Exploring Alternative Experimental Approaches for Wall Heat Transfer Assessment - The Enhanced Thermometric Method

The energy balance of a building heavily relies on transmission losses through its envelope. It is crucial to develop a thorough understanding of the actual thermal behavior of a building envelope, aiming for maximum accuracy with minimal invasiveness. A novel noninvasive experimental technique is the Thermometric Method (THM), which remains underexplored, particularly concerning the effects of boundary conditions on the surface heat transfer coefficient. This paper discusses the results of applying the Thermometric Method in a laboratory setting. The method is based on Newton's law of cooling and the determination of the surface heat transfer coefficient through dimensionless group theory. The experimental setup involves utilizing a hot box apparatus, surface and air temperature probes, and an anemometer. The experimental campaigns have been conducted under stationary conditions, and the results demonstrate that the Thermometric Method yields comparable results to the most common Heat Flux Meter (HFM) method. A percentage difference of -16.8 % was obtained by comparing the Enhanced-THM (E-THM) and HFM methods.