The effect of the short wave radiation and its reflected components on the Mean Radiant Temperature: modelling and preliminary experimental results

In outdoor as well as indoor environments, human thermal sensation strongly depends on the direct component of solar radiation incident on the body. Nevertheless, even though the direct component exerts the major contribute on this issue, especially in indoor environments and confined spaces, the diffuse and reflected components of the solar radiation also affects the thermal sensations of people. Despite this evidence, simple and reliable methods designed to take into account the effect of solar radiation on the indoor radiantfield enveloping the human being in indoor environments are hardly available. This article aims to provide a contribute on this topic, proposing a model for the computation of the meanradiant temperature (MRT) in indoor environments in presence of solar radiation. The most innovative facet of the proposed model regards the computation of the effects of the radiation components reflected by the internal surfaces. Moreover, in order to try a preliminary validation of the model, an experimental campaign was also carried out and MRT values were measured in positions either directly irradiated by the sun or shielded from directirradiation. The purpose of the measurements was to preliminarily analyze the extent of the accuracy with which the model might predict the rise of MRT due to solar direct irradiation.