The Study of Architectural Geometry and Shape in the Energy Balance of Glazed Roofs

Triggered by the global call for low-carbon design, the idea of “productivity for a building envelope” has permeated the role of building to produce alternative (renewable) energy alongside weather and solar protection, and the authors hypothesized that the geometrical shape and configuration of a roof is a significant contributor to low-carbon design. Bibliometric networks such as VOS Viewer revealed a gap among most research works which have yet to discover “roof geometry” as a design determinant for photovoltaic electricity production. In this study, the authors tested their hypothesis by studying and comparing the balancing of solar energy harvesting and energy consumption and saving due to the uncontrolled admittance of daylight, glare, and solar heat gain of different geometric shapes of roofs in the subtropical climate. Twelve recent signature public buildings in Shenzhen city are studied for the tendency of architectural geometry of roof shapes. These roof shapes are then simplified and classified into three distinct geometries—square, pyramidal, and curvilinear—for comparative study of the best-performing low-carbon architectural geometry. The results of the simulations using the “Daysim” and “Energy-Plus” models show the desirability of an optimized design. The preliminary findings shed light on the preferred use of specific roof shapes for enhanced PV output. The curvilinear geometry has been shown to be the most effective of all. This study targeted the roof potentials by multiple criteria and a parametric evaluative protocol for building design known as the energy balance paradigm. This research paves the way in (1) changing the impression of the roof as a mere weather protector to that of a “productive roof” in response to the global call for carbon neutrality, (2) raising the awareness of architectural geometry (i.e., the building envelope), focusing on the roof form and its shape in response to low-carbon design requirements, and (3) identifying multiple criteria for the low-carbon design of architectural roof geometry.

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