Air Conditioning via Liquid Desiccant Dehumidification

Zephyr is developing an alternative to the standard, vapor-compression (VC) driven air conditioner (AC) that will reduce energy consumption by 50% over today’s highest-efficiency ACs while using no refrigerants. This is achieved by replacing conventional ACs’ inefficient VC method with one employing evaporative cooling preceded by efficient liquid desiccant dehumidification. What sets us apart from others pursuing dehumidification-plus-evaporative-cooling approaches is our desiccant regeneration system. The key challenge in any desiccant-based dehumidification system is removing the moisture from the desiccant so that it can reused in the dehumidifier. This regeneration step is typically done by heating the desiccant to boil off water. This does result in some energy savings over VC, but the improvement is modest and leaves room for further gains. The heart of the Zephyr AC is its novel desiccant regeneration system. Inspired by recent efficiency innovations in the desalination industry, we avoid the use of a VC heat pump to achieve further energy savings. This approach avoids direct desiccant heating and doubles dehumidification and cooling efficiency relative to the most efficient VC systems. The objective of this proposed project is to build on initial work to develop a regenerator, incorporate it into a full AC system and demonstrate a sufficient level of energy efficiency and model compliance to justify commercial product development.