Daylight Factor simulation methods

Window design plays an important role in achieving energy efficient buildings and in providing thermal comfort of building occupants. This paper investigates a newly developed aerogel window and the potential improvement on the comfort factors of an office in relation to daylighting. Improved comfort levels can impact on health and wellbeing of building occupants leading to knock on effects on absenteeism and productivity. A simulation tool was presently created that will easily enable comparison of different façade design and their impact on heat and light transmission and therefore enable optimisation. One of the most important aspects of the present work was comparing the performance of the newly developed aerogel window against the more traditional Argon-filled, coated double-glazing. Whereas the aerogel window provided an extremely low heat-loss index of 0.3W/m2K, the latter usually offered a centre-glazing U-value of 1.4W/m2K. On a like-with-like basis the daylight transmissio...

At the heart of this proof of evidence is an evaluation of the regeneration benefits and disbenefits of the First Development Site (FDS) proposals for the Compulsory Purchase Order (CPO) Land. In my evidence I will describe, explain and analyse how the FDS proposals are likely to impact on the Aylesbury Estate and contribute to the well-being of Estate residents in Sites 1b and 1c, in the interests of the residents and in the wider public interest. In order to do this I will provide an explanation and discussion of four complex concepts: ‘gentrification’, ‘community’, ‘regeneration' and ‘mixed communities’.  Gentrification, due to its conceptual weaknesses, struggles to encompass the complexities of the FDS proposals.

Mixed communities-led regeneration is supported by independent academic research for the benefits it can bring. Despite this, it is regarded by some objectors and academics as de facto gentrification. That position is not tenable and objectors have to explain how the disbenefits of the FDS scheme outweigh the obvious and substantial benefits in the short, medium and long term. The policy and practice of mixed communities are not perfect and do not offer utopian solutions in the case of the Estate. It is evident though, that this approach in the present socio-economic climate, has the capacity to deliver genuine improvements to troubled estates, the Aylesbury included.

I conclude that the FDS proposals will bring genuine aspirational regeneration to the Estate. The FDS proposals are likely to bring significant sustainable improvements in the conditions of Aylesbury residents suffering from aspects of deprivation, often multiple in nature. Others to benefit will be incoming residents who find a home in the FDS, especially an affordable one, and those who find employment during the long construction phase and after completion. Nevertheless, a long term view must be taken regarding: safeguarding, delivery and resourcing of this estate regeneration programme.

Finally, I conclude that under section 226, the Council must show that the FDS proposal for the CPO Land promotes or improves one or more of the: social, economic or environmental well-being of the area. This is right and proper because the FDS scheme impinges on tenants’ and leaseholders’ property rights. There are undoubtedly and unfortunately some disbenefits associated with the CPO proposals. However, drawing on the evidence presented in this proof, I am convinced that the regeneration benefits of the FDS scheme for the CPO Land are substantial, guaranteed to be delivered and far outweigh the disbenefits. I look forward to the CPO being confirmed so that the benefits can be achieved, to improve the lives, livelihoods and life chances of Aylesbury Estate residents.

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Proper assessment of indoor daylighting conditions can significantly reduce energy consumption due to artificial lighting and can improve indoor visual comfort. This paper gives a critical review of the fundamental aspects of daylighting indices with the aim to provide a broad overview of methods and indices available to assess daylighting from varying points of view. Assessments cover distribution, availability over time and in specific climatic contexts, uniformity in the space, visual comfort issues and the relations between each of these aspects and a proper building and lighting design. A special focus on the assessment of indoor spatial and temporal uniformity is given. An analysis of the application of day-lighting design by researchers and designers according to several area of interest is also presented.

A well-integrated shading device has a greater positive impact on school building than any other sustainable building strategies. The present research aims to propose and evaluate several architectural shading devices that can be integrated into educational building designs in daylight-illuminated classrooms lit from a single side in semi-arid climates. These elements have a potential in allowing the penetration of natural daylight with improve indoor thermal environment and eventually reduce the energy consumption through cooling and artificial lighting. The final goal of the research is to obtain the optimal parameters (geometry and materials) of shading devices for the simulated orientation of classrooms in the case study.
A computerized simulation tool (IES<VE>) is used to carry out the
investigation; taking a typical public school building in Erbil City as the
empirical background of the semi-arid climate. A series of simulations are performed to determine the average illuminance value and the uniformity of the illuminance distribution in the classroom under various lighting conditions and orientations without shadings fitted to the window. Then the numerical results are found to be compared with the illumination properties of different shading devices that have been considered. The results indicate a different optimal shading device in terms of enhancing daylight properties in the classroom. By giving appropriate physical dimensions, various shading devices can achieve the average illuminance requirement of (300-500 lux) and improve the lighting uniformity ratio (0.40– 0.42) for east orientation within appropriate material. Correspondingly, by using optimal shading device, the required illuminance ratio of 0.5 can be obtained simply in the classroom, accordingly, reduce the lighting power cost compared with the base-case.

