i diyed it, but its a common practice in the beer brewing world.

the general idea is that because cold air is heavier than warm air, standard refrigerators are the least efficient, because the cold air pours out onto the ground every time you open one, requiring the whole thing to be recooled after every opening. but chest freezers keep all the cold air even when open because the opening is on the top.

the way it works is to connect the power supply to a secondary thermostat. you run a temperature sensor inside, and it cuts the power to the freezer when the pump reaches 40 degrees F. this way the freezer cant freeze because the power keeps being cut. it kicks back on at 44 degrees F. Its in the 80s today, and the pump runs for like 30 minutes in the morning, 30 minutes in the evening. and stays cool inside all day. the power consumption with this method is very low.