A novel evaluation criterion for GSHP systems based on operative performances

This work proposes an innovative approach to the ground source evaluation for heat pump systems. The initial characterization of the soil (e.g. thermo-physical properties, temperature...) is integrated with classical considerations about HVAC design. In particular, we propose to analyze the viability of a ground source project through the evaluation of its final operative performances. The achievable savings with respect to alternative technologies become the key-parameter for project viability and system design. The proposed methodology aims to investigate the best level of exploitation of the ground source according to soil thermo-physical properties, local external climate, building thermal load, and back-ups efficiency. Through a plain test case, we show how the utilization of the sole GSHP technology, even if technically feasible, might not be the best design solution: indeed, the large number of required ground heat exchangers could make the project unfavorable. On the contrary, a proper synergy among GSHP and back-up generators leads to notable energetic and economic benefits, ensuring higher energetic performances, lower installation costs, and a sustainable exploitation of the ground-source.