How should I estimate uncertainty by the GUM (Guide to the expression of uncertainty) method for an indirect solar dryer?
The International Guidelines of Uncertainty in Measurement GUM (JCGM/WG, 2008) are used for calibrating solar equipment.
The GUM process can be summarized in four steps:
1. Determine the measurement equation.
2. List or estimate the standard uncertainty analogous to a standard deviation associated with each variable in the measurement equation (e.g. voltage, irradiance) and for each component that might introduce uncertainty tovthe calibration process (e.g. interpolation, environmental conditions).
3. Calculate the combined standard uncertainty using the root-sum-of-squares method for all standard uncertainties in step 2.
4. Calculate the expanded uncertainty by
multiplying the combined standard uncertainty by the coverage factor, k, or prescribed coverage factors for known distributions of measurements representing the single value of the quantity to be measured (e.g. Gaussian, triangular, rectangular).