Solar Lighting System Research Articles

Design of a Hybrid Fiber Optic Daylighting and PV Solar Lighting System

Residential buildings with limited natural lighting are generally lit by fuel-based electricity which contributes to increase of CO2 concentration in the atmosphere. This paper presents the design of a hybrid fiber-optic daylighting and PV solar lighting system for household applications. The system is composed of a light collecting subsystem, a light guiding subsystem, an optical fiber light diffuser subsystem and corresponding control system. Preliminary system performance shows that, the developed system could provide comfortable and natural indoor illumination. Meanwhile, the hybrid lighting system can provide an average of 9h of electric lighting under clear sky conditions, and reduce 158.2kg of carbon dioxide emission in a year within the tested dark room of 5m2.

Degradation of chloramphenicol using a combination system of simulated solar light, Fe2+ and persulfate

Solar irradiation (λ ≥ 290 nm) has been introduced into a traditional Fe2+ activated persulfate (PS) system (Fe2+/PS). The combination system of solar light, Fe2+ and PS system (solar/Fe2+/PS) exhibited a rapid and continuous oxidation of chloramphenicol (CAP) in solution, and showed great advantages over the Fe2+/PS process by accelerated degradation efficiency. A presumed reason is that Fe2+ was slowly and continuously recycled by solar light, and the reductive photolysis Fe3+ to Fe2+ was promoted concomitantly with the production of additional hydroxyl radical (HO). The optimal dosages of PS and Fe2+ were determined by batch experiments. pH significantly influenced CAP degradation, and an acidic condition favored the reaction. Both HO and sulfate radical (SO4−) were considered to be the mainly oxidant to remove CAP, and HO had a higher contribution than SO4−. The presence of HCO3−, NO3−, NO2−, H2PO4−, HPO42− demonstrated adverse effects on CAP decay in solar/Fe2+/PS process. Coexisting Cl− ions slightly accelerated the CAP degradation rate at an appropriate concentration (0.6–6 mM) but gradually inhibited at a higher Cl− (12–36 mM) content. The results clearly showed that CAP presented the slowest degradation rate in wastewater, and the colloids should be taken into consideration prior to the application of solar/Fe2+/PS for wastewater treatment. Nonetheless, up to 89.7%, 94.7%, and 65.4% of CAP were removed from the filtrate, permeate, and retentate within 100 min, respectively. It is expected that the modified process could be applied for CAP removal from wastewater containing a considerable colloids/organic content. Finally, 8 major intermediate products were identified and the preliminary degradation pathways were proposed.

Evaluation of a large dish-type concentrator solar lighting system for underground car park

To utilize solar energy more efficiently and reduce lighting power consumption in underground public spaces such as car park, a large dish-type concentrator solar lighting system is put forward along with its evaluation, which is a unique design to apply a laminated layer of beam split thin-film coating and thin-film solar cells onto the dish reflector. The collected sunlight is split into 2 parts, one being reflected into a fiber optical bundle and transmitted for daylighting, while the rest being absorbed by solar cells for electricity generation as the other way to replenish daylighting. A set of 4 solar lighting systems using 3.28-m diameter dish are designed to meet the lighting requirement in a 1771-m2 underground car park. A mathematical model is adopted to calculate the output power and conversion efficiency of solar cells distributed on the parabolic dish surface. The indoor illuminance distribution is given by lighting simulation. The results indicate that the average daylight illuminance in the car park can vary between 62.7 and 284 lx on February 25, 2016 and between 62.7 and 353 lx on August 17, 2016 for 2 chosen days, respectively. For the presented design, the electricity produced by solar cells is just enough to power light-emitting diodes for lighting meeting a criterion at night. Considering about 19% conversion efficiency of solar cells and the efficacy of 129.5 lm/W of light-emitting diodes, the hybrid solar lighting system can have about 40% utilization ratio of solar energy, so it can be concluded that a sufficient lighting provision can be provided by the proposed large dish-type concentrator solar lighting system for applications in underground car park.

