using home AC system as a freezer

[steve thailand]

hi, i need to make a small walk in freezer. i already have a small PU panel room i bought for another job that fell though so i want to use it as a chiller/freezer. i want to get down to about freezing, not super cold.

i also want to do it on the cheap.

i can buy a 2 part home AC system here second hand very cheaply, the kind with the compressor outside and evaporator unit inside.

normally the lowest temp you can set on a home AC system is about 15C but is there a way to mess with the temp control system so it keeps running all the way to 0 or below?

will a home AC system even do that or does it require a specially designed freezing system? if technically possible, who would you go about fooling the temperature controller?

thanks, steve

[lawrence1]

are you serious?

[steve thailand]

yes, can i assume from your reply that its not possible?

[tbirdtbird]

Compressors are rated for operating temp. Home ac system will not/cannot get cold enough for this

[monkey spanners]

hi, i need to make a small walk in freezer. i already have a small PU panel room i bought for another job that fell though so i want to use it as a chiller/freezer. i want to get down to about freezing, not super cold.

i also want to do it on the cheap.

i can buy a 2 part home AC system here second hand very cheaply, the kind with the compressor outside and evaporator unit inside.

normally the lowest temp you can set on a home AC system is about 15C but is there a way to mess with the temp control system so it keeps running all the way to 0 or below?

will a home AC system even do that or does it require a specially designed freezing system? if technically possible, who would you go about fooling the temperature controller?

thanks, steve


Hi Steve,

No, is the simple answer, i won't go into the many technical reasons why, your time and money would be better spent on a propper freezer system, be it new or second hand.

Jon

[Scramjetman]

To get the air to near 0°C will require the coil temperature to be well below 0°C - maybe as low as -10 or -15°C. Any moisture will freeze on the coil and block the airflow. You need to add defrost control to stop this.

Without getting too technical, the colder the required temperature, the greater the power required from the machine. A machine that can hold its own in a room at 22°C definitely won't make it at 0°C

It will cost less in time, energy, materials and problem solving to put the right equipment in first up.

That being said, you can often learn very quickly from expensive mistakes.:D

[mad fridgie]

I am going to disagree with you guys (do not shoot me yet)
If your AC unit is a reversable unit (heating and cooling), then stick the out side unit in the box and the inside unit outside.
Defrost is already storted.
Ok a bit of playing with the controls to control temp.
But really you should just bite the bullet and do the job proper

[lawrence1]

mad fridgie

[mad fridgie]

mad fridgie
Well it is Friday and beer O'clock

[paulpaswan]

it is not practical in our world of refrigeration if you change it that real means you will need to change most of your components in the system of an aircon to suite a freezer the best you can do is removing the comp then you calc the power you can generate and providently have the volume space calc its heat load then the condenser capacity and do some other

[Scramjetman]

Actual Madfridgie is probably right. That's a clever idea.

You'll still have heaps of problems though simply because of misapplication.

The indoor (used here as an outdoor unit) generally has less capacity than the outdoor coil. The outdoor coil is sized to get rid of not only the heat absorbed from the indoor coil but also the heat of compression as well.

So when you swap them around, you now have the coil with less capacity trying to reject large amounts of heat absorbed from the large coil indoors + the compressor heat. Once the ambient temp gets up a bit, it's going to have a heart attack and stop on head pressure.

Have fun with that. ;)