A Thermal Model of a Fiber Optic Bundle for a Hybrid Solar Lighting System

2005 ◽  
Author(s):  
Michael J. Cheadle ◽  
Gregory F. Nellis ◽  
Sanford A. Klein ◽  
William A. Beckman
Keyword(s):  
Energy Consumption ◽  
Thermal Model ◽  
Fiber Optic ◽  
Management Strategies ◽  
Design Tool ◽  
Lighting Energy ◽  
Solar Lighting ◽  
Reduce Energy Consumption ◽  
Lighting Systems ◽  
Cooling Loads

Hybrid solar lighting (HSL) systems distribute natural sunlight to luminaires located in office or retail buildings in order to reduce energy consumption associated with conventional lighting systems. HSL systems reduce energy consumption directly by reducing the lighting energy and indirectly by reducing the associated cooling loads. A key component of the HSL system is the fiber optic bundle (FOB) that transmits the light from the collector to the luminaire. The observed thermal failure of the FOB when exposed to concentrated sunlight has motivated the development of a thermal model of this component. This paper describes the development of a predictive thermal model of the heat transfer in an FOB for an HSL system. The model is verified experimentally against temperature measurements obtained in the lab under controlled conditions and provides a powerful design tool that can be used to evaluate alternative thermal management strategies.

scholarly journals Preliminary Study on the Performance Evaluation of a Light Shelf Based on Reflector Curvature

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4295 ◽  
Author(s):  
Heangwoo Lee ◽  
Janghoo Seo ◽  
Chang-ho Choi
Keyword(s):  
Performance Evaluation ◽  
Energy Consumption ◽  
Natural Lighting ◽  
The Future ◽  
Lighting Energy ◽  
Effective System ◽  
Fixed Type ◽  
Preliminary Study ◽  
Reduce Energy Consumption ◽  
Lighting Systems

The consumption of lighting energy in buildings continues to rise, and many studies are being conducted to address this problem. As part of such initiatives, research is being performed on light shelves, which are natural lighting systems. However, most prior studies focused on variables for operating flat reflectors and light shelves. This study aims to evaluate the performance of curved light shelves to prove their effectiveness and derive optimal specifications for them. The following conclusions were reached. The optimal light shelf angles for a flat light shelf were found to be 30°, 20°, and 20° for the summer, mid-season, and winter, respectively, and accordingly, a movable light shelf system would be suitable for all three seasons. The optimal light shelf angles for a movable curved light shelf with an arc angle of 60° were found to be 30°, 30°, and 10° for the summer, mid-season, and winter, respectively. The optimal light shelf angle and arc angle for a fixed-type curved light shelf were found to be 20° and 60°, respectively. A fixed-type curved light shelf designed according to these optimal specifications can reduce energy consumption by 3.6% in comparison to a movable flat light shelf. Consequently, the curved light shelf is considered an effective system, and additional studies analyzing various other factors should be carried out in the future.

scholarly journals Preliminary Results on Luminaire Designs for Hybrid Solar Lighting Systems

2001 ◽  
Author(s):  
D. D. Earl ◽  
J. D. Muhs
Keyword(s):  
Intensity Distribution ◽  
Fiber Optic ◽  
High Angle ◽  
Optical Efficiency ◽  
Spatial Intensity Distribution ◽  
Spatial Intensity ◽  
Fluorescent Lamps ◽  
Solar Lighting ◽  
Lighting Systems ◽  
Two Hybrid

Abstract We report on the design of two hybrid lighting liminaires that blend light from a fiber optic end-emitted solar source with electric T8 fluorescent lamps. Both designs involve the retrofit of a commercially-available recessed fluorescent luminaire with minimal reductions in the original luminaire’s optical efficiency. Two methods for high-angle dispersion of fiber optic end-emitted solar light are described and the resulting spatial intensity distributions, simulated using ZEMAX, are compared with standard cylindrical fluorescent tubes. Differences in spatial intensity distribution are qualitatively characterized and potential design improvements discussed.

