Jung-Chang Wang

Development of vapour chamber‐based VGA thermal module

Purpose – The purpose of this paper is to describe how a traditional metal base plate is replaced with a vapour chamber, a two‐phase flow heat transfer module with high heat transfer efficiency, to effectively reduce the temperature of heat sources as graphic processing unit (GPU) of smaller area and higher power.Design/methodology/approach – As a first step, the nature of flow field of a vapour chamber‐based thermal module with heat sink is simulated and analysed through computational numerical method. Second, a sample is prepared according to the theoretical results and the performance of thermal modules is tested together with thermal performance experiment.Findings – The results show that when the fin height from vapour chamber top to fan bottom area is more than 3 mm and not more than 8 mm, the vapour chamber‐based thermal module can achieve the optimum heat dissipation and the maximum heat flux may exceed 90 W/cm2. Also, when copper fins are 3 mm in height, 0.2 mm in thickness, 53 in number and spac...

Program for Rapid Computation of the Thermal Performance of a Heat Sink with Embedded Heat Pipes

This article uses Visual Basic commercial software to develop a Windows program for rapidly calculating the thermal performance of a heat sink with embedded heat pipes. A heat sink with embedded heat pipes transfers the total heat capacity from the heat source to the base plate with embedded heat pipes and fins sequentially, and then dissipates the heat flow into the surrounding air. The computing core of this Windows program employs the theoretical thermal resistance analytical approach with iterative convergence, as stated in this article, to obtain a numerical solution. The results show that the estimation error between the numerical and experimental solutions is less than 5%. From this Windows program, the optimum height of the embedded heat pipes inserted through fins is 21mm and 15mm for one pair and two pairs of embedded heat pipes, respectively.

Analyzing Thermal Module Developments and Trends in High-Power LED

The solid-state light emitting diode (SSLED) has been verified as consumer-electronic products and attracts attention to indoor and outdoor lighting lamp, which has a great benefit in saving energy and environmental protection. However, LED junction temperature will influence the luminous efficiency, spectral color, life cycle, and stability. This study utilizes thermal performance experiments with the illumination-analysis method and window program (vapour chamber thermal module, VCTM V1.0) to investigate and analyze the high-power LED (Hi-LED) lighting thermal module, in order to achieve the best solution of the fin parameters under the natural convection. The computing core of the VCTM program employs the theoretical thermal resistance analytical approach with iterative convergence stated in this study to obtain a numerical solution. Results showed that the best geometry of thermal module is 4.4 mm fin thickness, 9.4 mm fin pitch, and 37 mm fin height with the LED junction temperature of 58.8°C. And the experimental thermal resistances are in good agreement with the theoretical thermal resistances; calculating error between measured data and simulation results is no more than ±7%. Thus, the Hi-LED illumination lamp has high life cycle and reliability.

Air Cooling Module Applications to Consumer-Electronic Products

The purpose of this chapter is to describe how a air-cooling thermal module is comprised with single heat sink, two-phase flow heat transfer modules with high heat transfer efficiency, to effectively reduce the temperature of consumer-electronic products as Personal Computer (PC), Note Book (NB), Server including central processing unit (CPU) and graphic processing unit (GPU), and LED lighting lamp of smaller area and higher power. The research design concentrates on several air-cooling thermal modules. For air cooling, the extended surface, such as fin is usually added to increase the rate of heat removal. The heat capacity from heat source conducted and transferred through heat sink to the surroundings by air convection. Thus, the aim of adding fin is to help dissipate heat flow from heat source. The air convection heat transfer mechanism was shown in the figure 1, which can be separated into forced and free/nature convection through dynamic fluid device as fan. The chapter is divided into three parts; first part discusses optimum, performance analysis and verification of a practical convention parallel plate-fin heat sink. Second part employs two-phase flow heat transfer devices, such as heat pipe, thermosyphon and vapor chamber comprised with heat sink to consumer-electronic products. The last part utilizes air-cooling thermal module in other industrial areas including injection mold and large motor. A conventional plate-fin heat sink is composed of a plate-fin heat sink and a fan. Thermal resistance network is often employed to analyze the thermal model and system in the industry. The overall thermal resistance includes interface resistance, base-conduction resistance, and convective resistance. It is worth developing a model for a conventional aircooling device that takes heat sink configuration and airflow conditions into account in order to predict the device’s thermal performance when developing laminar-, transition-, and turbulent-flow regimes. Although, solving the high heat capacity of electronic components has been to install a heat sink with a fan directly on the heat source, removing the heat through forced convection. Increasing the fin surface and fan speed are two direct heat removal heat sink in order to solve the ever increasing high heat flux generated by heat source from consumer-electronic products. They can reduce the total thermal resistance from 0.6 °C/W to 0.3 °C/W. Lin & Chen (2003) and Wu et al. (2011) has been developed an analytical all-in-one asymptotic model to predict the hydraulic and thermal performance of

Vapor chamber in high performance server

This article describes how to evaluate the thermal-performance of vapor chamber-based thermal module, which has existed in the thermal-module industry for a year or so especially in server application. Thermal-performance of the thermal module with the vapor chamber can be determined within several seconds by using the final formula associated with thermal-performance experimental method deduced in this paper. From the results, the thermal performance of the vapor chamber thermal module is times than that of pure copper base plate. And its thermal performance is closely relate to its dimensions and heat-source flux, in the case of smallarea vapor chamber and small heat-source flux, the thermal performance will be less than that of pure copper material. The maximum heat flux of the vapor chamber is over 800,000 W/m2, its thermal performance will increase with input power increasing, and the calculating error is no more than ±3%.

