Simulation pathway for estimating heat island influence on urban/suburban building space-conditioning loads and response to facade material changes

Abstract

Environmental thermal loading on urban buildings is expected to increase owing to the combined influence of a warming climate, increasing frequency and severity of extreme heat events, and the urban heat island (UHI) effect. This paper presents how a computationally efficient estimation pathway could be utilised to understand UHI influence on building energy simulations. As an example, this is examined by considering UHI influence on the space-conditioning loads of office buildings within urban and suburban conditions, and how the trend of replacing heavyweight facades with lightweight alternatives could affect their surrounding microclimates, as well as building energy use. The paper addresses this through simulations of street canyons based on the urban Moorgate and suburban Wimbledon areas of London. Results show that with all scenarios including the UHI within a dynamic thermal simulation presents between 2.5 to 9.6 % net increase in annual space-conditioning. The study also demonstrates that the trend in urban centres to replace heavyweight facades with lightweight insulated alternatives increases space-conditioning loads, which in turn increases UHI intensity to create a warming feedback loop. The study therefore stresses the significance of including microclimate loading from the UHI in estimating urban and suburban energy use, and the combined simulation approach is presented as a computationally efficient pathway for use by built environment designers.

Adaptive comfort assessments in urban neighbourhoods: Simulations of a residential case study from London

“…The Gloucester Terrace simulation for the FamOcu profile agreed, although the EldOcu profile demonstrated the daytime average for all bedrooms as marginally higher than evening; possibly explained by higher daytime occupancy resulting in marginally increased gains. The performance of the envelope and its material properties are key determinants of how the lagged temperature response is experienced, with envelopes with higher thermal inertia likely to shift this risk to evening and nocturnal periods [23,41]. In bedrooms this shift could lead to nocturnal discomfort, sleep deprivation, and heat-related health issues.…”

“…The framework is based on multiscale energy balances and Monin-Obukhov similarity theory and is composed of four coupled sub-models. A summary of principal data exchanges is presented in Gunawardena et al [23], while detailed description of its workings is included in Bueno et al [22,24], with field data validations from Basel, Toulouse, and Singapore included in Bueno et al [22,24] and Nakano et al [25]. The framework is primed with the input of a rural weather file, which is used by the sub-models to calculate temperature and humidity values to compile a modified urban canyon-specific weather file.…”

“…The framework is primed with the input of a rural weather file, which is used by the sub-models to calculate temperature and humidity values to compile a modified urban canyon-specific weather file. This output file can then be used by dynamic building thermal modelling software to simulate indoor conditions and energy use of buildings representative of the canyon neighbourhood [23].…”

Interactive Buildings: A Review

“…Actively controlled façade: Shading [4], dynamic insulation [5], BIPV [6,7], RASF [7] Hours to minutes Interactive façade design: Glazing [8], construction material and envelope surface properties [9][10][11][12] Diurnal, seasonal, and life cycle Integrated design Passive design: Green roof [13], phase change materials [14,15], passive PV cooling [16,17], thermally activated building systems [18] Diurnal…”

“…The construction materials selected for the building envelope also affect the interactions of the building with the environment. Gunawardena et al simulate and test different envelope materials for two locations in London to capture their effect on heating and cooling energy use as well as contribution to the UHI effect [9]. They find that the common practice of replacing heavy envelope material with lightweight insulated envelopes increases the need for air conditioning by 2.5% to 9.6%, which also contribute to UHI because higher air-conditioning needs lead to increased amounts of heat rejected from the buildings [9].…”