This study addresses the measurement of the globe temperature. For this purpose, two globe thermometers with different diameters (50 and 150 mm) and a variety of thermal environmental conditions were considered. The assessments of the response times and of the influences of the globe diameter and the air velocity on the measured globe temperatures are discussed. The results of the response times clearly put in evidence that the values usually stated in the literature can be questioned and that longer measurement periods must be considered. In fact, response times >30 min were obtained in 68% of the tests performed. Moreover, differences >20ºC were obtained between the 150 and 50 mm sensors, highlighting the influence of the globe diameter. The analysis of the effect of the air velocity on the globe temperature shows mean relative differences >30% between tests in still air and with the higher air velocity considered (1.81 m s–1). On the basis of measurements carried out with the 50 mm globe, correction equations to the standard globe temperature for both natural and forced convection are proposed.

This paper presents an algorithm that calculates the radiative view factors based on Stokes’ theorem. The authors propose a formulation where the original surfaces are divided into a grid of elementary areas and Stokes’ theorem is applied for the determination of the view factors between these elementary areas. With this approach, the account of the shading effect of obstructions is significantly improved. The capabilities of the proposed formulation were tested with the calculation of radiative view factors between flat and curved surfaces. The results obtained showed a good agreement with the corresponding analytical solutions, with relative errors (REs) lower than 2%. The proposed methodology was also compared with the application of the double integral area formulation and a better agreement was found, between RE and the CPU, using the present formulation.