Hybrid Renewable Energy Systems for Public Buildings: Optimization and Sustainability

This study develops an optimization model for hybrid renewable energy systems (HRES) to improve energy efficiency and sustainability in public buildings. A case study at the Faculty of Mechanical Engineering in Mostar integrates a water-to-water heat pump, photovoltaic panels, solar collectors, and a small wind turbine. A two-step optimization process was used: the Simplex method optimized the thermotechnical system, minimizing the Net Present Cost (NPC), while Homer Pro determined the optimal electricity generation configuration. The VIKOR method ranked six scenarios based on energy, environmental, and economic criteria. Results show that Scenario S5, featuring a 120 kW water-to-water heat pump and solar collectors covering 60% of domestic hot water demand, achieved the lowest primary energy consumption (58,438.6 kWh), lowest CO2 emissions (19,284.7 kg/year), and the most favourable Levelized Cost of Heating/Cooling (LCoH/C). Scenario S2, with pellet and air-to-water heat pumps, exhibited the highest autonomy (100%) but at a higher cost. The study confirms that HRES, particularly heat pump-based solutions, can cut emissions and reduce reliance on fossil fuels while maintaining economic feasibility. These findings support the transition towards prosumer-based energy models, aligning with Bosnia and Herzegovina’s decarbonization goals.