Refrigeration (Civ4)/Civilopedia

Refrigeration is the technology of cooling objects to temperatures below the current ambient temperature. In addition to its most obvious function of chilling or freezing foods to delay spoilage, refrigeration plays a vital part in modern human civilization. Air conditioners allow people to live and function in environments that would otherwise be too hot. And many mechanical and electronic devices require cooling to function properly.
A number of advanced technologies are heavily dependent upon refrigeration. Superconductors, for instance, function best at extremely low temperatures. Space ships and suits must be refrigerated if their inhabitants are to survive in direct sunlight. And the interruption of a nuclear reactor's cooling system is likely to have extremely unfortunate consequences for those nearby.
The invention of the first modern refrigeration system is in dispute, with scientists from England, Australia, Germany and the United States laying claim to the honor. The earliest refrigeration machines were built to make ice; they were constructed in the 1850s. The first home refrigeration systems were constructed around 1900, and the first air conditioning systems were implemented several years later. Residential air conditioners began to gain widespread use in the United States in the 1950s.