Summer Thermal Comfort and Self-Shading Geometries in Passivhaus Dwellings: A Pilot Study Using Future UK Climates

Abstract

This study uses numerical thermal simulation to investigate the potential use of building geometry to eliminate or reduce current and future thermal discomfort overheating risk in UK Passivhaus dwellings. The study focused on the optimum inclination of a south façade to make use of the building shape to self-protect itself. Dynamic simulation modelling software was used to test a range of different inclined façades with regards to their effectiveness in reducing overheating risk. The research found that implementing a tilted façade could completely eliminate the risk of overheating for current UK climates, but with some consequences for natural ventilation and daylighting. Future overheating was significantly reduced by the tilted façade. However, geometric considerations could not eradicate completely the risk of thermal discomfort overheating, particularly by the 2080s.

Proceedings of the 27th Conference on Computer Aided Architectural Design Research in Asia (CAADRIA) [Volume 2]

“…Shading had a lesser impact in our study than in other studies (e.g. Lavafpour and Sharples, 2015), however in our case the project constraints limited the use of shading which limited its potential to combat overheating; furthermore the dense occupancy assumed for the current project increases the importance of internal loads over external ones. While the window dimensions were fixed, we noticed that rooms with higher glazing fractions had a higher overheating risk.…”

“…The studies that specifically analyse overheating risk in Passive House buildings tend to conclude that glazing fractions and shading are the most important factors (e.g. Lavafpour and Sharples, 2015;McLeod et al, 2016). However, this is based on a very small number of studies; more research is required to shed light on this complex issue.…”

Do passive houses need passive people? Evaluating the active occupancy of Passivhaus homes in the United Kingdom

“…Both occupants regarded their home environment to be comfortable, with the naturally ventilated Passivhaus achieving lower energy consumption. A recent increase in research of overheating issues in Passivhaus projects has brought occupant interaction into the spotlight [33] [34] [35] [36] [37] [38] [39]. This makes the process of adaptive comfort and the need to investigate occupant behaviour ever more important.…”

An industry case study using parametric modelling to facilitate Passive House design

“…The few researchers who have run this type of analysis do so using other software like MATLAB 10 or Python and EnergyPlus, 11 and occasionally also Rhino/Grasshopper and LadybugTools 6 to automate the simulation of many design options. They sometimes use algorithms to optimise parameter settings 12 or conduct sensitivity analyses. 9,13 The results of these studies are typically used to develop insights into the most effective ways to attain Passive House compliance in a particular context, such as one relating to a particular building type or climate zone.…”