Average Illuminance Research Articles

The effects of lamp types and surface reflectance combinations on the subjective perception of a simulated lit hospital ward environment

PurposeGood illumination creates an aesthetic environment that may positively influence patients’ well-being and provide comfort to the hospital staff. This study aims to focus on exploring the energy efficiency of lighting and subjective perception of the lit environment in a hospital ward to assess quality indicators of ambient lighting conditions.Design/methodology/approachThe existing conventional tubular fluorescent lamp–based lighting system in the surveyed patients’ ward was retrofitted with light-emitting diode (LED) luminaires to explore illumination and energy parameters. Thereafter, a software lighting model was created, simulated and analyzed. A Web-based survey with five bipolar adjective pairs in a semantic differential scale was conducted with 48 participants to record and analyze their subjective responses pertaining to the variations in lamp types and surface reflectance combinations.FindingsThe findings imply that the LED tubular lamp–based illumination was deemed more adequate compared to other lamp types and the effects of variations in room surface reflectance combinations on the participants’ responses were statistically significant at α = 0.05 level. The simulated horizontal work plane average illuminance level varied from 131 to 171 lx, mean room surface exitance (MRSE) levels remained between 30 and 90 lm/m2 and overall uniformity of illuminance remained between 0.5 and 0.7.Originality/valueIn a hospital ward illuminated by LED tubular lamps, variations in room surface reflectance combinations for a constant luminous flux package output from the lamps may affect the subjective perception of users and the correlation between horizontal work plane average illuminance and MRSE is found to be highly linear (coefficient of determination > 0.97).

“Gradient” Experiment in Horticulture Lighting

Introduction. A characteristic feature of most experimental research works on horticulture lighting is the need to vary the main parameters of the light regime while maintaining other environmental factors at the same level throughout the experiment. The approach to creating the requisite variety of variations of light regime parameters in one cycle of plant cultivation, considered in this work, may be acceptable for reducing the time of experiments or for exploratory works. The aim of the work is to show the possibility of using the illuminance gradient as a source of variation in its value in experimental works on horticulture lighting. Materials and Methods. We used an LED lamp with a cosine light spatial distribution, placed above the work surface, on which containers with sweet pepper plants were placed. The optical density of the leaves in various spectral ranges was used as a biometric parameter characterizing the response of a plant to the level of illumination. Results. A significant gradient of illumination was observed on the working surface. With the same range of illumination, the number of containers with plants for a given zone is different and is sufficient to test statistical hypotheses. The values of the average illumination by zones provided the range of illumination change by 2.5 times. The standard deviations of illumination by zones were 97–163 lux and were practically no correlated with the values of the average illumination. Discussion and Conclusion. The developed mathematical model of a gradient experiment in horticulture lighting makes it possible to determine the possible number of replicates during the experiment, the average illumination value, the standard deviation, the coefficients of variation and uniformity in each zone of plant placement, based on the lighting and layout parameters of the lighting installation. It has been experimentally found that the use of a luminaire with a cosine light distribution provides an illumination gradient on a horizontal surface, the average values of which in individual zones form a linear illumination scale. Coefficients of illumination variation in individual lighting zones with the parameters set in the example were 3.0–11.5%. The coefficients of variation of the optical density of the leaves of pepper plants grown under the conditions of the gradient experiment on illumination were 6.0–11.6%. The differences in the mean values of the optical density of plant leaves in different zones of gradient illumination are statistically significant. This allows us to recommend the use of the proposed method for searching experiments on horticulture lighting.

