Subjective assessment of visual comfort in a daylit workplace with an electrochromic glazed façade

Electrochromic (EC) glazing is increasingly employed in building façades to achieve better visual comfort for the occupants. EC glazing can modulate the light entering through the façade by varying the solar transmittance of the glass and therefore can work as a shading strategy to minimize solar heat gains or glare. However, it also alters the spectrum and distribution of light entering through the façade, which influences certain visual attributes associated with a space. This user assessment study evaluates some of these attributes including the colour perception of the elements inside and outside the room, the uniformity of daylight distribution, the clarity of the view through the glazing and the perception of glare when the sun is in the field of view. Results indicate a visual transmittance (τv) of 0.6% is sufficient to control glare when the sun is in the peripheral field of view (FOV) while τv,n-n of 0.14% is required to control glare when the sun is close to the central FOV. Most of the participants did not perceive the colours of outdoor environment as natural when seen through EC glazed window. The majority of participants also desired to change the glazing configuration by adding an additional shading device.

Large lightwells to revitalize a deep office building in Lausanne

The city of Lausanne is built on fairly steep slopes, with the consequence that some buildings are leaning against what could be described as cliffs and, therefore, have only one glazed facade. The Rue Saint Martin office building has been built during the 1970s. Because of its important depth (~23m from the façade), the spaces located at the back were totally deprived of natural light. During the renovation of this building, the architects wanted to create large openings in the roof and in the floors’ slabs in order to provide daylight to the rear spaces. The close collaboration between Estia1 and Archespace2 allowed for the design and implementation of an efficient daylighting system that provides a new quality of use for the interior spaces and a new identity for the building.

Fachadas vidriadas: cálculo de transmitancia térmica

Glazing is one of the dominant features of modern and contemporary architecture. This envelope design may have a great impact on operational energy demand of buildings. In this work, glazed façade systems available in Argentina are analyzed, with the purpose of determining the associated thermal transmittance ranges, in terms of the profiles’ design, the type of glazing and the size of glass panes. First, by using bidimensional numerical calculation, the impact of several profile design parameters on thermal transmittance is studied, highlighting the relevance of glazing fixing methods, to then calculate the thermal transmittance of the entire facade. The results indicate that the thermal transmittance value of glazed facades, mainly depends on the transmittance of the glass used, and exceeds this by 24% on average.

Evaluation of Thermal Comfort Performance of a Vertical Garden on a Glazed Façade and its Effect on Building and Urban Scale, Case Study: An Office Building in Barcelona

The aim of this paper is to investigate the thermal performance of vertical gardens by comparing the thermal comfort of bare (glazed) and green façades in the Mediterranean climate. The proposal consists of applying a vegetation layer on a glazed façade that could control solar radiation and reduce indoor air temperatures. This study investigates the thermal performance of green façades of an office building in the Mediterranean climate. For this purpose, the Gas Natural Fenosa Office Building as a case study was simulated, that is located on a site next to the coastline in Barcelona. Dynamic building energy simulation was used to determine and assess indoor thermal conditions and, for this reason, the IES VE as a simulation tool has been utilized. Thermal comfort was assessed through the adaptive comfort approach and results were analyzed and presented in the terms of indoor comfort conditions during occupied hours. As a result, the article shows that applying a green façade as a vegetation layer caused a reduction in the internal and external façade surface temperatures, as well as the indoor air temperature of the workplace. Additionally, enhancing indoor comfort in summer is closely associated with reducing the external surface temperature. In winter, it also protects the exterior surface from the low temperature of the outside, and all of this greatly increases thermal comfort performance.

