Thermal performance assessment of wall assemblies: criteria importance theory and AHP approach

Abstract

The problem of the “best” choice in terms of the ecological, durable, cheap and energy-effec-tive material of envelope construction has been considered in the paper. For the numerical assess-ment of the thermal performance, the Multi-Criteria Decision Analysis (MCDA) techniques as Ana-lytical Hierarchy Process (AHP) and Criteria Importance Theory (CIT) were used. There were pro-posed eight types of wall assemblies a natural material, namely: hempcrete, adobe, strawbale panel, earthbag, cordwood, structured insulated panel (SIP) (plywood + ecofiber), hempcrete + straw and compositional building thermo-block. As an objective function for the search of the best alterna-tive the integral index was proposed which consist of thermo-physical and economic criteria. As the thermo-physical criteria component of the index were taken the u-value of the envelope W/m2K, the dimensionless decrement factor of the envelope f and the internal areal heat capacity of the envelope k1, kJ/m2K according to ISO 13786:2017. As economic criteria of the integral index, the authors proposed the cost of the wall material Q, UAH/m2 and the mass of the wall m, kg/m2. The analysis of the conducted research has shown, that the one hand there is no absolute “leader” in the ranking of the wall assemblies according to the proposed criteria and considered type of MCDA technique, but the other hand by comparison of the results, there were revealed that the top three alternatives in both AHP and CIT technique are walls of “B”, “D” and “E” type with different point order, achieved in each MCDA calculation technique.