INVESTIGATION OF A LIQUID DESICCANT SYSTEM FOR AIR DEHUMIDIFICATION WORKING WITH AN IONIC LIQUID IN A TWOSTAGE REFRIGERATION SYSTEM FOR COLD STORES

摘要

Electrically-driven compression chillers are the commonly used technology for cooling and dehumidifyingair. Open sorption systems are an alternative to conventional air dehumidification technology. The separationof the cooling of the air and the air dehumidification by a combination of a closed absorption chiller forcooling and a thermally-driven open sorption system for dehumidification bears the potential to reduceprimary energy consumption because part of the heat rejected from the closed absorption refrigeration cyclecan be used to drive the dehumidification cycle in a two-stage process.The desiccant must achieve a high vapour pressure depression at the available driving temperature level ofthe heat rejected from the closed absorption refrigeration system in order to reach a low absolute air humiditywhich is required for low temperature refrigeration in order to avoid frost. Ionic liquids may fulfill this andother requirements since to a certain extent the vapour liquid equilibrium can be designed according to theboundary conditions of the respective application.In the paper at hand, the experimental results of a liquid desiccant system for air dehumidification workingwith an ionic liquid designed for an application down to -20℃ for cold stores are presented. The systemunder investigation has been built up at the TU Berlin. The experiments presented here focus on thedehumidification capacity of the system.