Design and numerical optimisation of the NRG-Foam composites

FACHINOTTI, VICTOR; PERALTA, IGNACIO; STORTI, BRUNO; BRE, FACUNDO; SEBASTIÁN TORO; ÁLVAREZ HOSTOS, JUAN CARLOS; CAGGIANO, ANTONIO

2021-01-01/2021-01-31

Mecánica

Vivienda-Otros

This deliverable describes the numerical tools developed by CIMEC to determine the effective thermal properties of materials for building envelopes, with emphasis on composites containing foams and phase change materials (PCM), taking advantage of the synergetic interplay between thermal insulation and thermal-energy storage (TES) capacity.First, we develop an automatic generator of finite element meshes of the representative volume elements (RVE) ofcementitious foams with spherical pores, whose inputs are the pore histogram and the porosity. This mesh generator also produces finite meshes of the RVE of NRG-Foam, which is basically a cementitious foam where the cement phase includes phase change materials (PCMs) for an improved thermal energy storage (TES) capacity. Secondly, wedevelop a computational tool for the homogenisation of the effective thermal conductivity on these RVEs. Regarding the effective heat capacity of NRG-Foams, it is computed applying the mixture law to the cement paste-air and the cement-PCM systems. By this way, considering different RVEs (i.e., different pore histograms and porosities), cements, PCM type and volume fraction, we virtually conceived 1188 materials, which are generally composites of cement, PCM and air. All these materials are included in a vademecum of materials for building envelopes. This is a database containing the effective properties of materials that are going to be chosen in order to optimise the performance of the walls in building envelopes taking into account the wall orientation and the building location. As an example, we consider the minimisation of the cooling and heating degree-hours in Frankfurt (Germany), Bilbao (Spain), Sofia (Bulgaria) and Sauce Viejo (Argentina), whose weather conditions are described in detail using theirrespective typical meteorological year (TMY).