Innovative Configurations of Large Scale Heat Pipes

2005 ◽  
Author(s):  
Jessica Sheehan ◽  
Donald Jordan ◽  
Douglas T. Queheillalt ◽  
Pamela M. Norris
Keyword(s):  
Heat Pipe ◽  
Large Scale ◽  
Heat Pipes ◽  
Heat Spreader ◽  
Pipe System ◽  
Pipe Systems

A large-scale heat pipe is one of many possible solutions to the modern day problem of quickly dissipating high amounts of concentrated heat. While heat pipes are a proven technology, little research has been directed at large-scale heat pipe systems. Two configurations of large-scale heat pipes are investigated in this study. The two configurations examined were a 2’ × 2’ heat spreader plate (a type of heat pipe) and an innovative heat pipe system that combines traditional heat pipes and heat spreader plates. The heat spreader plate, when tested, quickly becomes isothermal and works as a traditional heat pipe. This demonstrates the ability of this large-scale heat pipe configuration to work effectively to spread out high amounts of deposited heat. The experimentation on the innovative heat pipe system gave similar results, showing that the configuration works as a traditional heat pipe.

Sector Rotating Heat Pipe With Interconnected Branches and Reservoir for Turbomachinery Cooling

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Brian Reding ◽  
Yiding Cao
Keyword(s):  
Experimental Study ◽  
Heat Pipe ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Practical Solution ◽  
Pipe System ◽  
Current Configuration ◽  
Cooling Technique

Heat pipe technology offers a possible cooling technique for structures exposed to high heat fluxes, as in turbomachinery such as compressors and turbines. However, in its current configuration as single heat pipes, implementation of the technology is limited due to the difficulties in manufacturability and costs. Hence, a study to develop a new radially rotating (RR) heat pipe system was undertaken, which integrates multiple RR heat pipes with a common reservoir and interconnected braches for a more effective and practical solution to turbomachinery cooling. Experimental study has shown that the integration of multiple heat pipe branches with a reservoir at the top is feasible.

Solar Load Ratio Parameters for a Passive Solar Heat Pipe System

2015 ◽  
Author(s):  
Logan S. Poteat ◽  
M. Keith Sharp
Keyword(s):  
Heat Pipe ◽  
Load Ratio ◽  
Building Design ◽  
Weather Data ◽  
Prediction Algorithm ◽  
Solar Heat ◽  
Pipe System ◽  
Thermal Network ◽  
Pipe Systems ◽  
Passive Solar

The Solar Load Ratio (SLR) method is a performance prediction algorithm for passive solar space heating systems developed at Los Alamos National Laboratory. Based on curve fits of detailed thermal simulations of buildings, the algorithm provides fast estimation of monthly solar savings fraction for direct gain, indirect gain (water wall and concrete wall) and sunspace systems of a range of designs. Parameters are not available for passive solar heat pipe systems, which are of the isolated gain type. While modern computers have increased the speed with which detailed simulations can be performed, the quick estimates generated by the SLR method are still useful for early building design comparisons and for educational purposes. With this in mind, the objective of this project was to develop SLR predictions for heat pipe systems, which use heat pipes for one-way transport of heat into the building. A previous thermal network was used to simulate the heat pipe system with Typical Meteorological Year (TMY3) weather data for 13 locations across the US, representing ranges of winter temperature and available sunshine. A range of (nonsolar) load-to-collector ratio LCR = 1–15 W/m2K was tested for each location. The thermal network, along with TMY3 data, provided monthly-average-daily absorbed solar radiation and building load to calculate SLR. Losses from the solar aperture in a heat pipe system are very low compared to conventional passive solar systems, thus the load-to-collector ratio of the solar aperture was neglected in these preliminary calculations. Likewise, nighttime insulation is unnecessary for a heat pipe system, and was not considered. An optimization routine was used to determine an exponential fit (the heart of the SLR method) to simulated monthly solar savings fraction (SSF) across all locations and LCR values. Accuracy of SSF predicted by SLR compared to the thermal network results was evaluated. The largest errors (up to 50%) occurred for months with small heating loads (< 80 K days), which inflated SSF. Limiting the optimization to the heating season (October to March), reduced the error in SSF to an average of 4.24% and a standard deviation of 5.87%. These results expand the applications of the SLR method to heat pipe systems, and allow building designers to use this method to estimate the thermal benefits of heat pipe systems along with conventional direct gain, indirect gain and sunspace systems.

