Analysis of the accuracy of the sky component calculation in daylighting simulation programs

Acosta, Ignacio; Muñoz, Carmen; Esquivias, Paula M.; Moreno, David; Casas, Jaime Navarro

doi:10.1016/j.solener.2015.06.022

Cited by 39 publications

(20 citation statements)

References 17 publications

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“…These economic results are more significant than the Stockholm ones (a NPV10 increase of 24.3%, 34.8% and 40.7% in the three cases) due both to the higher electric energy cost in the United Kingdom and the higher annual energy saving of lighting control systems in London. 35.6% compared to Stockholm and London, respectively), obtaining the highest economic savings for rooms 8.00 m wide or more (average NPV10 of 1209.58 €, an increase of 81.0% and 33.7%, respectively), especially for rooms 9.00 m deep. In the same way, the greatest economic savings after 10 years are obtained when smart systems are used, with an average NPV10 improvement compared to case 1, of 74% for case 2 and 123% for case 3.…”

Section: Cost Effectiveness In Londonmentioning

confidence: 91%

“…Given that variations in the threshold cited would affect the results on the impact of energy efficiency from lighting smart controls, the illuminance value must be chosen carefully, based on use. The spacing between luminaires was calculated using Dialux 4.12, a simulation program validated by previous studies [35] and widely used in electric lighting design. In accordance with the results obtained, the separation between luminaires in each of the rows was optimized to achieve a uniformity value above 0.6 and an average illuminance of 500 lx, obtaining a spacing of 1.25 m, as can be seen in Figure 2.…”

Section: Lighting Design Of the Room Modelmentioning

confidence: 99%

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Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

et al. 2018

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Daylight performance metrics provide a promising approach for the design and optimization of lighting strategies in buildings and their management. Smart controls for electric lighting can reduce power consumption and promote visual comfort using different control strategies, based on affordable technologies and low building impact. The aim of this research is to assess the energy efficiency of these smart controls by means of dynamic daylight performance metrics, to determine suitable solutions based on the geometry of the architecture and the weather conditions. The analysis considers different room dimensions, with variable window size and two mean surface reflectance values. DaySim 3.1 lighting software provides the simulations for the study, determining the necessary quantification of dynamic metrics to evaluate the usefulness of the proposed smart controls and their impact on energy efficiency. The validation of dynamic metrics is carried out by monitoring a mesh of illuminance-meters in test cells throughout one year. The results showed that, for most rooms more than 3.00 m deep, smart controls achieve worthwhile energy savings and a low payback period, regardless of weather conditions and for worst-case situations. It is also concluded that dimming systems provide a higher net present value and allow the use of smaller window size than other control solutions.Smart control strategies require the assessment of different variables: the window size is essential to determine electricity consumption [9], as are the reflectance of the room surfaces and the location of the building [10]. The illuminance controls also have a significant impact on the thermal comfort of occupants, mainly due to solar heat gain, so that algorithms should take all possible variables into account [11]. One of the most common smart controls is that of dimming systems [12,13], which adjust the electricity power of the luminaires. The dimmer can be controlled by illuminance-meters which significantly reduce the power consumption in electric lighting [14,15].According to the latest studies [16][17][18], the strategies for lighting control can reduce power consumption by up to 50% when using dimming systems and close to 30% using occupant detectors. However, these technologies are not widespread, given the difficulties in installation, the limitations of the prediction algorithms, and the individual management preferences of occupants [19][20][21]. It is therefore important to emphasize the benefits from all these strategies, quantifying their energy efficiency and economic profitability, and avoiding an overestimation of the savings or overly optimistic analysis. Hence, the use of dynamic daylight metrics will provide a better whole-year fit. Unlike daylight static concepts, dynamic metrics allow the accurate quantification of energy savings in electric lighting, including variables not considered by static metrics, such as weather conditions, occupancy hours or illuminance thresholds required by the task being carried out [22-24]. Aim a...

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Section: Cost Effectiveness In Londonmentioning

confidence: 91%

Section: Lighting Design Of the Room Modelmentioning

confidence: 99%

Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

et al. 2018

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“…DaySim was developed to provide a more efficient calculation of illuminance or luminance time series under varying sky conditions than that originally provided by RADIANCE. This lighting software has been validated by several researchers [24,25] who have determined accuracy by applying the CIE test cases [26]. The calculation parameters used by this program in this research are shown in Table I.…”

Section: B Programmentioning

confidence: 99%

Analysis of Visual Comfort and Circadian Stimulus Provided by Window Design in Educational Spaces

Acosta¹,

Campano²,

Molina³

et al. 2019

IJET

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Light is the main variable which affects to the circadian rhythm, promoting up to 70% of the melatonin suppression. In comparison with the visual system, the circadian system requires more light to be activated and is more sensitive to blue light. As can be deduced, daylighting represents an ideal light source for circadian entrainment. Architectural and design features, such as window size and room reflectance, impact the amount of circadian stimulus that occupants will receive. This study aims to quantify the circadian stimulus promoted in classrooms, according to the window size and reflectance of the surfaces. A first trial is carried out, monitoring the spectral power distribution perceived by the eyes of the students according to different orientations and observer's positions. Secondly, several simulations are developed, using the daylight simulation program DaySim 3.1 and defining a classroom model with a variable window size and reflectance. The results show the noticeable impact of the reflectance of the inner surfaces in the circadian stimulus calculation, as well as the effect of the window size.

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“…DAYSIM was developed to provide a more efficient calculation of illuminance or luminance time series under varying sky conditions than that originally provided by RADIANCE. This lighting software has been validated by several researchers [24], [25] who have determined accuracy by applying the CIE test cases [24]. The calculation parameters used by this program in this research are shown in Table I.…”

Section: B Programmentioning

confidence: 99%

“…Weather data for all locations are taken from the Energy Plus reference [ 25 ], based on direct normal and diffuse horizontal irradiances and the sky model defined by Perez et al [26].…”

Section: Sky Conditionsmentioning

confidence: 99%

Analysis of Circadian Stimulus and Visual Comfort Provided by Window Design in Architecture

Acosta¹,

Molina²,

Campano³

2017

IJET

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Abstract-Light is the major synchronizer of circadian rhythms to the 24-hour solar day. Compared to the visual system, the circadian system requires more light to be activated and is more sensitive to short-wavelength light. Daylighting is an ideal light source for circadian entrainment. Architectural and design features, such as window size and room reflectances impact the amount of circadian stimulus that the patient will receive. DaySim 3.2 simulations were used to determine the percentage of days that occupants would receive a minimum circadian stimulation of 0.50 for at least an hour during the morning. According to a phototransduction model of the human circadian system, a circadian stimulation of 0.50 is equivalent to suppressing the hormone melatonin by about 50%. This circadian stimulus criterion is examined for different window to wall ratios, for two average room reflectances, and for four latitudes. The present paper provides an example of a tool that could be used to assist designers in fenestration and interior design.Index Terms-Circadian stimulus, daylight autonomy, visual comfort, window.

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Analysis of the accuracy of the sky component calculation in daylighting simulation programs

Cited by 39 publications

References 17 publications

Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

Analysis of Visual Comfort and Circadian Stimulus Provided by Window Design in Educational Spaces

Analysis of Circadian Stimulus and Visual Comfort Provided by Window Design in Architecture

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