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 electrochemical batteries coupled with an electric motor. In a previous study, several potential alternative energy storage/power systems were examined, evaluated for their specific energy and specific power, and compared to electrical batteries and hydrocarbon fuel storage. Additionally, the power and energy requirements of fixed wing MAV and rotary wing MAV were calculated, for comparison with the different alternatives. In the present study a novel PCM open cycle storage/power system for MAV applications is proposed, based on those requirements. It is an open cycle that uses the ambient temperature as its hot reservoir. Promising initial results, in terms of specific power (45-70W/kg), specific energy (24-45W-hr/kg) and open-cycle thermodynamic efficiency (22-54%), are presented.