Search results

The purpose of this research is to investigate natural illumination properties of one of the classrooms in the School of Architecture at Izmir Institute of Technology, located in Turkey, which is the northern hemisphere.

In this study, the definitions of the basic terms in daylighting, such as daylight factor, illuminance, glazing ratio, are given first. Then, a luxmeter and a lighting simulation software, Velux, are used in order to calculate variable lighting factors during daytime, at different storeys, at different directions, for the classes. Velux is a proprietary software and it enables natural lighting analysis practically.

Chosen classrooms are examined regarding their having sufficient natural illumination. The height of windows from the floor is changed, and the resultant effects on natural lighting in the classrooms are determined by using the lighting simulation program, Velux. The study shows that daylight factor and illumination near the window decreases as the height of the window above the floor increases. However, the illumination increases away from the window, giving greater uniformity to the lighting. At the same time, the usable depth of the classroom increases. The tall and narrow windows bring the daylight near themselves.

Practical window design decisions can help architects to provide effective and healthy natural lighting for interiors.

Adjustment of the dimensions of the windows is important in order to balance the energy consumption of buildings. This study investigates natural lighting depending on both experimental measurements and simulation software, Velux.

The purpose of this paper is to determine the approximate window-to-wall ratio (WWR), window width-to-height ratio (WHR) and sill level for a room in Rasht–Gilan province and to present an optimal window in each of the WWR ranges providing the minimum energy consumption by integrating artificial lighting and thermal analyses, whilst maintaining internal comfort conditions using dynamic evaluation.

The process of modelling has four main steps: 1 – defining the building's features and requirements, 2 – validating input weather file data by on-site measurement, 3 – determining input parameters for the lighting and thermal analysis and 4 – clarifying variable parameters and fitness function for the optimization algorithm. Also, the survey study is performed in a daylit office room, in which 30 employees are employed to answer the questions in three different times of a day. In this process, the impact of daylight on their visual comfort is surveyed in 1,350 different illuminance levels which are manually recorded.

The range of useful daylight illuminance (UDI) values is determined as 200–1,000 lux. The optimum range of WWRs in the case study is 15%–25%. Also, due to the appropriate window height, electric lighting could be decreased by 40%.

Thermal and lighting performance in buildings is the relation of facade characteristics to environmental sustainability. Recent studies focussed on optimizing WWR and window characteristics considering thermal comfort and energy analyses. However, architects need freedom for designing façade and making decisions in their first sketches. Thus a guideline for optimum window conditions in each WWR is required. Also, considering occupants' behaviour in practical buildings, the visual comfort investigation is a gap in WWR optimization.

Electric lighting accounts for a large share of energy consumption in commercial buildings. Utilization of daylight can significantly help to reduce the need for artificial lighting, increase workers productivity, customers’ satisfaction and consequently improve sales. However, excessive use of glazing and absence of lighting controls can contribute greatly to higher energy need for heating and cooling and cause undesired glare effects. Thus, optimizing the size, position and materials of external glazing, with the addition of deflectors and dynamic artificial lighting, can become key aspects in the design of sustainable low energy buildings. The purpose of this paper is to analyze daylight potential and energy performance of a hall-type commercial building, situated in the cold climate of Finland, by utilizing different combinations of skylights, windows and lighting controls.

The authors have used computer simulations to estimate daylight and energy performance of a single floor commercial building in relation to various combinations of skylights and windows with variable glazing materials, light deflectors and zonal lighting controls.

The results show that electric light energy saving potential ranges from a negligible 1.9 percent to a significant 58.6 percent in the case of glass skylights and wall windows using multi-zone lighting control. Total delivered energy ranges between increase of 1.5 and 21.2 percent in the cases with single zone lighting control and between decrease of 4.5 percent and increase of 4.5 percent in the cases with multi-zone control. The highest decrease in primary energy consumption was 2.2 percent for single zone and 17.6 percent for multi-zone lighting control. The research underlines the significant potential of electric light energy savings using daylighting strategies that, including the control of direct solar access for glare and internal gains, can be more than 50 percent.

