Effect of mass extractions and injections on the performance of a fixed-size humidification-dehumidification desalination system

► A model for mass extractions/injections in fixed-size HDH systems was developed. ► An increase in gained output ratio (GOR) of 10% was predicted. ► Better performance gains were found at higher extraction/injection temperatures. ► The optimal flow rate of the extraction/injection was ~ 40% of the feed flow rate. ► The sizing problem for the humidifier and dehumidifier is discussed.