Energy Consumption For Artificial Lighting Research Articles

Semi-Transparent PV and Double-Glazed Windows for Heat Reduction and Electricity Generation: A Study for Office Buildings in Tropical Climate

This research aims to develop a methodology for the evaluation of the potential energy saving and energy generation of semi-transparent PV and double-glazed window in Indonesia office buildings. The evaluation is based on Comsol software. The heat transfer equations for the inside the enclosure between the glass have been constructed according to the natural convection equation. The simulations were accomplished for four orientations from January until December and compared to a single-glazed window. The results show that it is possible to reduce the energy consumption for artificial lighting and air-conditioning using appropriate control systems and furthermore to generate electricity using semi-transparent photovoltaic panels in windows. The use of semi-transparent PV and double-glazed window has proven to be more effective in reducing heat transfer in buildings and generate electricity. East-facing double-glazed windows produce the most electricity, approximately 341 kWh.

The Architectural Design of Building Façade Models Related to Optimizing Daylight Distribution

Lighting control integrated with daylighting is recognized as an important and useful strategy in energy efficient building design. One of the right factors to reduce energy consumption for artificial lighting during the day is the maximum utilization of sunlight. The aim of this research, distribution of daylight into the building analysis with five models of building facades and value of illuminance in the morning, afternoon and evening with orientation of the window openings to the northeast and southwest. Bank Mega is one of the tall buildings in Makassar Indonesia, which is located in a coastal area that is not blocked by other tall buildings, so this building is the object of research as a basis for designing façade models on building envelopes. The methodology this study is quantitative, analyzing the performance of sunlight as a source of daylighting in office buildings. This paper presents field measurements in office buildings, namely in rooms that are oriented northeast and southwest. The analysis in the two spaces is a reference to determine the effect of sunlight on the orientation of the building. In this study also conducted visual perception experiments by submitting questionnaires to 43 respondents. the results show that there are some complaints for employees, because of the high illuminance value in certain areas. Furthermore, simulate using the Radiance Illuminance Program software to determine the illuminance value of room in the morning, noon and afternoon with five building facade model designs, i.e., massive glass, vertical, horizontal, diagonal, and vertical-diagonal model. The results presented in this paper show that the distribution of daylight in an east-oriented room is higher in the morning than in the evening and noon. Whereas in the southwest orientation it is inversely proportional, the value of light distribution is higher in the afternoon than in the morning and noon. Accordingly, orientation of the building affects distribution of daylight. The massive glass facade model without using sun shading has the highest light distribution value compared to other façade models, but can cause glare and excessive brightness. Furthermore, the second highest distribution of daylight with the vertical facade model, but there are also areas that exceed the standard illuminance level for workspaces, but only in areas near window openings. The combined model of the vertical-diagonal facade which also has a high distribution of illuminance value and to redirect daylight deep into building interior simultaneously in the morning, afternoon and evening. Accordingly, façade model on envelope of building affects distribution of daylight. The aesthetic value of architectural design shows that the appearance of the building does not look monotonous or massive, when using the building facade models because there are attractive areas in the building envelope.

Characteristics of office lighting energy consumption and its impact on air conditioning energy consumption

The energy consumption of office buildings has increased sharply since the 21st century with the increasing urbanization coverage. At this stage, the energy consumption of office buildings in China mainly comes from air conditioning and lighting. This paper obtains the regression equation of natural lighting illumination and radiant heat gain under different curtain conditions through experiments and simulations, and gives the theoretical calculation process of curtain regulation of office thermal and light environment and energy consumption. DeST and Ecotect software were used to analyze the thermal and light environment and energy consumption of the office. The results show that setting curtains in the room can effectively improve the indoor thermal light environment, the higher the transmittance of curtains the lower the lighting energy consumption, the higher the number of high temperature hours of natural room temperature and the greater the radiant heat gain. The room with thick curtains has the lowest energy consumption for air conditioning in summer, followed by the room with thin curtains, and the room without curtains has the highest energy consumption for air conditioning. The room without curtains has the lowest energy consumption for artificial lighting, the room with thin curtains has the second lowest, and the room with thick curtains has the highest electricity consumption for artificial lighting. The air conditioning energy consumption accounts for the main building energy consumption, followed by the lighting energy consumption. After setting curtains in the office, the air conditioning energy consumption caused by the solar radiation heat entering the room through the exterior windows is smaller than the lighting energy consumption caused by artificial lighting. Therefore, the installation of internal shading with moderate transmittance and good thermal insulation performance can make the energy saving of lighting and air conditioning energy consumption reach the optimal value.

