Lighting features in indian-style traditional architecture

Due to the effect of impinging solar radiation, high thermal loads can be predicted in buildings ¡n many climates of South-East Asia. The logical need to protect and ventílate the fagades has been known for centuries. Features such as the jalis or lattice work combined with deep overhangs and elements conceived to reflect excessive sunlight such as water tanks or ritual ponds have adorned Indian-style palaces and temples since ancient times. Those features have subsequently inspired modern architects like Le Corbusier, Antonin Raymond, Benjamín Polk and Geoffrey Bawa to cite just a few. Climatic control elements were well suited to the craftsmanship of traditional architecture but their use as industrial producís that could be prefabrlcated ¡s more controversial. Not only has the climate changed since the origin of Indian-style architecture, but also the use of glazing has increased in an alarming way and thus the need to protect the fagades is now even more demanding. If this is not properly done the performance of air-conditioning Systems would be compromised and the lifespan of the Windows would result severely affected. Nonetheless, depending on the type and reflective nature of the shading system selected, undesirable effects for ventilaron, comfort and especially for day-lighting tend to occur in the space that, paradoxically, we are trying to protect. In this paper, within the context of Indian civilization we will present the simulation of the radiative field generated by different types of solar protection and reflective surfaces, especially ponds and Systems of louvres or brise-soleil. In the process we intend to extrapólate the procedures for ancient fabrics to some modern counterparts found in internationally acclaimed buildings and to obtain useful design insights for future projects

ANNUAL DAYLIGHT SIMLUATIONS WITH EvalDRC: ASSESSING THE PERFORMANCE OF DAYLIGHT REDIRECTING COMPONENTS

EvalDRC is a newly developed daylight analysis tool for the evaluation of Daylight Redirecting Components (DRC) in architectural spaces. It focuses on the accurate simulation of light redirection with help of the lighting software environment RADIANCE. It employs various key technologies, among them are: a) the daylight coefficient method, b) characterisation of the light redirection behaviour of materials and specially designed systems with appropriate data models, and c) daylight metrics. We present several enhancements to these key technologies and the currently existing tools. In the context of daylight coefficients, we improve the solar contribution calculation by using realistic 0.5° solid angle sun primitives, thus generating True Sun coefficients. For simulating light redirection behaviour, we introduce Contribution Photon Mapping, a recent add-on to the RADIANCE environment. In addition, we introduce monthly breakdowns of the established daylight metrics Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE), to provide a more detailed assessment of DRC performance throughout the course of a year. The paper gives an overview of the mentioned annual daylight simulation key technologies, and explains how our enhancements and developments surpass the current approaches and lead to a versatile tool, capable of producing meaningful and detailed simulation results.  A description of the implementation and an application example is given, rounded off by a discussion of the current state of the ongoing work and a tentative outlook

BIPV Visual Assessment for Architecture Retrofitting

Typical architecture designers convey through vague and qualified notions. With the increasing number of PV installations on buildings, architects are forced to corporate with technicians and engineers in the design processes. However, the communications between them are often hindered because unlike architects who communicate through semantic descriptors and visual images, engineers are used to interact with quantified terms. One way to solve this problem is adapting visual impact assessment for PV installed on façade so that one can foresee and evaluate its final overall effect in a way that is comprehensible for both sides. The visual impact assessment is a method mainly used in landscape design for evaluating the influence manmade changes caused on natural landscape. Now it is vastly used on aesthetic assessment for wind farms being built on open landscapes all over the world. Comparing with wind farms, the relevant researches for Photovoltaics are rather underdeveloped. The estimation of visual effect created by integrating solar energy components on open landscape is rarely investigated, let alone on architecture where it is more complicated because more aesthetic factors are involved. With the increasing number of Photovoltaics installed or to be installed on architecture facades, it is necessary to develop a rational visual assessment tool to better evaluate the appearance outcome of the final installation. Based on summarizing research experiences and literatures from former visual impact assessments, this paper tries summarize the possible factors that are relevant for AIPV installation, and changes and extensions on existing theories are being made when necessary. The final results will benefit architects, engineers during the planning process, and eventually for law regulator in laying down clear and reasonable urban planning regulations regarding installing PV in urban areas. In the end, the author will apply the visual impact theory on a retrofitting project where AIPVs are assigned to be installed on a church in Lucerne, Switzerland

