A Survey of Solar Envelope Properties Using Solid Modelling

Abstract

Solar envelope is a concept for regulating solar access in urban planning. It is a roof-like imaginary surface over a given piece of land that controls the maximum allowed building height in order to avoid casting shadows on the neighbours during a specific period. The volume of solar envelopes regulates building density, depending on geometric attributes and time (plot size and proportions, orientation, ground slope, latitude, duration of insolation). This work compares the effect of such factors on the size of solar envelopes on a variety of land parcels, individually or in groups. Repeated applications of solid modelling are used to calculate in each case the values of ‘Solar Volume Coefficient’, i.e. the volume of a solar envelope per unit of its base as a measure for comparisons. Results show the influence of the various factors affecting the geometry of solar envelopes. Among other findings, it is also shown that solar envelopes generate urban densities lower than conventional urban regulations. The total volume of solar envelopes over an area ( ‘Solar Building Potential’) can be increased by raising the reference level of solar envelopes ( ‘shadow fence’ or ‘solar fence’). Lower urban densities are compensated by facilitating solar applications, as well as by enhancing daylight, ventilation, and vistas in the urban context, thus creating new ‘solar cityscapes’ exemplified here on existing street patterns.

Understanding Computational Methods for Solar Envelopes Based on Design Parameters, Tools, and Case Studies: A Review

“…For example, the "True" condition is indicated with a bullet point, whereas the "False" condition remains empty. The results illustrate that some references nearly fulfill all of the listed parameters (e.g., [39,67,68]), while others require only six parameters ( [30,34,71,72]) to construct solar envelopes. This is because each reference is affected not only by the type of applied computational method but also by the design concept of the projects that often involve more parameters.…”

“…These references are consequently not further included in the main discussion of the review. In addition, this study identifies one previous review of solar envelope properties authored by Stasinopoulos [30]. However, this recent study focuses on the construction of solar envelopes based on solid modeling techniques [31], an area that can benefit from further consideration in our review that systematically addresses: (1) a comprehensive study of computational solar envelopes based on various methods, tools, and contextual settings of various case studies, (2) an in-depth investigation of design parameters that correspond to different computational methods and the identification of relevant parameters for each method, and (3) several criteria that enable the further analysis of current gaps and future directions of the study.…”

“…These tools are then defined according to three specific criteria. The first category of tools includes those preferred by authors who use popular CAD-related platforms to run the simulations of solar envelopes (e.g., [30,34,45,46,51,60,71,72,87]). The second category consists of a custom-built module that is generated from a particular function of existing digital tools such as T4SU in SketchUp [50], SolCAD [79] and Calcsolar [56] in Autocad, solar envelope tools in Revit [36], and the Solar Toolbox plugin in Grasshopper [90].…”

L'enveloppe solaire : un retour vers le futur

“…Plusieurs travaux ont utilisé l'enveloppe solaire comme un dispositif d'évaluation de l'accès solaire afin de vérifier si une construction enfreint le droit solaire [8][9][10][11][12][13][14]. D'autres travaux ont étudié son impact sur d'autres facteurs de conception tels que la densité urbaine obtenue [12,[15][16][17][18][19][20] ; la consommation énergétique [21] ; le captage solaire [22,23] et le confort thermique extérieur [24] et intérieur [25].…”

“…Plusieurs chercheurs ont démontré que les ambitions de densification [20,77], de réduction de la consommation énergétique [21] et de préservation du confort thermique [83] que prétend l'enveloppe solaire ne sont pas toujours atteintes. Cependant, la plupart des travaux se focalisent sur l'accès solaire pour un bâtiment isolé sans prendre en considération les rétroactions et la mutualisation avec son environnement immédiat.…”