Firoj Ismail Mulani, Jeeng-Min Ling
This study presents a comprehensive optimization framework for Net Zero Energy Buildings (NZEBs), emphasizing decarbonization through the integration of renewable energy sources (RES), battery energy storage systems, and air conditioner-integrated water heating systems. The optimization process is explicitly aligned with green electricity tariff structures and incorporates domestic hot water (DHW) consumption behaviors to enhance system efficiency and promote environmental sustainability. The approach examines various configurations of photovoltaic systems, battery storage capacities, and dual-function heating and cooling appliances to determine the most effective design in terms of cost, energy performance, and reliability, and achieve net-zero electricity within the NZEBs. By leveraging advanced mathematical modeling and simulation tools, the research identifies optimal component sizing tailored to different consumption patterns and time-of-use pricing schemes. Key economic considerations, including feed-in tariffs (FiTs), export tariffs, and operational cost savings, are integrated into the optimization process to ensure both affordability and a return on investment. A significant innovation in this framework is the inclusion of user-specific hot water demand behavior, which allows for dynamic adjustment of the system based on real-world thermal Load profiles. Furthermore, the strategic use of green energy tariffs has been shown to significantly enhance financial outcomes, reducing payback periods by 16.99%, 17.60%, and 18.17% for Load Profiles A, B, and C, respectively, compared to standard tariffs. Battery storage emerges as a critical driver of performance optimization. Under standard tariff conditions, increasing the battery size for Load Profile A by 12.72% reduces the payback period by 41.98%. In comparison, a 28% increase in battery size for Load Profile C reduces the payback period by 39.52%. Under green tariffs, these benefits become even more pronounced. Load Profile A sees a 41.32% decrease in payback with a 32.39% larger battery, and Load Profile C achieves a 38.55% reduction with a 22.65% increase in storage. These findings underscore the combined economic and environmental advantages of increasing battery capacity within NZEB configurations. Notably, the optimized system shows considerable potential to support decarbonization efforts, achieving estimated annual CO₂ emission reductions of approximately 24.03 tons for Load Profile A, 22.09 tons for Load Profile B, and 19.93 tons for Load Profile C within the NZEBs. Such significant reductions make a meaningful contribution to broader regional and international carbon-neutrality objectives, demonstrating how well-integrated renewable energy and storage strategies can drive the development of climate-resilient, sustainable buildings. © 2026 Published by Elsevier Ltd.
Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan City, 710301, Taiwan; Department of Automotive Engineering, Universitas Negeri Padang, Padang, 25132, Indonesia
