A review of solid desiccant dehumidifiers: Current status and near-term development goals in the context of net zero energy buildings

Due to a galloping rise in the energy demand by the buildings in the recent decades, the transition from a conventional building to a sustainable net zero energy building (NZEB) has been realized globally. However, ensuring the occupants’ thermal comfort in an energy effieicnt manner under the typical hot and humid operating condition, still remains as one of the major challenges towards achieving the ambitious goal of NZEB. With the advent of new classes of microporous and mesoporous materials, conjugation of desiccant dehumidifier with traditional vapor compression system, also known as “hybrid air-conditioner” has emerged as a promising space cooling technology, that can potentially handle the time-dependent fluctuations of cooling load in NZEB without consuming much energy directly from the grid. Albeit significant progresses have been made in the last decade, there exist many challenges that need to be addressed prior to robust implementation of this technology for space cooling in NZEBs. This article represents a broad perspective in this regard; moreover, by identifying the near-term development goals, it portrays an image of the next generation desiccant technology that will be capable of handling the hourly variation of cooling load in NZEB in an energy efficient manner. In addition, detailed discussions on the current progress of the solid desiccant technologies and their regeneration methods have been presented according to the various system configurations and research focuses.