PV Driven Heat Pumps for the Electric Demand-Side Management: Experimental Results of a Demonstrative Plant

The energy performances of a smart air-conditioning plant installed at the University of Calabria, constituted by heat pumps and a storage tank, are introduced. The same plant is configured as an alternative electric storage system because connected, by means of an appropriate internal electric micro-grid, to a 4kWp PV generator. The electric microgrid manages the electrical fluxes in order to increase the self-consumed rate. The storage tank covers the mismatching between solar energy availability and heating requests, by accumulating the PV electricity surpluses under the form of hot/cold water. Moreover, a long-term storage system is represented by the conditioned building: A radiant system, in fact, is exploited to activate the building thermal mass. A suitable control strategy was developed to activate overheating or undercooling strategies in presence of a saturated tank, in order to avoid the transfer of PV electricity to the external grid, increasing the system profitability. The conceived system coordinates the operation of the air-conditioning plant with other electric loads, favoring the building-plant system to be less dependent from the external grid.