Investigation and development of plate fin heat exchangers for ammonia absorption refrigerator

The Brazed Plate Fin Heat Exchanger (hereinafter called PFHE) is one of typical compact heat exchangers (CHEs) for the process industries. These PFHEs are widely used in following areas: Air separation plants, Petrochemical plants such as ethylene plants, Fuel cell plants, Regenerator for gas turbines, Evaporators or Condensers for heat pump, and etc. This paper introduce the investigation and development of new applications of PFHEs made of stainless steel for Ammonia Absorption Refrigerator (AAR). The fundamental system of AAR was established over 100 years ago, and recently it is widely used all over the world However in Japan, the number of AAR plants is limited because of the special odor and inflammability of ammonia The majority of refrigerators still use chlorofluorocarbon gas. During recent years, as interests in global environmental issues increase, including problems of chlorofluorocarbon gas, the absorption refrigerator featuring both non-freon refrigerant and power saving is becoming very important AAR can provide cold energy as low as -50 degrees C using waste heat which can be obtained from co-generation systems as heat sources. AAR provides features which fit for the needs of the times. The conventional AAR could not win popularity due to stringent security regulations, larger size and higher cost compared to electrically-driven refrigerators. In these circumstances, attention was placed on PFHEs which provide high heat transfer capabilities, and studies' were made to greatly reduce the refrigerant storage rate as well as to reduce the size to the level that can compete with electrically-driven refrigerators. This activity is performed in collaboration with Osaka Gas co.,ltd. and Hitachi Zosen Corporation.