Energy performance of cross-laminated timber panel (X-Lam) buildings: A case study

To mitigate the impact of climate change, building designers have to mature novel approaches that enable occupants to remain comfortable in the predictable more warming climate, as well as reduce the environmental footprint and emissions intensity of the building fabric. According to Energy Performance of Buildings Directive (EPBD), energy-efficient buildings represents one of the most accredited ways of reducing energy consumptions in the urbanized area as it requires both high-performance components and technical systems. In the last decades, Cross Laminated Timber Panel (X-Lam) buildings become very popular among the designers of passive and nZEB buildings for their earthquake resistance, excellent air tightness and thermal insulation, which allow achieving remarkable energy savings. In this paper the thermal performance and the indoor comfort of a Cross Laminated Timber Panel (CLT) building, have been evaluated. This simulation study was carried out adopting two approaches, steady state and dynamic regime, both in Catania and Bolzano two cities that, even belong in the Mediterranean area, are characterized by different climates. Dynamic numerical simulations were performed on a yearly basis through the software Design Builder, both in free-floating conditions and with an air-conditioning (AC) system. Furthermore, the effect of natural ventilation (N.V.) on the thermal behavior of the CLT building was investigated. The two approaches have provided almost the same energy needs in winter but a significant difference was revealed in summer in both sites. CLT building can lead to indoor overheating of the building in the hottest days of the summer period not only in Catania. Indeed, dynamic simulations in free-floating conditions have highlighted that the X-Lam building fabric suffers even in Bolzano where the operative temperature ranges from 27.2 °C to 31.8 °C. Moreover, the adoption of N.V. strategies can improve the indoor thermal conditions reducing maximum value of operative temperature around 1.0 °C.