Thermal Performance of Integrated Plate Heat Pipe With a Heat Spreader

2000 ◽  
Vol 123 (3) ◽  
pp. 189-195 ◽  
Author(s):  
Koichiro Take ◽  
Ralph L. Webb
Keyword(s):  
Heat Pipe ◽  
Thermal Contact ◽  
Heat Pipes ◽  
Passive Cooling ◽  
Test Results ◽  
Air Flow Rate ◽  
Heat Spreader ◽  
Plate Heat ◽  
Cooling Method ◽  
Notebook Computers

The air flow rate available for cooling of notebook computers is very limited. Thus, notebook computer manufacturers desire a “passive” cooling method. Heat pipes are typically used to transport the heat from the CPU to a forced convection, air-cooled condenser. This paper describes a passive, keyboard sized aluminum Integrated Plate Heat Pipe (IP-HP) that has been developed for notebook computers. Analysis was performed to estimate the several thermal resistances in the heat pipe, including the effect of the vapor pressure drop. The modified design using a heat spreader at the evaporator significantly reduces the heat pipe resistance. Further work was done to evaluate the thermal contact resistance at the IP-HP/CPU interface. Test results show that the IP-HP can reject 18 W while maintaining the CPU 65°C above ambient temperature.

An Evaluation of the Wicking Characteristics of Stochastic Open-Cell Nickel Foams

2006 ◽  
Author(s):  
Jessica Sheehan ◽  
Douglas T. Queheillalt ◽  
Pamela M. Norris
Keyword(s):  
Pore Size ◽  
Heat Pipe ◽  
Friction Factor ◽  
Capillary Tube ◽  
Nickel Foam ◽  
Heat Pipes ◽  
Working Fluid ◽  
Open Cell ◽  
Pipe System ◽  
Nickel Foams

Heat pipes are a very efficient device which can be used for the rapid transfer of thermal energy. Small and microscale heat pipes are used in a variety of applications such as electronics and microprocessor coolers. As the size of the heat pipe devices increase, the volume and rate at which the working fluid is replenished in the evaporator region becomes an important parameter influencing the performance of the heat pipe system. Here, a stochastic open-cell nickel-foam has been evaluated for use as the wick material in heat pipes. The pore size of the open-cell nickel foam was modified via compression in the through thickness direction in order to evaluate its wicking characteristics and fluid flow resistance as a function of pore size. These properties are controlled by the effective pore size (controlled via through thickness compression) of the nickel foam. The equilibrium wicking height was measured by a simple flow experiment. The mass flow rate and the differential pressure of the crushed foams were measured at each thickness to generate a friction factor as a function of pore size. The equilibrium wicking height results were compared to a simple analytical model of a single capillary tube and found to be in reasonable agreement and the friction factor followed the same trend as the equilibrium wicking height. The experiments were used to evaluate the suitability of stochastic open cell nickel foams as wicks for heat pipe systems.

Hot Spot Elimination by Thin and Smart Heat Spreader

2015 ◽  
Author(s):  
Mohammad Shahed Ahamed ◽  
Yuji Saito ◽  
Masataka Mochizuki ◽  
Koichi Mashiko
Keyword(s):  
Heat Pipe ◽  
Hot Spot ◽  
Electronic Devices ◽  
Electronics Cooling ◽  
Heat Pipes ◽  
Metal Plate ◽  
Confined Space ◽  
Heat Spreader ◽  
Clock Speed ◽  
Wick Structure

