Indoor Thermal Distribution Assessment of Multi-Unit Residential Buildings (MURBs) for Envelope Designs

Global climate change has induced negative environmental, social and economic impacts at a significant rate during the last decade. Excessive greenhouse gas (GHG) emissions have become a primary contributor to climate change. Global fossil fuel-based energy consumption is responsible for over 60% of anthropogenic GHG emissions ( https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data ). According to the International Energy Agency, the building sector is accountable for 30% of global energy consumption and 27% of global GHG emissions ( https://www.iea.org/topics/buildings ). Therefore, building energy efficiency and advanced green building design concepts to reduce emissions and energy consumption have attracted attention and are becoming a global priority (Bunting et al. in Urban Stud 39:2531–2552, 2002). However, while pursuing energy and emissions reduction goals, many green buildings have lost attention towards building indoor environmental quality (IEQ). Particularly for residential buildings, thermal comfort and indoor air circulation are vital aspects for maintaining proper IEQ levels regardless of the total energy consumption (Li et al. in Energy 237, 2021). A growing number of concerns have occurred recently related to the IEQ of green buildings. Multiple surveys and public hearings provide proof and statistics with an opposing view towards satisfactory IEQ levels in green buildings (Burge in Occup Environ Med 61:185–190, 2004). This paper aims to investigate the impact of energy efficiency measures of green buildings on the indoor thermal conditions of MURBs. A baseline building was defined using the minimum envelope requirements according to the National Energy Code of Canada for Buildings (NECCB) with predefined indoor temperature values ( http://www.nationalcodes.nrc.gc.ca/eng/necb/publications_summary.html ). Then, alternative envelope designs were introduced to enhance energy efficiency, and indoor temperature distribution was analysed using energy and computational fluid dynamic (CFD) simulations. The annual energy savings amount was compared with the indoor temperature distribution variations after the envelope upgrades were introduced. The findings of this study are directed at assisting the policy and decision-making process towards the development of IEQ standards for MURBs. Moreover, it is aimed to open pathways and discussion points for how green building initiatives should change or adapt to deliver optimum energy-efficient designs without compromising the vital IEQ parameters in residential buildings.