Phase-change-materials as energy source for micro aerial vehicles (MAV)

While there are many different challenges in the development of micro aerial vehicles (MAV), one of the severe limiting factors in terms of weight is the energy storage/power system. Most of the MAVs developed to date are based on electrical motors. In the present study, several potential alternative energy storage/power systems are examined, evaluated for their specific energy and specific power, and compared to electrical batteries and hydrocarbon fuel storage. Analysis of the power and energy requirements of different MAV configurations, suggests that a specific power of 35-60 W/kg for fixed wing MAV and 65-85 W/kg for rotary wing MAV are needed. The required specific energy for a short mission of 20 min is 15-25 W h/kg for fixed wing MAV and 30-40 W h/kg for rotary wing MAV. Based on these requirements, a novel PCM open-cycle storage/power system is proposed. It comprises of an open cycle that uses the ambient temperature as its hot reservoir. Promising initial results, in terms of specific power (45-70 W/kg), specific energy (24-45 W h/kg) and open-cycle thermodynamic efficiency (22-54%), are presented. Owing to the high potential of the proposed PCM open-cycle, we believe that the development of new PCM materials specifically designed for this purpose is highly deserving.