Euy Joon Lee

Performance Comparison Study on LFLP and DBLP Daylighting System

Key Words: DoubleBlind(이중블라인드),LightCollecter(집광부),LightTransformer(변광부),LightPipe(광파이프)초록:본논문에서는자연채광시스템LFLP(LinearFresnelLightPipe)와DBLP(DoubleBlindLightPipe)시스템을비교하였다.LFLP시스템은평행한빛을선형프레넬렌즈를이용하여선형형태로빛으로집광하여자연채광에이용하는시스템이며, DBLP시스템은베네시안형태의블라인드를이용하여빛을반사시켜자연채광에이용하는시스템이다.DBLP시스템은LFLP시스템을개선한것으로시스템앞쪽에위치한블라인드는태양의고도에따른빛을,뒤쪽에위치한블라인드는태양의방위각에따른빛을변광부로반사시키도록설계되었다.DBLP시스템의변광부는콘모양으로이루어져있으며블라인드에의해반사된빛을산광부로보내주는역할을하며, 산광부로들어온빛은실내조명에사용된다. 따라서맑은날(clear sky)을기준으로두시스템의효율을비교하면DBLP시스템이LFLP시스템보다세배높게나오는것으로나타났다.Abstract:TheLFLP(LinearFresnelLightPipe)systemusesalinearFresnellenstofollowthesunandconcentratestheparallel sunlight intoaline. ALFLPdaylightingsystemhasbeendevelopedandupdatedtoaDBLP(DoubleBlindLightPipe)daylightingsystemtoimprovetheoverallsystemefficiencyinthemorningandafternoon.Thenewdesignconsistsofadouble-blindstylewithacone-shapedlighttransformer.Theblindsareusedtocollectthesun’saltitude and azimuth movements through the day. Behind the twosets of blinds is the light transformer, which isbasedonaparabolic-shapedlightconcentrator.Thelighttransformerisdesignedtoefficientlydeliverlightwithinathirty-degreeradialspreadsothatthelightpipecaninternallyreflectthelight.Theresultsofscale-modeltestsareencouraging,andtheefficiencyisthreetimeshigherthanthatofthepreviousLFLPsystem.

Identifying, Prioritizing, Measuring and Verifying Clean Energy Solutions for Korea's Public Building Renewable Energy Obligation Policy

Under the Renewable Heat Obligation (RHO) public buildings in the Republic of Korea larger than 10,000 m 2

An Experimental Performance Comparison Study of Solar Heat and Power Hybrid Unit Module

A solar heat and power hybrid system can simultaneously generate electricity and thermal energy. In this study, several experiments were carried out with a solar heat and power hybrid unit. Then, a method to increase the photovoltaic efficiency and amount of thermal energy was suggested based on a comparative analysis. The experiment was conducted using only the photovoltaic system as a reference case, with the photovoltaic-thermal air system as a hybrid case. A numerical increase in the photovoltaic efficiency per 1°C was suggested based on a comparative data analysis of these two cases. In this experiment, the surface temperature on the air hybrid system was 13.52°C lower than that in the reference case, and the photovoltaic efficiency was increased by 5.09. The amount of thermal energy produced was 15.69 Wt per 1°C difference between the ambient and outlet temperatures. In this paper, therefore, a photovoltaic efficiency increase of 0.34 per 1°C is proposed for the air hybrid system based on the analysis of the experimental data.