Heat pipes are recognized as an excellent heat transport devices and extensively investigated for applications in electronic cooling. Different types of heat pipes have been developed such as micro/miniature heat pipes, loop heat pipes and so on, and these heat pipes have been widely applied in the field of electronics cooling such as notebook, desktop, data center; as well as aerospace, industrial cooling field. However, in recent years the application of heat pipe is widening to the filed of hand held mobile electronic devices such as smart phone, tablet pc, digital camera etc. With the development in technology these devices have different user friendly functions and capabilities, which requires the highest processor clock speed. In general, high clock speed of processor generates lot of heat which need to be spread or removed to eliminate the hot spot. It becomes a challenging task to cool such electronic devices as mentioned above with a very confined space and concentrated heat sources. Regarding to this challenge, ultra thin flat heat pipe is developed; this newly developed heat pipe consists of a special fiber wick structure which can ensure vapor spaces on the two sides of the wick structure. In this paper a novel thin spreader is proposed to eliminate the hot spot; generally the proposed heat spreader consists of 0.20mm thick metal plate and ultra thin heat pipe of 0.40mm thickness soldered in its body. Maximum thickness of this spreader is 0.63mm. Metal plate is 60mm × 110mm in size; and the ultra thin heat pipe can be fabricated from different original diameter ranges from 2.0mm to 3.0mm Cu tube. Theoretical and experimental analysis have been done to evaluate this thin spreader. In addition, some real application of this spreader will be introduced in this paper.

scholarly journals Heat Pipe as a Passive Cooling System Driving New Generation of Nuclear Power Plants

2021 ◽  
pp. 30-38
Author(s):  
Ziba Zibandeh Nezam ◽  
Bahman Zohuri
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Nuclear Power ◽  
Power Plants ◽  
Cooling System ◽  
Heat Pipes ◽  
Passive Cooling ◽  
Nuclear Power Reactor ◽  
Pipe System ◽  
New Generation

The technology of the Heat Pipe (HP) system is very well known for scientists and engineers working in the field of thermal-hydraulic since its invention at Las Alamos Nation Laboratory around the 1960s time frame. It is a passive heat transfer/heat exchanger system that comes in the form of either a constant or variable system without any mechanical built-in moving part. This passive heat transfer system and its augmentation within the core of nuclear power reactors have been proposed in the past few decades. The sodium, potassium, or mercury type heat pipe system using any of these three elements for the cooling system has been considered by many manufacturers of fission reactors and recently fusion reactors particularly Magnetic Confinement Fusion (MCF). Integration of the heat pipes as passive cooling can be seen in a new generation of a nuclear power reactor system that is designed for unconventional application field such as a space-based vehicle for deep space or galaxy exploration, planetary surface-based power plants as well as operation in remote areas on Earth. With the new generation of Small Modular Reactor (SMR) in form of Nuclear Micro Reactors (NMR), this type of fission reactor has integrated Alkali metal heat pipes to a series of Stirling convertors or thermoelectric converters for power generation that would generate anywhere from 13kwt to 3Mwt thermal of power for the energy conversion system.

scholarly journals Heat Pipe System as a Component of Spacecraft Electronics

2021 ◽  
pp. 363-377
Author(s):  
Nikita Yu. Sokolov ◽  
Vladimir A. Kulagin ◽  
Dmitry A. Nesterov
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Electronic Devices ◽  
Heat Pipes ◽  
Optimization Method ◽  
Maximum Temperature ◽  
Pipe System ◽  
Heat Transfer Capacity ◽  
The Mathematical Model ◽  
Flat Heat Pipe

We report on the results of optimizing a single flat heat pipe into an arrangement of heat pipes. A comparison is drawn at the same temperatures and occupied volumes and for a specific maximum temperature of radio-electronic devices. The end result of our studies is that the limiting heat transfer capacity has been found for a single heat pipe and two- and three-level heat pipe assemblies with various heat transfer media. Versatility of the mathematical model enhanced by the optimization method has been proved

AUTOMATED CHARGING OF EMBEDDED HEAT PIPE SYSTEMS

2012 ◽  
Vol 3 (2-4) ◽  
pp. 233-245
Author(s):  
Wessel W. Wits ◽  
Johannes van Es ◽  
Gert Jan te Riele
Keyword(s):  
Heat Pipe ◽  
Pipe Systems

scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

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