Home Made Freezer Box Fridge/Air Con .




Introduction: Home Made Freezer Box Fridge/Air Con .

Check your countrys refrigerant handling rules before you attempt this.

If you live in Australia only attempt this if you are an Air con mechanic or Car mechanic with a refrigerant handling license .

If not you can make a system out of a water pump instead.

This Is a guide on how to make a Freezer box powered by a fridge compressor .

This system uses The very basic must have components of a fridge .

Compressor : To pump the refrigerant around the system

Heat Exchangers : These copper coils are used to rejected heat at the condenser and absorb heat and the evaporator

Metering device : This Is a must have component , to meter the liquid refrigerant into the evap coil and to created a pressure drop .

Refrigerant Gas : This 134a Gas which is used in most cars fridges/freezers , Its used to create a reversible phase change from a liquid to a gas . In the evaporator the gas changes from a liquid to a gas , In the condenser the opposite is done. When it changes state like this it either gives of or absorbs heat .


The basic idea of this system is to keep ice water cool at temps bellow freezing .

The coils are submerged into water . The Cooler box has been split into two parts .

The condenser on the right gives of heat and makes the water warm . 
The water is changed when it the temp gets to high . Or can be set up to slowly drip new water in while dripping and the same rate the warm water.
Ive used water as the medium instead of air . so there is no hot air coming out of the system.

Step 1: Tools and Materials


A Brazing device either a hand held torch or an oxy set.

Copper tube cutters

Pipe benders

Conduit cutters or a hack saw

Hack saw


1/4 copper pipe ( DO not use plastic or anything else with refrigerant gas!)

A Cooler box or a Styrofoam box

Styrofoam divider

A fridge or freezer compressor ( Remove from an old fridge one that has lost its gas already )

A hand valve or a capillary tube


Drain hose

Pvc Pipe glue

Step 2: Piping Up the System

I used 1/4 copper pipe . I Made the condenser on the right square to fit in more . I used pipe benders to make this shape , You can get a similar bend with your hands its pretty impossible to kink 1/4 pipe . You could also keep the coil round .
The coil comes in roll about 300 diameter . I made the coil abit tighter by bending it just a tiny bit every so often .

You could also have the condenser in a separate tank . A round bucket and keep the coils round .

I used old gauge hoses just to make it abit more portable and easily dismantled . Also the only hand vavle i had at the time only fitted on hoses .

I would recommend just using copper all the way.  And making the condenser coil bigger than i did . Should be around 40% . Normally the condenser is bigger than the evap . But with the water been used instead of air it can be abit smaller .

With the old compressor you have found . Figure out what side is the discharge ( the red hose in my pictures) and what side is the suction ( the blue hose).
The smaller pipe coming out will be the discharge and the bigger the suction.

Following the Diagram bellow .

4 is the compressor the discharge pipe then goes to the (1) condenser

the outlet of the condenser then goes to the metering device( hand valve) .

The gas then travels to the evaporator as cold vapor.

The outlet of the evaporator is The suction pipe.

I have cut in little notches with a hack saw blade so the lid closes and doesnt hit the pipes .

Step 3: Running the System.

You should also Vac the system out before adding gas. To stop moisture freezing up at your metering device.

You need Add gas before you can run the system .

The system that you removed the old compressor should say how much gas it took. This is only an rough idea .
The system i removed my compressor from took 80grams . 0.08kgs not much at all . Slowly add the gas until the system is running well.
I ended up adding 65grams of gas.

You will have to play around with the hand valve until you get the system running coldest . Open it up a tiny bit until you can hear gas going through . 95% closed.

I have picture of the coil iced up with about half of a inch of ice around it , but cant get the upload picture thing working atm.

Step 4: Adding Air Con Mod

I have not had time to do this step yet .

But the idea is to have a Spiget onto the lid of the box so i can tape 300mm duct onto the back of the fan.
The water in the evap side is only half full . So retangle holes can be cut around that size of the box .

Air will be sucked in through these wholes and the cool air from the freezing water will blow out of the fan.

Step 5: Extra Notes and Info

The temps of the system are as follows.

0c is freezing temp of water .

Water temp after 20 mins .


Evap coil temp


Condenser water temp if no fresh water going in after 20 mins

38c on the top inch of the water then about 30c under this.

Condeser Coil temp


Ive been putting the waste warm water into my washing machine . You could wait over night if you have 2 buckets and the water would be cool again .

Things i would do different , if i had a drain hose on the condenser near the top . to drain the top hot water . There seems to be a hot layer of water on top which gets thicker over time. If this water was changed instead of the colder water at the bottom it would work better.

The metering device is hard to calibrate correctly . It would be to hard to get a perfect length and bore of capillary tube but something close would work.

The charge of gas is just a guess, The perfect amount takes awhile to calculate .

Can the first few posters tell me if i have made any grammar mistakes or any more info i should add

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    8 Discussions


    4 years ago

    amazing! I love this instructable!


    Reply 4 years ago

    Thanks Mjtrini , This was a few years ago now . Ive acctually made a better system now and use it on a farm to cool beers and make warm water to wash dishes .


    Reply 4 years ago

    Impressive! I made a diy split type air conditioner based on similar principles. It worked OK until the old compressor gave up the ghost. Maybe in the future I will make a better version. Great work by you! I look forward to more instructables by you.


    6 years ago on Introduction

    Why put the condenser inside? you will heat up the inside. your COP will be very low bcuz of that.


    6 years ago on Introduction

    A hot water heat pump. In theory, you could preheat water in a tank before entering your hot water tank. Energy used to cool your home in the summer can concurrently heat your hot water.

    Maybe running water though a heat exchanger would be a better idea. as you wouldn't want the possibility of your refrigerant being released into your potable water.


    8 years ago on Introduction

    What was your superheat and subcool? What kind of pressure manifold do you have? What pressures are you running? What vacuum did you pull it down too? This Instructable is missing alot of key information to get a refrigeration system up and running "SAFELY".


    Reply 8 years ago on Introduction

    This project is aimed at People who have a refrigeration handling license.
    If they dont know how long to leave vacuum pump on they shouldn't be playing around with gas.
    They should use there common sense and practice what they have learned.

    Superheat and subcool varies on what heat load there is what your cooling etc.
    The metering device and the size of coils would be different.
    Superheat is something you play around with until you get the best performance.
    I adjust the metering device if i have no water in there.

    Why would it matter what manifold i used. There is a picture . I didnt even use a manifold but used the hand valve to close the system . There are Schrader valve both sides of the yellow hose.

    This project is to show people what can be made and to show trained people some ideas if there thinking of making a similar project .
    I dont want to tell every exact details and have everyone going out and using refrigerant .