Daylighting evaluation in deep plan office buildings with OPV windows through simulation on Radiance

This research aims to evaluate the OPV window (OPVW) potential application in a deep-plan multi-storey office building, in order to verify its contribution to indoor daylighting quality. OPVW is a cost-effective technology with reduced environmental impact, suitable for application in a multi-story office building due to its potential to adapt to different architectural configurations, lightness and transparency, etc. In an earlier study developed by the authors, an experiment was conducted with a generic office room scale model. Three window materials were compared under real sky conditions (overcast and clear): 3 mm single glass (A scenarios); single glass with OPV (B scenarios); and single glass with application of solar control film (C scenarios). In the present study the same parameters from the experiment were used as input for simulations on Radiance, whose results were compared to previous (work plane illuminance, Daylight Factor and model interior photographs). We found similarities between them. Thus, further results were produced: isolux curves, Daylight Glare Index and render images. The rendered images show a brighter view at A scenarios, and at B and C scenarios. Even if average illuminance is reduced, a better daylight distribution and a reduction in glare are achieved. DGI indicates perceptible glare for some of A scenarios. On the other hand, at most of B and C scenarios, glare was below the perceptible range. Furthermore, the scenarios with OPVW (B scenarios) still show one more advantage: the energy production for artificial lighting when illuminance values are not sufficient.

XMM–Newton observations of the narrow-line Seyfert 1 galaxy IRAS 13224−3809: X-ray spectral analysis II

ABSTRACT Previously, we modelled the X-ray spectra of the narrow-line Seyfert 1 galaxy IRAS 13224−3809 using a disc reflection model with a fixed electron density of 1015 cm−3. An additional blackbody component was required to fit the soft X-ray excess below 2 keV. In this work, we analyse simultaneously five flux-resolved XMM–Newton spectra of this source comprising data collected over 2 Ms. A disc reflection model with an electron density of ne ≈ 1020 cm−3 and an iron abundance of $Z_{\rm Fe}=3.2\pm 0.5\, \mathrm{Z}_{\odot }$ is used to fit the broad-band spectra of this source. No additional component is required to fit the soft excess. Our best-fitting model provides consistent measurements of black hole spin and disc inclination angle as previous models where a low disc density was assumed. In the end, we calculate the average illumination distance between the corona and the reflection region in the disc of IRAS 13224−3809 based on best-fitting density and ionization parameters, which changes from 0.43$\sqrt{f_{\rm AD}/f_{\rm INF}}$ rg in the lowest flux state to 1.71$\sqrt{f_{\rm AD}/f_{\rm INF}}$ rg in the highest flux state assuming a black hole mass of $2\times 10^{6}\, \mathrm{M}_{\odot }$. fAD/fINF is the ratio between the flux of the coronal emission that reaches the accretion disc and infinity. This ratio depends on the geometry of the coronal region in IRAS 13224−3809. So we only discuss its value based on the simple ‘lamppost’ model, although detailed modelling of the disc emissivity profile of IRAS 13224−3809 is required in future to reveal the exact geometry of the corona.

Simulations and Analysis of the Optimum Uniformity for Pedestrian Road Lighting Focusing on Energy Performance and Spill Light in the Roadside Environment

Road lighting uniformity is an essential lighting quality parameter for motorists and pedestrians and varies with lighting design parameters. Increased road lighting uniformity may result in benefits, such as increased reassurance and perceived safety for pedestrians or an increased overall visual perception. However, no previous study has investigated how road lighting uniformity varies with lighting design scenarios or how the uniformity of various lighting design scenarios affects other essential parameters, such as energy performance and obtrusive light. This study aimed to investigate: (I) how uniformity varies with different road lighting design scenarios, and (II) how uniformity correlates with energy performance and risk for increasing spill light. The study is limited to pedestrian roads. We performed photometric calculations in ReluxDesktop for more than 1.5 million cases with single-sided pole arrangements and for various geometries of road width, pole distance, pole height, overhang, and luminaire tilt. The results were analyzed with a set of five relevant metrics that were calculated and analyzed together with uniformity. For the evaluation, we used the minimum luminaire power needed to achieve an average illuminance of 10 lx, the power density indicator (DP), edge illuminance ratio (REI), and we introduced two new indicators for spill light on the ground in the border areas: the extended edge illuminance ratio (extended REI) and the spill flux ratio (RSF). The results show that increased uniformity levels may significantly increase energy consumption and spill light, but that both these impacts can be relatively controlled if uniformity is kept under certain limits. The investigated cases also demonstrated that improper lighting planning significantly increases adverse effects, such as spill light.

