Technical and cost analyses of two different heat storage systems for residential micro-CHP plants

The heat storage system represents a key component for micro-cogeneration plants since it permits to store the unused thermal energy during electricity production for a later use. Nevertheless, it also represents a consistent additional cost that has to be taken into account in order to evaluate the profitability of the micro-CHP system with respect to the separate generation. In this paper the results of a technical and of a cost analysis of two different types of thermal energy storage systems for residential micro-CHP plants are presented. Indeed, in the present work hot water thermal energy storage systems and latent heat thermal energy storage systems have been dimensioned for different micro-CHP systems producing electrical and thermal energy for two different buildings situated in Italy. For each analysed micro-CHP system an adequate thermal energy storage capacity is estimated on the basis of the operational logic and of the electric and thermal loads, and the sizing of the cylindrical tank and of the coil heat exchanger relative to both types of thermal energy storage systems is performed. Comparisons in terms of components cost between hot water thermal energy storage systems and latent heat thermal energy storage systems are performed as well.