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The use of phase change materials (PCMs) as a building integrated thermal storage may contribute to improving building energy performances. This article focuses on the integration of PCMs in the roof with a non-ventilated air layer, in order to assess thermal performances of a dedicated test cell, especially for thermal comfort. An experimental equipment was set up at Reunion Island under tropical and humid climatic conditions. A mathematical model, based on the apparent heat capacity method is used to predict the actual impact of PCMs on energy consumption as well as thermal comfort. Once the comparisons are performed with simulations, the use of the psychrometric chart, Predicted Mean Vote and Predicted Percentage of Dissatisfied indexes, shows that in the tested configurations, thermal comfort can be improved. Indeed, as well as to enhance the thermal energy storage, the given configuration also reduce the solar radiation through the roof, due to the reflective properties of PCMs panel surfaces. A positive effect on inside air temperature of the full-scale experimental test cell is particularly observed.

International audience; This paper presents initial values of global and diffuse luminous efficacy at Saint-Pierre (Reunion Island). Firstly, data used were measured for a period of 6 months, from February to June 2008. During this period, all defined day-types have been studied (clear, cloudy and intermediate). Generally, the meteorological database of Reunion does not contain information for illuminance values. On the other hand, the local meteorological center has a 60-years-old database for solar irradiance (W.m-2). So it is important to determine Luminous Efficacy in order to find illuminance from solar irradiance (or luminance from solar radiance). The measured data were analyzed, and empirical constant models were developed and presented in this paper in order to determine luminous efficacy under different sky conditions. A comparison between these empirical constants (models) and existing models has been made. The method used to define sky conditions (overcast, intermediate and clear) and day-types characterization as well as classification will be presented in this work.