Multivariate analysis for assessing the thermal performance of vertical opaque envelopes in extended regions

We introduce a statistical methodology to evaluate the thermal performance of vertical opaque envelopes and provide the most adequate design of energy-efficient buildings located across extended regions. The analytical procedure was applied to the extensive Argentinian territory with a variety of climates and a limited number of networked meteorological stations. Although the study was conducted over a full year, results are presented for January and June, when the building energy demand for heating and cooling is most significant, taking into account the local climate, the thermal properties of the walls and the effects of the daily variation in the solar radiation. By using the Fourier series expansion of the sol-air temperature and multivariate analysis, we first correlated the weather data and the steady-state and time-dependent heat fluxes transmitted by conduction through five types of typical walls facing north and south in 10 climatically differentiated cities where full weather data were recorded. Then, the mean values of the sol-air temperature and the amplitude of its time variations were interpolated throughout the territory, thus yielding the spatial distributions of these parameters for a typical day in the months of interest. Finally, the calculation of the heat fluxes exchanged through building opaque envelopes was extended to the whole country.