RESEARCH ON THE HEAT TRANSFER AND PERFORMANCE OPTIMIZATION OF LOOP HEAT PIPE FOR COOLING OF THE HIGH POWERED LED

摘要

While the issue of environmental problem becomes serious,the energy saving is requested from the illumination sector.And, as the attractive candidate for next generation illumination, the interest has been focused on the LED.However, the performance of LED decreasesdue to the high junction temperature, over 85 degrees, shorting the life time.Therefore the evaluation of heat transfer and performance optimization of loop heat pipe operation conditions for cooling high powered LED was made.As working fluid of loop heat pipe,HFC-134a and HFO-1234yf is applied.Optimal parameters were confirmed to be 70％ for the amount of working fluid, the outer diameter of down comer tube and riser tube was φ 10, the height of fin was 3mm, the pitch of fin was 5mm.As the results, the thermal resistance level was achieved 0.0419K/W and 0482K/W with using R-134a and HFO-1234yf, respectively.It is recognized that the possible use HFO-1234yfinstead of R-134a, as low GWP working fluid.