Comparative Analysis of the Daylight and Building-Energy Performance of a Double-Skin Facade System with Multisectional Shading Devices of Different Control Strategies

There is a tendency toward larger transparent envelopes in architectural design, which could causes excessive energy consumption and visual discomfort. Using advanced shading systems with control strategies could potentially improve the indoor environmental quality and reduce the building energy consumption. In this research, daylight and thermal performances of a double-skin facade (DSF) system with multisectional shading devices using combinations of roller shades and blinds along with different control strategies were investigated under three representative climatic conditions of China. The performance of DSF systems with and without shading devices were comparatively analyzed by evaluating the annual heating, cooling, and artificial lighting energy consumption, daylight availability, and visual discomfort index using EnergyPlus and Radiance. The results indicated that the DSF with a multisectional shading system and proper control algorithms can save up to 6.8% and 4.8% for annual building energy consumption in Xiamen and Shanghai, respectively, but slightly increased by 2.4% in Beijing, when compared with the baseline without any shading device. For daylight performance, the multisectional shading system with proper control strategy shows a significant contribution to eliminating annual sunlight exposure (ASE) and discomfort glare while maintaining the daylight availability at a similar level compared to the system without shading. Meanwhile, the combination could improve spatial daylight autonomy (sDA) by 11.9%, 16.7%, and 19.1% in Xiamen, Shanghai, and Beijing, respectively, when compared with the individual shading system.

Façade elements for room illumination with integrated microstructures for daylight redirection and LED lighting

Lowering energy consumption of buildings is a common task, which is addressed in this presented research by the development and application of a micro structured system that successfully redirects daylight in order to light an office room instead of blocking it by shading systems. Designed as a common three-pane window compound and built utilizing manufacturing methods for mass production, namely hot embossing and UV imprinting, it can be handled as a common façade element. Measurements in the equipped office room prove a significant lowering of energy consumption for artificial lighting. This research is accompanied by the development of another façade element integrating an artificial luminaire to take care of situations in which no daylight is available, but without changing the location of the illumination source. The luminaire realized as micro structured surface emitter is incorporated as a window compound together with the LEDs used in a test façade, while offering a clear view to the outside. The view through the system is measured by a setup that partly mimics human perception. This transparent façade element emits light to the rooms ceiling for indirect illumination. Not yet being as efficient as standard lighting solutions, it offers new design options in reducing the use of common luminaires and in opening up new usable space at the ceiling and interior.

Feasibility analysis of energy-saving potential of the underground ice rink using spectrum splitting sunshade technology

The original intention of skylights for underground ice rinks is to introduce natural light, but incoming solar radiation also affects the ice quality and ice-making energy consumption. As public sports and fitness venues of “Ice Cube”, sustainable operation of the underground ice rink with transparent skylights, has attracted much attention of architectural designers. To reduce the energy consumption without affecting indoor natural lighting, the heat transfer process of a skylight is discussed and modeled, and an advanced sunshade technology using Antimony Tin Oxide (ATO) nanofluids is proposed to filter UV/NIR and reserve visible light for indoor natural lighting. Meanwhile, two factors’ effects, including outdoor solar irradiation and mass fraction of ATO nanofluids on the energy-saving potential of an underground ice rink, are discussed, and results indicate that spectral energy of UV and NIR decreases by 23.16% and 32.99% respectively, with 20 ppm ATO nanofluids, but the energy during visible light region only reduces by 11.56%. Additionally, a high mass fraction lowers indoor solar radiation but also lifts artificial lighting energy consumption, and the mass fraction of 200 ppm is recommended as the optimal mass fraction with annual total energy consumption of 392 GJ.

A Novel Cost-efficient Daylight-based Lighting System For Public Buildings: Design And Implementation

In this study, design and implementation of a new cost-efficient daylight-based lighting control system is proposed to provide energy saving in a public building with a conventional lighting system. Energy gain recovery and regional daylight utilization coefficients are obtained by conducting daylight measurements in all indoor spaces of the building where the proposed lighting system will be applied. Daylight value is continuously transferred to the control system through the pyranometer placed outside and the need for artificial lighting is calculated by using sectional daylight utilization coefficients. Thereby, maximum benefit from daylight is realized when unnecessary energy consumption for artificial lighting is reduced. Experimental measurement results show that the proposed daylight-based lighting control system provides an average energy efficiency of the building at the level of 60 %. Additionally, the required investment, such as operating cost and payback period for converting an existing conventional lighting system into the proposed system, are discussed in detail. Cost analysis shows that the payback period of the proposed system can be reduced by 5 years compared to the conventional system.

