The “Filigrana” system for a fair look in facades solar-panel embedded

Solar energy is the most available and easy to use of the renewables available for buildings. Retrofitting the building stock goes through a designed, non-emergency placement of solar panels. In some cases, rooftops are not the best option: for example, in residential buildings they are not equally availa-ble to all owners or in commercial centers they are cluttered with chillers, AHUs, and so on. In contrast, the integration of solar collectors into the vertical envelope raises some visual issues related to the image of the urban environment, which has to deal with dark, shiny surfaces that are, moreover, suboptimally oriented with respect to the sun’s rays and therefore ineffi-cient. This paper focuses focused on the new design of a thermal insulation system that incorporates photovoltaic or thermal solar collectors and allows for dimensional flexibility, scalability, and custom finishes. Retracing the development of the optimal shape of thermal insulation cladding, devices that enable the application of photovoltaic strings or solar thermal panels are also illustrated and visual results in different contexts are proposed. The pro-ject result, originally named Filigrana and covered by an Italian patent, has been brought to the level of pre-feasibility by Dreamet S.r.l. (Modena, Italy) under the name “Aster”: it allows the free choice of color of cladding, the replacement of all or part of the solar collectors over time depending on their technological evolution, and, most importantly, it is designed to improve the orientation of solar collectors on the vertical walls of buildings. Shopping malls and warehouses may be the main target, but the system also allows for managing access to photovoltaic energy for each of the individual tenants, avoiding impromptu and random additions to facades and improving the pas-sive thermal performance of the building envelope.