Development of an analytical model to investigate the effects of the extraflux versus the sky and the ground and optimization of the radiative characteristics of a thermochromic paint for a typical Italian location

In this study, the analytical model of the heat transfer through a two-layers wall is developed. The main novelty consists into considering also the extraflux versus both the celestial vault and the ground, which are usually assessed by adopting simplified methodologies suggested by standards. The validation of the model is performed by means of the comparison of its outputs in terms of heat fluxes leaving and penetrating the wall with the ones produced by the well-known dynamic energy simulator EnergyPlus. After that, different kinds of thermochromic paints are investigated, with the aim to highlight their potentialties. Finally, an optimization process is conducted in order to evaluate the radiative characteristics of an ideal thermochromic paint, producing advantages for both the winter season and the summer season.In this study, the analytical model of the heat transfer through a two-layers wall is developed. The main novelty consists into considering also the extraflux versus both the celestial vault and the ground, which are usually assessed by adopting simplified methodologies suggested by standards. The validation of the model is performed by means of the comparison of its outputs in terms of heat fluxes leaving and penetrating the wall with the ones produced by the well-known dynamic energy simulator EnergyPlus. After that, different kinds of thermochromic paints are investigated, with the aim to highlight their potentialties. Finally, an optimization process is conducted in order to evaluate the radiative characteristics of an ideal thermochromic paint, producing advantages for both the winter season and the summer season.