# Integrated Deep Renovation of Existing Buildings with Prefabricated Shell Exoskeleton
## 2 AdESA System: An Anti-Seismic, Eco-Efficient Wooden Shell
### Energy Layer  
As for the energy performances of the building, the AdESA system is conceived to minimize the primary energy consumption by improving the thermal insulation of the building envelope (coupling a thermal layer to the structural layer), reducing infiltration, and providing a better level of comfort for the users. Interestingly, in the design of the AdESA energy layer, the thermal properties of the wooden structural layer can be exploited in order to combine the insulation efficiency and the thermal inertia of the material. This way, the target energy consumption performances can be attained with a reduced thickness of the thermal insulation layer, minimizing the environmental impacts at the construction stage.  
Figure 4: Possible technologies for over-resistant and dissipative connections.  
A wide range of insulating materials may be adopted. In the following (Figure 5), a classification of the possible insulating material is proposed, which considers the technological and environmental characteristics of each thermal material, thus allowing for a more conscious selection of the energy solution. The materials are classified in terms of: material category (high-performance, foam, polystyrene, and fiber-based); cost ranges; insulation performance (equivalent thickness to obtain the same energy performance--transmittance U = 0.2 W/m\({}^{2}\)K); pros and cons; and \"eco score\". The \"eco score\" is an indication of the environmental impacts of each material throughout its life cycle (best performances are indicated by 1, the worst by 4). The classification has been determined by considering the origin of the materials, their composition, and their possibility of being recycled/reused against their disposal, according to the work proposed by [30].  
Considering such classification, in order to obtain the same energy performance, high-performance materials, such as vacuum insulation panels [31] or Aerogel blankets [32], require a lower thickness but have higher environmental impacts; on the other hand, more eco-efficient materials, such as natural fiber-based panels (cellulose, glass wool, rock wool panels), need a higher thickness, also having detrimental repercussions from the architectural point of view.  
Parametric analyses were carried out to calculate the thermal transmittance of a building for different thicknesses of the thermal and of the CLT structural layer, both considering or neglecting the presence of the as-built construction and accounting for different insulating materials. Figure 6a shows the resulting wall thickness of different insulation materials, with the aim of achieving the selected thermal transmittance of 0.24 W/m\({}^{2}\)K to comply with the energy-saving regulations.  
An example is reported in Figure 6b for the combined thicknesses of a CLT structural layer (conductivity: 0.13 W/mK; capacity: 2.00 kJ/kgK; density: 600 kg/m\({}^{3}\)) and of an expanded polystyrene (EPS) thermal layer (conductivity: 0.03 W/mK; capacity: 1.25 kJ/kgK; density: 25 kg/m\({}^{3}\)), which is one of the most widespread insulating materials due to its good performance and low costs. For the configuration called \"As-built + AdESA\", a 12-centimeter inside concrete layer, a 6-centimeter outside concrete layer, and a 2-centimeter plaster layer were also considered.  
Figure 5: Properties of different thermal insulation materials to be applied for the energy layer of the AdESA system.