Advanced integrated multi-generation system for waste heat recovery: Cost assessment and multi-objective optimization

• Integrating various energy systems to achieve the highest performance • Comprehensive analysis, namely, energy, exergy, exergo-economic, and optimization is carried out • Optimized system cost rate reached 0.92 $/h which is 10.86% lower than unoptimized case. This study presents the design, thermodynamic assessment, cost analysis, and multi-objective optimization of an advanced integrated multi-generation system for maximizing waste heat recovery. The proposed configuration simultaneously delivers electricity, cooling, heating, and potable water, making it suitable for building applications. The system integrates multiple technologies to enhance waste-heat utilization. An Organic Rankine Cycle (ORC) forms the core of the power generation unit. A single-effect absorption cycle provides cooling and heating to meet building thermal demand. A supercritical CO₂ recompression cycle and a reverse osmosis (RO) unit further improve overall efficiency and freshwater production. In addition, a thermoelectric generator (TEG) converts low-grade residual heat into supplementary electricity. Performance evaluation was conducted using EES and MATLAB. A genetic-algorithm-based optimization was applied to maximize energy and exergy efficiencies and minimize cost. The optimized system produces 508.7 kW of net electricity, 52.06 kW of cooling, 73.43 kW of domestic hot water, and 1.956 kW of additional power from the TEG. Overall, the integration of ORC, absorption, sCO₂, TEG, and RO technologies demonstrates strong potential for efficient waste-heat recovery, highlighting its applicability in future sustainable building and multi-purpose energy systems.