Evaluation of impact of passive design measures with energy saving potential through estimation of shading control for visual comfort

2017 ◽  
Vol 42 (3) ◽  
pp. 220-238 ◽  
Author(s):  
Lakshya Sharma ◽  
K Kishan Lal ◽  
Dibakar Rakshit
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Climatic Conditions ◽  
Design Parameters ◽  
Visual Comfort ◽  
Passive Design ◽  
Lighting Energy ◽  
Insulation Thickness ◽  
Heating Loads ◽  
Cooling Loads

Residential and commercial buildings together account for one-third of world’s final energy consumption, thus making energy management in buildings of considerable significance. Passive design concept that depends on climate and location can be used as an effective and economical method to reduce the energy consumption in buildings. Seven cities in India, each representative of different geographic and climatic conditions, were selected for analysis. This article studies how the peak cooling and heating load are affected by varying some of the passive design parameters for each of the seven cities. The parameters varied are wall insulation thickness, roof insulation thickness, overhang depth, window orientation, and window-to-wall ratio. Results show that optimized passive design could reduce the peak cooling and heating loads by about 50%. Shading reduces cooling loads but is found to increase heating loads. In some of the locations, both heating in winter and cooling in summer are needed and designers should adopt appropriate passive measures depending on the location. Also for the same building, evaluation of shading is done in the context of lighting energy savings. An algorithm has been developed to iteratively alter and analyze set of roller blind positions to maintain visual comfort; as a result, the corresponding potential annual energy savings due to lighting were estimated. It was also observed that even after providing visual comfort to the occupants, energy savings only reduced by approximately 1% as compared to the case when visual comfort was overlooked.

scholarly journals The identification of variables influencing personal lighting conditions of office workers

2020 ◽  
pp. 147715352097695
Author(s):  
J van Duijnhoven ◽  
MPJ Aarts ◽  
ER van den Heuvel ◽  
HSM Kort
Keyword(s):  
Energy Consumption ◽  
Mixed Models ◽  
Weather Conditions ◽  
Office Workers ◽  
Lighting Control ◽  
Know How ◽  
Lighting Conditions ◽  
Daily Schedule ◽  
Reduce Energy Consumption ◽  
Lighting Systems

The main reason lighting control is being applied is to reduce energy consumption. However, there are many more reasons for lighting control to be optimised in buildings. Lighting systems can be controlled to enhance or optimise effects beyond vision. Automatic control of electric lighting systems or daylight systems is one way of adjusting someone’s personal lighting conditions. In addition, it is relevant for office workers to know how they can adjust their personal lighting conditions themselves in order to optimise their effects beyond vision (e.g. alertness). Therefore, this article describes a process of identifying predictors that influence personal lighting conditions. The dataset used in this article is gathered during a field study in the Netherlands in spring 2017. This article describes linear mixed models for daily mean illuminances and correlated colour temperatures both throughout the entire day and only at work. These models demonstrated that weather conditions, fixed and flexible personal conditions, office worker’s daily schedule and workspace characteristics influence personal lighting conditions. Weather conditions and fixed and flexible personal conditions though are difficult or impossible to control by the office workers themselves. However, adjustments in personal lighting conditions can be accomplished by the office workers themselves by changing their daily schedules and the workspace characteristics. The findings show that these two predictor categories may explain 4% to 20% of the variance in personal lighting conditions.

Ecological Sustainability of Fiber Optic Solar Lighting in the Future of the State of Qatar

2010 ◽  
Author(s):  
Mohammad AhsanShaikh ◽  
Musbah S. Mahfoud
Keyword(s):  
Energy Consumption ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Electric Energy ◽  
Electrical Energy ◽  
The State ◽  
Total Energy Consumption ◽  
Electric Energy Consumption ◽  
Solar Lighting

