Thermal transpiration based pumping and power generation using solid oxide fuel cells

Hydrocarbon fuels have very high energy density as compared to conventional batteries and hence are a better alternative to conventional batteries for power generation at small scale. A miniature thermochemical system for small scale power generation from hydrocarbon fuels is proposed. Any gaseous/liquid fuel processing device requires a pumping system. Due to heat and frictional losses associated with conventional pumping systems at small scales and orientation sensitivity of buoyancy based pumping systems, they are unprofitable for pumping in a miniature thermochemical system. In order to solve this problem, a thermal transpiration based pumping system is devised. A combustor is developed which can pump its own reactants by thermal transpiration without any external power supply i.e. a self-sustained pumping operation is obtained in the combustor. It is further integrated with a single chamber SOFC for power generation. This combustor can pump propane into itself at a flow rate of 40 ml/min and generate temperatures in excess of 400 °C. This temperature is high enough to initiate and sustain single chamber SOFC operation with a peak power density that can go up to 420 mW/cm². Such a system when developed completely will have applications in MEMS and microelectronics.