scholarly journals Design and Development of a Fiber-Optic Hybrid Day-Lighting System

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Sean Lawless ◽  
Ravi Gorthala
Keyword(s):  
Solar Collector ◽  
Fiber Optic ◽  
Tracking System ◽  
Prototype System ◽  
Total System ◽  
Light Weight ◽  
Lighting System ◽  
Tracking Accuracy ◽  
Acceptance Angle ◽  
Fresnel Lenses

The primary objective of this study was to develop a fiber-optic hybrid day-lighting system for mobile application such as military shelters in order to cut energy use and the use of fossil fuels. The scope included the design, development, and testing of a hybrid lighting system that is capable of producing about 16,000 lm output with design challenges including light-weight, compactness, and optics that can tolerate a high tracking misalignment. The designed system is comprised of two subsystems: the solar collector and the solar hybrid lighting fixture (SHLF). The solar collector, consists of a housing, a structural stand (tripod), a dual axis tracking system, Fresnel lenses, secondary optics, and fiber-optic cables. The collector is a telescoping aluminum box that holds eight 10-in diameter Fresnel lenses, which focus sunlight onto eight secondary optics and deliver uniform light to the fiber-optic cables. The secondary optics have filters to block UV/IR. The optics has been designed to have a high half-acceptance angle of 1.75 deg and can accommodate a tracking accuracy of 1.50 deg or better. This novel SHLF consists of two components: a solar fiber-optic system and a light emitting diode (LED) system. The fiber-optic cable is coupled to an acrylic light diffusing rod that delivers the sunlight into the room. During sunny periods, the solar fiber-optic lighting could provide full illumination level. In order to keep the same level of lighting during cloudy periods, the LED portion of the light fixture can supplement the output of the SHLF. A compact, light-weight prototype system was built and tested. The results showed that the system's output per lens for the 20 ft cable was about 1750±50 lm at a global solar illuminance of 115,000 lx. The total system was capable of delivering 14,000 lm of sunlight.

Development of a Fiber-Optic Hybrid Day-Lighting System for Mobile Shelter Applications

2017 ◽  
Author(s):  
Sean Lawless ◽  
Ravi Gorthala
Keyword(s):  
Solar Collector ◽  
Fiber Optic ◽  
Tracking System ◽  
Light Output ◽  
Fresnel Lens ◽  
Wind Loading ◽  
Lighting System ◽  
Tracking Accuracy ◽  
Fiber Optic Cable ◽  
Fresnel Lenses

This paper discusses a Fiber-Optic Hybrid Day-Lighting system that can cut energy consumed by buildings for lighting significantly. This system is designed for mobile applications such as military shelters. The system is comprised of two primary components: the solar collector and the Solar Hybrid Lighting Fixture. The first component, the solar collector, consists of a housing, structural stand, a dual axis tracking system, Fresnel Lenses, secondary optics, and fiber-optic cables. The collector is integrated into a dual-axis tracker, which is then mounted on a tripod. The tripod can be staked into the ground and weighed down to protect the system from any wind loading and the collector height can be adjusted so that there is no shading of the collector by nearby structures. The collector with an aluminum housing holds eight 10-inch diameter Fresnel Lenses that focus sunlight onto eight secondary optics based on TIR (total internal reflection) which filter UV/IR and deliver uniform light to the fiber-optic cables. The secondary optic is coupled to the fiber-optic cable with index matching gel so that Fresnel reflection losses are minimized. The solar collector tracks the sun’s movement through the day with a dual-axis tracker (azimuth/tilt), ensuring the light is concentrated into the fiber-optic cables. The optics has been designed to have a high half-acceptance of 1.75° and can accommodate a tracking accuracy of 1.50° or better. The opposite end of the fiber-optic cable attaches to the second part of the Day-Lighting system, the Solar Hybrid Light Fixture (SHLF). The SHLF comprises of two lighting systems: 1) a solar fiber-optic system and 2) an LED system. The fiber-optic cable is coupled to an acrylic light diffusing rod that evenly delivers the light into the room. During sunny periods, depending on the length of the cable, solar fiber-optic lighting could provide full illumination of the space. In order to keep lighting uniform even during fluctuations of the light output from the sun during cloudy periods, the LED portion of the light will allow for constant lighting at a lower power consumption. The LED lighting has dimming capabilities due to a photosensor that regulates the light output of the LEDs based on how much solar light is delivered by the fiber-optic cables. On a typical sunny day with an overall concentration factor of ∼400 from the Fresnel Lens system to the optical fiber, it is possible to generate an output of 2,000 lumens with a 20-foot cable, with each fiber-optic cable experiencing a 1% loss of light per foot of cable. The LED portion of the hybrid light fixture produces about 1,800 lumens as well.

