Determination of interior daylight illuminance is the key step in daylighting schemes. Recently, climate-based daylight metrics (CBDMs) which considers the real climatic data for the location has ...been adopted to evaluate the dynamic daylight performance. However, the usual method to calculate the CBDMs is full scale computer simulations which are quite time demanding and designated skills are required. Architects and building practitioners prefer simple methods to assess daylight performance particularly during initial design process when various building schemes and concepts are being appraised. Daylight factor (DF) is the traditional daylight metric and it has a strong relationship with room parameters which can be simply modified to fit the design criteria. This paper puts forward a series of simple mathematical expressions to correlate the CBDMs with DF metrics (DFMs). The vertical outdoor illuminance at the window center point and the 49 interior points were simulated via the RADIANCE software. The results showed that there are strong correlations between these daylight metrics. The proposed approach would be useful to building professionals conducted in visual comfort, fenestration and daylighting design and evaluation in the preliminary design phase.
The Internal quality environment in a room/office purely depends on the daylighting. Light pipe offers to bring sunlight through passive way to the core of the building. Reduce the use of electric ...lighting and utilization of light pipes can create suitable visual activity and contribute more comfort than electric light. This paper aims building light pipe design optimization on lighting level by using cloud based simulation.
This research investigates the daylight regulation compliance of existing multi-family housing developments located primarily in Stockholm (Lat.: 59,33 °N), Sweden. A representative sample of 54 ...buildings consisting of 10.888 individual rooms was modelled according to archived documentation drawings and evaluated by use of Radiance simulations, to test their compliance with the current Swedish daylight regulation. The studied buildings were selected according to their relevance to major architectural typologies of Swedish urban planning history (1926–1991). The assessment was based on a point Daylight Factor scheme (DFP), which stipulates that a specific point in a room should achieve a Daylight Factor DFP ≥ 1%, for the room to be sufficiently daylit. Results indicate that specific architectural typologies consistently yield poor DFP levels compared to other ones. A moderate correlation was found between the density of surroundings and the percentage of compliant rooms per housing development. Finally, the results indicate the existence of distinct periods during Swedish urban planning history, when daylight performance of multi-family houses was affected by different planning practices. Future investigations are under development to evaluate the occupants’ perception of daylight in their apartments, to help define new daylight performance indicators and benchmarks for Swedish households, taking into consideration the limitations of the daylight indicator embedded in the current regulation.
•Daylight compliance according to Swedish regulations was tested for 54 buildings.•Three out of four buildings did not comply with the current requirement.•Tower-block and semi-open building typologies exhibited the highest compliance.•Urban density correlated moderately (R2 = 0,645) with development compliance.•Median Daylight Factor correlated strongly (r = 0,979) with regulation metric DFp.
In buildings of residential and tertiary sectors, daylight issues primarily respond to increasing needs regarding the occupants' well being and visual confort as well as to the supply of natural ...light for working, by decreasing energy consumption due to necessary artificial lightning for the internal human activities. Daylight optimization at an early design stage can be referred to a way of designing architectural forms that take advantage of the prevailing urban context, such as existing shadow masks, to achieve a comfortable interior environment while minimizing energy use and reliance on artificial lighting systems. Our past study concluded in the development of EcCoGen, which is a kind of software that belongs to the family of tools based on interactive generative genetic algorithm optimization. The software generates solutions evaluated according to certain criteria, including mainly energy performance issues. Since the energy evaluation is included in the software features, we aimed to enhance software's applicability including energy reduction due to lighting issues via visual comfort optimization. Based on this objective, in this paper we describe a simple methodology to optimize the daylight potential of an architectural form at an early design stage. A numerical approach conducted employing the DIALux 4.5copy is presented while a variety of simulation scenarios has been investigated on the basis of Doehlert and Box-Behnken DOE (design of experiments) methods. Our purpose is to develop accurate enough regression models for daylight factor prediction at an early design stage, when the problem's data are not precisely determined (dimension of glazing area, materials, opacities). To validate this statistical forecast system, many simulation scenarios were carried out and the statistical results are in compliance with the numerical simulations. The regression models' results show that the error caused by simplification is acceptable in most conditions, and a lot of coupling calculation is saved. Finally, a formal error analysis for the resulted regression models has been conducted to validate its forecast capacity. As a conclusion the statistical reduction of complex numerical modeling to simple regression models in the form of polynomial equations aims to assist architects and engineers to directly obtain a high precision estimation of their architectural form's daylight potential at an early design stage.
•Office daylighting design has to take interior layout and porosity into consideration.•Daylight field measurement of two office spaces shows 53% and 41% lighting savings.•No significant difference ...in visual appraisal despite difference in Daylight Factor coverage.•Daylight Factor alone is not accurate and sufficient to justify daylight performance.•Visual Appraisal, Lighting Energy Savings and Discomfort Glare do not correlate with Daylight Factor.