A method of partition design for open-plan offices based on daylight performance evaluation

Daylight performance has a considerable effect on occupants' comfort and satisfaction of office buildings. Nowadays, open offices are a common typical plan, in which the workstations are separated via partitions. These partitions completely affect daylight performance due to their height, material, and arrangement. Therefore, the optimum design of partitions is vital to boost the daylight performance. The current paper presents a method in form of a tool for designing and evaluating of partitions based on the main daylight metrics. Considering the climatic and urban situation of the building (in form of epw file, and the shading effect of adjacent buildings), in addition to the office characteristics (office layout, window size, and orientation), the used method changes the above-mentioned parameters of partitions and evaluates the daylight availability, visual comfort, and lighting energy demand, presented in the form of a Grasshopper plugin. The developed tool has been used to define the optimum workstation layout for an office building in Tehran. Results indicate that an increasing panels' reflectivity compensated reduction of the received daylight caused by partitions height incensement. 20% reduction in partitions reflectivity, and 0.2 m increase of partitions’ height, decrease the spatial daylight autonomy daylight by 9.47% and 4.36%, while increasing the artificial lighting energy consumption up to 10.01% and 6.27%, respectively. The presented tool provides an evaluation method of partitions arrangement optimization in open-offices for designers and architects during the design and retrofit procedure.

Conditions for ensuring energy-saving use of translucent structures of exterior wall envelope

The article focuses on determining the translucent structures of exterior wall envelope (TSEWE) properties influence on the total energy balance of the room. The dependence of the energy consumption for artificial lighting on the daylight factor, coefficient of relative penetration of solar radiation (CRPSR) and TSEWE area is determined for Ternopil city. The relationship between the electricity expenses for heating and cooling the room by channel air conditioners on the size and properties of TSEWE is established. Inequalities were obtained that allow us to establish the conditions under which the TSEWE use will have a positive effect on the total energy balance of the office room for the Ternopil city. According to the obtained results, it is possible to determine the thermal resistance, CRPSR and the TSEWE area at which energy savings will occur while observing the climate conditions in the room prescribed by regulations documents.

A framework outlining a daylight responsive model for smart buildings

The intensity of daylight varies due to periodical changes in the sun’s position, changing cloud-cover over the region, and other weather-related phenomena. Thus, artificial lighting remains a major component of the overall energy consumed in smart buildings. This necessitates corrections for maintaining optimum lighting levels in these buildings, by enhancing the positioning of artificial lighting sources with respect to outdoor lighting conditions. In this paper, a methodological framework is proposed for developing a daylight responsive model to minimize energy consumption for artificial lighting. This could be achieved by optimizing the usage of natural lighting in the built-environment, with the aid of Geo-location and sun-path tracking in a simulated model using Unity software. This smart daylight responsive model integrated with Virtual Reality (VR) would aid in designing an efficient lighting system utilizing Building Information Modelling (BIM). Further, this framework would help architects, engineers, and other stakeholders to collaborate, and virtually visualize the lighting conditions in smart buildings. In conclusion, an energy-efficient model for lighting can optimize the energy usage pattern in smart buildings, effectively increasing the usage of natural lighting.

IMPACT OF FACADE CONFIGURATION ON ENERGY CONSUMPTION OF SCHOOL BUILDINGS IN CONSTANTINE (ALGERIA)

In Algerian school buildings, heating and artificial lighting energy consumption counts for the important proportion of spending. Facade configuration is one of the major reasons because it affects the heating, cooling and lighting energy consumption of building. So, it is necessary to study the energy saving optimal design of transparent envelope for classrooms. In this paper, the impact of some parameters of transparent envelope on overall energy consumption (heating, cooling and lighting) are investigated using the two computer simulation softwares Ecotect analysis 2011 and Daysim 3.0. These parameters are: the orientation, the window to floor ratio, the heat transfer coefficient U and luminous transmittance LT of glazing materials. The results show a complex interdependence among these design variables.

