Towards Passive Design Strategies for Improving Thermal Comfort Performance in a Naturally Ventilated Residence

Passive design integrates a wide range of climate-based strategies to increase occupant thermal comfort and minimise the need for mechanical systems for heating and cooling. The aim of this study was to improve the thermal comfort performance in a naturally ventilated residence through the identification and evaluation of the best set of passive design strategies. A two-storey residence located in Washington, United States with a temperate climate was selected as the case study residence. A reference simulation model was developed by replicating only the orientation and massing of the case study residence, while certain assumptions were made for other building characteristics. Thermal comfort performance analysis was conducted in the DesignBuilder software. A set of design strategies were introduced as interventions followed by simulation runs to efficiently track progress. From the reference simulation model to the final intervention model, a 50% reduction in the annual discomfort hours was anticipated in the five selected zones of the residence. Following the integration of four major interventions, the target discomfort hours were met in three zones—library, bedroom 1 and bedroom 2, with 53.03%, 60.42% and 58.94% reduction in discomfort hours, respectively. The two remaining zones—living and lounge also had a notable improvement with a reduction of 43.93% and 45.99%, respectively. The successful design strategies included—incorporation of triple glazed, low-emissivity and argon filled openings with wooden frames; integration of overhangs in south-facing windows, minor reduction of openings in the east and west façade, and addition of blinds for window shading; and use of an energy code standard construction for the building components and further addition of insulation in the building envelope. The most effective intervention was the customisation of the window operation schedule based on seasonal air temperature differences to optimise natural ventilation. This study demonstrated that occupant thermal comfort can be significantly improved throughout the year with the appropriate use of passive heating and cooling strategies, thereby reducing energy consumption and the environmental impact of buildings.