Wayan Nata Septiadi

Application of Al2O3 Nanofluid on Sintered Copper-Powder Vapor Chamber for Electronic Cooling

The development of electronic devices pushes manufacturers to create smaller microchips with higher performance than ever before. Microchip with higher working load produces more heat. This leads to the need of cooling system that able to dissipate high heat flux. Vapor chamber is one of highly effective heat spreading device. Its ability to dissipate high heat flux density in limited space made it potential for electronic cooling application, like Central Processing Unit (CPU) cooling system. The purpose of this paper is to study the application of Al2O3 Nanofluid as working fluid for vapor chamber. Vapor chamber performance was measured in real CPU working condition. Al2O3 Nanofluid with concentration of 0.1%, 0.3%, 0.5%, 1%, 2% and 3% as working fluid of the vapor chamber were tested and compared with its base fluid, water. Al2O3 nanofluid shows better thermal performance than its base fluid due to the interaction of particle enhancing the thermal conductivity. The result showed that the effect of working fluid is significant to the performance of vapor chamber at high heat load, and the application of Al2O3 nanofluid as working fluid would enhance thermal performance of vapor chamber, compared to other conventional working fluid being used before.

The Effect of CuO-Water Nanofluid and Biomaterial Wick on Loop Heat Pipe Performance

The determinants of heat pipe performances are its wick and working fluid, instead of controlled by the material, dimension, and the shape of heat pipe. This study aimed to determine the effect of using nanofluid on the performance of Loop heat pipes (LHP) with CuO-water nanofluid that using biomaterials wick. LHP was made of 8 mm diameter copper pipe, with the diameter of evaporator and the condenser was 20 mm respectively and the length of the heat pipe was 100 mm. The wick was made of biomaterials Collaria Tabulate and the working fluid was CuO-water nanofluids where the CuO nanoparticles were synthesized by sol-gel method. The characteristic of the Tabulate Collaria biomaterial as a wick in LHP was also investigated in this experiment. The results of the experiments showed that the temperature differences between the evaporator and condenser sections with the biomaterial wick and CuO-water nanofluid were less than those using pure water. These results make the biomaterial (Collar) and nanofluids are attractive both as wick and working fluid in LHP technology. Keywords: loop heat pipe, wick, biomaterial, nanofluid.

Effect of Concentration and Loading Fluid of Nanofluids on the Thermal Resistance of Sintered Powder Wick Heat Pipe

Heat pipes have been widely used as one of the alternative methods to absorb more heat in the cooling systems of electronic devices. One of the ways to improve the thermal performance of heat pipes is to change the fluid transport properties and flow features of working fluids using nanofluids. The purpose of this research was to investigate the effect of Al2O3-water nanofluids concentration and fluid loading to the thermal resistance between evaporator and adiabatic section of copper straight sintered copper powder wick heat pipe. In this research, sintered powder wick heat pipes were manufactured and tested to determine the thermal resistance of the sintered powder wick heat pipes which charged with water and Al2O3-water nanofluids. The concentrations of the nanoparticles were varied from 1 %, 3% and 5 % of the volume of the base fluid. The result shows that Al2O3-water nanofluids have the ability to reduce the temperature at the evaporator section and the thermal resistance of heat pipe. The increase in nanofluids concentration could give significant effect to reduce the thermal resistance of heat pipes. The amount of working fluid charged into the heat pipes also gives an effect in heat pipes thermal resistance, where the thermal resistance was lower when the heat pipe was charged with 60% of its volume. The formation of coating layer at sintered powder wick also can fixed the wick porosity and cause roughness on the surface of granular pore which the increased of capillary could give the effect for enhancement of heat pipe performance.

Performance of the Solar Collector with Vacuum Tubes and Dual Heat Pipes Based on Wick Length Variation

The increasing number of non-renewable energy and the rising need of energy caused some global issue. We always interested to discuss how human being could create and improve an instrument that can extract energy from renewable energy resources, which is clean and applicable. One instrument that can extract energy from the sun is solar water heater. Solar water heater, consist of two main components. The first one is storage tank, and the other is solar collector. The purpose of this research is to design, manufacture, determine the performance of the solar collector with vacuum tubes and dual heat pipe based on the wick length variation. This experiment used a 150 Watt halogen lamp as the simulator of the sun. A copper fin was utilized to collect heat from the sun and transfer the heat to heat pipes. Adiabatic walls made from Styrofoam and plywood were set to prevent heat transfer to the environment due temperature difference. The performance of the heat pipe was investigated based on the wick length inside the heat pipe. The flow characteristic inside of the heat pipe and the thermal resistance depend on the wick length. The study found that the full-length wick heat pipe has the best performance with 0.37 K/W thermal resistance, and the efficiency of the system reach 34.95%. This is the highest value compared to the half-length and three-quarter length wick heat pipe.

Boiling Phenomenon of Tabulate Biomaterial Wick Heat Pipe

This research purposed to know the performance of heat pipe using wick made from biomaterial. Biomaterial (Coral) is the porous media which has the relative homogenous and small porous structures. The homogenous structures and the small biomaterial have the better capillarity and could be used as wick to circulate condensate in heat pipe. The heat pipe made from copper pipe with 50 mm in length and the inside and outer diameter was 25 mm and 24 mm in each, with the wick as thick as 1 mm made from Tabulate. Heat sink was adhered to the condenser part of heat pipe as wide as 637.5 cm2. The study was the observation of phenomena in porous media boiling between biomaterials with solid copper, in which the observations were made by using High Speed Video Camera (HSVC). Tabulate biomaterial has the porous structure which quite homogeny and the best capillary energy. The biomaterial as wick heat pipe could keep the condition of heat pipe from easily reachs the transition condition.

Analysis of CuO-Water Nanofluid Application on Heat Pipe

Since their first introduction to the world, both heat pipe and nanofluid have caught the interest of many researchers. Heat pipe with its unique and exceptional capability in transferring heat passively and effectively, was studied intensively and developed extensively for many applications. While nanofluid with its higher thermal conductivity and some other upgraded properties compared to conventional fluid rose as appealing research subject especially on fluid and thermal research area. This study analyzes the utilization of CuO-water nanofluid on biomaterial wick heat pipe. Laboratory-developed CuO-water nanofluid was used as working fluid for vertically straight-shaped biomaterial wick heat pipe. From the experiment, it was shown that the application of CuO-water nanofluid reduced the heat pipe thermal resistance up to 83%. It was figured out that this enhancement is due to the combination of higher thermal conductivity and better wettability of the fluid. It was also found that the heat pipe with nanofluid did not show significant degradation though being inactivated for several weeks. However, it was figured out that unlike the application of low concentration nanofluid, application of high concentration nanofluid was insignificant in improving thermal performance of the heat pipe.

Thermoelectric Heat Pipe-Based Refrigerator: System Development and Comparison with Thermoelectric, Absorption and Vapor Compression Refrigerators

Thermoelectric coolers have been widely applied to provide cooling for refrigerators in addition to conventional absorption and vapor compression systems. To increase heat dissipation in the thermoelectric cooler’s modules, a heat pipe can be installed in the system. The aim of this study is to develop a thermoelectric heat pipe-based (THP) refrigerator, which consists of thermoelectric coolers that are connected by heat pipe modules to enhance heat transfer. A comparative analysis of the THP prototype and conventional refrigerator with vapor compression, absorption and thermoelectric systems is also presented. The prototype system has a faster cooling down time and a higher coefficient of performance than the absorption system but still lower than vapor compression system