Estimation of Junction Temperature and Thermal Resistance of LEDs Mounted On Different Heat Sinks by Numerical Simulation and Thermal Transient Measurement

2016 ◽  
Vol 42 (5) ◽  
pp. 241-251
Author(s):  
Dheepan Chakravarthii M K ◽  
Shanmugan S ◽  
Mutharasu D
Keyword(s):  
Numerical Simulation ◽  
Thermal Resistance ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Thermal Transient ◽  
Transient Measurement

Variation of thermal resistance with input current and ambient temperature in low-power SMD LED

2018 ◽  
Vol 35 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Muna E. Raypah ◽  
Dheepan M.K. ◽  
Mutharasu Devarajan ◽  
Shanmugan Subramani ◽  
Fauziah Sulaiman
Keyword(s):  
Low Power ◽  
Thermal Resistance ◽  
Ambient Temperature ◽  
Light Emitting Diode ◽  
Operating Conditions ◽  
Input Current ◽  
Junction Temperature ◽  
Total Thermal Resistance ◽  
Content Type ◽  
Thermal Transient

Purpose Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED. Design/methodology/approach Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software. Findings As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔRthJS) and total thermal resistance (ΔRthJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔRthJS and ΔRthJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature. Originality/value Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.

scholarly journals Performance and Thermal Analysis of Aluminium Oxide Filled Epoxy Composite as TIM for LEDs

2014 ◽  
Vol 11 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Nur Jamaludin ◽  
P Anithambigai ◽  
S Shanmugan ◽  
D Mutharasu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Epoxy Resin ◽  
Milling Process ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
System Level ◽  
Al2o3 Powder ◽  
Effective System ◽  
Transient Measurement

Al2O3powder with various particle sizes was prepared by milling process and mixed together with epoxy resin in order to increase the thermal conductivity of resin and decrease the junction temperature of the LEDs. Al2O3 powder filled epoxy resin was applied as thermal interface material (TIM) for an effective system level analysis of thermal transient measurement. The result depicted that the milled Al2O3 powder for 3 hour powder showed the highest thermal conductivity and hence lower in thermal resistance of LED. Moreover, the driving currents also influence the thermal resistance and achieved low thermal resistance when measured at 350mA. The thermal properties of the sample were tested using t3ster. The surface morphology of the samples was tested using FESEM.

Thermal Transient Measurements on High Power LEDs with Different MCPCB Substrate

2012 ◽  
Vol 488-489 ◽  
pp. 1363-1368 ◽  
Author(s):  
P. Anithambigai ◽  
D. Mutharasu
Keyword(s):  
Thermal Resistance ◽  
High Power ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Dielectric Material ◽  
Function Evaluation ◽  
Substrate Thickness ◽  
Circuit Boards ◽  
Thermal Transient ◽  
Transient Measurement

This study elucidates the significance of thermal transient measurement based on structure function evaluation particularly on high power LEDs. The metal core printed circuit boards (MCPCBs) were redesigned with reference to the product datasheet. Aluminium nitride was employed as the dielectric material of the MCPCBs and thermal performance of copper and aluminium substrate with different substrate thickness has been reported in this paper. It was observed that the aluminium based MCPCBs performed better heat dissipation compared to the copper based MCPCBs. In addition, when two different thicknesses of the MCPCB substrates were compared, it was observed that the thicker substrate performed a lower thermal resistance compared to the thinner substrate MCPCB. The junction to board thermal resistance was determined using the standard transient dual interface method.

scholarly journals Influence of a Thermal Pad on Selected Parameters of Power LEDs

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3732
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Tomasz Torzewicz ◽  
Marcin Janicki
Keyword(s):  
Optical Properties ◽  
Thermal Resistance ◽  
Optical Power ◽  
Junction Temperature ◽  
Operating Parameters ◽  
Cold Plate ◽  
Optical Efficiency ◽  
Forward Current ◽  
Measurement Results ◽  
Set Up

This paper is devoted to the analysis of the influence of thermal pads on electric, optical, and thermal parameters of power LEDs. Measurements of parameters, such as thermal resistance, optical efficiency, and optical power, were performed for selected types of power LEDs operating with a thermal pad and without it at different values of the diode forward current and temperature of the cold plate. First, the measurement set-up used in the paper is described in detail. Then, the measurement results obtained for both considered manners of power LED assembly are compared. Some characteristics that illustrate the influence of forward current and temperature of the cold plate on electric, thermal, and optical properties of the tested devices are presented and discussed. It is shown that the use of the thermal pad makes it possible to achieve more advantageous values of operating parameters of the considered semiconductor devices at lower values of their junction temperature, which guarantees an increase in their lifetime.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

Experimental Measurements of the Flow and Heat Transfer of a Square Jet Impinging on an Array of Square Pin Fins

2002 ◽  
Author(s):  
Johnny S. Issa ◽  
Alfonso Ortega
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Flow Behavior ◽  
Jet Impingement ◽  
Tip Clearance ◽  
Heat Sinks ◽  
Clearance Ratio ◽  
Cross Sectional ◽  
Pressure Loss Coefficient ◽  
Air Jet

An experimental investigation was conducted to explore the flow behavior, pressure drop, and heat transfer due to free air jet impingement on square in-line pin fin heat sinks (PFHS) mounted on a plane horizontal surface. A parametrically consistent set of aluminum heat sinks with fixed base dimension of 25 × 25 mm was used, with pin heights varying between 12.5 mm and 22.5 mm, and fin thickness between 1.5 mm and 2.5 mm. A 6:1 contracting nozzle having a square outlet cross sectional area of 25 × 25 mm was used to blow air at ambient temperature on the top of the heat sinks with velocities varying from 2 to 20 m/s. The ratio of the gap between the jet exit and the pin tips to the pin height, the so-called tip clearance ratio, was varied from 0 (no tip clearance) to 1. The stagnation pressure recovered at the center of the heat sink was higher for tall pins than short pins. The pressure loss coefficient showed a little dependence on Re, increased with increasing pin density, and pin diameter, and decreased with increasing pin height and clearance ratio. The overall base-to-ambient thermal resistance decreased with increasing Re number, pin density and pin diameter. Surprisingly, the dependence of the thermal resistance on the pin height and clearance ratio was shown to be mild at low Re, and to vanish at high Re number.

Influence of selected factors on parameters of a cooling system with a Peltier module and forced air flow

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krzysztof Posobkiewicz ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Cooling System ◽  
Heat Sinks ◽  
Cooling Power ◽  
Cooling Systems ◽  
Content Type ◽  
Peltier Module ◽  
Peltier Modules ◽  
Forced Air

Purpose The purpose of this study is to investigate the validation of the usefulness of cooling systems containing Peltier modules for cooling power devices based on measurements of the influence of selected factors on the value of thermal resistance of such a cooling system. Design/methodology/approach A cooling system containing a heat-sink, a Peltier module and a fan was built by the authors and the measurements of temperatures and thermal resistance in various supply conditions of the Peltier module and the fan were carried out and discussed. Findings Conclusions from the research carried out answer the question if the use of Peltier modules in active cooling systems provides any benefits comparing with cooling systems containing just passive heat-sinks or conventional active heat-sinks constructed of a heat-sink and a fan. Research limitations/implications The research carried out is the preliminary stage to asses if a compact thermal model of the investigated cooling system can be formulated. Originality/value In the paper, the original results of measurements and calculations of parameters of a cooling system containing a Peltier module and an active heat-sink are presented and discussed. An influence of power dissipated in the components of the cooling system on its efficiency is investigated.

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