A Smart Multifunctional Modular Facade Panel for Building Renovation: A Comparative Assessment across European Climates of Energy Efficiency and Thermal Comfort

Abstract

This study presents a comprehensive comparative assessment of a multifunctional modular facade panel for building renovation, integrating HVAC (Heating, Ventilation, and Air Conditioning) and photovoltaic (PV) systems. Three panel versions are analyzed: a conventional metal-framed version, a slim version with reduced thickness, and a timber framed version featuring bio-based materials. In addition to conventional thermostatic HVAC control, a thermal comfort control approach based on the Predicted Mean Vote (PMV) index is evaluated. Various wall panel configurations are explored by altering key components, including the insulation layer, the PV area (BIPV), and HVAC control strategies. These are virtually tested through scenario analysis on a case study building with different pre-renovation envelope thermal conditions. Four representative European climate clusters—Mediterranean, Oceanic, Continental and Nordic—are selected to investigate optimal renovation strategies in terms of energy performance and thermal comfort. Subsequently, building-level simulations are conducted using TRNSYS software to evaluate the performance of modular panels on a typical multifamily residence envelope with varying external wall U-values under different climatic conditions. A parametric study of 480 cases highlights key trade-offs between insulation, PV integration, and HVAC control methods. Notably, PMV-based control may occasionally lead to improved energy efficiency and occupant comfort compared to conventional thermostatic control. Overall, this study underscores the potential of multifunctional modular facade panels to enhance building performance in diverse European climates.