Optimization of annual electricity consumption costs and the costs of insulation and phase change materials in the residential building using artificial neural network and genetic algorithm methods

Overuse of energy resources (especially in residential building) has been one of the most important issues in recent decades. Researchers have often focused on the use of PCM (Phase Change Materials) and insulators to reduce energy consumption in a particular climatic condition. However, these materials themselves create a new cost. In this research, it is tried to use PCM and insulation in such a way that the costs are optimized. Hence, the effect of variation of several design parameters such as insulation thickness, PCM thickness, melting temperature, phase change temperature and insulation conductivity on the reduction of the objective functions such as annual electricity costs of building and the cost of building materials is investigated. Unlike most other studies that focused on the particular climate, this research aims to conduct the multi-objective optimization for various climatic conditions. Hence, building models in 8 cities with different climatic conditions is simulated using Energy Plus software. For multi-objective optimization, 36 Design of Experiment points based on the design variables are considered for each city. The annual cost of electricity consumption in the building and the cost of building materials are calculated by Energy Plus software. The relation between design variables and objective functions is then predicted by the GMDH (Group Method of Data Handling) neural network and the equations between input and output are obtained. Afterward, the Pareto optimal points of objective functions are acquired using the GA (Genetic Algorithm). Finally, the effect of the multi-objective optimization on occupant's thermal comfort is analyzed. The results indicated that using insulator and PCM with optimal properties can minimize the objective functions by a range of 12-18 % in cold, moderate and semi-arid cities, But PCM and insulator are not much recommended for hot and humid cities.