Parametric study of the impact of building envelope systems on embodied and operational carbon of residential buildings

Purpose: Buildings are responsible for the consumption of around 40% of energy in the world and account for one-third of greenhouses gas emissions. In Saudi Arabia, residential buildings consume half of total energy among other building sectors. This study aims to explore the impact of sixteen envelope variables on the operational and embodied carbon of a typical Saudi house with over 20 years of operation. Design/methodology/approach: A simulation approach has been adopted to examine the effects of envelope variables including external wall type, roof type, glazing type, window to wall ratio (WWR) and shading device. To model the building and define the envelope materials and quantify the annual energy consumption, DesignBuilder software was used. Following modelling, operational carbon was calculated. A “cradle-to-gate” approach was adopted to assess embodied carbon during the production of materials for the envelope variables based on the Inventory of Carbon Energy database. Findings: The results showed that operational carbon represented 90% of total life cycle carbon, whilst embodied carbon accounted for 10%. The sensitivity analysis revealed that 25% WWR contributes to a significant increase in operational carbon by 47.4%. Additionally, the efficient block wall with marble has a major embodiment of carbon greater than the base case by 10.7%. Research limitations/implications: This study is a contribution to the field of calculating the embodied and operational carbon emissions of a residential unit. Besides, it provides an examination of the impact of each envelope variable on both embodied and operational carbon. This study is limited by the impact of sixteen envelope variables on the embodied as well as operational carbon. Originality/value: This study is the first attempt on investigating the effects of envelop variables on carbon footprint for residential buildings in Saudi Arabia.