Lighting energy savings, as well as visual and non-visual user benefits have been widely attributed to daylighting. This paper explores daylight design strategy, visual appraisal, Daylight Factor (DF), lighting energy usage and discomfort glare using two green building offices in Malaysia, which have incorporated daylighting into both façade and interior design. Visual appraisal surveys were collected from 39 and 145 subjects in the open plan working space of the Energy Commission Building (ECB) and Public Works Department Block G (PWD), respectively. The survey focused on task brightness, colour appearance, uniformity and lighting preference. Discomfort glare assessed via occupant point-of-view luminance maps was juxtaposed here from a glare study involving the same buildings. Illuminance loggers were used to monitor artificial lighting usage as well as the DF on a selected floor of each building. There were no significant differences in occupant responses to the visual appraisal survey for both office spaces. Using MS1525:2014 and Green Building Index (GBI NRNC) tool as baselines, the DF performance of both offices differs significantly: PWD had a 45.5% daylit area, with ECB a 14.8% daylit area for DF >1%. However, lighting energy usage results show substantial savings of 53% and 41% occurred from daylighting. These findings of visual appraisal, DF, lighting energy savings and discomfort glare show a discrepancy in using only the DF to justify the daylight performance of an office space in a tropical climate such as Malaysia. The findings suggest that equivalent consideration should be given to interior design to facilitate daylighting, which is often beyond the control of designer, but in the hands of office end users.
Daylight metrics act as a useful tool to quantify the potential of natural light in an architectural space as well as the energy savings promoted by a suitable design of windows, atriums, and ...skylights. Accordingly, a new indoor lighting metric is proposed, minimum daylight autonomy, defined as the percentage of occupied time when an illuminance threshold can be met by daylight alone under continuous overcast sky conditions. This novel concept can determine an approximation of the maximum use of electric lighting and the quantification of minimum energy savings without the need for advanced calculation tools. Although daylight factor is the most widespread concept, it cannot forecast energy savings as accurately as dynamic metrics. In addition, daylight autonomy is the most usual dynamic definition, because it estimates the energy consumption of on-off electric lighting systems depending on weather conditions. However, there is no link between static and dynamic metrics, because both concepts are based on different variables. This research proposes the calculation procedure for minimum daylight autonomy, as well as the equations that serve to predict dynamic metrics based on static metrics, after confirming the accuracy of the simulation program that calculates the metrics using a test cell under real conditions.
Daylighting plays a key role in occupants' thermal and visual comfort as well as developing a sustainable environment. Windows size, shape, and the relevant room dimensions are three major factors ...that affect the quality and quantity of daylighting. Window to Floor Ratio (WFR) is a key parameter is being used to assess the quantity of daylighting and affects the quality of interior design of buildings. Determining Daylight Factor (DF) is a complicated analysis related to obtaining sufficient natural light and simultaneously avoiding overheat. In this paper, DF was applied to measure and assess the validity of current standard WFR suggested by Iran's National Building Daylight Regulation. In addition, Uniformity Ratio was assessed to discover and control the quality of daylighting. 24 alternatives were analysed based on window shape, size, and space dimensions to assess DF and uniformity. The results show the current WFR is not accurate therefore, based on Daylight Credit (LEED), BREEAM, and Green Star standards; an optimal range of WFR, 15–24%, was presented which also controls glare and overheat. The study also indicated how window shape and size affected the average DF and uniformity simultaneously.
•Defining upper and lower bound range for window-to-floor area ratio, WFR•Assessing the effect of window shape and size as well as floor area on daylighting•Presenting an accurate WFR range considering uniformity ratio and overheat•Developing a methodology for calculating Daylight Factor
Effective Use of Daylight in Office Rooms Burmaka, Vitalii; Tarasenko, Mykola; Kozak, Kateryna ...
Journal of daylighting,
08/2020, Letnik:
7, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The rational use of daylight can significantly reduce the cost of electricity for artificial lighting. This research aims at investigating the parameters of translucent structures of building ...envelope, and the value of daylight factor, for which maximum efficiency of daylight usage is achieved in office rooms. The study analyzes the dependence duration of daylight autonomy in office rooms, on the value of daylight factor for four European cities. The specific daylight autonomy (h/(year∙m2)) of office rooms were found. It was proved, that regardless the size of the rooms, the maximum specific daylight autonomy in Ternopil city (at illumination of 300 lx, which is prescribed by regulations), with lateral daylight, occurs when the daylight factor is in the range of 1.7% to 1.9%. Maxima – at 1.8%. At illumination of 500 lx, the maximum specific daylight autonomy will occur at a daylight factor range of 2.6% to 3.0%. Maxima – at 2.8%.
The daylight factor model given by Charted Institute of Building Services Engineers (CIBSE) was modified in this paper to incorporate time variations with respect to zenith angle (
θ
z
) and vertical ...height (
h) of working surface above ground surface which was normalized with central height (
H) of skylight dome. The modified model contains constant exponents which are determined using linear regression analysis based on hourly experimental data of inside and outside illuminance for each month of the year 2007–2008. The prediction of modified model is found in good agreement with experimental observed inside illuminance data on the basis of values of root mean square percentage error (
e) and correlation coefficient (
r). The annual average daylight factor values for big and small dome skylight rooms are determined as 2.3% and 4.4% respectively. The energy saving potential of skylight rooms for selected climatic locations in India is also presented in this paper.
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