Preliminary development of a non-contact method for thermal characterization of building walls: Laboratory evaluation

This work provides a preliminary experimental investigation with a laboratory setup for proposing a novel enhanced thermometric method, for the thermal characterization of building walls, utilizing a non-contact approach based on infrared thermometry. The goal is a non-invasive application in building diagnostics, particularly in heritage and architecturally sensitive contexts. This study aims to investigate two issues: (i) testing a procedure to automatically process data for determining suitable heat transfer coefficients when calculating heat fluxes when the thermometric method is applied; (ii) understanding the role of infrared thermometers in replacing contact temperature sensors in a proposed enhanced version of the thermometric method for heat flux calculation. Heat fluxes acquired through a commonly used sensor were compared with those computed through the proposed method based on convective and radiative heat transfer assessments. The findings validate the viability of the indirect procedure for calculating heat flux. However, discrepancies in surface temperature measurements were observed between contact and infrared sensors, with differences below 0.5 °C. This suggests that infrared thermometers may require careful consideration as they can underestimate surface temperatures, potentially necessitating corrections to obtain heat flux values comparable to those from conventional heat flux sensors.