Solid-State Pulsed Time-of-Flight 3-D Range Imaging Using CMOS SPAD Focal Plane Array Receiver and Block-Based Illumination Techniques

Full realization of a solid-state 3-D range imager based on the pulsed time-of-flight method is presented. The system uses block-based segmented illumination in the transmitter realized with a 16-element common anode laser diode bar. The receiver is based on a single chip 2-D SPAD/TDC 0.35 μm CMOS array with 32 × 128 SPAD pixels and 257 TDCs. Segmentation of the illumination improves the SN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BG</sub> R in the detection and results in simpler receiver realization than in the commonly used flood-illumination approach. The system is capable of producing cm-accurate 3-D range images within a FOV of 40° × 10° up to a range of 15 m in normal office lighting at a frame rate of ∼30 fps using a low average illumination power of only 2.6 mW. In background illumination of ∼20 klux, 3-D range images were captured at a distance of ∼13 m using the gated SPAD approach at a frame rate of ∼1 fps.

Simulation and Optimization of the Combined High-Gradient Magnetic Separation-Ultraviolet Photocatalysis (HGMS-UV/TiO2) System for Ballast Water Treatment

Ballast water has a negative impact on marine environment; the existing combined ultraviolet (UV) filtration system that for treating ballast water has relatively low effective rate and instability in inactivating microorganisms. In this study, the established high gradient magnetic separation-ultraviolet photocatalysis (HGMS-UV/TiO2) system was taken, the back propagation (BP) neural network and TracePro was used to simulate and analyse the UV field intensity in the system for optimizing. Further experimental verification was carried out with seawater sample to measure its inactivation effects on microorganisms including zooplankton, phytoplankton and bacteria. The results showed that HGMS-UVC/TiO2 system had good inactivation effect on zooplankton and bacteria, but relatively poor inactivation effect on phytoplankton. The optimal strategy for optimizing the UV intensity was further obtained, it is concluded that after adding ultraviolet A (UVA), the UV intensity distribution of the system is more uniform, and the average illumination intensity is also improved, but the optical path of UV in ballast water should not be too long. The optimized system could increase the intracellular K+ leakage of phytoplankton cells by more than 25%, indicating that the damage to cell membrane permeability was stronger. In conclusion, the optimized HGMS-UVA/UVC/TiO2 system can improve the inactivation capacity of microorganisms and provide basic theoretical support for improving the capacity and level of treatment in ballast water.

ANALYSIS OF THE ILLUMINANCE LEVEL IN A CLASSROOM FOR DIFFERNT SKY CONDITION

Nowadays, due to the decrease in renewable energy sources on a global scale, studies for the effective use of energy and reducing energy consumption gain importance. Buildings have an extremely important role in energy consumption. Educational buildings, which are used for educational purposes, are important in terms of both the duration of use and the comfort level of the user. While the aim in educational institutions is to increase the level of user comfort, the main target is to increase the efficiency in educational activities. In energy consumption, the rate of consumption due to lighting is quite high. For this reason, effective and appropriate design of natural and artificial lighting is important in terms of both user efficiency and minimizing energy consumption. In lighting design, natural and artificial lighting should be considered in an integrated manner. The design should be started by considering daylight as the primary energy source. The homogeneous distribution of light in the space is as important as the average illumination level in the classroom. The light should spread homogeneously in the space in a way that provides equal efficiency to every user. In this study, the illuminance level of a selected classroom in Niğde Ömer Halisdemir University Faculty of Architecture was analyzed. In the selected workshop, measurements were made in the 5 weeks selected in November and December, at different times of the day and in different sky conditions, when the artificial lighting elements were on and off. In the case of the lamp on, generally sufficient average illuminance level can be met in all measurement hours, while it has been observed that sufficient average illuminance level is provided by turning on the lamps in the cloudy sky condition.

