A novel calibration system for heat flow meters: Experimental and numerical analysis

The estimation and the reduction of thermal transmittance of building envelope components is crucial. Heat Flux Meters (HFMs), instruments devoted to this aim, unfortunately not always are provided with metrological traceability due to the lack of suitable reference standards, especially at critical conditions, such as in the low heat flux regime and low conductivity values. In this paper, the authors propose a novel calibration standard for heat flux meters and discuss the metrological performance of this apparatus operating at critical conditions. Besides experiments, a detailed numerical analysis has been conducted, validating obtained results against measurements. A validated numerical model has then been employed to design, improve and analyze the calibration system in different operating conditions, also through a parametric analysis. Numerical results enabled us to improve and define the required heat flux uniformity in a specific sub-region of the measuring section.