Design of an automatic solar lighting system

Today, the worldwide research trends are heading towards producing environmental friendly outcomes. Thus, today the electricity is mostly generated from renewable sources such as sunlight, wind, tides and other to reduce dependency on non-renewable sources like hydroelectrics, fossil fuels and others. This paper presents an innovation of the automatic lighting system with the solar as a source of the system. Charger controller circuit is necessary to cut off the current of the rechargeable battery when reaching its maximum voltage. Dark-on relay circuit functions as an automatic switch to the light so that the light will be automatically turned on when there is no light or at night. Otherwise, the light will be turned off. The system can be applied to the room light, outdoor light, corridor light, spotlight or streetlight. The system is low cost and beneficial for home usage to save electricity bills and when the occupants are absent for relatively long period of time.

Performance analysis of valve regulated lead-acid battery in solar street light system under field conditions in India

Batteries form an integral part of solar street lighting systems. Failure of battery in solar street lighting applications can render the complete system useless. At National Institute of Solar Energy (NISE), MNRE, Govt. of India, the whole campus is covered with solar street lights for illumination. It was observed that the batteries installed in these systems last for just 1–2 years. The aim of the study was to analyse degradation in capacity of lead-acid VRLA batteries after two years of operation under actual field conditions. The test results indicate the causes due to which the field batteries degrade much faster than the reference batteries installed and operated in lab environment.

Sun light transmission through silica optical fibers for lighting: an experimental study

The process of sunlight transmission through optical fibers has received considerable interest from the scientific community in recent times. The interdisciplinary emerging field has found many applications in the field of solar lighting, solar furnace, three dimensional solar cells etc. Most of the optical fiber based solar lighting systems have employed plastic fibers as the light transmission media and the use of silica fibers in such systems has not been given much attention. Further, the actual measured data/values of the light emanating from the output ends of fibers in such systems are rarely reported. In the present study, merits and demerits of employing silica and plastic fibers in transmitting sun light are discussed. A silica optical fiber based solar lighting system has been developed and after installing it on an indigenously fabricated sun tracker, its performance has been measured and reported. Based on experimental and simulated results, multimode silica fibers could turn out to be better light transmission media than the plastic fibers, particularly for the case when light has to be transported over longer distances. The findings reported herein stress the need for tailor made customized solar lighting design for different buildings.

Practical investigation for road lighting using renewable energy sources "Sizing and modelling of solar/wind hybrid system for road lighting application"

This study explains a design of a fully independent -off grid- hybrid solar and wind road lighting system according to geography and weather conditions recorded from the Egyptian National Research Institute of Astronomy and Geophysics. Presenting here the virtual simulation by using Matlab/Simulink & real-time implementation of road lighting system consists of 150 W photovoltaic cell, 420 W wind generator, 100 Ah acid gel battery and LED lighting luminar 30 W -12 VDC . Over three different stages; 1.Operating the system with PV only as power source, 2. Switching to Wind generator only configuration and 3. Running the hybrid design with both PV & Wind power sources ; load characteristics and output real-time data will be recorded, evaluated ,compared and validated against the virtual simulation generated by Matlab/Simulink model. The results of this research will be used to investigate the advantages of using a hybrid system to counteract the limitations of solar and wind as solo renewable energy sources due to adverse weather conditions ,the efficiency of the proposed system as an alternative for the current conventional road lighting poles as well as the accuracy of the virtual model data in order to be used for future adaptation of the model for different geographical locations.