Spectral Transmission of a Solar Collector and Fiber Optic Distribution Hybrid Lighting System

2007 ◽  
Author(s):  
L. C. Maxey ◽  
J. E. Parks ◽  
D. L. Beshears ◽  
D. D. Earl ◽  
M. V. Lapsa ◽  
...  
Keyword(s):  
Solar Energy ◽  
Hybrid System ◽  
Solar Collector ◽  
Fiber Optic ◽  
Renewable Energy Sources ◽  
Solar Spectrum ◽  
Solar Light ◽  
Spectral Transmission ◽  
Lighting System ◽  
Nir Light

Increased use of solar energy will reduce requirements for non-renewable energy sources such as fossil fuels and reduce associated greenhouse gas emissions. The benefits of replacing fossil-based energy with solar energy are often dependent on the application and operational or duty cycle for power demand. One particularly efficient use of solar energy is hybrid lighting. In hybrid lighting, solar light is concentrated into optical fibers and then coupled with supplemental electrical lighting to maintain a constant level of illumination. The system is able to offer reliable lighting with less energy consumption from the electrical grid (which is often driven by non-renewable sources). This technique offers energy efficiency benefits since the solar light is used directly and suffers no conversion losses. Furthermore, the solar spectrum provides an illumination that lighting engineers value for it’s quality; office inhabitants appreciate for its comfort; and retailers believe leads to increased sales. When available solar light is low, the hybrid system allows traditional light sources to reliably meet lighting demands. The success of the solar hybrid lighting system is dependent on the collection and transmission efficiency of the system. In this study, the spectral transmission of a hybrid lighting system is characterized. The system is composed of a 200-sun concentration reflective solar collector and a plastic fiber optic distribution network. The ultraviolet (UV), visible, and near-infrared (NIR) spectral transmission was characterized over a spectral range of 200 nm to 2400 nm. The UV and NIR performance of the system is critical since optical fiber damage can be caused by both UV and NIR light; thus, optimal system design maximizes the collection and transmission of visible light while minimizing the transmission of the UV and NIR light. Spectral transmission data for all components in the hybrid system are presented, and performance properties relative to solar applications are discussed.

Shadowtrack: A Novel Tracking System Based on Spreadspectrum Spatio-Temporal Illumination

2000 ◽  
Vol 9 (6) ◽  
pp. 581-592 ◽  
Author(s):  
Karri T. Palovuori ◽  
Jukka J. Vanhala ◽  
Markku A. Kivikoski
Keyword(s):  
Light Beam ◽  
Spread Spectrum ◽  
Lower Cost ◽  
Tracking System ◽  
Prototype System ◽  
Tracking Accuracy ◽  
Optical Noise ◽  
Absolute Position ◽  
Detection Point ◽  
Spatio Temporal