Effect of nighttime bedroom light exposure on mood episode relapses in bipolar disorder.

A previous cross-sectional study reported that nighttime light is associated with increased occurrence of manic symptoms in bipolar disorder; however, the longitudinal association between nighttime light and subsequent mood episode relapses remains unclear. We determined whether bedroom nighttime light was associated with mood episode relapses in patients with bipolar disorder. This prospective cohort study included 172 outpatients with bipolar disorder who participated in an Association between the Pathology of Bipolar Disorder and Light Exposure in Daily Life (APPLE) cohort study. A portable photometer was used to measure illuminance in the bedroom from bedtime to rising time during 7 consecutive nights for baseline assessment. Then, the participants were assessed at a 2-year follow-up for mood episode relapses. Of the 172 participants, 157 (91%) completed the 2-year follow-up, and 39 (22%) experienced manic or hypomanic episodes (with or without mixed features), during that time. In the Cox proportional-hazards model, the hazard ratio (HR) for manic/hypomanic episode relapses was significantly higher when the average nighttime illuminance was ≥3lux (n=71) than when it was <3lux (n=101; HR, 2.54; 95% confidence interval (CI), 1.33-4.84). In the multivariable model adjusted for a propensity score in relation to nighttime light, the relationship remained significant (HR, 2.17; 95% CI, 1.04-4.52). The association between nighttime light and depressive episode relapses was not significantly different. Keeping the bedroom dark at night may prevent hypomanic and manic episodes.

Modeling photovoltaic-electrochemical water splitting devices for the production of hydrogen under real working conditions

Photoelectrochemical splitting of water is potentially a sustainable and affordable solution to produce hydrogen from sun light. Given the infancy stage of technology development, it is important to compare the different experimental concepts and identify the most promising routes. The performance of photoelectrochemical devices is typically measured and reported under ideal irradiation conditions, i.e. 1 sun. However, real-life operating conditions are very different, and are varying in time according to daily and seasonal cycles. In this work, we present an equivalent circuit model for computing the steady state performance of photoelectrochemical cells. The model allows for a computationally efficient, yet precise prediction of the system performance and a comparison of different devices working in real operating conditions. To this end, five different photoelectrochemical devices are modeled using experimental results from literature. The calculated performance shows good agreement with experimental data of the different devices. Furthermore, the model is extended to include the effect of illumination and tilt angle on the hydrogen production efficiency. The resulting model is used to compare the devices for different locations with high and low average illumination and different tilt angles. The results show that including real illumination data has a considerable impact on the efficiency of the PV-EC device. The yearly average solar-to-hydrogen efficiency is significantly lower than the ideal one. Moreover, it is dependent on the tilt angle, whose optimal value for European-like latitude is around 40°. Notably, we also show that the most performing device through the whole year might not necessarily be the one with highest sun-to-hydrogen efficiency for one-sun illumination.

A Study on Street Lighting Design in Outdoor Space of Apartment Complexes

Crime is one of the important factors that threaten dwelling safety of the human in apartment complexes, the representative housing type in Korea. A well-planned lighting scheme at night provides a feeling of safety to the residents and serve as a deterrent to crime. Regarding these, this study propose a rational design process that can be utilized in the street lighting design considering the characteristics of the space and the complex on the basis of the objective illumination plan through Space Syntax and field survey. First, as shown in the results of spatial structure through space syntax, spatial structure and pedestrian street of most apartment complexes have planned according to the hierarchy and importance of the space. Average illuminance for each space and road and separation distance between lightings needs to be appropriately proposed to make a night view plan. Second, the horizontal and vertical illuminance were measured to be relatively higher when LED lighting was installed than MH lighting installed. It was found that LED lighting has a positive effect on facial recognition and is advantageous in terms of maintenance. Third, For efficient use of lighting, continuous maintenance and legal enforcement are required.

