Procedures in the construction of a test reference year for Porto-Portugal and implications for hygrothermal simulation

Abstract

The exterior weather is a key factor in the behaviour of buildings, which may affect mechanical resistance, durability and appearance of materials and components. Also, it may influence the indoor air quality, limit the comfort of users and increase energy costs. Therefore, exterior weather data is an important input for hygrothermal simulation, as a tool to previously assess the behaviour of buildings. In this work, the methodology to create a reference year according to ISO 15927-4 was assessed. The meteorological data were statistically analysed and the missing data were filled. Two reference years were obtained: one with gaps and the other without omissions, in order to find out what were the implications brought by filling the data. Hygrothermal simulations were conducted considering the two reference years. The results were statistically compared and they showed the reference years presented differences, although only three months are actually different. The outputs of the hygrothermal simulations are similar in some periods and different in the periods of time close to the months that are different in the reference years. Although these dissimilarities are highlighted by statistical differences they are not relevant enough to result in a significant difference in the durability of the materials.