Vapor chamber in high power LEDs

The vapor chamber has already been confirmed that its anti-gravity, high effective thermal conductivity and suited on the high heat flux of heat source as the integral heat spreader. This article describes how to evaluate the thermal-performance of LED vapor chamber-based plate with VCTM V1.0, which has existed in the thermal-module industry for a year or so especially in high power LEDs application. There are three kinds of LED based plates utilized to discuss the thermal performance and illumination. From the results, the thermal performance of the LED vapor chamber-based plate is many times than that of LED copper- and aluminum-based plate. And the LED vapor chamber-based plate works out hot-spot problem of 50 Watt high-power LEDs, successfully. The results are shown that the experimental thermal resistance values of LED copper- and vapor chamber-based plate respectively are 0.41°C/W and 0.38°C/W at 6 Watt. And the illumination of 6 Watt LED vapor chamber-based plate is larger 5 % than the 6 Watt. Thus, the LED vapor chamber-based plate has the best thermal performance above 5 Watt.

CHARGE AND DISCHARGE CHARACTERISTICS OF A THERMAL ENERGY STORAGE DEVICE

This article describes an experimental investigation on the thermal characteristics of a thermal energy storage device. It utilizes the superior heat transfer characteristics of wickless heat pipes and eliminates drawbacks found in the conventional thermal storage tank. This study purports to examine the functions of a thermal energy storage device having three operating modes, i.e., charge, discharge, and simultaneous charge and discharge. Different heat transfer mechanisms are identified in the thermal energy storage device under different operating modes. The thermal performance with alcohol and water as working fluid are also explored in the thermal energy storage device. The results show that a thermal energy storage device employing alcohol as the working fluid provides better performance. The system gives optimum charge and discharge performance under 35%–40% fill ratio and displays optimum charge efficiency of 73% and optimum discharge efficiency of 85%.

Novel green illumination energy for LED with ocean battery materials

This paper launches novel materials of LED with ocean battery. Ocean battery employs sea water existing by the nature as energy materials to drive LED lamp lighting. The analysing methods are thermal-, electric- and illumination-performance experiments to discuss the novel green illumination techniques. Ocean battery and LED are all DC components, there is no energy loss of current converter between them, and the ocean battery has more electricity in LED illumination. Vapour chamber (VC) and aluminium (AL) materials are assigned to be the LED PCBs. Results show that the effective thermal conductivity of the VCPCB is many times higher than that of the ALPCB, proving that it can effectively reduce the temperature of the LED and obtain more uniform luminance. And the output voltage and LED lighting start unstable resulting from the air bubble of ocean battery slight vibration.

Vapor chamber in high-end VGA card

The vapor chamber has been verified the excellent heat transfer efficiency and heat spreading performance utilized particularly in many high-power and small area heat sources. This paper analyzes and compares the thermal performance of a vapor chamber-based thermal module with a traditional Cu metal based plate embedded three heat pipes of 6 mm diameter at high heat flux GPU above 165 Watt. They are estimated and simulated the optimum fin design of aluminum heat sink through computational numerical method and thermal resistance analysis at constant P-Q performance curve of a same commercial blower. These results show that the total thermal resistance value of vapor chamber-based thermal module are under 0.273 °C/W from simulation analytical data and that of heat-pipes and copper based plate thermal module are all over 0.273 °C/W. Therefore, the thermal performance of vapor chamber-based thermal module can be accurately simulated and analyzed by applying the method introduced in this paper. The vapor chamber-based thermal module can achieve the optimum thermal performance and the critical heat flux may exceed 100 Watt/cm2. Consequently, the vapor chamber-based thermal module introduced in this paper is able to cope with future GPU named RV 970 and GTX 590 with high heat flux of more than 60 Watt/cm2.

Green-lighting recyclable device of LED-MGVC

There are many benefits for high-power Light Emitting Diode (LED) lamp including weightless, anti-seismic and small size and other advantages of energy saving lighting. And a vapor Chamber (VC) can replace the current five kinds of LED boards (PCB, MCPCB, IMS, CS, and DCBS) and become a new generation of high power LED vapor chamber-based plate resulting from the high heat transfer efficiency, light weight and anti-gravity [1]. Nevertheless, about 80% of electrical input power of high power LED lighting will be in the form of waste heat energy for the LED thermal management. Therefore, this paper is to study the high-power LED lighting technology green energy power for Micro-Generator with LED Vapor Chamber-Based Plate (LED-MGVC) device characteristics, in order to reach the green recycling of lighting energy efficiency. Power generation chip analysis with thermal performance-illumination experiment is utilized in this study that can deduce and verify the best current value Iη of LED-MGVC based on thermoelectric physical phenomena constituting the basic thermoelectric effect theory. The present study develops an original device of LED-MGVC, which composing a Thermoelectric Generator Modules (TGM) with the characteristics and components of LED-VCPCB [2], will absorb the waste heat energy from the LEDs source and convert thermal energy into electrical energy, in order to achieve the best thermal management of high power LED lighting modules.