SOFT-PV

Full project name: SOFT (Smart, Organic, Flexible and Translucent) - PV: Creation of a Photovoltaic Organic Cell on Fluoropolymeric Substrate to Integrate into Smart Building Envelopes

Period: 2019 - 2012

Funding Body: Fondazione Cariplo - Bando Ricerca Scientifica e tecnologica sui materiali avanzati 2009

Project Number: 2009 - 2671

Principal Investigator: POLIMI - BEST, Alessandra Zanelli, Andrea Campioli, Carol Monticelli, Paolo Beccarelli, Hend Mohamed Hibraim, Roberto Maffei

Partners: CNR ISMAC (Silvia Destri with Umberto Giovannella, Cecilia Pasini Guido Scavia, Incoronata Tritto), POLIMI- FISI (Guglielmo Lanzani with Haseinkhani Asl Sajjad, Michele Garbugli, Giulia Grancini, Marta Mroz, Luca Frezza, Francesco Scotognella)

This research dealt with Building Integrated Photovoltaic (BIPV) technology. The scientific and industrial communities are working on the theme PV but the promise of low cost photovoltaic power has not yet been realized. The integration of photovoltaic (PV) systems into building envelopes to replace conventional building materials must also be greatly improved.

During the 2 years of financed activities, how to combine the two main low cost technologies available on the market today - the ETFE cushion building technology for transparent envelopes and the 3rd generation of organic flexible PV cells - has been experimented, with the aim to create a new kind of smart façade or roof, employable both in renovation and new construction.

Ethylenetetrafluoroethylene copolymer (ETFE) cushions are also defined as “Soft technology”. They are multilayered, transparent, pneumatic building components, increasingly employed to replace glass technology in various building applications, especially where the use of glass is limited by size or cost. In the research proposal the ETFE cushions will become the inflatable substrate of an innovative fully integrated carbon tube PV building component.

The ultimate goal of the research program was the fabrication of a new kind of fluoro-polymeric foil (ETFE, THV, EFEP foil) fully integrated with a Smart, Organic, Flexible and Translucent photovoltaic cell (named SOFT-PV). The acronym “SOFT” (flexible) refers to the polymeric PV cells fabricated onto carbon nanotube (CNT) based electrodes, which will be created during the research program-

The flexibility and translucency both of the PV polymeric cells and ETFE cushions represented the pivotal evaluation aspect from which the research hypothesis began. The application of organic photovoltaic cells as a printable texture onto one of various ETFE transparent layers of an air-supported building component was achieved, but not at a fully building scale. Two relevant results of the research project were: i) the creation of a new OPV cell integrated on ETFE substrate and ii) the creation of a prototype of a sun-shading, insulated ETFE cushion.

The biennial research program - based on the cross-disciplinary collaboration between Architecture and Building Technology, Material Chemistry and Physics - proposes the following feasible objectives:

1. the modification of a translucent fluoro-polymeric substrate by embedding or depositing carbon tubes;

2. the creation of a demonstrator prototype of a SOFT photovoltaic cell;

3. the creation of a SOFT-PV cell integrated building component prototype, to predict its optical, thermal

and structural performance and to assess its environmental profile.

This building component could be produced and commercialized quickly with the following characteristics:

1. modular and adaptable, for façades and roofing;

2. lightweight and structurally resistant, made of pneumatic technology;

3. multi-chamber insulating cushion, composed of several fluoro-polymeric layers;

4. layers printed with graphic motifs provide sun-shading and sun-screening to varying degrees;

5. energy self-sufficient, integrated with a new kind of organic, flexible and translucent PV cell.

In contemporary architecture we note that multi-media, adaptable and smart building surfaces are becoming increasingly widespread, in order to respond to the current and future demand for “green buildings” and temporary buildings for cultural, entertainment or sporting events.

A SOFT-PV building component, which is a fully integrated photovoltaic building system, easy and cheap to assemble in new buildings or to retrofit onto existing roofs or façades, which can also be adjusted according to user requirements, could be an interesting objective for the increasingly relevant renewable energy oriented building market.