1940
No, They had no refrigerators in the 1700's.
We can trace the origin of stoves back to Ancient Greece. We can trace refrigerators, known as ice-boxes at the time, to 11th century Persia. (Modern electric refrigerators were invented in 1915). So your answer would be stoves.
Whirlpool, Haier, Kenmore and Norcold all manufacture refrigerators with removable ice holders.
In the early 1900's before modern refrigeration, ice houses would store large amounts of ice for delivery to people's homes in order to keep food fresh. Instead of electric refrigerators, kitchens would use ice boxes where this ice was kept.
I believe that the ice was cut in winter and stored in underground ice houses. Certainly the british aristocracy did this. In America this was commercialised, and the ice was delivered to ordinary homes that had ice boxes, which is what they still call refrigerators. My grandmother had a box outside of her kitchen which had a metal gauze door in it. Somehow through evaporation/ condensation it kept her dairy products and other food colder than the ambient temperature, it really worked. I believe that a woman has patented a similar device for sale in third world countries for people with no electricity.
People started smoking meat to preserve it, before the age of refrigerators or ice boxes. The meat is preserved due to dehydration and the antibacterial properties of absorbed smoke.
Inventions during the 1940's involving cooking included refrigerators, dishwashers, and small appliances. Electric refrigerators replaced ice boxes. Stand mixers replaced the wooden spoon and manual egg beater, making baking much easier.
maybe the convection currents.
No. Most refrigerators use a coolant system similar to air conditioners (which use freon).
technology of ice.
Ice is natural material present in frozen lakes and glaciers. In the past it was a resource and essentially mined during the winter and stored in ice houses to be sold as the coolant in ice boxes (a primitive refrigerator.) At the present time ice is manufactured by refrigeration systems making it a manufactured product, not a resource. Modern refrigerators do not rely on ice for cooling. the systems generate the cold without the ice.