Cost-Effective Light-Mixing Module for Solar-Lighting System Appended With Auxiliary RGBW Light-Emitting Diodes

A light-mixing module consisting of a compound parabolic concentrator (CPC) and a light-mixing tube is proposed herein to realize a uniform and efficient solar-lighting system. In this lighting system, the sunlight collected into a fiber and then guided to an indoor destination is the principal light source, while an auxiliary light source including multiple red, green, blue, and white (RGBW) light-emitting diodes (LEDs) is controlled by an auto-compensating module. To mix the principal and the auxiliary sources and to realize the uniform illumination, the light-mixing tube was coated with BaSO4 and optimized as a cylindrical tube. The design of the light-mixing tube is described and discussed in this article. According to the simulated results, the uniformity and the optical efficiency of the designed light-mixing tube are 82.9% and 85.7%, respectively, while from the experimental results, the uniformity of 85.9% and the optical efficiency of 83.3% have been obtained. In terms of the common indoor-lighting standards and the specifications of commercial components used in lighting systems, the proposed light-mixing module has demonstrated the high uniformity and acceptable optical efficiency. Additionally, since the main components of the light-mixing module can be designed as plastic optics, a cost-effective light-mixing module and a profitable lighting system can be realized. Thus, the performance and the price of the proposed light-mixing module fit the demands of the illumination market, while the proposed system shows the potential for indoor solar-lighting applications.

Design and development of a faceted secondary concentrator for a fiber-optic hybrid solar lighting system

Fiber-optic solar hybrid lighting for mobile application such as military shelters in remote areas is appealing since high initial costs of such systems appear to be justified. This paper addresses the aspect of two-stage optics for a fiber-optic solar lighting system for the mobile application. More specifically, the focus of this paper is on the design and development of a second stage or secondary concentrator. Two-stage optics offers a distinct advantage of higher sun angle tolerance and hence a low-accuracy tracker can be used for the mobile application. The objective of this study was to design and develop a secondary concentrator that yielded a minimized peak illuminance on the fiber-optic inlet and achieved uniformity, to avoid localized heat damage to the fiber inlet. In addition, the overall goal was to increase the lumen output from the two-stage optics. Specifications for the design of the two-stage concentrator were: (1) the primary stage concentrator was a 10-in. diameter Fresnel lens; (2) solar tolerance angle or the half-angle of acceptance was ±1.75°; (3) the fiber half-acceptance angle was ±40°; and (4) the fiber optic cable diameter was 0.5-in. Raytracing was used to determine the optimum geometry for the secondary lens. Among various geometries simulated included a conical secondary, a Compound Parabolic Concentrator (CPC), and a combination of conical and Compound Elliptical Concentrator (CEC). The analysis showed that a combination design comprising conical/CEC geometry was better than the conical and CPC geometries in terms of greatest overall light output and most reduced peak illuminance on the fiber optic cable. Prototype secondary lenses based on the design were fabricated from acrylic and optical silicones. Testing of the prototype lenses revealed that acrylic secondary performed better than the silicone lenses in terms of the measured lumen output. Testing also showed that the fiber-optic cable temperature was within the maximum operating temperature of acrylic and didn’t suffer any high temperature damage during the five month long outdoor testing.

Costs and impacts of potential energy strategies for rural households in developing communities

There are a variety of technologies that can help alleviate the energy poverty facing nearly 40% of the world's population today. Yet the most effective among a variety of options is often not clear due to the range of outcomes desired by various stakeholders, constraints imposed by the local conditions and needs, and factors dictating the application and use of these devices. To better understand and anticipate the differences between potential strategies, this article uses a multi-objective probabilistic system model previously developed by the authors to compare the baseline situation in a well-characterized village in Mali to six common single technologies including improved, advanced, communal, and LPG cookstoves; and solar water heating and lighting systems. An integrated strategy was also investigated. Outcomes in terms of energy access and use, health and climate impacts, economic costs and benefits, and quality of life were compared. Results showed that no single technology could optimally address all objectives simultaneously, and that objectives were often conflicting. An integrated approach that seeks to build upon the natural user tendencies to “stack” the fuels and devices that are most convenient and affordable for each task was found to produce the most significant impacts in all areas.

