Design Methodology: The “Ctra. Antiga d’Horta” site serves as an ideal testing ground for this methodology due to its resemblance to many party wall conditions in Barcelona. The initial step involves a comprehensive sun path study and solar radiance mapping to determine the feasibility of installing photovoltaic panels and to identify areas receiving the most and least sunlight. Following this, a radiance simulation map of the wall is created, and a contextual impact assesses potential improvements to residential living conditions. Window and balconies modules are strategically placed in shared spaces, such as staircases, to maximize benefits for all residents. A circular design approach then refines these elements. Heat and radiance simulations are conducted once the final facade openings are determined, optimizing PV module angles to account for site-specific obstructions and sunlight direction and deflection. The optimized panel configuration achieves an output of 75,919.6 kWh, a 15% increase in performance compared to panels mounted parallel to the wall. Vertical garden modules are incorporated into the facade design, replacing the least effective photovoltaic panels, typically at bottom area. It also improves the city’s human-level experience. The final optimized PV output is sufficient to supply 20 families annually in electricity consumption.

Construction and Flexibility: The project employs a modular construction system using mass timber,
known for its sustainability and low carbon footprint. The design features a primary vertical column
system that stands semi-independently from the existing facade, supported laterally by the original wall. Substructure grids are integrated within the primary grid to support PV modules or vertical garden modules. Windows and balconies are seamlessly integrated within the existing and new structure, and the new EFIS insulation layer enhances the thermal performance of the existing wall.

Impact: The Green Party represents a forward-thinking, sustainable and adaptive solution for Barce-
lona’s over 6,000 blind walls with prominent public presence, aligning with the goals of the “Plan for the Remodeling of Party Walls in the City of Barcelona,” initiated 25 years ago. By improving urban aesthetics, generating renewable energy, and benefiting residents, this methodology addresses the issues of blind party walls caused by perpetuating urban changes. The modular design and streamlined design process make it a model for efficiently updating similar walls throughout the city, fast-tracking the timeline of this initiative, and ultimately contributing to a more connected and sustainable urban environment.