One of the most useful technology ever invented is "Refrigerator." Every home has this amazing piece of innovation. It is used for cooling drinking water, fresh fruits, vegetables, cheese and ofcourse left over food.
As early as 1747, the basis for modern refrigeration had already been designed. Although, it was not appreciated during those times because the earlier versions used gas systems which occasionally leaked. They were unsafe for home use. The refrigerators and freezers were used only commercially. After forty years of development, refrigerators gained acceptance in the United States. By 1930s prices fell and non-toxic, non-flammable synthetic refrigerants such as Freon12 (R-12) were introduced.
Today, restaurant and food service operations are still required of commercial refrigerators. It is funny how refrigeration technology was like in the past and how people especially in the cold storage business take this pretty seriously.