Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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energy efficiencyESTECHHeat PumpPVT solar collectorTriple fluid evaporator


The invention refers to a  solar assisted heat pump, i.e. a heat pump that is coupled with a field of hybrid photovoltaic-thermal solar collectors in a synergistic way. Indeed, the evaporator of the heat pump heat pump can work with only cold ambient air or cold ambient air plus hot water coming from solar collectors leading to an increase of the heat pump performance in the last situation.

Technical features

In the proposed invention, the traditional air-to-refrigerant evaporator a heat pump is usually equipped with is replaced by a special triple-fluid water-air-refrigerant evaporator. The water circuit of this evaporator is connected to a field of hybrid  photovoltaic-thermal solar collectors. The solar collector field is used both to increase the water temperature and to produce electrical energy which is, partially or integrally, self-consumed by the heat pump itself. The temperature of the water leaving the solar collectors is not high enough to allow for space heating or domestic hot water production. However, since the water temperature is higher than the ambient temperature, the water is used, together with the air, as the cold source for the heat pump operation. This allows the heat pump to reach better  performances.

Possible Applications

  • Domestic or industrial heating and cooling;
  • Domestic hot water production;
  • Near zero energy buildings or zero energy buildings.


  • No penalization without solar irradiance and performance increase with solar irradiance;
  • Increase of the efficiency of hybrid solar collector that leads to an electric energy production increase;
  • Defrosting consumption reduction;
  • Reversible system for cooling season operation.