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Nouvelles technologies dans les systèmes frigorifiques et de conditionnement d'air à ammoniac.

New technologies in ammonia refrigerating and air-conditioning systems.

Auteurs : CICONKOV R., CICONKOV S.

Résumé

A short introduction describes the history of refrigerants starting with natural, then synthetic and nowadays the comeback of natural refrigerants. The thermodynamic, physical and safety properties of ammonia are presented. The advantages and disadvantages of ammonia are discussed. New heat exchanger technologies are developed. These are shell-and-tube types with carbon steel tubes doubly finned, with a spray evaporator and also with a dry-expansion (DX) evaporator. Over the past few years, new technologies appeared with stainless steel welded modules and with nickel brazed plate heat exchangers (PHEs). In the future, it is expected that microchannel heat exchangers, including air-cooled condensers and air coolers, will be introduced and will have excellent possibilities for ammonia and aluminium as materials. A new electromotor technology is being developed now, using encapsulated copper windings or aluminium windings for semi-hermetic ammonia compressors. A hermetic scroll compressor for small ammonia refrigerating systems is announced. One way of decreasing the ammonia charge is the application of indirect cooling. In the past few years, a large number of air-conditioning systems with ammonia-water chillers have been installed, in commercial and public systems. In large industrial systems where there is a need for low evaporating temperatures, the new concept is already applied with cascade refrigerating systems with NH3/CO2.

Détails

  • Titre original : New technologies in ammonia refrigerating and air-conditioning systems.
  • Identifiant de la fiche : 2007-1922
  • Langues : Anglais
  • Sujet : Technologie, Généralités
  • Source : Proceedings of the 37th International HVAC&R Congress [CD-ROM].
  • Date d'édition : 06/12/2006

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