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Disruptive sustainable TECHnologies FOR next generation pvWINdows

Periodic Reporting for period 2 - Tech4Win (Disruptive sustainable TECHnologies FOR next generation pvWINdows)

Reporting period: 2020-01-01 to 2021-06-30

Tech4Win aims to develop a very innovative transparent photovoltaic (PV) window based on the combination of an inorganic UV selective multifunctional coating (UV filter + UV selective solar) that is deposited on the first glass of the window, and an organic IR selective solar cell (OPV) that is implemented at the gap spacer of the window. This tandem-like structure will allow to generate on-site renewable energy (PCE ≥ 10%, with long term goal of ≥ 12%), guaranteeing a high-transparency degree (average visible transparency AVT ≥ 60%, with long term goal ≥ 70%), achieving a lifetime ≥ 10 years (long term goal ≥ 25 years) and with competitive manufacturing costs estimated in 160-200 €/m2.
The main objective of the project is to develop a set of transparent PV window prototypes (Small and Medium sizes) with strong improvements in level of transparency and visual quality in the visible region, energy generation, advanced filtering capacities, thermal behavior and energy impact. They will be exhaustively tested in a relevant environment for demonstrating their feasibility as a smart window. The key concept is based on the capacity to exploit the IR efficiency potential of organic based solutions with the robustness and stability of inorganic thin film concepts combining sustainable and industrial compatible technologies with demonstrated potential for cost reduction and sustainable mass deployment.
The proposed solution will avoid the use of critical raw materials ensuring the absence of potential problems for the future supply of the raw materials and allowing for a sustainable transfer to mass production levels.
The work performed since the beginning of the project and the main results achieved so far are summarized in the following points:
• Definition of requirements and specifications of the glazing system proposed for the Tech4Win window, including the analysis, selection and quantification of the key parameters to design and warranty the performance of the Tech4Win glazing system and the identification and analysis of main standards, regulations and technical codes;
• Development of semi-transparent OPV devices using polymers compatible with stability and industrial requirements, with the demonstration of solar cells with PCE 4.3% - 5.04% and AVT 41% - 59%, and the demonstration of optimized DBR’s allowing a relative increase of 5% of PCE. Durability studies of the active layers performed under 1 sun illumination conditions show fulfillment of stability targets (relative PCE degradation < 20% after 1000 h) when using UV filters developed in the project;
• Development and UV multifunctional ZnO and Zn(S,Se) coatings free of CRMs with band gap > 2.6 eV, high transparency (AVT in range 65% - 70%) and UV filtering > 99%;
• Demonstration of first proof of concept UV selective Zn(S,Se) solar cells with AVT = 69% and PCE = 0.5%. Development of alternative ZnO/a-Si cell devices showing AVT values ranging from 70% to 50% and PCE values of 0.3% and 0.52%, respectively;
• Multifunctional modelling of the UV and IR selective devices and of the Tech4Win window configurations, including: i) Implementation of optical models for the simulation of the Tech4Win window structure integrating the UV and IR selective devices, the DBR and the different glass panes and encapsulant layers for optical and aesthetic optimization; and ii) Definition and implementation of the BIPV widow subroutines for the modelling of the passive window properties in representative building cases (residential, offices);
• Prototype implementation and demonstration, including: i) development in ASPF of first RtR module devices transferring the processes developed at lab level; and ii) definition of lamination processes using IR and UV test devices representative of the final device configurations, with the demonstration of the stability of the OPV laminated devices under 1000 h DHT conditions;
• Circular Economy and Industrial scalability: Main activities developed have included: i) definition of the LCA and LCC models that are being implemented for the study of developed processes following an environmental point of view to verify that they totally respond to the eco-design regulations; ii) analysis of the DBR scale-up approach, with design of first schema of up-scaled sputtering equipment; and iii) identification of the industrial scale-up strategies and needs for the UV and IR devices;
• Dissemination and communication activities have been developed according to the PDER that was defined at the early stage of the project, adapted to the restrictions imposed by the Covid pandemic situation, including the launching of the project website and social media channels, a promotional project video, two Newsletter issues, a virtual workshop on Transparent PV and the presentation of relevant project results at highly recognized International Conferences and scientific journals;
• At Exploitation level, the IPR and Knowledge management strategy has been defined according to the background of each partner, the ownership of the foreground identified and the exploitation agreements among the parties involved. On the other hand, first versions of the Tech2Market analysis and Feasibility Study and Exploitation Strategy for all knowledge created in the project have been accomplished and are constantly being updated according to the project progress. The Feasibility Study has already been updated once and the next update is being worked on.
The expected results until the end of the project are summarized with the following operative objectives:
• O1: To define a common framework and standard operating procedures in terms of KPIs, requirements and specifications, ensuring consistent inputs and quality outputs;
• O2: To develop optical management strategies (distributed Bragg reflector (DBR) mirror) and device design architectures required to satisfy the PCE (≥ 10%) and light transmission demands of the windows quantified in terms of visual transparency (AVT ≥ 60%) and optical visual quality (CRI ≥ 70);
• O3: To develop device design encapsulation strategies and window architecture concepts compatible with the durability goals defined in the project: lifetime ≥ 10 years;
• O4: To build IR selective solar cell prototypes contributing with a PCE ≥ 7.5% a DBR mirror incrementing the IR cell relative efficiency by 25% and thin film UV selective multifunctional coatings with a demonstrated PCE ≥ 2.5% acting as UV surface filters (UV absorption > 99%);
• O5: To develop sputtering and Roll to Roll (RtR) printing industrial compatible and scalable processes to synthesize thin films based on CRM-free compounds;
• O6: To build modelling approaches to improve the aesthetic added value of the PV window and the implementation of simulation models to assess the passive impact of the PV window;
• O7: To demonstrate the technical feasibility of up-scaling of processes for the fabrication of M format size window prototypes under demanding conditions developing de-manufacturing strategies for circular economy and LCA approaches during the whole lifecycle of the smart window;
• O8: To define a Dissemination & Communication Plan and a Joint Exploitation Plan (including an Individual Exploitation Plan for each Partner) to allow a smooth market uptake of the new products/services.
First prototypes of chalcogenide and oxide based UV multifunctional coatings showing high transparen