Embodied energy data implications for optimal specification of building envelopes

Abstract

Highly insulated building envelopes have become more commonplace as environmental imperatives require reduction of building carbon footprints. Whilst increased insulation levels reduce operational energy demand, the additional embodied energy investment can increase the buildings' overall environmental impact. The embodied energy consideration can determine whether, and to what extent, additional insulation is justified. The following paper investigates the impact of uncertainties of embodied energy data on the cumulative operational and embodied energy analyses and holistically appraises its implications for different stakeholders involved with the construction sector. Limitations in current LCA calculation methods and high uncertainty of available data are recognised and reflected in the analyses through studying available EPDs of various types of insulation materials and by modelling a typical semi-detached residential building in the UK as the case study. The results of such approach illustrate 'optimum insulation thicknesses' beyond which the embodied energy penalty outweighs operational energy savings. These essentially represent idealised levels of building envelope insulation that can inform the development of future standards for low energy/carbon buildings and support the adoption of LCAs as decision making tools in informing the urgent debate of optimal insulation requirements of buildings.

Can vacuum insulation panels be cost-effective when applied in building façades?

“…It should be noted that the EU cost-optimal methodology focuses primarily on operational energy. Nonetheless, research studies have indicated that the embodied energy for thermal insulation materials may be higher than the operational energy they save during service life ( [52], [53], [54], [56]). The environmental impacts and the consumption of renewable and non-renewable primary energy on the embodied, transport, and operational energy for vacuum insulation materials should also be addressed, since vacuum panels may have an environmental impact greater than other insulation materials [55].…”

Parametric study of the impact of building envelope systems on embodied and operational carbon of residential buildings

“…total carbon (Resalati et al, 2020). Furthermore, Azari (2014) examined six environmental impacts based on envelope scenarios for a two-storey office building in Seattle, US.…”

“…Another study emphasised the combined assessment for operational and embodied carbon of various insulation types of a typical semi-detached residential building located in the UK. The additional insulation materials played a role in increasing total carbon (Resalati et al , 2020). Furthermore, Azari (2014) examined six environmental impacts based on envelope scenarios for a two-storey office building in Seattle, US.…”

Comparative life cycle assessment of different vacuum insulation panel core materials using a cradle to gate approach

“…Although VIPs offer very low thermal conductivity (0.004-0.007 W/(m.K)), up to 10 times better than other conventional thermal insulation materials (such as mineral wool, PUR, EPS and XPS), their relative embodied energy (EE) investment is higher. Resalati et al (2020) demonstrated in their study that the EE of fumed-silica based VIPs (GJ/m 2 ) for a given R-value (thermal resistance measured in m 2 .K/W) can also be up to 10 times (in the most extreme cases) greater than conventional insulation materials on a cradle to gate basis (Figure 1). The core material, barrier envelope, getter and desiccant are the main parts that make up a VIP (Figure 2) (Alam et al, 2011).…”