The field of office daylighting  is vital  for both energy efficiency practice and occupants’ visual comfort. With the
emergence of green building emergence in Malaysia, building designers are exploring avenues for energy efficiency
design;  one  common  strategy  is  daylighting.  The  majority  literature  reviews  on  daylighting  are  skewed  towards
temperate or developed countries, where sky luminous condition is different from that of the Tropics. Conventional
daylighting system designs redirect daylight from the envelope or atrium openings i.e. daylight shelves. Presumed to
be the pioneer daylight trough in the Tropics, this paper presents the simulated and in-situ lighting level measurements
prior to occupancy. This case study presents an as-built daylight trough design which is able to daylight the office
space as deep as 6 meters sufficiently. It achieves a lighting power density 1.90W/m2 and saves 39.2% of lighting
energy over conventional office lighting energy. Discussed further is the practicality of working with such a system,
including cost implication, return on investment and contractual challenges in reaching consensus of the design. The
results  reinforce  that  the  effectiveness  of  daylighting  design  is  very  dependable  on  the  sun  path  and  obstacles
surrounding  the  office  tower.  The  RADIANCE  simulation  correlates  well  to  field  measurement  results.  Further
investigation  into  the  light  trough,  its  lighting  energy  savings,  users’  interaction,  visual  comfort  and  glare  is  still
ongoing.

As many developing countries in the tropics begin to adopt various green building rating tools, there
is an urgency to revisit the assessment methodologies of daylight performance of office space. This paper aims to
evaluate the practicality of Daylight Factor as the preferred daylight performance metric, which is stipulated by
the local green building assessment tool Green Building Index (GBI) and MS1525. However, cited as an obsolete
and  complex  metrics,  various  literatures  have  questioned  the  reliability  and  accuracy  of  Daylight  Factor,
especially  for  the  usage  in  the  tropics.  It  also  suggested  that  the  horizontal  illuminance  measurement  of  office
space  undermines  the  complexity  of  visual  comfort  parameters  in  the  tropics.  This  is  evident  where  the  sky
condition is significantly different than that of the temperate. This case study paper also includes the author’s first
hand experience on daylight factor measurement which discusses the realism of simulation softwares and daylight
assessment  methodology  in  actuality.  This  subsequently  supports  the  arguments  that  any  daylight  performance
metrics, in this case Daylight Factor, does not necessarily reflect the visual satisfaction of an office space, as proof
of lighting energy savings and  post occupancy visual comfort acceptance are to be considered in total.

An analytical calculation of the magnetic field of a cylindrical permanent magnet linear generator is presented. The generator utilises a discrete Halbach permanent magnet array as magnetic field source. The array is constructed of permanent magnets that have a non-uniform length. To solve the governing equations, a direct solution method is used. The flux distributions in the air gap, inside the permanent magnet and in the shaft are calculated. Solutions that are derived using this method are compared with that obtained from the finite element analysis simulation method. Another method is also used in the field calculation, and the result is presented for comparison. © 2010 The Institution of Engineering and Technology.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5569883&tag=1

The dynamic nature of sunlight poses many challenges when defining quantitative and qualitative targets to effectively illuminate an interior space. Using a complex calculation approach in order to evaluate an appropriate sun lit space often disregards the real need of the final users, making Daylight Assessment completely ineffective as a response to multiple requirements.
An integrated approach that considers CBDM, Climate Based Dynamic Modelling, thus disregards from the process of existing dynamic analysis a comprehensive assessment of the preferences of the occupant, which may vary not only in relation to the target audiences, but also on the users positions in the room.
Based on these preliminary assumptions, the paper aims to define how to relate a dynamic quantitative approach with a qualitative assessment in order to get a comfortable daylit room to respond users’ needs. The paper proposes some reflections about what are the actual relation in-between natural light thresholds, according to national regulations, the quantitative evaluations, involving dynamic metrics and the actual users preference

The field of office daylighting is vital for both energy efficiency practice and occupants’ visual comfort. With the emergence of green building emergence in Malaysia, building designers are exploring avenues for energy efficiency design; one common strategy is daylighting. The majority literature reviews on daylighting are skewed towards temperate or developed countries, where sky luminous condition is different from that of the Tropics. Conventional daylighting system designs redirect daylight from the envelope or atrium openings i.e. daylight shelves. Presumed to be the pioneer daylight trough in the Tropics, this paper presents the simulated and in-situ lighting level measurements prior to occupancy. This case study presents an as-built daylight trough design which is able to daylight the office space as deep as 6 meters sufficiently. It achieves a lighting power density 1.90W/m2 and saves 39.2% of lighting energy over conventional office lighting energy. Discussed further is th...

