In a collaborative work led by Enerbasque and the Politecnico di Milano (POLIMI), with contributions from TU Wien, and CENER, a reversible ORC (rORC) prototype has been successfully manufactured following a comprehensive design process. The reversible ORC prototype is ready for testing at the labs of POLIMI.

Planning and construction

The operating conditions for the rORC system were selected by POLIMI based on an ad hoc numerical model, which also included an intensive investigation to select the most appropriate working fluid. Enerbasque designed in detail all the components of the system with particular care on the heat introduction and heat rejection heat exchangers that must be compatible with all testing facilities and reversible operation. The rORC prototype’s subcomponents were meticulously manufactured and assembled, ensuring correct operation. The rORC prototype is engineered for flexibility, capable of harnessing a wide variety of energy sources and waste heat at diverse temperature levels. A key component of this prototype is the reversible volumetric machine based on a twin-screw compressor/expander, allowing operating the cycle as a heat pump or as an ORC based on rotational direction.

Testing and validation

In the end of June 2024 the prototype was transported to the POLIMI facilities for testing and performance validation under conditions defined for the RESTORE system. After initial tests of the rORC unit, the unit has been connected to POLIMI lab of Laboratory of Energy Conversion and Storage, so that the reversible ORC prototype is ready for an extensive experimental campaign. It will be carried out by POLIMI with support from Enerbasque aiming to quantify the system performance under various off-design conditions and to evaluate the efficiency of the components at steady-state.

Further steps

As the project advances, performance test results from POLIMI will be released, providing critical insights into its operational efficiency. The successful completion of the test plan will validate the rORC machine for both operation modes, charging and discharging, demonstrating the potential of the technology. In addition, this step will unlock the next phase of the project, the relocation of the rORC to TU Wien, where it will be connected to the TCES Prototype with the aim of validating the RESTORE overall concept. This step is expected to be done soon, in early 2025.

Find out more about the prototype in this press release and the success story published by the Green Deal projects Support Office.

Images: Construction of the prototype (left) at Enerbasque facility, Plant arrival at POLIMI campus (middle), Plant installed at POLIMI laboratory (right)