Thermal comfort evaluation of a Rammed Earth residential building: case study: Yazd city in Iran

The main purpose of this research was to determine the thermal conductivity of Rammed Earth walls and assess thermal comfort in RE houses, particularly in the hot and dry climate of Yazd city. For this work a thermal conductivity test was performed on a Rammed Earth sample, and the wall's thermal resistance was calculated to evaluate thermal comfort conditions in a Rammed Earth building. Subsequently the building was simulated and were investigated using Fanger's comfort factors. (Fanger factors: Predicted Mean Vote [PMV] and Predicted Percentage of Dissatisfied [PPD]). Laboratory tests were performed, and a thermal resistance of 0.49 m2k/W was obtained for a 30 cm Rammed Earth wall. This lead to the consideration of a technical solution by Iran's national building regulations, Article 19. Based on this article, a three-layer wall with intermediate thermal insulation and a thickness of 10 cm for the external walls was designed. In this way, the wall's thermal resistance increased from 0.49 to 2.14 m2k/W, improving comfort conditions compared to walls without thermal insulation. It is recommended to increase the thermal insulation thickness from 10 to 15 cm to achieve fully comfortable conditions. Based on the results, the use of Rammed Earth is not recommended, and it appears that adobe material has historically been the best choice for the hot and dry climate of Iran.