Thermal behaviour optimization in thick bricks wall of architectural heritage

Abstract

The thermal envelope of a building plays a key role in its energy efficiency; therefore, accurately characterizing its behaviour is essential to reliably estimate energy consumption. In historic buildings, errors in these estimations can compromise the rehabilitation process and lead to ineffective interventions. Understanding the thermal behaviour of traditional construction systems allows for the establishment of realistic and non-invasive in situ assessment methods, which are crucial for appropriate energy retrofitting. This study evaluates the applicability of the Heat Flow Meter (HFM) method in thick brick masonry walls of historic buildings, by installing heat flux sensors on both sides of the wall. The analysis was carried out on a landmark 20th-century building over a 45-day winter monitoring period, assessing the thermal performance of the wall to validate the method’s effectiveness in heritage contexts, while identifying the advantages and limitations of the efficiency of its heating system. The results were compared with the theoretical model based on Fourier’s law, revealing notable discrepancies: daily periods were observed during which the wall simultaneously received heat from both the interior and exterior environments, contradicting the assumption of unidirectional heat transfer. This phenomenon highlights the potential of massive walls to act as dynamic thermal regulators. The study demonstrates the value of harnessing these ambient thermal gains as a passive strategy to improve energy efficiency without compromising indoor comfort established in regulations, and reinforces the relevance of traditional construction solutions in the sustainable conservation of built heritage.