Bistrot Project

The project “BIfacial SpecTRal splitting Optical concentrator for 4-Terminal photovoltaics (BISTROT)” is a project CNR-UVR AMICO2_PoC, through Next Generation EU PoC 2022 – PNRR del MIMIT-UIBM M1 C2 I6. The coordinator is CNR-IFN, Milan. The project started in February 2024 and ended in March 2025.

BISTROT is a Proof-of-Concept project, aiming at the experimental validation of a patented invention for the optical core of a bifacial photovoltaic module in 4-terminal configuration (Italian patent n. 812022000116502, dep.10/08/2022, Intern. PCT/IB2023/056165, dep.14.06.2023) . The system operates by spectrally splitting incoming sunlight. Its absolute novelty concerns the geometry and physical parameters and a counter-intuitive way to orient the module, whereby the particular inclination in the north-south polar direction is advantageous for bifacial operation.

Aims and Expected Results

The final objective of BISTROT was to provide initial experimental validation of its technology with field measurements. A prototype of the double-sided device was fabricated, with 4-terminal exit. The testing activity characterized its operation and energy yield.

BISTROT offers a 4-terminal photovoltaic module with high energy yield and low cost. Its novel geometry minimizes soil occupation and self-shading, it can operate in (quasi-stationary) conditions and bi-faciality exploits diffused light.

BISTROT is specifically aimed at applications using small size modules and provides a technological solution for two main possible application markets:

1. Building-Integrated PhotoVoltaic solutions for Zero-Energy Buildings, e.g. in photovoltaic blinds and active decorative elements.
   
2. Indoor photovoltaic, using internal ambient light to power building services, with an Internet-of-Things perspective and energy support for building automation and control.

INO role

The staff of the Solar Collectors Laboratory carried out the optical simulations for the new system configuration.