Transient modeling of high-inertial thermal bridges in buildings using the equivalent thermal wall method

• Two highly-inertial thermal bridges are analyzed using the equivalent thermal wall method.
• We present a method for obtaining the thermal properties of the equivalent walls.
• A strategy for the decomposition of the thermal bridges into several walls is devised.
• The transient performance of the equivalent thermal walls is compared with classical models.
• A reliable analysis of the transient thermal performance through thermal bridges is demonstrated.

The method of the equivalent thermal wall has been employed for modeling the transient response of high-inertial thermal bridges. A new strategy is presented in order to adjust the thermal properties of the equivalent three-layered wall, which takes into account the temperature distribution across the thermal bridge in a steady-state heat conduction scenario. Two different thermal bridge topologies created by the junction of a vertical wall and an intermediate or a ground floor slab are analyzed with this method, and its feasibility for the implementation in building energy simulation tools is discussed: if the thermal bridge is not considered, an underestimation of 25% in the heat flux across the bridge is predicted. If the thermal bridge is modeled but its thermal inertia is neglected, a time-delayed heat flux response is retrieved. Conversely, the simulation based on the equivalent wall method provides a response nearly identical to the actual dynamic performance of the thermal bridge.

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