This research combines accurate daylight and energy assessment for commercial hall buildings based in cold climate region with multiple design variations. The novelty of this work is the consideration of interior elements, shelves and deflectors, in the calculations. This is made possible through the combined use of validated simulation platforms for detailed annual daylighting and electric lighting calculation (Radiance and Daysim) and energy analysis (IDA-ICE, Equa Simulation AB). This method allows to obtain a reliable assessment of the potential of using natural light sources in buildings.

The purpose of this paper is to continue the debate started by M. Pitts and P. Chynoweth in previous issues of Structural Survey and examine some specific areas of concern regarding the methodologies used for calculating loss of daylight in Rights to Light cases.

Eight specific areas of concern are identified and each of these is analysed in turn, first to establish, where possible, the origin of the current methodology and then to test this against available current thinking.

There is a reasonable justification for adopting a value of 500 foot‐candles, although this is not in fact the minimum value. The only justification for using a Uniform Sky appears to be mathematical and another, more accurate, sky model could be used. The Waldram Diagram can legitimately be adjusted to any suitable dimensions provided that the measurements are always taken as a ratio of the chart area. There is no justification for using a work surface height of 850 mm, nor is there any evidence of justification for assuming that 1 foot‐candle of light is adequate for normal use but there is justification in legal terms for ignoring window frames, glazing and internal reflectance.

It can be shown that there is a case for reassessing the methodologies currently accepted by the Courts and therefore that there is scope for further research to establish a new more accurate method.

Whilst many are questioning the validity of daylight calculations in Rights to Light cases, this paper takes some of those questions and establishes whether there is in fact cause for concern.

This study investigated the building energy, glare and daylight performance of overhang using building simulation software Energyplus in order to identify an optimal depth in hot summer and cold winter zone. A typical building with different window-to-wall ratios (WWR) was modeled and different overhang depths were considered. Results showed that the optimal overhang depths are 0.9m (WWR=0.15), 1.16m (WWR=0.3) and 1.62m (WWR=0.57), respectively. The total energy savings from overhang design can be ranging from about 3% to 24% depending on WWR and overhang depth. Moreover, the regression relationship between optimal overhang depth and WWR is given to help identify the best overhang dimension at the design stage. The potential energy saving performance for different WWRs then can be roughly inferred according to a total energy saving chart without building energy simulation. In conclusion, to be applicable in buildings, an overhang depth of 0.6-0.8m is suitable in this region since it has a balance in energy performance and aesthetic appearance.

The purpose of this paper is to propose building code changes that would benefit both architectural design and the potential of achieving nearly zero energy goals by analyzing the architectural implications of the energy system boundaries within the Swedish code.

The analysis is driven by three questions that relate the national implementation of EU directive on nearly zero energy 2020 to the premises set out in the guidelines for revising the Swedish building code aiming at a performance-based regulation. A crucial part of the research is a comparative analysis of the design implications of the code to research findings in scientific articles on near-zero energy or low-energy design.

The energy system boundaries in the Swedish code are steering the architectural design and energy consequences of offices towards using less heat but more electricity. The energy section is also limiting the architectural design choices by ignoring the positive energy aspects of daylight. A proposal of a new comprehensive energy section taking all architectural design related energy aspects into account is presented, in order to support design of nearly zero energy buildings.

A building code that relates the energy system boundaries to form will help integrated design choices that are more likely to support the strive towards nearly zero energy buildings.

The paper reveals the design implication of the Swedish energy section to be counterproductive regarding energy efficiency as well as limiting architectural design choices.

Aims to examine judicial attitudes to current surveying practice in rights to light disputes. Tests the assumption that the use of the Waldram methodology is endorsed by the courts and seeks to establish whether, despite its acknowledged limitations, its continued use can be justified on this basis.

Analyses reported judgments.

Neither the 50‐50 rule, nor any other aspect of the Waldram methodology, has the status of a rule of law, or is otherwise approved of by the courts. On the contrary, the methodology has been the subject of judicial criticism. Although the courts frequently rely on the expert evidence presented to them, they have consistently expressed disquiet over aspects of the methodology. Particular concerns have been expressed over its inability to cater for the effects of sunlight and externally reflected light, on its dependence on internal room design, and on its failure to distinguish task illumination from general room lighting. There is also no indication that the judiciary are aware of the extent to which the Waldram threshold of adequate illuminance falls short of that prescribed by contemporary standards. The paper concludes that the courts' attitudes to the Waldram methodology cannot therefore justify its continued use by surveyors, either when acting in the capacity of expert witness, or when advising clients who may be contemplating litigation in a rights to light dispute.