This study gives a comparative analysis of available daylight planning tools and develops a rule-of-thumb method for determining street width to building height ratios, related to actual illumination levels inside urban buildings. Nine daylight planning tools for site planning and urban design decisions were identified, their characteristics compared, and the tools classified. Six of these tools were compared by applying them to a 200' x 400' (651 x 122 m) urban block at 40 degrees latitude. FAR allowed by the generated envelope was calculated for each tool and compared. A wide range of allowable building envelopes was found.

All prescriptive tools either specified or implied a street height to width ratio (H/W), but none provided a quantified basis for its proportion or exposure plane. A study was initiated to determine H/W in relation to average an minimum daylight factor within a building. A test was conducted using physical modeling in a mirror box artificial sky. Results of this test, plotting H/W against average daylight factor can be used as a preliminary design tool or as a way to determine zoning restrictions, while protecting daylight access.

This research study discusses the accuracy of 3dStudio Max Design software in simulating illuminance
distribution on pendentive dome mosque design. The case study is the Federal Territory Mosque in Kuala Lumpur,
Malaysia. The mosque has pendentive dome design similar to the design of the Ottoman mosques and Hagia
Sophia in Istanbul, Turkey. The accuracy level is evaluated based on comparisons between the predicted software
and the measured-on-site data on the illuminance distribution. Both field monitoring readings and computer
simulations of the mosque interior (prayer hall) were collected and data logged during the winter solstice, the day
when the sun was on a perimeter at its highest latitude at the Tropic of Capricorn (23° 26′ 16″ S) which occurred
on 21st December 2013. The illuminance level was measured at five locations inside the mosque. Result of this
study revealed similar readings between the measured on-field and predicted computer simulation data with small
marginal value difference. This study suggests acceptable accuracy readings provided by 3dStudio Max Design
software for lighting simulation.

This paper addresses the compromises that can be struck, using the passive architectural feature of sunshades, when balancing daylight and the accompanying thermal gains. Daylight inclusion subdivides the interior luminous environment into varying illumination level of light zones. Under and over-lit zone may affect visual and thermal comfort, and consequent energy consumption. However, if daylight can reduce the building&amp;#39;s use of electric light, while keeping HVAC load under control, it can reduce peak energy use, as well as total energy consumption. This paper presents a simulation study of evaluating luminous and thermal performance of most commonly used shading devices, for recent tall office buildings of Dhaka, in the context of the most preferred, south orientation, for this location. Six selected fixed external shading devices, from a field survey, have been evaluated, during the overheated period of summer, based on the light zone distribution vs HVAC load. The simulation results revealed that, both the geometrical, as well as the material characteristics of shading devices, can have significant influence on the desired performance. The results clearly indicate that, modification of the dimensional relations of light zone, by proper selection of shading devices, can enhance energy efficiency in offices of similar tropical areas.

This paper addresses the compromises that can be struck, using the passive architectural feature of sunshades, when balancing daylight and the accompanying thermal gains. Daylight inclusion subdivides the interior luminous environment into varying illumination level of light zones. Under and over-lit zone may affect visual and thermal comfort, and consequent energy consumption. However, if daylight can reduce the building's use of electric light, while keeping HVAC load under control, it can reduce peak energy use, as well as total energy consumption. This paper presents a simulation study of evaluating luminous and thermal performance of most commonly used shading devices, for recent tall office buildings of Dhaka, in the context of the most preferred, south orientation, for this location. Six selected fixed external shading devices, from a field survey, have been evaluated, during the overheated period of summer, based on the light zone distribution vs HVAC load. The simulation results revealed that, both the geometrical, as well as the material characteristics of shading devices, can have significant influence on the desired performance. The results clearly indicate that, modification of the dimensional relations of light zone, by proper selection of shading devices, can enhance energy efficiency in offices of similar tropical areas.

