Development of water-­lithium bromide absorption chillers based on asymmetric plate heat exchangers.

Abstract

Water/lithium bromide (LiBr) absorptions chillers typically use horizontally arranged tube bundles for the heat exchangers. The use of plate heat exchangers is hampered by the low vapor density and low permissible pressure losses in the steam flow. Objective of the work was the development of an absorption chiller in which all heat exchangers are designed as plate heat exchangers. A new asymmetric plate heat exchanger was developed with a channel height also appropriate for the conditions of the absorber and evaporator which represent the low pressure side of an absorption chiller. Applying this new heat exchanger a complete absorption chiller was designed and built. At nominal conditions of heating water 86/71 °C, cooling water 27/32 °C, chilled water 15/9 °C the chiller reached a cooling capacity of 65 kW which is about 20 % more than expected. The volume of the chiller was reduced by 40 % compared to a chiller with the same capacity using tube bundle heat exchangers.