1956.
The first refrigerator that worked with an electric motor driving a compressor was invented by Swedish engineers Brighton and Mendes in 1923. An American company later bought their patent and the first domestic refrigerators were produced in 1925.
The first refrigerators had separate electric compressors and freezers, with the latter usually placed in the home's floor kiln or storage room and connected to the electric compressor by piping, before being combined into one. Before the 1930s, most refrigerants used in refrigerators were unsafe, such as ether, ammonia, sulfuric acid, etc., or flammable, or corrosive, or irritating, and so on.
Then the search for a safer refrigerant began, and resulted in Freon. Freon is a non-toxic, non-corrosive, non-flammable fluorine compounds, it soon became a variety of refrigeration equipment refrigerant, has been used for more than 50 years. However, it was found that Freon had a destructive effect on the ozone layer of the earth's atmosphere. So people began to look for new and better refrigerants.
Expanded Information;
Precautions for repairing a refrigerator
1. Refrigerator repairs should be done with care of nearby smoke and fire. Especially after welding with gas tools, the gas flame must be extinguished before other overhaul operations.
Because the refrigerant meets the open flame. Sparks. Capacitors and other toxic gases. Do not weld in poorly ventilated or closed rooms. When discharging refrigerant, make sure the room is ventilated before proceeding with other operations. When cutting off the compressor return air and exhaust pipe, pay attention to the refrigerant and internal pressure in the system.
2, unplugged from the power supply, the refrigerator will be repaired, must be unplugged from the power supply, to ensure the safety of maintenance.
3, anti-electrocution, usually repair, the power should be cut off first. If you must check the circuit in the energized state, you should be careful of electric shock, and do not touch the electrified parts, maintenance, if you find the wire aging, should be replaced in a timely manner.
4, the correct use of parts, maintenance of parts to be replaced, must be the model of the parts, may not be replaced by other models or other brands of parts, not to mention the parts of the transformation of maintenance.
Baidu Encyclopedia - Refrigerator