Building energy performance analysis of ultra-high-performance fiber-reinforced concrete (UHP-FRC) façade systems

•Although UHP-FRC panels have thicker insulation layers with higher R-value compared with the conventional panels, they do not necessarily result in building energy reduction; the energy savings of using UHP-FRC panels depend on the building type and climate condition.•Energy savings of using UHP-FRC panels rather than conventional panels are higher in colder climates (e.g., Fairbanks) than those in temperate climates (e.g., San Francisco).•Buildings that are dominated by internal loads seem to benefit the least from UHP-FRC. Majority of building energy consumption is used to heat and cool enclosed spaces. An innovative ultra-high-performance fiber-reinforced concrete (UHP-FRC) façade system could potentially reduce this energy consumption by utilizing UHP-FRC's high structural strength and ductility hence more space for insulation. The energy performance assessment of innovative façade systems such as UHP-FRC panels could be misleading if the effect of building types and climate contexts on building energy consumption is not considered. Moreover, thermal bridging and hygrothermal analyses of UHP-FRC panels are needed to investigate the heat and moisture transfer within the panels in details. The objective of this paper is to investigate the combined effect of different building types and climate conditions on these panels’ energy performance and analyze the heat and moisture behavior within the panels in a detailed assembly scale. Numerical heat and moisture transfer simulations were conducted to evaluate the amount of risk of thermal bridging and risk of mold growth within innovative UHP-FRC façade systems. A probabilistic simulation-based building energy performance analysis was conducted to investigate the combined effect of different building types and climate conditions on the energy performance of UHP-FRC panel systems. The analysis was conducted for fourteen U.S. Department of Energy prototype buildings in fifteen climate zones (210 scenarios). The results of thermal bridging analysis showed that the UHP-FRC panel assembly provides unique thermal properties with higher thermal resistance compared with the conventional panel assembly. The UHP-FRC panel assembly minimizes the thermal bridging by eliminating the structural rebars. However, the energy savings of using UHP-FRC panels depend on the building type and climate condition. On average, energy savings are higher in colder climates (e.g., Fairbanks) than those in temperate climates (e.g., San Fr