Work

On the precise and estimated calculation of the main thermal time constant of dwellings

Year: 2025

Type: article

Abstract: An approximation calculation of the main thermal time constant has been used by researchers and engineers to gain a general understanding of how a building might respond to external dynamic solicitations. Those approximations assume generally that the building can be modeled by a simplified representation of thermal resistances and capacities. However, caution is necessary when using this approximation, as it may underestimate the thermal time constant value. In our study, the main thermal time constant is accurately calculated using modal analysis as both the physical representation and the solution method, while considering a large number of dwellings (246 377) under different ventilation rates (0, 0.5 and 5 volumes per hour). Then, clusters of dwelling with similar properties are identified. Finally, an estimated main thermal time constant is calculated for some clusters and compared to the precise one. The comparison shows that the error in time constant varies from cluster to cluster, and indoor temperature calculated with the estimated time constant may lead to overestimation in terms of overheating indicators and monthly cooling needs.

Source: Energy and Buildings

DOI: 10.1016/j.enbuild.2025.116763

Authors: Joshua Piñas, Gilles Lefebvre

Institutions: Université Paris-Est Créteil, Centre d'Études et de Recherche en Thermique, Environnement et Systèmes

Language: English

Topic: Building Energy and Comfort Optimization

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Climate action, Sustainable cities and communities

Open Access status: hybrid

Estimated APC paid: $4,260