The influence of façade design on the optimum window to wall ratio and overheating rate in UK Passivhaus dwellings for current and future climates: A Parametric Design Method

Lavafpour, Yahya; Sharples, Steve

Abstract

Many researches of overheating in buildings have focused on the optimisation of the window to wall ratio (WWR). However, the physical form of the building envelope has not been widely considered as a factor in optimisation investigations. This study examines if the optimum WWR might vary in response to slight geometrical changes to a façade’s design. An evolutionary parametric design method was used to generate a range of inverted pyramidal shaped envelopes with different inclination angles for each façade. This was implemented for an existing UK Passivhaus. The WWR was set as the main variable along with a sub variable of different weather data (both current and future climate scenarios). This paper, in particular, focused on minimising the overheating during the summer while reducing the primary energy use of the building. These two parameters were set as the objectives to be optimised using the parametric tool in the dynamic thermal simulation software DesignBuilder. The calculation used batches of Energy Plus simulations using a genetic algorithm. The results showed that the optimised WWR varied significantly when implementing different façade arrangements. Optimum self-shading shapes could allow more glazing to be used while still achieving thermal comfort in summer climate.

Citation

Lavafpour, Y., & Sharples, S. (2017, July). The influence of façade design on the optimum window to wall ratio and overheating rate in UK Passivhaus dwellings for current and future climates: A Parametric Design Method. Paper presented at Passive Low Energy Architecture, Edinburgh, Scotland

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: Passive Low Energy Architecture
• Start Date: Jul 3, 2017
• End Date: Jul 5, 2017
• Acceptance Date: Jul 7, 2017
• Publication Date: Jan 1, 2017
• Peer Reviewed: Peer Reviewed
• Keywords: overheating, WWR, self-shading, warming summer
• Additional Information: Title of Conference or Conference Proceedings : Passive Low Energy Architecture (PLEA)