Electric Lighting Energy Saving Through the Use of A Fresnel Lens Based Fiber-optic Solar Lighting System: Simulation and Measurements

This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600 lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

Solar Home Lighting System with AC and DC Loads

Solar Home Lighting System with AC and DC Loads

광화이버 및 Fresnel lens 적용 집광식 자연채광 시스템의 이용을 통한 조명에너지의 절감 : 시뮬레이션 및 실측 비교

본 연구에서는 2축의 태양추적장치에 프레넬 렌즈를 장착한 fiber-optic 설비형 자연채광시스템의 효율성에 대하여 이론적 분석을 수행하였다. ECOTECT와 RADIANCE를 기반으로 시뮬레이션 모델을 개발하여 다양한 조건하에서 자연채광 시스템뿐만 아니라 형광등을 이용한 인공조명에 대한 실내 조도분석과 함께 실측 데이터와의 비교연구를 수행하였다. 형광등을 이용한 실내조명의 경우, 평균조도는 사무실 실내 조도 기준을(KS A 3011 일반 사무실 [G]등급[300-400-600lux]) 충분히 만족하는 결과를 보여주었다. 한편, 디퓨져를 사용한 자연채광시스템의 경우도 사무실 실내 조도 기준을 넘는 것으로 나타났다. This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

Performance and impact evaluation of solar home lighting systems on the rural livelihood in Assam, India

This study was carried out in four districts of Assam to assess the technical functionality of the solar home lighting systems (SHLS), service delivery model, institutional mechanism, maintenance and monitoring, user's awareness and its impacts on rural livelihood. The study found that only 28.9% of the systems are functional, 62.3% are found working with minor faults and 8.8% are either non-functional or having major faults. The average working durations per day for winter, summer and monsoon seasons are 2.2h, 3.5h and 2.3h respectively. The study observes noticeable benefits due to adoption of SHLS such as reduction in kerosene consumption, increase in children's study hours, extended working hours of small businesses and income generation through mobile phone charging. One of the key reasons for unsatisfactory technical performance of SHLS is because of poor service delivery model and inefficiency in existing institutional structure such as passive village energy committee and non-availability of service centres or local technicians for post-installation maintenance. The study observes that user perceptions on the system are positive. However, cost considerations seem to be the main obstacle for system adoption. This study concludes that availability of local technicians, effective village energy committees, demand driven system design and appropriate social awareness towards livelihood improvement options will improve the sustainability and economic viability of the SHLS.

Performance Analysis of Valve Regulated Lead-Acid Battery in Solar Street Light System under Field Conditions in India

Batteries form an integral part of solar street lighting systems. Failure of battery in solar street lighting applications can render the complete system useless. At National Institute of Solar Energy (NISE), MNRE, Govt. of India, the whole campus is covered with solar street lights for illumination. It was observed that the batteries installed in these systems last for just 1-2 years. The aim of the study was to analyse degradation in capacity of lead-acid VRLA batteries after two years of operation under actual field conditions. The test results indicate the causes due to which the field batteries degrade much faster than the reference batteries installed and operated in lab environment.

SELCO India: Solar Energy for the Underserved

Solar Electric Lighting Company (SELCO) was established in 1995 to serve the energy needs of people living at the base of the pyramid in Karnataka, India. The CEO, Dr Satish Hande, focused on developing need-based customized solar energy products for off-grid customers. During the initial years, the company faced financial problems to meet its operational needs, which was eventually overcome. Solar Electric Lighting Company came up with several innovative products that increased productivity of customers. Though the products sold were priced low, care was taken to ensure that product quality was not compromised. The company subsequently faced several challenges. The appointment of dealers in lieu of its own branches did not deliver desired results. Increase in input costs landed SELCO in losses. Pressure from investors for profits when the company was facing financial crisis was the toughest of them all. Having overcome the obstacles, SELCO became profitable, expanded operations in six states of India and installed 200,000 solar lighting systems in a period of two decades. Several growth options presented themselves to Dr Hande. The most prominent being the need to make a choice of staying focused on customized products for the poor or cater to the upmarket, high-growth and profitable segment.

