Daylight availability knowledge is the first step for an energetic and visually e cient
building and city design. It can be estimated with the Vertical Sky Component (VSC), which is
defined as the ratio of the vertical di use illuminance over the unobstructed horizontal di use
illuminance, simultaneously measured at the same point. These illuminance magnitudes are obtained
from luxmeter measurements but these data are scarce. Alternatively, VSC can be obtained from
prior knowledge of the sky illuminance distribution, which can be measured with a sky scanner
device or by reference to the CIE (Commission Internationale de L’Éclairage) Standard classification
for homogeneous skies. Both approaches are compared in this study. The coherence of the results
obtained for the four cardinal orientations are analyzed by applying classical statistical parameters
and luxmeter measurements as references for the results. The measurement campaign was completed
between September 2016 and January 2019 in Burgos (Spain), as representative case study and specific
contribution of this work. It was observed that the VSC values were higher than 100 in many cases:
21.94% for the south- and 33.6% for the east-facing vertical surfaces. The study highlights the good
daylighting conditions in Burgos, mainly due to the predominance of clear skies over much of the
year. This fact implies high daylight availability that, with e cient city planning and building design,
could potentially lead reduction energy consumption of buildings, improvements in visual comfort,
and the well-being of occupants.Regional Government of Castilla y León under the “Support Program for Recognized Research Groups of Public Universities of Castilla y León” (ORDEN EDU/667/2019) and the Spanish Ministry of Science, Innovation & Universities under the I+D+i state program “Challenges Research Projects” (Ref. RTI2018-098900-B-I00). Diego Granados López also thankfully acknowledges the economic support from the Junta de Castilla-León (ORDEN EDU/556/2019
