Technoeconomic Optimization and Feasibility Assessment of a Geothermal–Heat Pump Multigeneration System for Sustainable Heating and Power Applications

This study presents a comprehensive thermodynamic and thermo-economic analysis and optimization of geothermal-based cogeneration and trigeneration systems integrating electricity generation, district heating, and heat pump-assisted greenhouse heating. Using detailed field data from an existing low-temperature geothermal power plant (120°C), three alternative configurations were developed and evaluated through high-fidelity Aspen Plus and EES simulations. The proposed approach aims to maximize geothermal resource utilization by combining power production with cascaded thermal energy recovery and heat pump-based upgrading. The results demonstrate that integrated multigeneration configurations significantly outperform the conventional single-purpose power plant. The optimized trigeneration system achieves an overall energy efficiency of 64.98% and an exergy efficiency of 75.94%, delivering 2.86 MW of net electricity and 19.71 MW of useful thermal output. The heat pump subsystem attains a coefficient of performance (COP) of 4.519, effectively upgrading low-temperature geothermal heat for greenhouse applications. From an economic perspective, the exergoeconomic unit cost of electricity is calculated as 0.03548 $/kWh, while the costs of district heating and heat pump-assisted heating are 0.03396 $/kWh and 0.06884 $/kWh, respectively. Under a retrofit-based framework—where existing geothermal infrastructure is treated as sunk cost—the optimized configuration exhibits a purchased equipment cost of 3.25×10 6 $ and a payback period of 2.688 years, indicating strong economic feasibility. Overall, the findings confirm that low-enthalpy geothermal resources can be utilized far more efficiently through cascaded energy use and heat pump integration. Beyond the specific case study, this work provides a transferable methodological framework for the thermodynamic and thermo-economic evaluation and optimization of geothermal multigeneration systems, supporting the development of sustainable, scalable, and multi-functional energy infrastructures. Optimized Geothermal Trigeneration System with Heat Pump Integration • Multigeneration geothermal–heat pump system modeled using real field data. • Integrated ORC and heat pumps boost energy and exergy efficiencies significantly. • District heating cost reduced to 0.03396 $/kWh with optimized configuration. • System delivers 2.86 MW of electricity and 19.71 MW of heat simultaneously. • Technoeconomic optimization shows a 2.688-year payback period.