Developing a two-criteria framework to rank thermal insulation materials in nearly zero energy buildings using multi-objective optimization approach

Abstract

One important opportunity to reduce energy waste and global warming is renovation, retrofit, and refurbishment of existing buildings. Adding a multi-layer internal insulation is an efficient way to upgrade an existing housing into a nearly zero-energy buildings, NZEB. There is a vast variety of products and solutions for the building envelope with different environmental impacts. In this paper a methodology is presented to establish a two-criteria framework to rank thermal insulation materials to be used in the envelope. The objective was to design an optimal insulation system based on a multi-objective approach to maximize the energy saving and minimize the environmental impact. Using twelve typical insulation materials with different thicknesses, a four-layer insulation system was developed and applied to a Case study, a typical multi-story apartment building located in a hot summer and cold winter zone. Results revealed there are several optimum solutions to significantly reduce the building energy consumption, with important differences in their environmental impacts. For the case study, eight Pareto-optimal solutions were derived using the two-objective optimization offering more than 70% reduction in the energy demand, and a global warming potential range of 192–1500 kgCo2 eq.