Low temperature refrigeration is the range of temperatures falling below what is normally considered industrial refrigeration and above the temperatures associated with the field of cryogenics. The temperature range of this classification is from -58°F to -148°F (-50°c to -100°C). This range of temperatures includes applications for food, pharmaceutical, and chemical processing. It is generally used in the petroleum and chemical industries as laboratory enviromnental chambers and thermal storage equipment.
The size and type of equipment used varies from small prepackaged low temperature enviromnental chambers of only a few horsepower (kW) to large custom- designed and often field-erected systems ranging to several hundred horsepower (kW). These larger units are by nature one-of-a-kind, designed and built for a specific purpose, for a specific duty at a precisely controlled low temperature con¬dition. The large units use a combination of one, two or more refrigerants in open cascade arrangements to obtain the de¬sired low temperature.