Multi-objective optimization method for reducing mutual interference in cockpit illumination.

The cockpit is a compact space comprised of various light-emitting devices. The light from different devices interferes and overlaps on the target surface. The light distribution requirements of different target surfaces are different. A suitable decision-making process is required to simultaneously meet the requirements of multiple target surfaces. A GPR-NSGA-II framework was proposed in the present study and a corresponding Gaussian process regression prediction model was established to predict and optimize multiple optical quality parameters in the cockpit. The luminous flux and beam angle of the typical luminaires were selected as controlled input parameters in a model case. The average illumination of targets that need lighting were set as constraints, and uniformity of illuminance of these surfaces and vertical illumination (direct light) of the eye position were set as the variables. An orthogonal experiment was conducted using the lighting model and a dataset was generated to validate the proposed framework. The results demonstrate that the solution set of luminescence parameters in cockpit illumination can be specified by GPR-NSGA-II framework.

Survey of lighting systems and aesthetic illumination design for various major parks in Ho Chi Minh City

The study was carried out from August 2019 to August 2020 at five major parks in Ho Chi Minh City. We aimed to survey the lighting system including bulb types, lamp types, illumination type, and average horizontal illuminance. The study was carried out by several methods such as a questionnaire of the characteristics of the lamp, observing, measuring, analyzing, synthesizing data, and evaluating. We divided each park by area, for example, main gate, side gate, main axis, branch road, lawn, activity area for investigation. The result showed that the parks having LED and HQ compact bulbs, which were popular chandeliers. Most parks had direct lighting to provide panoramic illumination, but did not reach the average horizontal illuminance. We propose an aesthetic illumination design for the central area of ​​the park with ideas from the history of the park's formation and development. The research results contribute to the improvement of the lighting system for the parks in Ho Chi Minh City.

Simulation-based analysis of luminous environment of OLED lighting-integrated blinds for PV–OLED blind systems

Photovoltaic (PV) blinds generate power and control the sunlight entering the rooms. The control of PV blinds to maximize the power generation is disadvantageous to the indoor lighting environment as it blocks daylight. This study developed a PV–OLED blind system with an organic light-emitting diode (OLED) lighting panel attached to the back of a PV blind slat. It maximizes PV power generation, supplements indoor illuminance, and enables easy installation because it is an integrated device. A simulation modeling method of OLED, a surface-type lighting that rotates according to the blind angle, was developed and verified using measurement values. In order to apply the surface-type lighting form, a method of applying several luminous intensity distribution data files was used where we divided the height and width of one OLED lighting panel. As the number of height divisions increased, the coincidence rate with the measured values of the simulation results tended to increase. Using the proposed modeling method, the indoor illuminance distributions according to the installation position of the OLED lighting panel and the control angle of the slat were analyzed. When the slat angle was close to 60°, the influence of OLED was the greatest, and the influence of daylight decreased as the slat angle was decreased. As the slat angle increased, insufficient daylight could be compensated with an OLED lighting panel. As the OLED lighting panel was installed in the lower part of the blinds, the uniformity ratio decreased, and the average illuminance increased.

사막기후 스마트팜 적용 냉방패키지시스템의 냉방효과 비교분석

The purpose of this study was to shorten the uncultivated period from about 5-6 months to 2 to 3 months. The uncultivated period of 5-6 months was due to midday temperature in the UAE soaring up to 47℃ and the high solar radiation causing problems in crop cultivation. This study intended to compare the effect of reducing high temperature and cooling load of greenhouse through simulation with covering material, external shading, and fan & pad evaporative cooling system to be applied to the UAE smart farm and use it to select equipment capacity such as chiller and cold storage tank. The average indoor illuminance and the peak cooling load were compared according to the type of covering material and the shading rate. When a fan & pad system was applied, the peak cooling load was reduced by 42.9% or 69.4% compared to the typical glass greenhouse (case 1) when the fan & pad system efficiency was 60% or 80%, respectively. It is expected to reduce the capacity of equipment for heat sources such as chiller and cold storage as much as the peak cooling load reduction.

