Grid-assisted photovoltaic power supply to improve self-sustainability of ground-source heat pump systems

In recent years the diffusion of distributed generation systems has undergone a considerable growth, driven by their increasing cost-effectiveness and by more stringent regulations on energetic efficiency of buildings. This paper jointly addresses two major issues, affecting two of the highest-market-potential microgeneration technologies: the high running costs of ground-source heat pump (GSHP) systems, and the forthcoming unprofitability of feeding into the grid the electricity generated by small-sized photovoltaic (PV) arrays, frequently installed on residential and commercial buildings. To take advantage of the availability of both technologies in the same building, a novel power supply system is presented, aimed at fulfilling the GSHP electricity requirements by self-consuming all the energy generated by the solar array, and complementing it with mains electricity. After an in depth analysis of the supply system architecture and operation, power consumption profiles resulting from the simulation of a real GSHP are investigated. Beyond highlighting primary design issues of such integrated system, this study demonstrates the suitability of the proposed solution to enhance self-sustainability of GSHP systems, and its instrumentality in reducing the consumption of non-renewable energy for cooling purposes in tropical and subtropical climates.