Helium as a carrier gas in humidification dehumidification desalination systems

A promising technology for small scale seawater desalination is the humidification dehumidification (HDH) system. This technology has been widely investigated in recent years. Since existing HDH systems have very high specific energy consumption, the authors have previously invented several ways to increase the energy efficiency of these systems. Even for these relativelyhigher efficiency systems the dehumidifier is expected to be large, owing to the large thermal resistance associated with the presence of non-condensable carrier gas (air) in the system. In this manuscript, we demonstrate that changing the carrier gas from air to helium a potential solution to this problem. In addition, the energy performance of a brine heated HDH system using helium relative to those using air is analysed in detail through well established on-design models for the components in the system.