Makes a further contribution to the debate, started in this journal in 2000, about the future of surveying practice in rights to light disputes.

Places new information in the public domain which has implications for judges in future rights to light cases, and for the professional liability of surveyors when advising clients in contemplation of possible rights to light litigation.

Presents the first comprehensive analysis of judicial attitudes to modern rights to light surveying practice since its introduction in the early part of the twentieth century.

Lighting in building sectors (consumes the highest energy in commercial buildings and the second highest in residential buildings in India) has very much potential for energy conservation in buildings. With the use of daylighting system, energy consumption in lighting can be lowered up to 30 to 40 per cent.

An experimental effort has been made in this paper to explore the internal wall coloring effect on the performance of tubular light pipe. Trace-pro software has been used and validated. With the help of this software, light pipe has been designed and simulated in a ray tracing mode. Assessment of four globally used prediction models has also been conducted to compare the performances in different seasons for light pipes in the composite climate of New Delhi.

It has been conducted based on three statistical indicators as mean bias error, root mean square error and R². Using regression, an empirical model for average internal illuminance has been developed as a function of light reflectance value (LRV) and solar altitude angle. Trace-pro results confirmed that maximum internal illuminance can be obtained with wall surfaces coated with high LRV color. Finally, by using of a single light pipe system for a test room with the artificial lighting system and applying continuous dimming control, the amount of electrical energy has been saved up to 38.5 per cent per year.

After going through the literature, it has been identified that there has been no paper published which explores the effect of colors of the internal walls on the performance of the light pipe. Along with this, the comparison between existing empirical performance models and find out which model gives the best result in different seasons has been carried out for New Delhi, India.

Over the last few years it has been established that there is a need to re‐evaluate the basis of assessment of the sufficiency of daylight, in rights to light cases, where the loss of daylight after obstruction might lead to injunction and/or damages. The purpose of this paper is to further examine whether the methodology used by surveyors, whereby the effect of glazing, window frames and internal reflectance are ignored, is valid and whether theoretical values can be translated into real values obtained through practical experimentation.

Modern methods of assessment of daylighting, for design purposes, calculate a whole room average as a percentage of available daylight from a Commission Internationale de l’Eclairage (CIE) sky whereas Waldram's methodology, in rights to light cases, results in a contour line marking the series of points in a room where the task lighting, from a uniform sky, would be insufficient for normal use. These two methods appear incompatible and the conundrum is that whilst the courts are seeking to determine adequacy of daylighting to a room, the practitioners need to be able to measure the reduction in a way that has real meaning and can be valued.

By comparing theoretical results using the Waldram methodology with those obtained using the Building Research Establishment (BRE) methodology and with physical measurements on site and in an artificial sky dome, it can be demonstrated that results using the Waldram Diagram, or the proposed CIEL Diagram, can be translated into real values of daylighting for a room and that these values are more realistic than those obtained through the BRE methodology.

This research (which is ongoing) will be useful to practitioners and the courts in determining rights to light cases and is a significant contribution to the debate initiated in this journal by Michael Pitts some 12 years ago.

The responsibilities of the employer/facilities manager in today′s “commercial” world are extensive when considering the wellbeing of staff and the economic working of the office/building. One element of this tangled web is lighting. The recent publication by the Chartered Institute of Building Services Engineers (the professional body), Lighting Guide No. LG7, Office Lighting (1993), is an invaluable compendium in guiding professional “lighters” and the non‐expert in design standards. The guide is particularly useful not only in considering good practice, but also in identifying subjects where the employer is possibly vulnerable with respect to recent EEC legislation and health and safety requirements for satisfactory VDU operations working; and emergency lighting, among others. Examines the contents of LG7, highlighting areas of particular interest and likely concerns to the inquisitive facilities manager.