External walls in arid climates

Climate efficient design of external walls is one of the factors influencing energy conservation in buildings. The thermal performance of building envelopes in winter is mainly determined by thermal transmittance (U) to compare the thermal insulation of building materials. In summer the heat transfer through the building envelope should especially be considered in the arid regions. This region has cold winter and warm summer climate. External walls of vernacular buildings here have high thermal capacity. However, building materials with low thermal conductivity are common today. This paper compares the thermal performance of contemporary and conventional external walls in Iran to find an effective solution in both summer and winter. The analysis includes the comparison of TTC (thermal time constant) and U-values of external walls besides a thermodynamic simulation. The results indicate the thermal properties of external walls enhancing indoor thermal comfort, which can be adopted for energy efficiency standards in the arid regions.