Research on Night Light Comfort of Pedestrian Space in Urban Park.

The outdoor light environment significantly affects aspects of public psychological and physiological health. This study conducted experiments to quantify the effects of the light environment on visitor light comfort in urban park pedestrian space. Nine sets of lighting conditions with different average horizontal illuminance (2 lx, 6 lx, 10 lx) and colour temperatures (5600 K, 4300 K, 3000 K) were established virtual reality scenarios. Subjective light comfort was evaluated, and electroencephalogram (EEG) was measured on 18 subjects to comprehensively study the effects of different light environments on human light comfort. The results of the comprehensive evaluation showed that colour temperature had a very significant impact on subjective light comfort, with warm light being generally more favourable than cool light in enhancing human subjective light comfort. The results of the EEG analysis show that the average horizontal illuminance is an important factor in the level of physiological fatigue, and that physiological fatigue can be maintained in a superior state at an appropriate level of illuminance. Based on the results of both subjective and objective factors, a comprehensive analysis was carried out to propose a range of average horizontal illuminance (4.08 lx, 6.99 lx) and a range of colour temperature (3126 K, 4498 K) for the comprehensive light comfort zone in urban park pedestrian space.

Optimized Micro-Pattern Design and Fabrication of a Light Guide Plate Using Micro-Injection Molding.

This study examined the uniformity of illuminance field distributions of light guide plates (LGPs). First, the authors designed microstructural patterns on the surface of an LGP. Then, a mold of the LGP with the optimal microstructural design was fabricated by a photolithography method. Micro-injection molding (μIM) was used to manufacture the molded LGPs. μIM technology can simultaneously manufacture large-sized wedge-shaped LGPs and micro-scale microstructures. Finally, illuminance values of the field distributions of the LGPs with various microstructures were obtained through optical field measurements. This study compared the illuminance field distributions of LGPs with various designs and structures, which included LGPs without and those with microstructure on the primary design and the optimal design. The average illuminance of the LGP with microstructures and the optimal design was roughly 196.1 cd/m2. Its average illuminance was 1.3 times that of the LGP without microstructures. This study also discusses illuminance field distributions of LGPs with microstructures that were influenced by various μIM process parameters. The mold temperature was found to be the most important processing parameter affecting the illuminance field distribution of molded LGPs fabricated by μIM. The molded LGP with microstructures and the optimal design had better uniformity than that with microstructures and the primary design and that without microstructures. The uniformity of the LGP with microstructures and the optimal design was roughly 86.4%. Its uniformity was nearly 1.65 times that of the LGP without microstructures. The optimized design and fabrication of LGPs with microstructure exhibited good uniformity of illuminance field distributions.

