2
$\begingroup$

Common home freezers usually have the lowest temperatures of about -24 degrees Celsius. Freezers that go lower exist but these are much more expensive (times much). I wonder whether a common kitchen freezer (standalone without fridge) could be easily hacked to achieve lower temperatures than those -24C (like -40 or -60/-80).

I guess the task is either to hack the thermostat for lower temperature or to disable the termostat at all and supply custom thermo-regulation-circuitry (attach thermometer and then switch the whole freezer on/off as needed to regulate the temperature).

Any ideas how to do this? I guess the structure of the freezer should probably be able to withstand a bit lower temperatures that what it is designed for.

$\endgroup$
4
  • 5
    $\begingroup$ Start by studying the refrigeration cycle and the constraints that the choice of refrigerant imposes on the achievable temperatures. $\endgroup$ – Transistor Mar 22 at 21:56
  • 4
    $\begingroup$ The "hack" is easy: find the thermistor or thermocouple in the freezer and reroute it so it's outside the frig. The cooling system will continue to attempt to reduce the temperature without stopping; that will tell you how cold the existing compressor, refrigerant, etc. can make your freezer. $\endgroup$ – Carl Witthoft Mar 23 at 11:47
  • 1
    $\begingroup$ you might start freezing in other parts of the fridge, overpowering defrosters, blocking drainage lines etc $\endgroup$ – Pete W Mar 23 at 13:07
  • 4
    $\begingroup$ IF it's just for short term, do what I did and get 10kg of dry ice from a Dairy (crushed or solid bricks) and use a well-insulated plastic picnic box -45 'C. $\endgroup$ – Tony Stewart Sunnyskyguy EE75 Mar 24 at 2:42
5
$\begingroup$

No. The minimum temperature is set by the characteristics of the refrigerant. You could conceivably use a refrigerant with the characteristics you want, governed by a new thermostat setting, but I suspect that it will require a redesign of the refrigeration system.

$\endgroup$
1
  • $\begingroup$ You should edit to say "the minimum temperature is limited by ..." $\endgroup$ – Carl Witthoft Mar 24 at 12:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.