This paper explores the possibility of characterising the degree of fenestration of a certain city by studying a limited building sample. For the case study of the Eixample district of Barcelona, window-to-wall ratio (WWR) guiding values are provided and the role of the date of construction and the façade orientation is assessed regarding the opening size. Results indicate that not only average WWR values but also dispersion indicators should be provided to adequately describe façade fenestration. The age of construction has found to be a helpful parameter to approximate representative WWR values of a tissue reducing the uncertainty.
Façade design has significant effects on inner conditions of spaces and also on the energy needs to achieve user’s comfort. In this regard, the proportion of glazed surfaces to opaque ones plays a key role. Although the link between the fenestration ratio and energy demand for a space has been widely addressed in literature, a considerable number of these studies were based on isolated models, disregarding the effect of the urban surroundings. The aim of this paper is to provide insights on the impact of the window-to-wall ratio (WWR) on thermal energy demands taking into consideration a specific urban context. The Eixample district of Barcelona, with Mediterranean temperate climate, has been selected as the case study. Heating and cooling energy needs have been evaluated for a single residential space by means of computer simulations in Design Builder for different positions within the tissue. Results show that, from a thermal point of view, the design of façade openings within an urban context should vary depending on the orientation and the degree of obstruction, as a reflection of the differences in energy balance within the building envelope.
The urban canyon model has been recurrently used as a basis for many solar access studies. However, its conception as endless structures disregards the effect of street intersections, despite being characteristic elements of urban fabrics. This paper aims to evaluate the impact of street discontinuities on solar access over building façades. The potential of crossings to increase the available radiation has been assessed through computer simulations in dense urban environments in a Mediterranean location. For the cases studied, results show that local effects of an intersection almost disappear beyond a speci¿c distance for each aspect ratio, which can be helpful to determine the suitable level of detail for solar analyses at an urban fabric scale.
The link between city morphology and urban energy consumption, although proved, requires further research. In that sense, the analysis of parameters describing the urban texture may be a useful approach for energy assessment at a city scale. Some geometrical parameters have been used to study urban energy aspects related to the radiative phenomena, such as heat island or even a rough indicator of solar energy availability in locations where direct radiation is not determining. This paper aims to explore the correlation between one of these parameters -the Sky Factor (SF)- and direct solar radiation over facades, as a characterization tool of solar access within an urban context. Barcelona, a Mediterranean city where direct sunlight and the built environment density are deciding factors, has been chosen as case study. At different points of the facade for several urban canyons, SF value and direct solar radiation for different orientations and times of the year have been computed using Heliodon software. Both results have been related one to another and it has been found that, for a specific latitude, it is possible to define a smooth dependence between these parameters, if the orientation is taken into account. This paper shows that, beyond the SF threshold of 0.42, direct solar radiation on the facade reaches an almost asymptotic value for all orientations and times of the year.
As a result of the current economic and energy crisis, it has become necessary to rethink
urban planning, starting from a global concept of efficiency and considering buildings not as
isolated entities, but as part of an urban system, which consumes energy on a much larger
The connection between urban morphology and microclimate is a widely discussed question,
including issues like the urban heat island phenomenon or outdoor comfort in open spaces.
However, there is still a lot of work to be done regarding the influence of these microclimatic
variations on building energy consumption. In that sense, would it be possible to apply
efficient measures of microclimate modification on an urban scale to increase comfort levels
in public spaces while at the same time, reducing building consumption?
This paper focuses on urban canopy shading. Its effectiveness as a shading device and its
capability to improve outdoor climate in areas with an excess of solar radiation is widely
demonstrated. In this case, its effect on indoor climate of is evaluated.
The case study is located in Cordoba (Spain), as an example of a climate with a hot and dry
summer (according to CTE, level 4). A complete street canyon model has been created. Two
buildings, one on each side of the street canyon, have been tested using an energy
simulation software (Design Builder). Model features and simulation settings correspond to
real values. Urban canopy shading effectiveness has been analyzed according to cooling
demand decrease, taking into account both buildings. Spatial factors (street orientation,
width-height ratio, windows-opaque ratio) and material factors (U-values and skin mass, %
obstruction) have been considered.
Results show 18% to 45% cooling demand decrease due to the canopy shading. Spatial
factors are much more relevant than material factors: windows-opaque ratio is a determining
factor, in contrast to mass and U-values. This study shows the importance of evaluating both
urban facades, which means working from an urban perspective beyond the local scale of a