This paper presents a novel tracking system combining the advantages of light-beam scanning and spread-spectrum techniques. Tracking is performed by scanning the tracking volume with several unique light patterns and detecting the variations in illumination at the tracked points. Due to the low correlation of the patterns, their phases can be individually detected and the absolute position of the detection point calculated. The light patterns can be produced with simple lamps using rotating shadow masks, yielding greater power and range while being safer and of lower cost than comparable lasers. The use of spread-spectrum sequences in the patterns makes the detection insensitive towards external or cross-coupled optical noise. A simple prototype system is demonstrated to be capable of an angular tracking accuracy of 2 mrad with a range of several meters. The limitations of the method together with some unconventional applications and modifications of the system are discussed.

scholarly journals Development of a Safety Management System Tracking the Weight of Heavy Objects Carried by Construction Workers Using FSR Sensors

2021 ◽  
Vol 11 (4) ◽  
pp. 1378
Author(s):  
Seung Hyun Lee ◽  
Jaeho Son
Keyword(s):  
Random Forest ◽  
Decision Tree ◽  
Safety Management ◽  
Tracking System ◽  
Construction Workers ◽  
Gradient Boosting ◽  
Prototype System ◽  
Construction Site ◽  
Average Accuracy ◽  
Smart Safety

It has been pointed out that the act of carrying a heavy object that exceeds a certain weight by a worker at a construction site is a major factor that puts physical burden on the worker’s musculoskeletal system. However, due to the nature of the construction site, where there are a large number of workers simultaneously working in an irregular space, it is difficult to figure out the weight of the object carried by the worker in real time or keep track of the worker who carries the excess weight. This paper proposes a prototype system to track the weight of heavy objects carried by construction workers by developing smart safety shoes with FSR (Force Sensitive Resistor) sensors. The system consists of smart safety shoes with sensors attached, a mobile device for collecting initial sensing data, and a web-based server computer for storing, preprocessing and analyzing such data. The effectiveness and accuracy of the weight tracking system was verified through the experiments where a weight was lifted by each experimenter from +0 kg to +20 kg in 5 kg increments. The results of the experiment were analyzed by a newly developed machine learning based model, which adopts effective classification algorithms such as decision tree, random forest, gradient boosting algorithm (GBM), and light GBM. The average accuracy classifying the weight by each classification algorithm showed similar, but high accuracy in the following order: random forest (90.9%), light GBM (90.5%), decision tree (90.3%), and GBM (89%). Overall, the proposed weight tracking system has a significant 90.2% average accuracy in classifying how much weight each experimenter carries.

scholarly journals High Precision Optical Tracking System Based on near Infrared Trinocular Stereo Vision

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2528
Author(s):  
Songlin Bi ◽  
Yonggang Gu ◽  
Jiaqi Zou ◽  
Lianpo Wang ◽  
Chao Zhai ◽  
...  
Keyword(s):  
High Precision ◽  
Stereo Vision ◽  
Near Infrared ◽  
Nearest Neighbor ◽  
Tracking System ◽  
Optical Tracking ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Dynamic Tracking ◽  
Trinocular Stereo

A high precision optical tracking system (OTS) based on near infrared (NIR) trinocular stereo vision (TSV) is presented in this paper. Compared with the traditional OTS on the basis of binocular stereo vision (BSV), hardware and software are improved. In the hardware aspect, a NIR TSV platform is built, and a new active tool is designed. Imaging markers of the tool are uniform and complete with large measurement angle (>60°). In the software aspect, the deployment of extra camera brings high computational complexity. To reduce the computational burden, a fast nearest neighbor feature point extraction algorithm (FNNF) is proposed. The proposed method increases the speed of feature points extraction by hundreds of times over the traditional pixel-by-pixel searching method. The modified NIR multi-camera calibration method and 3D reconstruction algorithm further improve the tracking accuracy. Experimental results show that the calibration accuracy of the NIR camera can reach 0.02%, positioning accuracy of markers can reach 0.0240 mm, and dynamic tracking accuracy can reach 0.0938 mm. OTS can be adopted in high-precision dynamic tracking.

