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Fiber-optic daylighting systems have been shown to be a promising and effective way to transmit sunlight in the interior space whilst reducing electric lighting energy consumption. To increase efficiency in terms of providing uniform illumination in the interior, the current need is to illuminate optical fiber-bundle with uniform light flux. To thi...
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... The collection part of the system, also called the daylight collector, can be either passive (no sun tracking) or active (with sun tracking). Tracking-based daylight collectors mostly use Fresnel lenses [18,19,[24][25][26][27][28][29] or reflectors [30] in order to concentrate the incident sunlight. ...
A carefully designed daylight collector for a tubular skylight is necessary to serve the occupants’ illumination needs under the dynamic trajectory of the sun. This work simulated an improved configuration of a passive daylight collector comprising parabolic and conical reflectors in a modeled room using the lighting software tool TracePro. Results indicated that the lighting performance of the proposed design configuration was significantly enhanced under low altitude sun in comparison with conventional tubular skylights (with revolved parabolic and cylindrical reflectors) [Light. Res. Technol. 52, 495 (2020)10.1177/1477153519872794] and hemispherical transparent dome as daylight collectors by more than ${\sim}{30}\% {-} {40}\%$ ∼ 30 % − 40 % and ${\sim}{110}\% {-} {130}\%$ ∼ 110 % − 130 % , respectively.
... Passive daylighting systems are relatively less costly compared to active systems. Though passive systems have compromised efficiency (Nair et al., 2014;Ullah and Whang, 2015) a carefully designed system serves the illumination needs of the occupants and is also well within the reach of common households economically. A tubular daylight guidance system (TDGS), one of the passive daylighting systems alternatively called tubular skylight (TS) or lightpipe, brings daylight into interior spaces where traditional skylights and windows simply cannot reach. ...
... In the United States, 16.2% of energy was consumed for lighting purposes by the commercial and residential buildings only in 2020 [5,6]. Therefore, an intention to lessen energy consumption due to artificial lighting in buildings is in the plan [7]. ...
Feeding the existing 7 billion and ever-growing population around the world urges farmers to adopt alternative ways. Research indicates that the demand for alternative farming will only increase as fertile lands become scarcer each and every year. Emerged from this need, “agritecture,” often called vertical farming, has attracted a great deal of attention recently. Vertical farming is centered around growing plants by adopting methods like hydroponic, aeroponic, or aquaponic and staking the layer vertically up to the sky or going deep in the ground. Lighting is the integral component of the vertical farming systems, which can be natural or artificial and should be provided at a specific intensity and spectrum. The world is already in need of energy to tackle the soaring energy demand due to the rising population and industrialization. Researchers have been trying to utilize alternative sources, and the heat and illumination of the sunlight is always the widespread field of interest. In vertical farming, using hybrid solar lighting can also be an appealing approach. However, the fiber optical cable is one of the critical components of this system, which is used to transmit the light to the luminaire. Since this cable plays a vital role in transmitting the power, the exposure of the surface of the cable to different rays from the directed sunlight is of primary concern to avoid any thermal failure. If not designed properly, the temperatures at the inlet of the fiber optical cable can reach to very high values, resulting in both physical and chemical changes in the cable, and in some cases, local burnings. A literature survey revealed that there are only a few studies that dealt with the thermal management of fiber optical cables. In this study, we analyze the thermal behavior of fiber optical cables for a vertical farming application, which was supported by the United States Department of Agriculture SBIR Phase I program. To do that, we adopted a Finite Element Analysis (FEA) based approach. Before carrying out the full simulations, the simulation methodology was verified by replicating an existing study in the literature. Once confirmed, a full parametric sweep analysis was conducted to see the effects of material and geometric properties of the fiber optical cable on the temperature increase at the inlet. This study is novel in the sense that there are no prior studies that targeted the effects of material and geometric properties on the thermal behavior of the fiber optical cables so the users could make the appropriate choices for the cable selection or could custom design their cables for specific lighting conditions. The results were presented and discussed, and future research directions were indicated.
... To make matters even worse, the formation of the IMC layer is accelerated by the process of aging [5,6]. To minimize the adverse effects of aging, several elements, including bismuth (Bi), nickel (Ni), antimony (Sb), cobalt (Co), and indium (In), have been micro-alloyed with the SnAgCu (SAC)-based solder alloy [7][8][9][10]. Among several materials, SAC-based solder alloys have shown positive prospects. ...
