Performance of dry-assembled wooden walls with bio-PCM

In order to increase sustainability in buildings, an appealing alternative is the use of eco-agglomerated cork boards. Cork is a prominent bio-based material available in the Mediterranean region that shows attractive features: it can endure substantial thermal variations, can be produced by recycled waste and residual cork; presents optimal thermal insulation properties, is breathable, and offers minimal carbon footprint compared to other insulation materials. However, building envelopes made of such lightweight materials, are characterized by a limited thermal mass; therefore, the application of PCM is ideal for improving the envelope ability to attenuate peak loads both in heating and cooling and delay the action of the external forcing on the indoor environment. To make them compliant with sustainability constraints, bio-based PCM can be considered as a viable option. The chapter proposes a bio-based PCM dry-assembled wooden panel that can be employed to realize sustainable and energy-efficient buildings. The proposed solution is made of biological cork panels stiffened by a 2cm OSB layer, supported by wooden laths that create internal air gaps and confer suitable mechanical resistance. These gaps accommodate flexible sheets containing bio-PCMs, which consist of a patented mixture of inorganic hydrated salts known for their high latent heat storage capacity and thermal stability. Simulation results conducted using EnergyPlus demonstrate that a bio-PCM with a melting temperature of 23°C represents the best compromise that conciliates cooling and heating demands in a typical Mediterranean climate. Therefore, the wall system was tested experimentally in a climatic chamber to determine the dynamic performance when subject to sinusoidal external forcing. The results indicate significant improvements in the dynamic thermal transmittance and insulation performance compared to a dry-assembled system without PCM. Finally, the chapter proposes an analysis of the attainable energy savings for a prefabricated Temporary Housing Unit construction, realized with massive use of cork to promote sustainability, characterized by easy assembling and disassembling processes, reusable materials, and limitation of the environmental impact. The simulations, conducted under various climate conditions using EnergyPlus, revealed, on an annual level, that the single-layer configuration can save 20.5% of energy in continuous operation and 21.5% in scheduled operation. The addition of a second PCM layer led to higher savings, of 28.8% in continuous operation and 33.3% in scheduled operation.