Transition Planes for Visual Comfort: Out View with Complex Fenestration System Design at Restaurants in Spain

This work deals with daylighting for quality indoor atmospheres, considering building skins. In recent years, almost all retrofit facades of restaurants are highly glazed façades, boosting glare, sun ray absorption and overheating inside. Most of the time, they are not integrated with daylight control; therefore, lighting and out view requirements are not so balanced. Taking into account this daylighting complexity, an alternative façade system is proposed to simulate by Radiance. Previously, perception simulations are compared with measured data, in order to discretize the simulations. In addition, for one point three different view are assessed as: work plane, relation plane and the out plane. Subsequently, two virtual façade models, windows combined by complex fenestration system (CFS) as prismatic film (PF) and highly glazed façade, are tested according to daylighting. For that, three indexes have been used: daylight glare probability (DGP), daylight glare index (DGI) and daylight autonomy (DA). The results show that the proposed complex façade has a good light contribution with less absorption, while maintaining the outside view. In addition, the DGI is needed to test the out plane, because DGP is more suitable for lower luminance; therefore, each visual plane should be assessed regarding different visual comfort conditions, or parameters and methods. Accordingly, the mean DGI result of window combined by CFS is approximately lower in 5% than highly glazed façade. However, the DA of highly glazed is higher in 5%, but the DA of window combined by CFS is enough, above 80%. Definitely, the complex scene at restaurant with the proposed integrated façade system improves light performance and indoor atmosphere.

Experimental Study on Energy Efficiency of Multi-Functional BIPV Glazed Façade Structure during Heating Season

Building integrated photovoltaics (BIPV) is technology that can significantly increase the share of renewable energy in final energy supply and are one of essential technologies for the nearly zero-energy buildings (nZEB), new build and refurbished. In the article (a) an experimental semitransparent BIPV glazed façade structure with 60% of PV cell coverage is shown; (b) energy efficiency indicators were developed based on identified impact parameters using experimental data; and (c) multi-parametric models of electricity generation, preheating of air for space ventilation, and dynamic thermal insulation features that enable prediction of solar energy utilization in different climate conditions are shown. The modeled efficiency of electricity production of BIPV was in the range between 8% and 9.5% at daily solar radiation above 1500 Wh/day, while low impact of outdoor air temperature and ventilation air flow rate on PV cell cooling was noticed. Between 35% and 75% of daily solar radiation can be utilized by preheating the air for space ventilation, and 4.5% to 7.5% of daily solar radiation can be utilized in the form of heat gains through opaque envelope walls.

DESIGN OF SOUND INSULATION OF FULL GLAZED FACADE

The paper deals with an office building project where one part of the building was changed to a clinic as a project modification before its finalization. However, the medical offices are in the noise protected indoor space where the hygienic noise limits are stricter. It leads to the higher standards of the facade, which was already designed by an architect. According to the traffic noise, there is an overload in that area of the office building, so it was necessary to develop the noise simulation of the outdoor noise and then to verify the sound insulation of the fully glazed facade or develop potential improvements in the construction. The mock-up was built for the verification of the model and the final results were confirmed by the measurement for the building’s approval.

Le Corbusier’s Cité de Refuge: historical & technological performance of the air exacte

Despite a number of attempts by Le Corbusier to implement the combination of ‘respiration exacte’ with the ‘mur neutralisant’ he was never able to test the viability of his environmental concepts in a realised building. The Cité de Refuge, which was built with a more conventional heating system and single glazed facade, is however unique in that unlike the other potential candidates for the implementation of these systems, the building, as built, retained a key design feature, i.e. the hermetically sealed skin, which ultimately contributed to the building’s now infamous failure. It is commonly argued that Le Corbusier, however, abandoned these comprehensive technical solutions in favour of a more passive approach, but it is less well understood to what extent technical failures influenced this shift. If these failures were one of the drivers for this change, how the building may have performed with the ‘respiration exacte’ and ‘mur neutralisant’ systems becomes of interest. Indeed, how their performance may have been improved with Le Corbusier's later modification of a brise-soleil offers an alternative hypothetical narrative for his relationship to technical and passive design methodologies. Keywords: environment, technology, performance, history, Cité de Refuge DOI: http://dx.doi.org/10.4995/LC2015.2015.796