SHADING AND LIGHT INTERCEPTION IN THICKETS OF INVASIVE ACER NEGUNDO AND SORBARIA SORBIFOLIA

The aim of the work is to establish how greatly the light conditions change under the leaf canopy of two invasive plant species in the Middle Urals - Acer negundo and Sorbaria sorbifolia . In June - August 2020, using a portable light meter, 8370 measurements of illumination were performed in forest parks (at a height of 1.5 and 0.5 m, i.e. above and below the canopy of the leaves of the invasive shrub S. sorbifolia and the native shrub Rubus idaeus ; in random points under the canopies of Pinus sylvestris ; on glades, paths and forest edges) and in urban habitats (at a height of 1.5 m and 0.5 m in dense thickets of the invasive tree A. negundo and other tree species). The average illumination intensity was as following: under S. sorbifolia - 4 ± 1 lux × 10; under R. idaeus - 7 ± 1 lux × 10; in A. negundo thickets - 13 ± 2 lux × 10; in thickets of other tree species - 25 ± 4 lux × 10; under the canopies of urban pine forests - 80 ± 10 lux × 10; in the forest edges - 96 ± 14 lux × 10. In dense thickets, A. negundo intercepts about 94% of the light falling on its canopies, S. sorbifolia - about 93%. This is significantly higher than the light interception level in habitats used as control: other tree species canopies of greatly urbanized habitats intercept about 89%, the thickets of R. idaeus - about 82%. Thus, invasive plants reduce the amount of light available to other plant species in communities significantly more than native plants.

Simulation and Experimental Study of Light and Thermal Environment of Photovoltaic Greenhouse in Tropical Area Based on Design Builder

In order to study the adaptability of photovoltaic greenhouses to climate in tropical areas, a photovoltaic greenhouse model (photovoltaic panel coverage rate: 76.9%) was built in this study according to a 1:1 proportion. The distribution law of the indoor illuminance, temperature, and humidity were studied simultaneously in the photovoltaic greenhouse by actual measurements and simulation. The filed data are shown as follows: (1) Illuminance: in limited rain winter, the average illuminance and light transmittance were 7.02 kLux and 25.77%, respectively (10:00–16:00); but in different weather conditions during summer, the average illuminance and light transmittance were 15.47 kLux and 32.35%, respectively (9:00–16:00). (2) Temperature and humidity: the indoor temperatures of the greenhouse were between 22.1 and 29.3 °C in limited rain winter, with a relative small temperature difference between indoor and outdoor environments; the relative humidity values were between 69% and 97%; but in summer, the temperatures at all indoor test site were higher than outdoor sites, with an average temperature difference of 2.7 °C and relative humidity values between 46% and 94%. According to the simulation by Design Builder, the average light transmittances were 33.09% in winter and 37.54% in summer, the temperature difference between winter and summer was less than 1 °C, and the relative humidity decreased with the increase of temperature, which basically coincided with the filed data. The results of the analysis showed that the illuminance, temperature and humidity of the photovoltaic greenhouse can satisfy the production requirements of shade-enduring and neutral crops. At the same time, by comparing the illumination, temperature and humidity of the photovoltaic greenhouse with that of an ordinary greenhouse, the former had good adaptability to climate in tropical areas, which can achieve the goal of photovoltaic generation and agricultural production synchronously.

Integration of Horizontal Light Pipe and Shading Systems in Office Building in the Tropics

ABSTRACT Many high-rise office buildings in the tropics have a full-glazed facade and a deep open-plan space. Without any external shading, the office space has a non-uniform daylight distribution and glare problem. A deep open-plan space design also causes insufficient daylight levels in the area distant from the building perimeter. Previous studies about Horizontal Light Pipe (HLP) mainly focused on system improvement in capturing, transporting, and distributing daylight into deep space. Integration of HLP as a light transport system that can deliver daylight deeper into building interiors and shading systems consist of Light Shelf (LS), blinds that can redirect and reduce the excessive daylight level near the side window are proposed and studied. The research objective is to explain the daylight performance of the integration of HLP and shading systems. The research method is experimental with Radiance-based simulation as a tool. Surabaya (latitude 7.38° S and longitude 112.79° E), a typical city in the Tropics, was chosen for the simulation. Daylight level, daylight distribution, and Daylight Glare Probability (DGP) of office room with East-facing window are compared with office room with HLP and shading systems. The results showed that the integration of HLP and shading systems increased the average illuminance level in the deep area reached 135 % and reduced the average illuminance level in the area near the side window reached 55 %. HLP and shading systems also increase the daylight distribution inside space and slightly improve the DGP but still in the range of imperceptible for building users.