Design, Development and Performance Test of Two-Axis Solar Tracker System

2014 ◽  
Vol 704 ◽  
pp. 350-354
Author(s):  
Muhammad Ikram Mohd Rashid ◽  
Nik Fadhil bin Nik Mohammed ◽  
Suliana binti Ab Ghani ◽  
Noor Asiah Mohamad
Keyword(s):  
Tilt Angle ◽  
Solar Collector ◽  
Performance Test ◽  
Tracking System ◽  
Electrical Power ◽  
Solar Thermal ◽  
The Sun ◽  
Solar Pv ◽  
Design Development ◽  
Solar Tracking

The energy extracted from photovoltaic (PV) or solar thermal depends on solar insolation. For the extraction of maximum energy from the sun, the plane of the solar collector should always be normal to the incident radiation. Sun trackers move the solar collector to follow the sun trajectories and keep the orientation of the solar collector at an optimal tilt angle. Energy efficiency of solar PV or solar thermal can be substantially improved using solar tracking system. In this paper, an automatic solar tracking system has been designed and developed using DC motor on a mechanical structure with gear arrangement. The movements of two-axis solar trackers for the elevation and azimuth angles are programmed according to the mathematical calculation by using the Borland C++ Builder. Performance of the proposed system over the important parameter like solar radiation received on the collector, maximum hourly electrical power has been evaluated and compared with those for fixed tilt angle solar collector.

Effect of Corrugated Cover Directional Transmittance on the Thermal Performance of a Solar Collector

1981 ◽  
Vol 103 (2) ◽  
pp. 144-152
Author(s):  
T. F. Smith ◽  
S. Chaidar
Keyword(s):  
Solar Energy ◽  
Periodic Function ◽  
Thermal Performance ◽  
Solar Collector ◽  
Radiative Heat ◽  
Structural Strength ◽  
Heat Losses ◽  
Light Weight ◽  
Fiberglass Composite ◽  
Reduced Costs

The benefits of light weight, structural strength, and reduced costs without significant reduction of transmission of solar energy of a corrugated fiberglass composite cover promise wide utilization of this cover in solar collectors to suppress convective and radiative heat losses from the absorber panel. In order to evaluate the thermal performance of a collector with a corrugated cover, the directional transmittance of the cover must be available. A study was undertaken to develop a model for the directional transmittance of a corrugated cover as represented by a sinusoidal periodic function. As an application of this model, hourly and daily thermal efficiencies of a solar collector with a corrugated cover are presented.

scholarly journals Unsupervised Learning in RSS-Based DFLT Using an EM Algorithm

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5549
Author(s):  
Ossi Kaltiokallio ◽  
Roland Hostettler ◽  
Hüseyin Yiğitler ◽  
Mikko Valkama
Keyword(s):  
Em Algorithm ◽  
Expectation Maximization ◽  
Tracking System ◽  
Model Parameters ◽  
Calibration Data ◽  
Tracking Accuracy ◽  
Time Period ◽  
The Em Algorithm ◽  
Device Free ◽  
Localization And Tracking

Received signal strength (RSS) changes of static wireless nodes can be used for device-free localization and tracking (DFLT). Most RSS-based DFLT systems require access to calibration data, either RSS measurements from a time period when the area was not occupied by people, or measurements while a person stands in known locations. Such calibration periods can be very expensive in terms of time and effort, making system deployment and maintenance challenging. This paper develops an Expectation-Maximization (EM) algorithm based on Gaussian smoothing for estimating the unknown RSS model parameters, liberating the system from supervised training and calibration periods. To fully use the EM algorithm’s potential, a novel localization-and-tracking system is presented to estimate a target’s arbitrary trajectory. To demonstrate the effectiveness of the proposed approach, it is shown that: (i) the system requires no calibration period; (ii) the EM algorithm improves the accuracy of existing DFLT methods; (iii) it is computationally very efficient; and (iv) the system outperforms a state-of-the-art adaptive DFLT system in terms of tracking accuracy.

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