Slim type SmartWall module delivering high-performance renovation, improved comfort, and strong NZEB potential built for buildings where conventional retrofits cannot fit.
The Slim-type SmartWall corresponding to the Renovation Package 3 of REHOUSE project is owned by Advanced Management Solutions (AMS) and has been integrated in the Greek demo-site. It offers a high-performance renovation solution for buildings where space, architectural constraints, or heritage rules prevent the use of thicker prefabricated façades. At just 70 mm, the module integrates Vacuum Insulation Panels (VIP), a steel frame with thermal break and optionally a slim fan coil mounted internally. Despite its compact form, it delivers a U-value of 0.22 W/m²K, enabling substantial improvements in energy performance even in challenging climates.
This slim-type SmartWall has been evaluated within a comparative assessment of three different applications via performance simulations (using TRNSYS) conducted under Mediterranean, Oceanic, Continental and Nordic climatic conditions. Parameters included in the assessment are the PV contribution – in terms of the PV area installed, the HVAC control comparing a thermostatic to Predicted Mean Vote (PMV)-based control (developed by NTUA) and the vulnerability of the envelope expressed from the U-value of the existing masonry (figure 1).
Results indicate that such module achieves thermal performance comparable to substantially thicker façades. The VIP insulation maintains low thermal conductivity, minimizing heat loss and enabling applicability in both temperate and cold climates. Integration with building-integrated photovoltaics (BIPV) facilitates compliance with nearly zero-energy building (NZEB) targets: Mediterranean climates often require no additional PV, Nordic climates require modest PV coverage, and Oceanic/Continental climates achieve NZEB levels with higher PV ratios (figure 2).
Indoor thermal comfort is improved through PMV-based HVAC control, which reduces thermal discomfort hours by 25–63% compared to standard thermostat regulation, with minor increases in energy consumption. In warmer climates, PMV control can also enhance cooling efficiency (table 1).
The prefabricated module is engineered for rapid installation with minimal disruption, suitable for dense urban contexts or retrofits with spatial constraints. Overall, the Slim-type SmartWall demonstrates that substantial energy performance improvements and enhanced occupant comfort can be achieved with ultra-thin façade systems, even where conventional retrofit approaches are infeasible.
Role of NTUA in REHOUSE:
They contribute in the project with their expertise in the energy assessment of building materials, components and systems, using both experimental and numerical simulation techniques. In addition, NTUA.HMCS is responsible for the Life Cycle Assessment (LCA) of the Renovation Package 3 following a component-level analysis. Last but not least, the Lab of NTUA.HMCS specializes in determining the thermal and fire behaviour of conventional and innovative building materials and systems implementing a multi-scale approach that starts from micro-scale material level, to meso-scale assessment at component level ending to macro-scale assessment at system level.
Authors’ names: Emmanouil Katsigiannis, Petros Antonios Gerogiannis, Ioannis Atsonios, Maria Founti
National Technical University of Athens (NTUA), Lab of Heterogenous mixtures and Combustion Systems (HMCS), Zografou Campus, Heroon Polytechniou 9 – 15780 Athens, Greece
- Website: http://hmcs.mech.ntua.gr/
