Young Moon Yu

Study on the Design and Optical Characteristics of LED Emergency Exit Lighting with Flameproof Enclosure

In the hazardous areas, it is essential to use of electrical equipment of explosion-proof. In this paper, the prototype of LED explosion-proof emergency exit lighting with flameproof enclosure using light guide panel (LGP) was designed and fabricated, and then lighting characteristics of the prototype were compared to those of the commercial products. The weight and interal volume of the designed prototype in this study were reduced 46% and 54%, respectively compared to commercial products. The measured average luminance of the prototype of LED explosion-proof emergency exit lighting was 400.5㏅/㎡. Using of LGP, the uniformity of light of the prototype was enhanced compared to that of the commercialized products and hence the visibility of pictogram was improved. The prototype was endured until 5.2 atmosphere under the hydraulic testing for flameproof enclosure.

Design and Characterization of LED Engine Module for the Application of Thermoelectric Device

Variation of thermal resistivity depending on temperature difference and measurement of thermal resistivity of thermoelectric device in LED lighting engine module were studied. Power generated from waste heat and photometric characteristics of LED engine module were measured. From the measured and analysed data, the followings were concluded. Control of temperature difference at the low temperature was advantageous for LED module compared to temperature difference control at high temperature. The sum of the measured thermal resistance of LED module and thermoelectric device was 2.654K/W and the measured total thermal resistance was 2.41K/W. In a thermal simulation, minimum LED p-n junction temperature was 69.3℃ when 23 pieces of pins with 1mm thickness were used. When 700mA was applied to the LED engine module, 0.086W of maximum power was obtained with 0.15A of load. Light efficiency of LED module with thermoelectric device was 126.9lm/W and 3.7lm/W of efficiency decrement.

Analysis of the Thermoelectric Devices' Power Generation Performance for Utilizing the Waste Heat of LED Tunnel Lighting Module

In this paper, we propose the LED(Light-Emitting-Diode) emergency lighting in a tunnel by using the thermoelectric devices. To achieve high generated power, thermoelectric device should be have high Seebeck coefficient and small contact area. Also, we reveal that a moderate heatsink required for high generated power. From the waste heat of LED tunnel lighting module (25W), the generated power was 0.062W by thermoelectric device, and it could illuminate for 1hour after charge the battery of emergency lighting during about 101hours.

Thermal Design of High-power 5 Watt LEDs-based Searchlight

The heat dissipation conditions of high-power 5 watt LEDs-based searchlight modules were optimized with varying LED bar`shape, materials, and ambient temperature. The LED junction temperature was estimated by using Computational Fluid Dynamics simulation. The optimal heat dissipation conditions were found as follows; LED bar` shape: L