The surface finish (SF) becomes a part of the solder joint during assembly and improves
the component’s reliability. Furthermore, the SF influences the solder joint’s reliability by affecting the thickness of the intermetallic compound (IMC) layer at the solder interface and copper pads. In this experiment, five different alloys are used and compared with the SAC305 alloy, two of which, Innolot and SAC-Bi, are bi-based solder alloys. This study includes three common SFs: electroless nickel immersion gold (ENIG), immersion silver (ImAg), and organic solderability preserve (OSP). The performance of three surface finishes is examined in terms of component characteristic life. All of the boards were isothermally aged for twelve months at 125 C. The boards were then exposed
to 5000 cycles of thermal cycling at temperatures ranging from 40–+125 C. Most of the current research considers only one or two factors affecting the reliability of the electronic package. This study combines the effect of multiple factors, including solder paste content, SF, isothermal aging, and thermal cycling, to ensure that the test conditions represent real-world applications. In addition, the electronics packages are assembled using commercialized alloys. The current study focuses on
a high-performance alloy already present in the electronic market. The failure data were analyzed statistically using the Weibull distribution and design of experiments (DOE) analysis of variance (ANOVA) techniques. The findings reveal that the micro and uniformly distributed precipitates in solder microstructures are critical for high-reliability solder joints. Re-crystallization of the thermally cycled solder joints promotes the local formation of numerous new grains in stress-concentrated zones. As the fracture spreads along these grain boundaries and eventually fails, these new grains participate in crack propagation. Aging significantly worsens this situation. Finally, although the ENIG surface finish with its Ni layer outperforms other SFs, this does not imply that ENIG is more reliable in all solder paste/sphere/finish combinations.
... where, Q out /Q in -Efficiency, L-length of fibre, dBloss-Attenuation. Another geometric property to be considered while installing optical fibre inside buildings is bend radius [46]. The salient conclusions on the influence of minimum bend radius are: ⅰ) decrease in the degree of bending and increase in radius of curvature of results in lower bending loss and increased transmission efficiency [47], ⅱ) minimising bend radius can reduce local density variation, thereby the dispersion losses of fibre cable [48], ⅲ) every fibre has a critical value for bend radius to minimise light loss, which is the minimum value beyond which the bending loss starts to increase [43,49], ⅳ) the critical bending value depends on both the constituent fibre material and the thickness of cladding/coating [50] and ⅴ) the minimum bend radius of POF is reported to be smaller than its counterparts as it is made of ductile-flexible polymer material and has lower stiffness [15]. ...
... Some studies have shown that a combination of SOF and POF helps utilise the benefits of both kinds of fibre, i.e., SOF being more heat tolerant reduces the heat damage and POF being more flexible, helps in easy wiring and transportation into deep plan rooms [22,35,46,67]. Important considerations while using a combination of SOF and POF are: ⅰ) the aperture of the two fibres needs to match exactly with the other ⅱ) the joint between SOF and POF should be adequately coupled to avoid any mismatch loss in the interface [67]. ...
The lighting load can be reduced either by improving the efficiency of artificial lighting or by supplementing daylight to the building interiors with Innovative Daylighting Systems (IDS). Fibre optic daylighting system is an up-and-coming IDS that utilises direct and diffused sunlight to illuminate deep-plan buildings without location and orientation constraints. The system can benefit both building occupants and owners by attaining comfort conditions, improving productivity, saving cost and contributing to sustainable goals. This paper aims to review and summarise previous studies on fibre-optic daylighting system by categorising it into five individual subsystems: light-carrying optical fibre cable, suitable collectors, diffusers, fibre–collector interface and fibre diffuser interface. Each subsystem is reviewed and analysed based on its material property, geometrical parameters, output measurements and performance. The advantages and shortcomings of the types of optical fibre cable are explained after investigating the material characteristics and transmission efficiency parameters. Collectors used in conjunction with fibre cable are classified and analysed based on the principle, mode of study, design specification, concentration achieved and output performance. Diffusers at the fibre end used for even distribution of light have been studied to compare the sizing, spacing and output spectral characteristics. Additionally, the collector–fibre and fibre–diffuser interfaces have been reviewed. We conclude the paper by identifying the shortcomings of the system and giving some pointers towards gap in the literature that needs to be addressed to improve the system's present state and aid its widespread implementation.
... Illumination" made in Myongji University by Irfan Ullah and Seoyong Shin [15] tries a different approach and combines a 300mm diameter of very large Fresnel lens combined with small plano-concave lenses to focus the light into the 2mm bundle of plastic optical fibers again combined with silica optical fibers. Also, another important part of this research is that as shown in the Figure 3.5, to match the indexes of the plastic optical fibers and reduce heat absorption of the fiber optic cables the combination of the plano-concave lenses are used with silica optical fibers. ...
