Analysis of a energy storage system integrated with renewable energy plants and heat pump for residential application

The use of small storage in low voltage (LV) systems can spread because costs are decreasing and because it is more sustainable to optimize the energy produced locally from renewable sources. In the new eco-buildings approach the use of heat pump for heating and cooling appears more and more appropriate. The recent Italian Technical Standard CEI 0-21 describes features and installation schemes for the connection of electrical storage in the point of connection of the LV electrical systems for active and passive users. The aim of this paper is to evaluate the energy and the economic performances of an Electrical Storage System (ESS based on lithium batteries) integrated by small renewable energy plants in a single family house. The energy performances are evaluated to increase the self-consumption from local renewable energy sources through different ESS sizes in different climate zones. The methodology investigates different configurations of the system in terms of capacity of storage and nominal power of PV plants in order to analyze the annual self consumption and costs for air condition through heat pumps and other household appliances. Further, it has been calculated the energy exchange with the grid. The study takes in to account connection scheme of energy storage systems and PV plants as shown in the Italian Standard. The study is based on an empirical approach to achieve a global evaluation of the system. Different Simulink models have been integrated to realize a dynamic simulation of the entire system. A Matlab program launches the simulation different times with different configuration of battery capacity and PV plant. The results shows that the total self-consumption can increase of about 50% in the best energy performance case with biggest ESS size in the study.