Minimizing energy consumption for artificial lighting in a typical classroom of a Hellenic public school aiming for near Zero Energy Building using LED DC luminaires and daylight harvesting systems

The energy consumption for the artificial lighting in school buildings is one of the main consumers of electricity. In Greece, there is a large number of school buildings with quite old lighting systems using luminaires with T8 and sometimes T12 fluorescent lamps and degradated translucent diffusers. Due to the economic crisis, the public sector failed to invest in LEDs and although daylight is adequate during the year, the adoption of control technology is rather slow. The paper, using a typical classroom of a Greek public school, examines a number of lighting technologies (with AC and DC supply) together with two daylight harvesting systems. The first one uses one stand-alone photosensor per luminaire while the second one sensor per control zone, in an effort to calculate energy savings and light adequacy. The dimming curves of the DC LEDs were measured along with the installed power of the photosensors. The results show that the existing 90.5 kWhp/m2 of annual lighting primary energy consumption can be reduced to 0.55 kWhp/m2. The maximum annual reduction of CO2 emissions was 32.44 kgr/m2 for classroom areas, which is translated to 201929 tn for the whole country. It is evident that the path to Zero Energy School Buildings goes through the mandatory use of daylight controls.

Study on the overall energy performance of a novel c-Si based semitransparent solar photovoltaic window

This paper introduces a novel c-Si based building integrated photovoltaic (BIPV) laminate. It was produced by cutting standard crystalline silicon solar cells into narrow strips and then automatically welding and connecting the strips into continuous strings for laminating between two layers of glass. The overall energy performance of the BIPV insulated glass unit (IGU) including power, thermal and daylighting performance was investigated experimentally. The daily energy conversion efficiency of the active solar cell area was about 15% on sunny days, but it was less than 12% on cloudy days and overcast days. Due to the combined effect of both the semi-transparent PV laminate and the insulated glass unit, the solar heat gain coefficient (SHGC) of the BIPV IGU was as low as 0.25, which was much lower than commonly used glazing windows. Daylight analysis by means of high dynamic range (HDR) cameras and daylight glare probability (DGP) indicated that the BIPV IGU could reduce discomfort glare to some extent compared to clear glass windows. The net energy production of the BIPV IGU was estimated without considering the differences in HVAC energy use in this study. The artificial lighting energy consumption was about 431 W h/day while the average BIPV electricity production for the same period was 1940 W h/day. The net power generation was therefore 1509 W h/day for this BIPV IGU in Berkeley, California. Shading tests for the BIPV IGU were also conducted and the results revealed that the vertical configuration of solar cell wiring in the BIPV laminates was much more sensitive to horizontal shading patterns than vertical shading models. Thus, if shading was unavoidable in some cases, a reasonable arrangement of PV strings should be considered to bring down the energy loss as much as possible. Also, the impacts of environmental factors on the energy conversion efficiency of BIPV IGU were analyzed. Specifically, the power output declined by 0.42% of the peak power for each Celsius degree temperature rise. Thus, if more attention was paid to the heat dissipation issue of BIPV IGU, the overall energy conversion efficiency would be improved.

A Vision of Daylight Technologies for High-Rise Residential Building in Tropic

Sidelighting is still the primary lighting opening for most buildings in all part of the world. The technology allows only limited penetration of daylight that causes a high energy consumption for artificial lighting. Using a right daylight technology in high-rise residential building could saving more energy and have a good impact on productivity and occupant’s health. This paper discusses the daylighting technologies for high-rise residential buildings in tropical area with literature review method. Some factors such function of systems, location, ability to change and transparency/the view outside will be the factors that must consider in selecting daylight technologies for high-rise residential building in tropic. The diffuse light-guiding system is a practical daylight technologies for deep floor plan building in tropics. The studies shows that potential daylight technology is diffuse light-guiding system that composed from light shelf, fish sytem and anidolic system. The performance of light shelf influenced by direct sunlight. Its increasing iluminance near window area and causes uneven distribution of illumination in the room. Fish system shows better performance than ordinary blinds, however the result is from integration of fish system and external blinds at low internal illuminance. Application anidolic system in tropical area improving illuminance ratio by factor 3.3, reducing glare by 14%, under overcast sky could transfer daylight upto12.5 m and under intermediate sky up to 20 m. For future work, anidolic system expected to respond sky conditions and direct sunlight for improvement in tropical area.

