Novel MEMS-Based Boiler Development for Low Temperature Applications

A novel MEMS-based boiler is fabricated and tested. The device is designed to operate from low-temperature heat sources using capillary action channels. The channels supply working fluid to the heated boiler surface, eliminating the need for traditional working fluid pumps. Two basic types of construction are evaluated. First, a more traditional silicon-based device is constructed and tested. Fabrication of the silicon boiler utilizes standard micro-fabrication practices. Second, a copper-based unit is fabricated and tested. Fabrication of the copper boiler focusses on low-cost techniques performed outside the scope of traditional micro-fab procedures. Results of these tests show the promise of non-traditional metals in low-temperature MEMS-based applications. The effectiveness of the copper boilers is shown to be 60% greater than their silicon counter parts. The copper-based prototypes exhibited a maximum evaporation rate for working fluid pumped across the boiling surface of 4.21 mg/sec.