A new diffuse luminous efficacy model for daylight availability in Burgos, Spain

Dieste-Velasco, M.I.; Díez-Mediavilla, M.; Alonso-Tristán, Cristina; González-Peña, David; Rodríguez-Amigo, M.C.; García-Calderón, T.

doi:10.1016/j.renene.2019.08.051

Cited by 8 publications

(10 citation statements)

References 23 publications

(84 reference statements)

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“…Generally, luminous efficacy is defined as the ratio of daylight illuminance to solar irradiance expressed in lumens per watt (Janjai et al, 2014;Seo, 2018). At the determination of luminous efficacy, illuminance values can be generated from measured irradiance values, and this will become useful input for subsequent daylight availability calculations (Dieste-Velasco et al, 2020). In simple mathematical terms, if E represents illuminance measured in lux and I represent irradiance in W/m 2 , then luminous efficacy (K) is…”

Section: Review On Energy Efficiency Daylight Illuminance and Luminou...mentioning

confidence: 99%

“…, 2013). Strictly speaking, there is unavailability of daylight data in many areas (Dieste-Velasco et al. , 2020).…”

Section: Review On Energy Efficiency Daylight Illuminance and Luminou...mentioning

confidence: 99%

“…However, long-term data measurement is the most effective and accurate method (Li et al, 2015). Strictly speaking, the measurement practice favours solar irradiance than daylight because, unlike solar irradiance, there is a scarcity of daylight measuring stations (Dieste-Velasco et al, 2020;Mayhoub and Carter, 2011). Also, most building façade designs require vertical and inclined daylight illuminance data (Li et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…, 2015). Strictly speaking, the measurement practice favours solar irradiance than daylight because, unlike solar irradiance, there is a scarcity of daylight measuring stations (Dieste-Velasco et al. , 2020; Mayhoub and Carter, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Application of luminous efficacies for daylight illuminance data generation in subtropical Hong Kong

Aghimien

2022

SASBE

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PurposeDaylight plays a crucial role in the attainment of building energy savings. Harnessing daylight in building designs will require the need for daylight illuminance data. However, daylight illuminance data are scarce due to few measuring stations. Aside from being sparse, illuminance measuring stations can be expensive to set up, thus making the luminous efficacy model a better alternative. Hence, this study attempted to model horizontal luminous efficacies under the 15 Commission internationale de l'éclairage (CIE) standard skies. Therefrom, daylight illuminance was estimated from a proposed vertical luminous efficacy model.Design/methodology/approachMeasured solar irradiance, daylight illuminance and luminance distribution data were gathered from the local measuring station in Hong Kong. The luminance distribution data were used to classify the skies into the 15 CIE standard skies. Next, the solar irradiance and daylight data were used to derive the horizontal luminous efficacies under each standard sky. Furthermore, a vertical luminous efficacy model developed using the measured data was described, and this was used to predict vertical illuminance.FindingsIt was observed that Skies 1, 8 and 13 seem to be predominant in Hong Kong. Also, the result showed that constant luminous efficacies could be used for deriving illuminance data. Furthermore, horizontal luminous efficacy ranged from 40 to 190lm/W, indicating that daylight can provide sufficient visibility during working hours. The vertical luminous efficacy model proves to offer reasonable estimations of vertical illuminance data.Research limitations/implicationsFurther work needs to be done with more measured data to cover for spring seasons. The described model still needs to be fitted with different world climates to ascertain its universal applicability. The evaluations need to be done under obstructed sky conditions to cater for dense and clustered urban centres.Practical implicationsThe discussed luminous efficacy model could be used to derive illuminance data in the absence of measured daylight illuminance data, especially in the subtropical region. Also, the comparative advantage of daylight over artificial lighting was highlighted in this study.Originality/valueUnlike previous studies, this paper discusses the luminous efficacies of global, direct and diffuse components under the 15 CIE standard skies. Furthermore, the described luminous efficacy analysis provides an approach for deriving vertical and horizontal illuminance data. Such vertical data will be required for analysing building lighting requirements, sensible heat from electric lighting, and energy savings from daylighting controls. Also, the information on horizontal luminous efficacies will help evaluate solar roof and skylight designs.

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Section: Review On Energy Efficiency Daylight Illuminance and Luminou...mentioning

confidence: 99%

“…, 2013). Strictly speaking, there is unavailability of daylight data in many areas (Dieste-Velasco et al. , 2020).…”

Section: Review On Energy Efficiency Daylight Illuminance and Luminou...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Application of luminous efficacies for daylight illuminance data generation in subtropical Hong Kong

Aghimien

2022

SASBE

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“…To overcome this paucity, researchers and practitioners have developed methods to estimate the illuminance from the broadband irradiance, i.e., the downwelling solar irradiance received at surface measured by pyranometers from 280 to 2800 nm, since there are much more stations measuring the latter or it can be assessed at any place from satellite images ( [6,7]). Several empirical relationships have been published (see e.g., [8,9]), which differ in form and parameters and whose results are strongly dependent on other meteorological variables and/or sky conditions.…”

Section: Introductionmentioning

confidence: 99%

Using Copernicus Atmosphere Monitoring Service (CAMS) Products to Assess Illuminances at Ground Level under Cloudless Conditions

et al. 2021

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Natural daylight is recognized as an important variable in the energy performance of buildings. A method that estimates the global illuminance received on a horizontal surface at ground level and its direct component at normal incidence under cloudless conditions is presented. The method uses the k-distribution method and the correlated-k approximation to compute a set of clearness indices integrated over 13 spectral bands covering the range 380–780 nm. A spectral resampling technique, including a spectral disaggregation and a spectral linear interpolation, is applied to these indices for providing a detailed set of solar irradiances at 1 nm in spectral resolution over the whole range. Then, these are weighted by the standardized CIE action spectrum for human eye for assessing the illuminance. Inputs to the method include the total column contents of ozone and water vapor as well as aerosol optical properties produced by the Copernicus Atmosphere Monitoring Service. Estimates of illuminance were compared to high-quality 1 min measurements of illuminance that were collected from two experimental sites located in two different climatic zones. A slight overestimation is observed for the global illuminance: the bias is between +1 klx and +3 klx, i.e., between +1% and +4% in relative value. The root mean square error varies between 5 klx (8%) and 6 klx (9%). The squared correlation coefficient ranges between 0.95 and 0.97. At the site providing the direct illuminance at normal incidence, the performance of the method is lower compared to global illuminance with a lower squared correlation coefficient of 0.53. The bias, relative bias, RMSE, and rRMSE are +7 klx, +9%, 12 klx, and 15%, respectively. The uncertainty of the method is of the order of the uncertainty of the measurements. The method offers accurate estimates of illuminance in cloudless conditions at high spatial and temporal resolutions useful for construction industries and operators as well as thermal simulation tools for optimal building design strategies.

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A new modified method of all-sky radiance distribution based on the principle of photothermal integration

Yao,

Song,

et al. 2024

Applied Energy

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A new diffuse luminous efficacy model for daylight availability in Burgos, Spain

Cited by 8 publications

References 23 publications

Application of luminous efficacies for daylight illuminance data generation in subtropical Hong Kong

Application of luminous efficacies for daylight illuminance data generation in subtropical Hong Kong

Using Copernicus Atmosphere Monitoring Service (CAMS) Products to Assess Illuminances at Ground Level under Cloudless Conditions

A new modified method of all-sky radiance distribution based on the principle of photothermal integration

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