Marmara University Tubitak 2209-A Supported Graduation Project/Thesis Presentation Department of Electrical and Electronics Engineering
... It has been observed that the passive daylighting systems are easy to construct and they cost less as compared to the active system, but the efficiency of an active system is much higher than the passive systems. 11,12 In an active system, the beam component of sunlight is focused on the fibre bundle inlet using a concentrator, for example, Fresnel lens and parabolic mirrors. 11 A very high temperature is attained at the focus plane while concentrating the beam sunlight which leads to various design challenges. ...
... 11,12 In an active system, the beam component of sunlight is focused on the fibre bundle inlet using a concentrator, for example, Fresnel lens and parabolic mirrors. 11 A very high temperature is attained at the focus plane while concentrating the beam sunlight which leads to various design challenges. Normally, the conventional Fresnel lens is designed using cuts according to an aspheric surface profile in order to minimize the imaging optical aberrations. ...
Daylighting using natural illumination system (NILS) is gaining popularity due to transition to the renewable and non-conventional energy resources. In the proposed work, optomechanical design, numerical analysis, experimentation and integration of a modular Fresnel lens for NILS to effectively harness the sunlight is discussed. The modular and integrated design delivers uniform light at the receiving area of the daylight transportation system. This modular Fresnel lens is a combination of linear Fresnel lenses designed to offer a moderate concentration ratio to avoid hot spots. The distribution of solar radiation on the focal plane/entry section of the plastic optical fibre bundle (daylight transportation system) is simulated using the ray-trace technique for a lens system with a concentration ratio of 81. The irradiance distributions at the focal plane were found uniform with a radiometric and photometric transmission efficiency of 72.45% and 85.96%, respectively, for the lens element. The overall photometric transmission efficiency of the system with 10 m long plastic/acrylic optical fibre cable was found as 40.97%.
... Himawari and Parans (Mayhoub, 2014). The efficiency of these tracking-based devices is much higher than the non-tracking-based passive systems (Ullah and Whang, 2015) but the use of quartz optical fiber as a light transport system and precise sun-tracking requirements makes the system very costly. This limits the device to be utilized widely by common households. ...
... This determined that optical fibers have historically been used in telecommunication and sensing systems to transmit signals in the infrared domain [126][127][128][129]. However, the recent technological advances in fields like UV photolithography [130,131], laser surgery [132][133][134], and fiberbased photovoltaics [135][136][137][138][139][140][141] have given a new impulse towards the development of waveguides able to withstand the damaging effects of high-energy photons and maintain a high transmittance of UV and optical signals. ...
Due to its unique properties, amorphous silicon dioxide (a-SiO2) or silica is a key material in many technological fields, such as high-power laser systems, telecommunications, and fiber optics. In recent years, major efforts have been made in the development of highly transparent glasses, able to resist ionizing and non-ionizing radiation. However the widespread application of many silica-based technologies, particularly silica optical fibers, is still limited by the radiation-induced formation of point defects, which decrease their durability and transmission efficiency. Although this aspect has been widely investigated, the optical properties of certain defects and the correlation between their formation dynamics and the structure of the pristine glass remains an open issue. For this reason, it is of paramount importance to gain a deeper understanding of the structure–reactivity relationship in a-SiO2 for the prediction of the optical properties of a glass based on its manufacturing parameters, and the realization of more efficient devices. To this end, we here report on the state of the most important intrinsic point defects in pure silica, with a particular emphasis on their main spectroscopic features, their atomic structure, and the effects of their presence on the transmission properties of optical fibers.
... Fiber-optic daylighting networks have been considered to be a promising and efficient way to deliver sunlight into interior spaces while reducing the amount of electricity used for electric lighting [2]. Li and Yuan [3] proposed a novel design of a parabolic trough solar thermal and lighting system to improve the efficiency as well reduce the expense of a daily lighting system. ...
A hybrid solar lighting/ thermal system utilized a parabolic solar dish as a solar collector illustrated in this paper. A two-axis tracking system was developed and employed to improve the energy output of a concentrating solar system (CSP) that produces hot water and light. During the daytime, sunlight is transmitted by fiber optics to an indoor photovoltaic PV device to generate electricity, or it can be used directly as daylighting. The heat generated is used to heat water. The findings show that the proposed system is a low-cost, high-performance approach for solar energy use in building energy efficiency, and readily available tracking components and tools. The experimental work shows that the maximum efficiency of the hybrid solar lighting/ thermal system controlled with a dual-axis solar tracking system was 32.2%.