Development of ANN Based Model for Solar Potential Assessment Using Various Meteorological Parameters

Abstract Solar potential assessment is very useful for various applications like solar heating, agriculture, solar lighting system and solar power plant erection etc. The objective of the current study is to identify theoretical potential of solar radiation for solar energy applications in hilly state Himachal Pradesh. Artificial Neural Network (ANN) is used to predict solar radiation using site specific measured data of Hamirpur for training and testing. The input variables used are temperature, rainfall, sunshine hours, humidity &barometric pressure to predict solar radiations. To identify the effect of various input parameters on solar radiations three ANN based models have been developed represented by ANN-I5, ANN-I4& ANN-I3.To obtain best prediction result, the number of input parameters of the input layer have been varied between 3 to 5 and hidden layer neuron have also been varied between 10 to 20. The best mean absolute percentage error (MAPE) calculated for these models (ANN-I5, ANN-I4 & ANN-I3) are 16.45%, 18.77% and 19.39% respectively. The ANN-I5 (temperature, humidity, barometric pressure, rainfall and sun shine hours), model has shown good prediction accuracy as compared to other two models. This study shows that various numbers of meteorological parameters mostly affect the forecasting of solar radiation. The method in this paper can also be used to identify the solar energy potential of any location worldwide where it is not possible to install direct measuring instrument.

The Non-Isolated Type Flyback-Boost Combination Converter for Solar Light LED

This paper, proposes a non-insulated type flyback-boost combination converter that has the step-up and down function as a converter for an independent solar light LED pole light system. The proposed combination converter is composed with the use of one switch, and the step-up function works with discontinuous current mode. The proposed electric power circuit allows for improving the efficiency of converting energy by removing the RCD(Residual-current device) snubber of the existing flyback converter, connecting the terminal to output and transferring the stored energy in the leakage inductor of transformer to output. Simulations and experiments were conducted to validate the proposed circuit and the results were discussed.

Remote monitoring of solar PV system for rural areas using GSM, V-F & F-V converters

The Small capacity photovoltaic (PV) systems like solar lantern and home lighting systems installed in remote rural area often fail without any prior warning due to lack of monitoring and maintenance. This paper describes implementation of remote monitoring for small capacity solar PV system that uses GSM voice channel for communication. Through GSM analog signal of sine wave with frequency range 300–3500 Hz and amplitude range 2.5–4 V is transmitted. Receiver is designed to work in the same frequency range. The voltage from solar PV system in range of 2 to 7.5 V can be converted to frequency directly at the transmitting end. The frequency range from 300–6000 Hz can be sensed and directly converted to voltage signal at receiving end. Testing of transmission and reception of analog signal through GSM voice channel is done for voltage to frequency (V-F) and frequency to voltage (F-V) conversions.

An optimal design analysis of a novel parabolic trough lighting and thermal system

In order to reduce the cost and improve the efficiency of daylighting, an innovative parabolic trough solar lighting and thermal (PTL/T) system is designed and analyzed in this paper. Parabolic trough solar lighting and thermal system uses parabolic trough collector (PTC) controlled by two-axis solar tracking system as solar collector. The collected sunlight is split by a cold mirror into visible light and infrared. The visible light is reflected by cold mirror, re-concentrated by a second-stage Fresnel lens, and then delivered by plastic optical fiber to the buildings for daylighting. The infrared goes through cold mirror, reaches thermal system, and is used for heating generation. The basic structure of PTL/T was outlined and described. The dimension of fiber bundle and parabolic trough was chosen after an optimal analysis. The cost of illuminating unit area was expressed as a function of illumination space dimensions and critical components efficiency. A case study was conducted to get a specific optimized illumination area and PTC area for the first time. The optimized result is to use 8-m2 PTC as collector to illuminate 500-m2 office space. The total solar energy utilization efficiency is 39.4%, with the lighting efficiency of 16.3% and thermal efficiency of 23.1%. The maximum energy savings and simple payback period were calculated for 10 typical cities when applied in residential, commercial, and industrial sectors. The amounts of greenhouse gas-emission reductions were also calculated. The payback period in Sunbelt region is as low as less than 10 years like in Los Angeles. The results show the proposed PTL/T system is competitive compared with traditional solar energy systems. Copyright © 2016 John Wiley & Sons, Ltd.