Introduction to Cryogenics
– Cryogenics is the branch of physics that deals with the production and effects of very low temperatures.
– The word ‘cryogenics’ comes from the Greek words ‘kryos’ meaning cold and ‘genes’ meaning born or produced.
– Cryogenics is used in various fields, including medicine, aerospace, and energy.
– The study of cryogenics began in the late 19th century with the liquefaction of gases.
– The discovery of superconductivity in the early 20th century revolutionized cryogenics.
Cryogenic Applications
– Cryogenics is used in the storage and transportation of liquefied gases, such as liquid nitrogen and liquid helium.
– It is used in the preservation of biological materials, such as sperm and embryos, for medical and research purposes.
– Cryogenics is essential for the operation of superconducting magnets in MRI machines and particle accelerators.
– It is used in the cooling of electronic components to improve their performance and reliability.
– Cryogenic fuels, such as liquid hydrogen, are being explored for use in space exploration and as a clean energy source.
Cryogenic Engineering
– Cryogenic engineering involves the design and construction of systems and equipment that can operate at extremely low temperatures.
– Materials with low thermal conductivity, such as stainless steel and copper, are commonly used in cryogenic systems.
– Cryogenic insulation is crucial to minimize heat transfer and maintain low temperatures.
– Cryogenic fluids, such as liquid helium, have unique properties that require specialized handling and storage techniques.
– Cryogenic safety measures are essential due to the potential hazards associated with extremely low temperatures.
Cryogenic Processes
– Cryogenic cooling is used in various industrial processes, such as freezing food and preserving pharmaceuticals.
– Cryogenic grinding is a technique used to reduce the size of materials by freezing them and then breaking them apart.
– Cryogenic distillation is used to separate and purify gases by exploiting their different boiling points at low temperatures.
– Cryogenic liquefaction is the process of converting gases into liquids by reducing their temperature below their boiling points.
– Cryogenic refrigeration is used to achieve and maintain low temperatures in scientific research and industrial applications.
Future Developments in Cryogenics
– Researchers are exploring the use of cryogenics in quantum computing, which relies on the properties of superconducting materials.
– Cryogenic storage and transportation technologies are being developed to support the emerging field of cryonics, which aims to preserve human bodies or brains for future revival.
– Cryogenic energy storage systems are being investigated as a means to store excess renewable energy for later use.
– Advances in cryogenic engineering are enabling the development of more efficient cryocoolers and cryogenic systems.
– Cryogenic research continues to push the boundaries of low-temperature physics and expand our understanding of the universe. Source: https://en.wikipedia.org/wiki/Cryogenics
In physics, cryogenics is the production and behaviour of materials at very low temperatures.
The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (or –153 °C) to distinguish these terms from the conventional refrigeration. This is a logical dividing line, since the normal boiling points of the so-called permanent gases (such as helium, hydrogen, neon, nitrogen, oxygen, and normal air) lie below 120 K, while the Freon refrigerants, hydrocarbons, and other common refrigerants have boiling points above 120 K. The U.S. National Institute of Standards and Technology considers the field of cryogenics as that involving temperatures below -153 °C (120 K; -243.4 Fahrenheit)
Discovery of superconducting materials with critical temperatures significantly above the boiling point of nitrogen has provided new interest in reliable, low cost methods of producing high temperature cryogenic refrigeration. The term "high temperature cryogenic" describes temperatures ranging from above the boiling point of liquid nitrogen, −195.79 °C (77.36 K; −320.42 °F), up to −50 °C (223 K; −58 °F). The discovery of superconductive properties is first attributed to Heike Kamerlingh Onnes on July 10, 1908. The discovery came after the ability to reach a temperature of 2 K. These first superconductive properties were observed in mercury at a temperature of 4.2 K.
Cryogenicists use the Kelvin or Rankine temperature scale, both of which measure from absolute zero, rather than more usual scales such as Celsius which measures from the freezing point of water at sea level or Fahrenheit which measures from the freezing point of a particular brine solution at sea level.
