An Evaluation of the Combined Effect of Window Shading and Thermal Mass to Reduce Overheating

Carlos Jimenez-Bescos

doi:10.1007/978-3-030-00662-4_53

Abstract

Thermal mass has the benefit of regulating energy in buildings and generates potential savings in energy and CO2 emissions. Window and local shading can provide shelter and reduce the severity of overheating during the year and mostly during the summer period. The aim of this study was firstly to evaluate the influence of window shading to reduce overheating and secondly to assess the thermal mass benefits in the presence of shading devices to alleviate the impact of overheating. This study was based on dynamic thermal simulations to analyse the performance of different window and local shading devices to avoid overheating. Twenty building simulation models were performed using the Energyplus plugin in DesignBuilder to evaluate the effect on the thermal mass behaviour to mitigate overheating according to different window shading devices. This study confirmed, as expected, that the use of window shading helps to alleviate the overheating hours in the test room and as such, improving the thermal comfort and reducing the need for cooling. Furthermore, when the window shading devices are coupling with thermal mass and night ventilation, the reduction on overheating hours achieved will reach a reduction of over 50% with respect to not exposing the thermal mass. In conclusion, exposing the thermal mass coupled with a night ventilation strategy provides a reduction on overheating hours, which is increased by using different window shading devices. Exposure of the thermal mass provides a good strategy for reducing the need for cooling and increasing thermal comfort.

Highlights

Overheating issues are becoming more common nowadays in the built environment as a consequence of the effect of climate change, the use of thermal mass presents a good opportunity for non-domestic buildings to regulate the indoor environment, while saving energy and CO2 emissions
Exposing the thermal mass coupled with a night ventilation strategy provides a reduction on overheating hours, which is increased by using different window shading devices
The simulations were modelled without the inclusion of cooling to control overheating, as the main purpose of the simulations were to evaluate the benefits of coupling the thermal mass and purge night ventilation

Summary

Introduction

Overheating issues are becoming more common nowadays in the built environment as a consequence of the effect of climate change, the use of thermal mass presents a good opportunity for non-domestic buildings to regulate the indoor environment, while saving energy and CO2 emissions. The literature [1, 2] has presented the benefits available by the use of thermal mass and when coupled together with night ventilation. According to the Zero Carbon Home [3], combining the effects of thermal mass and night purge ventilation create benefits to reduce overheating. In non-domestic buildings, the thermal mass tends to be hidden behind a false ceiling mainly for acoustic reasons. By making use of the thermal benefits to regulate the indoor thermal comfort, overheating in summer can be reduced and the need for cooling minimised, allowing a reduction in energy consumption and the respective CO2 emissions savings [4]

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