Optimization-based design of insulating cementitious foams combined with phase change materials for NZEBs

This work aims to introduce a new multiobjective optimization method for designing insulating cementitious foams combined with phase change materials (PCMs) to improve the energy performance of buildings. To achieve this, the multiobjective Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and EnergyPlus software are dynamically coupled. Parametric models for PCMs and insulating cementitious foams are implemented in EnergyPlus to optimize their thickness and the PCM melting temperature. The BESTEST 900 from ANSI/ASHRAE Standard 140-2011 is chosen as a case study to evaluate the performance of the different designs. As objective functions, the annual heating and cooling loads are calculated in Sofia city, Bulgaria-EU. The results reveal several conclusions in terms of physics correlations between the design variables and objective functions. Regarding the total annual loads, the best design reduces 8.95% of the loads (compared to the Baseline model) by using 10 cm of cementitious foam combined with 2.5 cm of PCM with a melting temperature of 24.41 °C.