Italian researchers have developed a reversible heat pump-ORC Carnot battery that stores surplus residential PV electricity as heat and converts it back into electricity when needed. Simulations showed that optimizing the ORC expander speed could raise round-trip efficiency to 35%, while enabling the system to meet the modeled household’s daily electricity demand.
Researchers from the University of L’Aquila in Italy have designed a reversible Carnot battery (R-CB) integrating a heat pump (HP) and Organic Rankine Cycle (ORC)-based units.
Their concept leverages the complementary operation of both systems: the reversible heat pump can deliver heating or cooling depending on seasonal demand, while the ORC system enables the recovery and conversion of low-grade thermal energy into electricity.
ORC is a thermodynamic process that generates electricity by using an organic working fluid with a low boiling point to convert low-temperature heat sources into mechanical work, which is then transformed into electrical power. Compared with the conventional Rankine cycle, it is better suited for low- and medium-grade heat recovery applications because the working fluids can efficiently vaporize at relatively low temperatures, enabling effective energy conversion from waste heat sources such as industrial exhaust, geothermal energy, or solar thermal systems.
