• Solar Energy
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• v.19 no.1
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• pp.1-8
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• 1999

Electrochromic $WO_3$ thin films were prepared by electron beam deposition. The transmission and durability of films were investigated. Coloring and bleaching experiments were repeated in an electrolyte of propylene carbonate with 0.6M of $LiClO_4$ by cyclic voltammetry. Spectrophotometer was used to measure the transmission in the degraded films. The 5000 ${\AA}$ thick film was found to be the stable after repeated cycles. The durability of the annealed film also showed improvements over unannealed samples. Tungsten oxide films with titanium content of about $10{\sim}15$ mol% was found to be most stable, undergoing the least degradation during the repeated cycles.

• Current Optics and Photonics
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• v.4 no.5
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• pp.441-445
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• 2020

A novel design for a Fresnel lens for a solar end-pumped laser is demonstrated in this paper. The new hybrid Fresnel lens includes two parts, inner and outer. The inner part is a twice-total-internal-reflection and vertical-transmission lens. The outer part is a once-total-reflection and vertical-transmission lens. The radius of the Fresnel lens is 600 mm, and its focal length is 750 mm. The concentrating performance of the Fresnel lens is examined using TracePro. The results show that the concentration efficiency has been greatly improved. The total concentration efficiency of the hybrid Fresnel lens reaches 73.2% when the radius of the laser rod is 3 mm. This design can simplify the concentration system of a solar end-pumped solid-state laser.

• Journal of the Korean Solar Energy Society
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• v.24 no.3
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• pp.55-63
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• 2004

빛이 입사각별로 태양투과율이 제어되어지는 첨단 창과 같은 물체를 통과할 때 투과되는 성분은 직달투과와 산란투과성분으로 볼 수 있다. 직달투과는 물체를 통과하면서 일정한 방향으로 굴절되어 투과되는 성질을 말하고, 산란투과는 직달투과를 제외한 나머지 방향의 성분들의 형태를 말한다. 이러한 첨단 창의 냉난방부하에 미치는 에너지성능을 평가하기 위해서는 산란투과에 대한 정보가 필요하고, 이에 대한 물리적 변수는 입사각, 출력각, 양방향 투과율 분산함수인 BTDF로 정의된다. 본 논문에서는 3개의 서로 나른 첨단 창 (1) $42^{\circ}/5^{\circ}$ 프리즘 창 판넬, (2) 레이저 컷 판넬 (3) $45^{\circ}$ 프리즘 3M 필름의 BTDF 데이터 획득을 위한 실험 방안을 소개하고, 실험을 통해 획득한 정보를 이용하여 계산식과 비교 검증을 하였다. 따라서 이 검증된 방안을 이용하여 지역별 냉난방 부하를 최소화 할 수 있는 입사각별로 태양 투과율 제어 판넬을 선정할 수 있게 되었다.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1435-1447
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• 2020

The seasonal variations in weather parameters can significantly affect the atmospheric transmission characteristics. Herein, we propose a novel augmented multiple regression algorithm for the accurate estimation of atmospheric transmittance and solar irradiance over highly localized areas. The algorithm employs 1) adaptive atmospheric model selection using measured meteorological data and 2) multiple linear regression computation augmented with the conventional application of MODerate resolution atmospheric TRANsmission (MODTRAN). In this study, the proposed algorithm was employed to estimate the solar irradiance over Taean coastal area using the 2018 clear days' meteorological data of the area, and the results were compared with the measurement data. The difference between the measured and computed solar irradiance significantly improved from 89.27 ± 48.08σ W/㎡ (with standard MODTRAN) to 21.35 ± 16.54σ W/㎡ (with augmented multiple regression algorithm). The novel method proposed herein can be a useful tool for the accurate estimation of solar irradiance and atmospheric transmission characteristics of highly localized areas with various weather conditions; it can also be used to correct remotely sensed atmospheric data of such areas.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.481-489
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• 1994

The $SnO_2$/(n)Si solar cell was fabricated by electron beam evaporation method, and their properties were investigated. In proportion to increase of substrate and annealing temperature, the conductivity of $SnO_2$ thin film was increased, but its optical transmission decreases because of increasing optical absorption of free electrons in the thin film. $SnO_2$/Si Solar cell characteristics were improved by annealing, but the solar cells was deteriorated by heat treatment above 500[.deg. C]. The optimal outputs of $SnO_2$/Si solar cell through above investigations were $V_{\var}$:350[mV], $J_{sc}$ ;16.53[mA/c $m^{2}$], FF;0.41, .eta.=4.74[%]

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.584-587
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• 2006

An energy generating greenhouse based on fluoropolymer envelope and fresnel lens is proposed. The outstanding properties of the fluoropolymer films make them very suitable for large scale solar applications. Extremely high optical transmission over the whole solar spectrum, combined with mechanical strength, and durability allows us to design a highly optimized greenhouses for both plant growing and energy generation. Systems such as photovoltaic triple junction cells are especially attractive since they have up to 35% efficiency with much less cell material when the sun beam is focused with concentrators such as fresnel lenses. Cooling such devices will enhance the efficiency and provide useful thermal energy that could be further utilized for various applications depending on the local demands. This article introduces the basic ideas and principles of the energy generating greenhouses as a first step towards the actual deployment of such systems under Korean environment.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.157-164
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• 2011

Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.35-43
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• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.331-336
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• 2012

Nowaday the conventional solar collector material prices are rising up because of pricy metal material over the world. The solar collector is too expensive to recycle to save the earth. Advanced polymer research is founded a high thermal resistant polymer and also it has high sun energy transmission. It also has cheaper material and easy manufacturing process, compare with conventional solar collector material. This paper is focussing on glazing simulation of polymer solar collector against wind pressure. The modeling geometry of polymer solar glazing are purposed by single layer, double layer hollow, zig-zag and tower. A simulation by using the Finite Volume was conducted to get Factor of Safety (FoS). The purpose of this paper is to find the best polymer glazing design, which can be as reference for the solar collector company to build Polymer. Hope fully new model of polymer solar collector has cheap, light, high sun energy transmitter, easy to be made and strong against wind force characteristics.

• Journal of Appropriate Technology
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• v.5 no.1
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.