Black globe free convection measurement error potentials

For thermal comfort research, black globes have become the de facto tool for mean radiant temperature, T_{M RT}, measurement. They provide a quick, cheap means to survey the radiant environment in a space with nearly a century of trials to reassure researchers. However, as more complexity is introduced to built environments, particularly by engineering spaces to separate radiative and convective modes of heat transfer for energy efficiency and comfort, we must reassess the relationship of globe readings in the context of their environments. In particular, corrections for globe readings taking wind into account [1, 4] rely on a forced convection heat transfer coefficient. The simulation proposed in this paper demonstrates the influence of free convection on the instrument’s readings. Initial studies show that the T_{M RT} and air temperature separations of 2 K could introduce errors equivalent to 0.1 m/s of air velocity, providing an additional mechanism for globe readings to track air temperatures.