The optimization of light-wells with integrating daylight and stack natural ventilation systems in deep-plan residential buildings: A case study of Tehran

Simultaneous access to fresh air and daylight is one of the main problems in deep-plan buildings, causing increasing energy consumption for artificial lighting and mechanical ventilation. The proper design of light-wells as an integrated system to simultaneously provide daylighting and natural ventilation is the main topic of this research. In this study, a pattern for horizontal and vertical cross-sectional form of light-wells has been suggested for better daylighting and stack natural ventilation performance in connected rooms to light-wells. This suggested pattern of light-well can be used in future projects, located in different places with similar climatic conditions. Furthermore, daylighting and natural ventilation performance in different types of light-wells have been evaluated. The main tool of this research is computer simulation using Energy-Plus, Design Builder and Daysim simulation programs. Results show that the square light-well with 4 × 4 m minimum dimensions and the rectangular light well with 3 × 4 m dimensions can provide adequate ventilation rate and annual illuminance to the rooms connected to the light-well, up to 4 floors under the roof. Nevertheless, the air velocity and airflow pattern inside these rooms are not desirable for cooling by natural ventilation trough the light-well. Also, the quality of ventilated air in rooms connected to light-wells is low because the inlet air to upper floors comes from the outlet air from the lower floor. Considering these results, a revised light-well has been suggested for better daylighting and stack natural ventilation performance with some changes in the horizontal and vertical cross-sectional form.

The Performance of Daylight through Various Windows for Residential Buildings


 A good daylighting strategy is necessary in order to decrease energy consumption for artificial lighting. To provide effective internal illumination, the placing of the right openings in the right positions with suitable type of window and glazing is important. This study focused on the various types and materials of the glass and window, in order to identify the quantity and quality of daylight that penetrates into the residential buildings. Based on a series of measurement, it was identified that type of glazing and window gives major significance on the performance of daylight and thermal performance in residential buildings.
 Keywords windows; illumination level; residential building; occupant’s perception.
 eISSN 2514-751X © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.

Performance of skylight illuminance inside a dome shaped adobe house under composite climate at New Delhi (India): A typical zero energy passive house

This paper presents annual experimental performance of pyramid shaped skylight for daylighting of a dome shaped adobe house located at solar energy park in New Delhi (India). This approach of single story dome shaped building with skylight is more useful for rural and semi-urban sectors for both office and residential buildings reducing artificial lighting energy consumption. The hourly measured data of inside and outside illuminance for three different working surface levels inside the existing rooms are presented for each month of the year. The embodied energy payback time of the skylight is also determined on the basis of lighting energy saving potential.

Semi-transparent PV windows: A study for office buildings in Brazil

This research aims to develop a methodology for the evaluation of the potential energy saving and energy generation of semi-transparent PV windows in Brazilian office buildings. The evaluation is based on computer simulations: a daylighting simulation for the investigation of the available annual daylight with different window systems using Daysim/Radiance program and the simulation of the energetic performance using the program EnergyPlus. The simulations were accomplished for two cities in two different climatic zones of Brazil and compared to a German city. The results show that it is possible to reduce the energy consumption for artificial lighting and air-conditioning using appropriate control systems and furthermore to generate energy using semi-transparent photovoltaic panels in windows. Though only one building geometry was analyzed the results suggest that the potential of this technology is high in Brazil.

The effect of different weather data sets and their resolution on climate-based daylight modelling

Climate-based daylight modelling is based on the available weather data, which means that the weather data used as input to the daylight simulations are of great importance. In this paper, the effect on the outcome of the daylight simulations of using one weather data file rather than another for the same location was investigated. Furthermore, the effect of using weather data sets with an hourly resolution compared to a one-minute resolution was investigated. The results showed that the lighting dependencies varied by up to 2% depending on the chosen weather data file and indoor illuminance threshold. The energy consumption for artificial lighting was underestimated when simulating with time steps of hourly means compared to one-minute resolution. The findings from this comparison show that the dynamic, short-term effects of the weather have a surprisingly small impact on the simulation outcome.

The Performance of Daylight through Various Type of Fenestration in Residential Building

A good daylighting strategy is necessary in order to decrease energy consumption for artificial lighting. To provide effective internal illumination, the placing of the right openings in the right positions with suitable type of window and glazing is important. This study focused on the various types and materials of the glass and window, in order to identify the quantity and quality of daylight that penetrate into the residential buildings. Based on a series of measurement, it was identified that type of glazing and window gives major significant on the performance of daylight and thermal performance in residential buildings.