The impact of increasing the building envelope insulation upon the risk of overheating in summer and an increased energy consumption

Abstract

This work describes a study aiming to establish the impact of the increase of the building envelope insulation upon the thermal performance of buildings. A particular emphasis is placed upon the consequences in terms of higher temperatures in summer, potentially leading to increased needs for installation of air-conditioning. This study also describes the coupled influence of other parameters that can reduce overheating, like solar shading and ventilation. The methodology is based on parametric studies obtained through simulations. The comfort analysis methodology is based on the adaptive approach. The results show that, with added insulation, it is necessary to control solar and internal gains more closely to avoid overheating in summer. Results also include the requirements to avoid airconditioning, in terms of window shading for each level of insulation and internal gains.

A Reflection on Low Energy Renovation of Residential Complexes in Southern Europe

“…Furthermore, if an extra insulation can bring some advantages in terms of thermal comfort in winter, this is not assured in summer for Mediterranean climate. A computer simulation study carried out on the influence of increasing thermal insulation on summer thermal comfort [17] showed there is a turning point where, depending on thermal inertia, ventilation and heat gains, an increase in thermal insulation leads to an increase of the number of hours of discomfort in summer. In the left side of Figure 19, an example of the variation of the percentage of hours of discomfort in summer, for a location in Portugal, in function of the level of insulation of the envelope is given for different values of the shading factor.…”

Assessing the accuracy of a simplified building energy simulation model using BESTEST: The case study of Brazilian regulation

“…The SM RTQ-C takes into account the building geometry (projection area, total floor area, envelope area and total volume area) and some parameters related to openings, such as WWR (window-to-wall ratio), FS (solar factor), AVS (horizontal shadings), AHS (vertical shading). The acronyms of WWR, FS, AVS and AHS are the same as considered in the RTQ-C. Wall and roof thermal transmittance were not included in the SM RTQ-C , in spite of its recognized importance in the thermal performance of the building envelope [28]. Thermal transmittance was not included because its effect on the building energy performance is not linear [29], and consequently the multi-linear regression did not provide satisfactory coefficient of determination when transmittance is taken into account.…”

A stepwise approach for assessing the appropriate occupant behaviour modelling in building performance simulation

“…Global and local building policies set stringent energy goals for new and existing buildings with the aim of reaching near zero energy and carbon emissions. However, concerns exist about the comfort-related risks arising from lowenergy, highly insulated buildings in a changing climate (Chvatal and Corvacho 2009;McLeod, Hopfe, and Kwan 2013;Sameni et al 2015).…”