ABSTRACT
The means used to control the vaporization and condensation of the gases used in refrigeration have also changed over the years. A gas or propane refrigerator is able to
control these processes by simply heating a gas such as ammonia that first vaporizes and then dissolves and condenses in water. This process involves no motor and is quite simple. However, gas refrigerators did not do as well in the marketplace as electric refrigerators that used a motor to control expansion and compression. In modern electric refrigerators there are automatic defrosters, icemakers, and many other features. When my grandmother passed away in the 1980s at the age of 94, she had four refrigerators in her farmhouse in Alabama. One was an icebox that had an upper compartment to hold a block of ice and a lower compartment to hold food. She also had a gas-operated refrigerator and two electric refrigerators, one of which had an icemaker and automatic defroster. All four refrigerators were in working order and in use. She used the icemaker in the newest refrigerator to keep the icebox supplied. She was fascinated by the technology of refrigeration and used the technology to preserve the food she produced on her farm. Her use of refrigeration technology definitely benefited our family.
