MEMS Water Separator for Fuel Cell Systems

Systems and Processes Engineering Corporation (SPEC) proposes a microelectromechanical systems (MEMS) approach to fabricate a compact, lightweight, efficient water recovery system for distributed shipboard power systems and unmanned air and undersea vehicles for United States Navy applications. The use of reformed naval logistic diesel fuel such as NATO F-76 and new H2 separation membrane technology allows high-purity H2 to be delivered to fuel cell power systems. Recovering water from the H2 separator membrane raffinate stream while maintaining membrane pressure will result in increased overall system efficiency of advanced energy delivery systems. Using MEMS fabrication techniques will enable reductions in system size and weight leading to improvements in water recovery efficiency. The SPEC design incorporates micro-machined silicon flowplates with integrated cooling channels to extract water from the raffinate stream in a highly efficient manner. Microfluidic channels isolated from the raffinate stream cool the flowplates to condense water vapor from the stream. Separate microfluidic pores collect the liquid water and transport it using capillary force. The MEMS approach also allows the use of electrostatic dehumidification technology to be incorporated into the water separator and thus provides further size reduction and efficiency improvements.