Daylighting in historical centres: the case of an architect's office in Seville

Historical towns ¡n Europe usually have as their main feature an extremely dense urban tissue. This, in turn, generates a wide variety of situations which make it difficult to provide adequate light to the ¡nside of buildings. On the other hand, the trend for revitalization of cities often demands a change in the utilization of spaces adding even more difficulties to the case because the previous constraints and standards are heavily modified. Architecture today must face this challenge as a new aim for creativity based on the idea of “design with the environment”. Basically, the achievement of the said urban renewal of oíd towns should not entail the creation of a kind of enclosure where sustainability is absent as the conservationists would have it. With this concept in mind, the complex process of building an architect's office was been launched, and though the starting situation was that of “a windowless fagade", a number of strategies have been devised to provide for sun and light in the working and living spaces. Simulations of the project taking into account the principies of radiant energy transfer have been duly conducted and after some corrections the office was completed and monitored. The procedure yields both the thermal gains and the luminous distribution of the building in order to assess the performance and comfort level on a seasonal basis. Therefore, we consider that the project is a valid example of sustainability in historical cities not merely because of the former but also due to its integration with professional practice and its attempt to address severe urban and political constraints

Climate based daylight simulations with EvalDRC – analysis of Daylight Redirecting Components

The new calculation tool EvalDRC enhances current strategies for the simulation of Daylight Redirecting Components (DRCs). It is built upon RADIANCE as a core simulation engine and uses the daylight coefficient method, climate based sky models for annual simulations, and daylight metrics for data reduction.  Contribution Photon Mapping is introduced as a new method for physically correct DRC simulation.  Further new features are separate: True Sun Coefficients for a less approximated, more accurate treatment of the sun contribution and monthly breakdowns of the Spatial Daylight Autonomy and Annual Sunlight Exposure metrics for more detailed information about DRC performance over the course of the year. To show the versatility of the tool, two application studies were carried out in which either measured Bidirectional Scattering Distribution Functions (BSDF) or detailed geometry models were used for the DRC simulation

A hybrid data-driven BSDF model to predict light transmission trough complex fenestration systems including high incident directions

The transmission and distribution of light through Complex Fenestration Systems (CFS) impacts visual comfort, solar gains and the overall energy performance of buildings. For most fenestration, scattering of light can be approximated as the optical property of a thin surface, the Bidirectional Scattering Distribution Function (BSDF). It is modelled in simulation software to replicate the optical behaviour of materials and surface finishes. Data-driven BSDF models are a generic means to model the irregular scattering by CFS employing measured or computed data-sets. While measurements are preferred by researchers aiming at realism, they are constraint by the measurement geometries of the employed instrumentation. Particularly for large samples prevailing in the field of building sciences, measurements of the BSDF for directions close to grazing are impacted by shadowing and edge effects. Reliable extrapolation techniques are not available due to the irregularity of the BSDF. Computational simulation is not limited by such constraints at the cost of lower realism. A hybrid approach is therefore proposed. The BSDF of a CFS is measured for incident elevation angles from 0° to 60°. For incident elevation angles from 0° to 85°, the BSDF of the sample is computed. The BSDF acquired by both techniques in the overlapping range of directions between 0° to 60° is compared and reveals good qualitative accordance. The variance of the direct-hemispherical reflection and transmission based on the two techniques is between 3% and 28%. A hybrid data-set is then generated, utilizing measurements where possible and simulations where instrumentation cannot provide reliable data. A data-driven model based on this data-set is implemented in simulation software. This hybrid model is tested by comparison with the geometrical model of the sample. The hybrid approach to BSDF modelling shall support the utilization of BSDF models based on measured data by selectively overcoming the lack of reliable measured or extrapolated data

Comparison of Measured and Computed BSDF of a Daylight Redirecting Component

International Conference CISBAT 2015 Future Buildings and Districts Sustainability from Nano to Urban ScaleThe Bidirectional Scatter Distribution Function (BSDF) of a selected Daylight Redirecting Component (DRC) is computed by a virtual goniophotometer using the enhanced photon map extension in Radiance, and compared to measured BSDF data. The DRC comprises a stack of tilted aluminum louvers with configurable inclination angle. The profile of the louvers is designed to control transmission depending on sun altitude, and to redirect light up towards the ceiling. The measured BSDF of the DRC is obtained from a scanning goniophotometer. For a sparse set of three source directions, the distribution is recorded at ≃ 250,000 receiver directions. The asymmetric angular resolution allows detailed observation of characteristic features in the distribution, which are assumed to persist over a range of source directions. For each pair of source and receiver directions in the measurement, the computed BSDF is generated from a model of the DRC, replicating the measurement with a virtual goniophotometer. The simulation relies only on the enhanced photon map extension for Radiance. The BSDF from measurement and simulation are compared qualitatively and quantitatively to discuss the degree of accordance. The presence of characteristic features and their topology is evaluated by comparing polar surface plots of the distributions and profiles of the scatter plane. The direct-hemispherical transmission is compared for each measurement and simulation. The RMSE of each computed distribution against the corresponding measurements is calculated to quantify the directionally resolved deviation. A high degree of qualitative accordance between the computed and the measured BSDF is achieved. Prominent features in the BSDF are represented by the model. A deviation of −6% to +15% is observed in a quantitative comparison of direct-hemispherical transmission by integration of computed and measured BSDF. The RMSE indicates higher deviations for lower source altitudes, where a direct transmission peak in the distribution is underestimated by the model. The method is proposed as a means to validate the capability of the enhanced photon map to predict transmission through DRC

