Analysis of thermal emissions from radiators in classrooms in Mediterranean climates

Abstract

Using computational fluid dynamics (CFD), this study focuses on the analysis of the thermal emissions of a typical classroom in an educational establishment in the south of Spain, and heated by radiators situated under the windows. It aims to study the way to exchange energy within the venue with this system. In order to do so a work methodology is developed which applies the Fanger method (PMV and PPD indicators) and the local thermal discomfort method to the isothermal curve sections generated by the CFD calculations, drawing up a series of lineal variation graphs on the temperature. This allows us to not only evaluate the degree of thermal comfort of the occupants in accordance with ASHRAE standards but also to carry out future comparisons between different thermal exchange system variants arising from the HVAC system. Following the application of this analysis the paper concludes that efficiency of the traditional radiator system to cope with the energy demand of the location is limited, given its incapacity to carry out a uniform exchange of energy between itself, the convective phenomena it generates, and the low relation between air volume/emitting surface, which translates into a lack of energy efficiency in the system, an aspect which is not usually contemplated in traditional analysis methods.