I wanted to find a cheep option to keep my 50w co2 laser cool. I decided to try using a fridge. I stripped it down being carful not to break any pipes. I then bent the evaporator and put it in an insulated tub. Then arranged the condenser so it was all together. I turned it on and after 30 mins the water went from 24deg to 11deg. I the tested it with the pump running and it still worked. Then the big test, I waited until the water was 14deg then ran the laser, small jobs at first. Then I tried a 20 min job.it kept cool not going above 17deg. I have fitted a thermostat to turn the fridge pump on when it goes above 14deg, with a 3 min delay between switching the pump on and off so not to damage the pump. It’s been working so well for days now. I wanted to share as I no it can be expensive getting decent coolers.
I also wanted a create a cheap solution to keep my 40w laser cool as the cost of a commercial chiller is more than I paid for my K40 and alternative solutions do not work. I had started with my normal bucket with two radiators in the water alongside my pump.
I then hit on the idea of putting the bucket in a second-hand worktop freezer.
I ran the two tubes through the side of the freezer and 3D printed a backing plate to hold the plumbing which included a tee piece for the temperature sensor and a flow sensor to switch off the laser if the pump were to fail.
Like with you, it worked and cooled the water to sub 10 degrees with the freezer on, but I was concerned that when the outside temperature is cold it might stay too cold even with the freezer off. I need not have worried as my pump is a large submersible type I inherited with the K40 and it will heat the water when the freezer is off so I bought a thermostatic controller, set it to 18 degrees and bingo, I can keep a stable temperature that cost me around $50 which allows me to do all the cutting I need to do.