The use of electric lighting in our homes and our workplaces stands for a significant portion of the society’s electric energy consumption. Furthermore, generating such electricity leads to the production of greenhouse gases. At the same time as the electricity is coming through our lamps inside our houses, an overflow of light is flowing down from the sky and hits the exterior of the same houses. At almost any day of the year, the daylight is superior in both the illumination level and quality compared to the artificial light we are using for our everyday tasks. A technology capable of collecting this abundant sunlight and distributing it, via optical fibers, into the interior of a building will be of great benefit. Sunlight is an abundant and infinite source of energy that is being underutilized in Qatar. The state’s climate is sunny most of the year, with temperatures ranging from 12°C to 48°C, and thus the solar source of energy is abundant. Therefore, it is of an economical benefit for the state to harvest and utilize this energy source in every way possible. In Qatar, a large part of electricity is used for indoor lighting during daytime, accounting for 10% of the total electric energy required for buildings. In many facilities, this percentage is even higher. For example, illumination in an office space of 400 m2 accounts for approximately 40% of the total energy consumption of the space. In fact, Qatar is recognized amongst the world’s largest consumers of energy per capita. According to the United Nations Statistic Division, relative to the size of Qatar’s economy, the country on a whole uses twice the amount of energy as the nations of Germany or Japan. As a partial remedy to reduce the consumption of electrical energy, Qatar can take advantage of its sunny climate, and thus it is possible to collect and focus sunlight on optic-fiber cables that transfer the light to indoor rooms, buildings and stores. In the present work, we wanted to cast some light on fiber optic daylighting and its potential use in a very sunny and relatively hot environment, such as that in Qatar. The main goal of this project was to explore the use of a lighting system based on fiber optics as the main light source.

Investigate the Potential Peak Energy Reduction of Integrated M-Cycle Evaporative Cooling With HVAC in Hot and Dry Climate

2019 ◽  
Author(s):  
Fahad Almehmadi ◽  
Ahmad Aljabr
Keyword(s):  
Energy Consumption ◽  
Thermal Model ◽  
Control Strategies ◽  
Evaporative Cooling ◽  
Space Environment ◽  
Cooling Load ◽  
Hourly Temperature ◽  
Peak Energy ◽  
Cooling Loads ◽  
The Impact

Abstract The purpose of the study is to investigate the potential energy saving of integrated M-Cycle evaporative cooling with HVAC. The model consists of three sub-systems which are thermal model of the typical house in Saudi Arabia, HVAC, and M-Cycle evaporative cooling. A thermal model of the typical house is performed to estimate the cooling load and then an integration between these sub-systems were built in MATLAB Simulink where the dynamic behavior of the whole system is examined. The house was simulated based on the actual hourly outdoor temperature and the physical properties of the house to estimate the cooling loads. To facilitate the simulation, the average hourly temperature is used. The results of the simulation show that energy consumption during peak hours can be reduced by up to 6%. It was found that the control system has a tremendous impact on controlling house temperature and cooling load. The impact of two different control strategies is investigated and their influence on house temperature and cooling loads are determined. It was found that PID control has advantage over On/Off control, in which the temperature in the space environment is kept uniform, and energy consumption is reduced by 20%.

Naval Energy Management System

2020 ◽  
Vol 26 (3) ◽  
pp. 20-25
Author(s):  
Laurențiu Bogdan Asalomia ◽  
Gheorghe Samoilescu
Keyword(s):  
Energy Consumption ◽  
Power Systems ◽  
New Technologies ◽  
Integrated Navigation ◽  
Integrated Navigation System ◽  
Efficient Management ◽  
Reduce Energy Consumption ◽  
Energy Efficiency Design Index ◽  
Green Ship

AbstractThe paper analyses the role of control and monitoring of electro-energetic equipment in order to reduce operational costs, increase profits and reduce carbon emissions. The role of SCADA and EcoStruxure Power systems is presented and analysed taking into account the energy consumption and its savings. The paper presents practical and modern solutions to reduce energy consumption by up to 53%, mass by up to 47% and increase the life of the equipment by adjusting the electrical parameters. The Integrated Navigation System has allowed an automatic control and an efficient management. For ships, the implementation of an energy efficiency design index and new technologies was required for the GREEN SHIP project.

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