Miniaturization of energy conversion systems: Energetic analysis

A great number of research groups and manufacturers are involved in the development of micro energy conversion systems. In particular the analysis is focused on heat exchangers and it deals with several aspects, such as the physical principles regulating heat and mass transfer in microchannels and the production process itself. Many benefits are expected from the on going process, such as improvement of the heat exchange, improved performances with partial loads, the opportunity to use innovative materials. On the other hand this process, started within the industrial sphere, could be boosted by the necessity of less costly production processes, through the cost reduction for materials and power, and through economy of scale. This paper aims to confirm if the actual trend of miniaturisation drives to effective benefits in terms of energy saving. For this purpose various aspects influencing the efficiency of the energy conversion devices are considered. For the efficiency of the global system (user, device and connection), special attention is paid to find the optimal trade off between the advantages due to the reductions of ducting and cycling losses and the disadvantages due to the negative influence of the size on the system's performance.