Guo-Dung J Su
National Taiwan University, Taiwan
Title: Design of a high-efficiency narrow spot headlampwith distributed LEDs
Biography
Biography: Guo-Dung J Su
Abstract
In this talk, we present a narrow spot headlamp system of the dual half circular parabolic aluminized refl ector (PAR). This system has a property that each of the half-circular PAR contains fi ve high-effi ciency and small package light emitting diode (LED) chips with 180o rotational symmetry. Concerning traffic safety, the design criterion of train headlamp is to meet the code of Federal Regulations (CFR). In terms of the forecast of illuminated position on a screen, analytic derivation has been developed to study the optical path of a ray which is perpendicular to and emitted from the center of the LED chip. This ray stands for the main emitted ray of the LED chip and it is inside of the illuminated spot by the LED source on the screen. Therefore, we can analyze design systematically for determining where the LED chips ought to be placed in the PAR reflector for minimizing electricity consumption while satisfying the reliability constraints on train headlamp to ensure traffic safety. Compared to a typical train headlamp system with incandescent or halogen lamp needing several hundred watts, the proposed system only uses 20.18W to achieve the luminous intensity requirements. Compared with the typical train headlamp system incorporating incandescent or halogen lamp with a power rating about 200 to 350W, the proposed system only uses 20.18W to achieve the luminous intensity requirements. If the train headlamp turns on 8 hours a day, one year can save electricity about 584kWh (=0.2kW8h/d365d). If electric power is generated from crude oil, according to the estimation of 0.26kg CO2/kWh in the literature, the proposed approach can eff ectively lower down about 152kg CO2 emission per year for a single lamp.