I've been looking at ways for proofing dough and fermenting pre-ferments prior to baking, in hot climates.
A cold insulated box, like the ones used for picnics, with an ice block brick chilled in a freezer seems a common option.
Some people use a thermometer with a remote temperature probe placed inside for better monitoring.
There is a guy in Greece who rewired an old fridge so that he could set it to proofing temperatures.
Here is a cheap option: One second hand 49litre fridge (a new one is about $100). This is set to it's lowest temperature so that it is 'always on'. Then use this temperature control unit. This is for a U.K. socket, but I am sure there will be versions for other sockets around the world. As soon as the fridge gets too warm this unit will power it up until the correct proofing temperature is reached.
For hot climates a beer, wine fermentation mat could be placed in a cold box or a mini fridge with the same temperature control device.