Comprehensive thermodynamic, economic, and environmental assessment of a novel ground source heat pump system for sustainable energy applications

Ground source heat pump (GSHP) systems have gained significant attention due to their high energy efficiency and environmental advantages in heating and applications, particularly within the building sector. By exploiting the relatively stable temperature of the ground, these systems provide reliable thermal performance under diverse climatic conditions. In this study, a novel GSHP configuration incorporating a cascade heat pump cycle is proposed as an alternative to the conventional single‐stage system. Comprehensive thermodynamic, exergo‐environmental, and economic analyses are carried out to evaluate and compare the performance of the proposed and conventional systems. The developed model examines the effects of key design parameters, local geographical conditions, and soil thermal properties on overall system behavior. Furthermore, several low GWP and ODP refrigerants are assessed to determine the most suitable working fluid. A multi‐objective optimization based on a genetic algorithm is conducted to identify optimal operating conditions. The results demonstrate that refrigerant selection has a pronounced influence on system performance, with R141b yielding the most favorable overall performance. Under optimized conditions, the proposed cascade GSHP achieves a 10.2% increase in COP, a 6.02% improvement in exergy efficiency, and a 9.6% reduction in environmental impact compared to the conventional system. Economic results also indicate a shorter payback period and higher net present value. However, the enhanced system requires a higher geothermal water flow rate due to increased evaporator heat demand.