Simulation of the energy performance of potential HVAC systems and implementation of renewable energy sources to achieve nZEB on the example of an office building in Nis

One of the key approaches to achieving an optimal balance between energy consumption and overall comfort in existing buildings lies in the use of sophisticated simulations for efficient management of HVAC systems. Modeling and simulating the energy performance of buildings represent a highly advanced technique that enables the predic-tion of complex system behaviors based on physical laws and principles. These simulations allow for precise solving of thermal equilibrium equations, taking into account all essential physical characteristics of the building, the com-plexity of the mechanical systems serving it, as well as a wide range of dynamic input variables throughout the entire calendar cycle. Critical factors significantly influencing energy consumption in buildings are region-specific climatic condi-tions, as well as individual user expectations regarding indoor temperature, humidity, and air quality. The methodology of this advanced research is based on the use of the state-of-the-art simulation tool Ener-gyPlus, which enables a detailed analysis of the building's energy performance. This holistic approach enables the enhancement of energy efficiency in existing buildings and optimization of HVAC system operation, resulting in significant energy savings and improved overall user comfort. Furthermore, this study aims to demonstrate the improvement of building systems themselves to achieve nZEB buildings and the utiliza-tion of renewable energy sources. The work is expected to use simulations of the model, along with additional systems, to minimize the net site en-ergy through PV panel-integrated systems compared to the model without such systems. The results obtained from the baseline model already demonstrate low energy requirements, while the use of PV panels is expected to result in even lower consumption. The total energy required to meet the building's energy needs is 41,109.67 kWh, which translates to 36.41 kWh/m² of the total building area. The paper will also demonstrate a reduction in CO2 emissions compared to the model without PV panel-integrated systems.