throw it into mid air and catch it. If it didn't break, then it has been finished. If it breaks, find ways to strength it like placing more glues or 3D printing a hard plastic frame to hold the whole core.

Casing was designed before the start of the project, so it is not hard to fit all things inside it. I use my laser cutter to cut the shape of the case with 3mm Acrylic sheet.

After sticking them together, I cut out a brown color wind tunnel just for decoration and matching the casing design. After the case has finished, I placed the cooling core into the case and glue it directly to the case with hot glue.

Wiring is complicated here, but it works in these two purpose.

The first switch is for switching on both of the Peltier. After the switch has been switched on, 5 Lithium ion Battery will power up the 2 Peltier with 3.7V.

And the second switch is for both Hot Fan and Cold Fan. After the switch is switched on, The 2 remaining Lithium ion battery will supply voltage to the DC DC converter, the 3.7V will be converted into 12V which power the two 12V fan.

The Wiring Steps are as follow:
1. Connect the positive terminal of 5 batteries to the first switch and 2 batteries to the second switch

2. Connect all ground together (Or common Ground) of the 5 and 2 batteries modules

3. Connect the first switch output to the positive terminal of the Peltiers

4. Connect the negative terminal to the common ground.

5. Connect the positive of the DC converter to the output of the second switch and grounded the negative terminal of the converter

6. Connect the output of the converter (12V) to the 12V DC Fan

7. Check the wiring by switching on both switch and observe any temperature change or if the fan has been switched on.

Connecting the Charging Board is as simple as connecting the 5 batteries' terminals to the Charging board 1 and the 2 batteries which supply power for the fan to the Charging board 2.

You can add a LED to the charging board so it look nicer when you plug it into the USB charging port.

Check your wiring with the diagram above. Make sure that you have two separated powering system for Peltier and the fans.

Just simply put all parts into the casing designed before, all things should fit perfectly if the parts meet your design.

During testing, the amount of wind coming out from the air hole is not enough to cool myself down. The cold wind diffuse away too quickly. To increase the wind speed, I designed a wind tunnel which has a smaller end compare to the input hole. You can use whatever material you want, better with heat insulating materials.

After adding warning labels and instructions, the Portable Air-conditioner has been done~

After using a while, I found that there may be over heating at the end of the Hot heat sink.

To solve this problem, you can either add one more fan at the bottom of the air-con, or place a wet tissue which moisten with 15% alcohol, which gives the best cooling effects.

1. Where is the idea of the casing came from?

Ans: In the anime of Expelled from Paradise, Angela Balzac, one of the main character, has a very cool telescope. Then, I follow the shape of her telescope and made myself a portable air-conditioner.

2. Where can I buy those parts from?

Ans: You can easily found them in online stores or local electronic shops.

3. I don't know how to wire the parts together. Any alternative method to do so?

Ans: If you hate logic gates and switches, you can use Arduino to replace all those troublesome wiring. But it requires a lot in programming skills though.

4. What is the logo means?

Ans: The logo is my personal logo on every invention. It has no special meaning.

If you have any questions about this invention, feel free to comment below, I will reply as soon as possible.