Optimal Coordination of Photovoltaic/Thermal Collectors and Ground-source Heat Pumps in Integrated Energy Systems

Ground-source heat pumps (GSHP) are widely used in integrated energy systems for their high energy efficiency ratio, but their excessive use would result in soil temperature attenuation, which negatively impacts the performance of the GSHP. The integration of photovoltaic/thermal collectors and ground-source heat pumps (PVT-GSHP) is considered a promising approach to address the problem of soil temperature attenuation. However, the coupling of heating energy among various energy supply devices and storage units and the soil thermal balance for long-term operation require coordinated scheduling of the system. In this paper, the soil temperature dynamics for long-term operations are established. The optimal scheduling problem is formulated as a mixed integer linear programming (MILP) problem considering the energy balance and complicated operating constraints of energy supply devices and storage units. Numerical testing results demonstrate that the optimal operation strategies of PVT-GSHP can ensure the low-carbon and economic operation of the system in cold regions. The soil thermal imbalance ratio could be reduced from around 37.5% to only 4%, thus the soil temperature can be well sustained.