Measurement of solar factor of glazing and shading devices using a solar calorimeter

This paper reports an evaluation of the accuracy of a solar calorimeter for the determination of the solar factor of glass samples and window shading devices. The first step of the assessment consisted of the use of internationally recognized mathematical procedures: ISO 9050 and the ASHRAE Fundamentals Handbook. The results obtained with the solar calorimeter for three types of glass and four solar protection devices were compared with the theoretical values given in these standards. In the second step of the assessment, the measurement results were compared with those obtained using the computer simulation program WINDOW7. Based on the results, it can be observed that the solar factor for the 6 mm clear glass showed a difference of less than 6% when compared to theoretical values obtained from standards. For 6 mm green glass and 8 mm silver glass the differences in relation to the theoretical results were close to 17% and 33%, respectively. The results obtained from WINDOW7 were found to be significantly different for the external shading (up to 40%). However, it was noted that the WINDOW7 results were closer to the values measured with the solar calorimeter than to the theoretical results given in the ASHRAE Handbook Fundamentals.