This study focuses on generating geometric design alternatives for an airport roof structure with an evolutionary design method based on optimizing solar heat gain and daylight levels. The method incorporates a parametric 3D model of the building, a multi objective genetic algorithm that was linked with the model to iteratively test for various geometric solutions, a custom module that was developed to simulate solar conditions, and external energy simulation environments that was used to validate the outcomes. The integral outcome was achieved through an iterative workflow of many software tools, and the study is significant in dealing with several space typologies at the same time, taking real-life constraints such as applicability, ease of operation, construction loads into consideration, and satisfying design and aesthetic requirements of the architectural design team.

Les conduits de lumière de type MLP (Mirrored Light Pipe) permettent de transporter et de distribuer de la lumière naturelle dans des pièces sombres éloignées des ouvertures traditionnelles. Ils offrent l’avantage de réduire au minimum la perte de lumière, tout en limitant la transmission de chaleur. Ils font partie de la catégorie des convoyeurs à réflexion spéculaire multiple. Il s’agit de collecter, concentrer et dévier la lumière du soleil à l’aide d’un dôme placé en toiture. Celle-ci est ensuite acheminée à travers un tube aux parois hautement réfléchissantes, puis diffusée au sein du local à l’aide d’un diffuseur. Au cours des dernières décennies, de nombreux auteurs ont établis des modèles de prédiction des performances de ces dispositifs tubulaires en fonction des diverses configurations existantes. Cette variété d’approches a eu pour conséquence directe une dispersion des résultats des performances des conduits de lumière et parfois des incohérences dans la retranscription ...

A well-integrated shading device has a greater positive impact on school building than any other sustainable building strategies. The present research aims to propose and evaluate several architectural shading devices that can be integrated into educational building designs in daylight-illuminated classrooms lit from a single side in semi-arid climates. These elements have a potential in allowing the penetration of natural daylight with improve indoor thermal environment and eventually reduce the energy consumption through cooling and artificial lighting. The final goal of the research is to obtain the optimal parameters (geometry and materials) of shading devices for the simulated orientation of classrooms in the case study. A computerized simulation tool (IES ) is used to carry out the investigation; taking a typical public school building in Erbil City as the empirical background of the semi-arid climate. A series of simulations are performed to determine the average illuminance ...

Light pipes MLP (Mirrored Light Pipe) are used to transport and distribute daylight in dark areas remote of the traditional openings. It offers the advantage of minimizing the loss of light, while limiting the transmission of heat. They belong to the category of conveyors multiple specular reflections. Its purpose is for collecting, reflecting and focusing the sunlight with a roof dome arranged. This is then fed through a tube with highly reflective interior surfaces and distributed within the room with a diffuser. In recent decades, many authors have developed models to predict the performance of these devices based on various existing configurations. This variety of approach has led directly to a dispersion of the results of predicted performance of light pipes and the inconsistency with respect to the actual behavior of the device. The objective of this publication is to highlight the disparity of these models. A literature review of different approaches and a comparative analysi...

This study focuses on generating geometric design alternatives for an airport roof structure with an evolutionary design method based on optimizing solar heat gain and daylight levels. The method incorporates a parametric 3D model of the building, a multi objective genetic algorithm that was linked with the model to iteratively test for various geometric solutions, a custom module that was developed to simulate solar conditions, and external energy simulation environments that was used to validate the outcomes. The integral outcome was achieved through an iterative workflow of many software tools, and the study is significant in dealing with several space typologies at the same time, taking real-life constraints such as applicability, ease of operation, construction loads into consideration, and satisfying design and aesthetic requirements of the architectural design team.

Les conduits de lumière de type MLP (Mirrored Light Pipe) permettent de transporter et de distribuer de la lumière naturelle dans des pièces sombres éloignées des ouvertures traditionnelles. Ils offrent l’avantage de réduire au minimum la perte de lumière, tout en limitant la transmission de chaleur. Ils font partie de la catégorie des convoyeurs à réflexion spéculaire multiple. Il s’agit de collecter, concentrer et dévier la lumière du soleil à l’aide d’un dôme placé en toiture. Celle-ci est ensuite acheminée à travers un tube aux parois hautement réfléchissantes, puis diffusée au sein du local à l’aide d’un diffuseur. Au cours des dernières décennies, de nombreux auteurs ont établis des modèles de prédiction des performances de ces dispositifs tubulaires en fonction des diverses configurations existantes. Cette variété d’approches a eu pour conséquence directe une dispersion des résultats des performances des conduits de lumière et parfois des incohérences dans la retranscription ...