Optimizing the Technological Efficiency of Hybrid Photovoltaic Systems to Fulfill the Energy Requirements of Emergency Shelters for Refugees of the Ukrainian War

Abstract

Hybrid photovoltaic systems have become a common solution for reducing energy consumption in specific objects and for customers in the present time. The efficiency of the entire system also depends on the technology of the battery inverter used. Generally, DC coupled inverters are known to be more energy efficient. However, in certain cases, AC coupled systems can provide better results. The ongoing aggression by Russia against Ukraine has escalated the problem of internal migration, which can only be solved by constructing new communities of emergency shelters. The integration of these units into the overloaded and damaged distribution grids in Ukraine must be carefully planned to limit power consumption and injection. Significant savings can be achieved by properly applying AC or DC coupled systems. This article discusses this phenomenon based on specific real cases that are defined by consumption profiles, battery storage system management, climate conditions, and PV system design. Simulations presented in the article demonstrate the expected annual energy flows for both technologies in a model situation. The differences between DC coupling and AC coupling solutions are explained through in-depth analyses of inverter behavior, battery behavior, charging strategies, charging losses, discharging losses, state of charge (SOC), cycle load, and the correlation between own consumption and inverter self-consumption. The results show that choosing the right battery inverter technology can lead to significant energy savings from the installed PV system. In certain cases, AC coupled systems not only offer higher flexibility and modularity but also higher energy efficiency for the hybrid system, lower grid feed-in, and better economic profitability.