(521c) Systematic Generation of Hybrid Insulation Materials Via Data Envelopement Analysis

Buildings are responsible of approximately 40% of the EU’s energy consumption, and also of the 36% of the CO2 emissions. For that reason, improvements to reduce both, the energy consumption and the energy embodied of the construction materials, are a key strategy to achieve the requirements proposed by the European Commission.

Improvements in new construction can’t achieve the goals proposed for 2050, for that reason, interventions in the actual buildings stocks represent an important opportunity. The improvement in this stock can be carried out by multiple ways, but improving the thermal envelope with insulation materials is one of the most extended application, which achieves better performance as thicknesses increases. This represents an important reduction in both, costs and environmental impact associated to the energy consumption. Despite that, such intervention requires initial investments that involve an environmental impact from manufacture, installation, dismantling and disposal of the materials which shouldn’t be neglected when suggesting improvements in buildings efficiency due to this embodied energy which can represent an important impact depending on the materials used.

The development of innovative insulation materials is gaining interest in the scientific community in recent years, creating materials with better thermal properties or with low embodied environmental impact, such as PCM or bio-based materials respectively. Despite those improvements, only a marginal fraction of the insulation market is relaying on this materials, for that reason, prefabricated insulation solutions may represent a solution.

A new methodology focused on a Data Envelopment Analysis (DEA) combined with thermal simulations of EnergyPlus has been performed to different insulation materials with the objective to achieve sandwich panels to increase the use of bio-based insulation materials.

The total cost of the intervention and the environmental impact associated to the energy consumption for heating and cooling a building and the life cycle of building materials are evaluated for different insulators and thicknesses, generating a high quantity of inputs to analyse with DEA. To reduce the amount of inputs, an objective reduction has been carried out, identifying those inputs which define the global performance and tanking out those which doesn’t gave extra details of the performance.

Once identified the key inputs, DEA finds the efficient thicknesses of some materials, which represent the materials that without combination achieve the better performance, and are also the materials which will be combined to generate the sandwich panels with the projections of the non-efficient solutions to the efficient frontier.

This study has been carried out in a cubicle like building, for 8 different insulation materials and 6 different thicknesses, which varies from 0.01 and 0.26 with increments of 0.05cm. Despite the initial amount of 11 objectives, after the objective reduction only 5 have been analysed, 4 environmental inputs and the total cost of the intervention, achieving 21 efficient solutions and 27 non-efficient ones. The non-efficient solutions have been projected to the efficient frontier, achieving the same amount of new combination of materials, which should be analysed to identify the feasible solutions. Finally those solutions have been implemented in the same model, including the energy simulation and the DEA model, finding 6 new efficient solutions for the 6 feasible projections.