Singapore’s Zero-Energy Building's daylight monitoring system

A setup to monitor the daylighting performance of different glazing types in Singapore is presented. The glazing is installed in the facade of four dedicated testing chambers in BCAA's Zero Energy Building in Singapore. These test rooms are equipped with sensors that both record illuminances on the work plane, and luminances as seen by occupants. The physical and logical design of the monitoring system is presented. Criteria to assess the daylighting performance are introduced, and initial results of the work in progress are presented

I-LIGHT, EIN WEBBASIERTES LERNSYSTEM ZUM ENTWERFEN MIT LICHT

Mit der steigenden Bedeutung architektonischer Beleuchtung steigt auch der Bedarf an entsprechender Lichtplanung. Die Möglichkeiten digitaler Instrumente haben Leuchten-hersteller erkannt, die 3D-CAD und Simulationen zur Erstellung von Präsentationen und das Internet als Verteiler einsetzen. Im Hochschulbereich ist es wichtig, Instrumente und Methoden anzubieten, mit denen die Wechselwirkung von Licht und Architektur anschaulich, nachvollziehbar und interaktiv erlernt werden kann. Einleitend werden in einem theoretischen Kapitel die Grundlagen der Lichtplanung und lernpädagogischer Konzepte aufgezeigt. Parallel wird der Stand der Technik auf den Gebieten des computerunterstützten Lernens und der Lichtsimulation vorgestellt und hinsichtlich der lernpädagogischen Eignung bewertet. Daraufhin wird ein Handlungsbedarf formuliert, der eine neuartige Integration der einzelnen Bereiche vorsieht. Er mündet in die Entwicklung eines interaktiven webbasierten Lernsystems zum Entwerfen mit Licht - I-Light - dessen Konzept und Realisierung in den folgenden Kapiteln beschrieben wird. In einer Beispielanwendung zeigt der Verfasser abschliessend auf, wie das Internet in dieser innovativen Verbindung mit 3D-CAD und Simulation einen neuen Beitrag zum besseren Verständnis des Mediums Licht in der Architekturwahrnehmung leistet. Den Kern dieses Lernsystems bildet ein neuartiges virtuelles Lichtlabor, in dem architektonische Planungsbeispiele dreidimensional dargestellt und interaktiv verändert werden können. Ein entwickeltes semantisches Szenenmodell sorgt dafür, dass Beleuchtung, Materialien und Begrenzungsflächen didaktisch angemessen variiert und verglichen werden, sodass visuelle Wirkungen überprüft und wichtige Zusammenhänge wahrgenommen werden können. Der Verfasser orientiert sich an der Lernmethode durch Simulation und bindet 3D-CAD- und Lichtsimulationsprogramme in das Lernsystem ein. Das berechnete fotorealistische Bild wird nicht - wie sonst üblich - als Präsentationsmaterial, sondern als interaktives Werkzeug angesehen. Da 3D-CAD und Lichtsimulationsprogramme viel Anwendungskenntnisse voraussetzen, verfolgt der Verfasser nicht das Ziel, den Benutzer mit diesen komplexen Programmen zu konfrontieren. Er entwickelt vielmehr ein neues System mit einer einfach zu bedienenden webbasierten grafischen Oberfläche, mit der eine 3D-Szene geladen, individuell verändert und gespeichert werden kann (Frontend). Es ermöglicht desweiteren die Fernsteuerung einer automatischen, fotorealistischen Simulation auf Knopfdruck, wobei via Internet die Berechnungen auf einem zentralen Hochleistungs-PC ausgelagert werden und nicht auf dem PC des Anwenders erfolgen. Für den Betrieb des Frontend ist nur ein durchschnittlicher PC mit einem Standard-Webbrowser notwendig. Für die Gegenstelle entwickelt der Verfasser eine neuartige Schnittstelle, die einen Standard-Webserver um die neuartige Möglichkeit des Speicherns und Ausführens von Lichtsimulationen erweitert (Backend). Das vom Verfasser vorgestellte System unterscheidet sich im didaktischen Konzept und in der technischen Realisierung von den bisher auf ähnlichen Gebieten existierenden Lösungen. Die interaktiven virtuellen Lichtlabore der architektonischen Planungsbeispiele stellen einen neuen Ansatz webbasierter Lernumgebungen dar, der zu einem neuen und besseren Verständniss von Licht in der Architektur führen kann. Zu den gewählten Werkzeugen (HTML, Java, VRML, Web-Server, Lightscape) gibt es auch nach Abschluss der Entwicklung noch keine ausgereiften Alternativen