A Review of Practical Applications of Heat Pipes and Innovative Application of Opportunities for Global Warming

2013 ◽  
pp. 145-212 ◽  
Author(s):  
M Mochizuki ◽  
A Akbarzadeh ◽  
T Nguyen
Keyword(s):  
Global Warming ◽  
Heat Pipes ◽  
Practical Applications

Surface Modifications of Bulk Micromachined Titanium Pillar Arrays: A Wick Material for Thin Flat Heat Pipes

2009 ◽  
Author(s):  
Changsong Ding ◽  
Carl D. Meinhart ◽  
Noel C. MacDonald
Keyword(s):  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Heat Pipes ◽  
Surface Modifications ◽  
Practical Applications ◽  
Plating Method ◽  
Modified Surfaces ◽  
Pillar Arrays ◽  
Extended Surface ◽  
Fundamental Research

Wicking materials with tunable wettability are of great importance for both fundamental research and practical applications such as heat pipes. In this work, we adopt recently developed titanium bulk micromachining[1] techniques to fabricate pillar arrays. Then we modify the micromachined pillars to form micro- & nano-textured (bitextured) titania structures (BTS). Further, we investigated how to plate gold on the modified surfaces to tune the wettability. A wicking material for heat pipe requires super wetting by common fluids such as water. We show theoretical studies and experimental work to investigate the wetting behavior of two different designs/samples. For heat pipe applications the BTS and plating gold not only increases the capillary pressure which enhances liquid pumping from condenser to evaporator, but also increases the heat transfer performance by extended surface and smaller pore sizes[2]. Testing results show that water can completely wet the micromachined Ti pillars (Design A: 5μm in diameter/5μm gap). The BTS helps increase the wetting speed by over 100% for this design. A second design with much larger diameter and gap (Design B: 100μm in diameter/50μm in gap) is also tested to compare with design A for wetting speed. Results show that Design B gives a wetting speed twice of Design A. Plating method is used to decrease pillar gap (from 50μm to 5μm) by growing gold on surfaces. This will help increase thermal conductivity of wicking material which is preferred for the evaporator and condenser regions of heat pipes. Wetting experiment is done on Sample B after plating with gold. Wetting results after Au plating show that wetting velocity decreases but is still significantly large.

Revised heating degree days due to global warming for 15 major cities of South Korea

2011 ◽  
Vol 32 (4) ◽  
pp. 377-383 ◽  
Author(s):  
Sung-Hwan Cho ◽  
Hyeong-Jung Kim ◽  
M Zaheeruddin
Keyword(s):  
Global Warming ◽  
Energy Consumption ◽  
South Korea ◽  
Degree Days ◽  
Practical Applications ◽  
Ambient Temperatures ◽  
Temperature Levels ◽  
Heating Degree Days ◽  
Equipment Size ◽  
The Impact

Because of the rapid rise in ambient temperatures in urban cities due to global warming, this research study was conducted to revise the heating degree days (HDDs) for main cities of South Korea. Current HDDs used in the design of heating systems were established some 30 years ago. Therefore, there is a need to revisit and revise the HDDs used in Korea. The HDDs were computed at five different indoor set-point and unloaded temperatures. The validity of the methodology used for computing HDDs was ascertained by comparing the calculated HDDs with the published values. The impact of the length of time on total annual HDDs was examined. The results show that higher temperature trends due to global warming witnessed over the past decade in general decreased the HDDs. The impact was higher for warmer climate cities than the cold regions. The revised annual HDDs for 15 major cities of South Korea are presented in this paper. Practical applications: The HDDs corrected for global warming effects for 15 major cities of South Korea presented in this article are useful for designers in estimating the impact on equipment size and energy consumption. Towards this end, several scenarios of global warming effects are presented by assuming several unloaded temperature levels. This is useful for the designers in examining the uncertainties in the estimation of energy consumption. The results published are also important for policy makers in South Korea to examine the need for revising the degree day database in light of the global warming trends.

Fundamental Issues and Technical Problems About Pulsating Heat Pipes

2021 ◽  
Author(s):  
Wookyoung Kim ◽  
Sung Jin Kim
Keyword(s):  
Review Paper ◽  
Heat Pipes ◽  
High Heat ◽  
High Heat Flux ◽  
Controversial Issues ◽  
Technical Problems ◽  
Practical Applications ◽  
Current State ◽  
Second Category ◽  
Shed Light

Abstract Since the introduction of Pulsating Heat Pipes (PHPs) in early 1990s, PHPs have received a lot of attention due to their obvious advantages such as the geometrical simplicity, and the potential for high-heat flux applications even without power consumption. Although numerous investigators have studied PHPs over the last three decades, there still exist a few controversial issues on fundamental characteristics and several technical problems in practical applications. To put finishing touches to the controversial issues and to shed light on technical problems, recent advances in PHPs are critically reviewed in this paper. The results of the critical review are classified into two categories: (i) fundamental aspects of PHPs and (ii) practical aspects of PHPs. First category focuses on reviewing the current state of the art on the fundamental characteristics of PHPs. Second category summarizes the technical problems which are resolved for utilizing PHPs in practical applications. This review paper would help researchers or engineers who are working on or utilizing PHPs.

scholarly journals Small-Sized Pulsating Heat Pipes/Oscillating Heat Pipes with Low Thermal Resistance and High Heat Transport Capability

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1736 ◽  
Author(s):  
Markus Winkler ◽  
David Rapp ◽  
Andreas Mahlke ◽  
Felix Zunftmeister ◽  
Marc Vergez ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermal Resistance ◽  
Heat Pipes ◽  
High Heat ◽  
Copper Plate ◽  
Heating Power ◽  
Air Cooling ◽  
Core Element ◽  
Practical Applications ◽  
Electronic Parts

Electronics (particularly power electronics) are the core element in many energy-related applications. Due to the increasing power density of electronic parts, the demands on thermal management solutions have risen considerably. As a novel passive and highly efficient cooling technology, pulsating heat pipes (PHPs) can transfer heat away from critical hotspots. In this work, we present two types of small and compact PHPs with footprints of 50 × 100 mm2, thicknesses of 2 and 2.5 mm and with high fluid channel density, optimized for cooling electronic parts with high power densities. The characterization of these PHPs was carried out with a strong relation to practical applications, revealing excellent thermal properties. The thermal resistance was found to be up to 90% lower than that of a comparable solid copper plate. Thus, a hot part with defined heating power would remain at a much lower temperature level and, for the same heater temperature, a much larger heating power could be applied. Moreover, the dependence of PHP operation and thermal properties on water and air cooling, condenser area size and orientation is examined. Under some test configurations, dryout conditions are observed which could be avoided by choosing an appropriate size for the fluid channels, heater and condenser.

Steady Liquid Flow and Liquid-Vapor Interface Shapes in Different Groove Structures in Micro Heat Pipes

2006 ◽  
Author(s):  
Mulugeta Markos ◽  
Vladimir Ajaev ◽  
G. M. Homsy
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Liquid Flow ◽  
Heat Pipes ◽  
Type Model ◽  
Practical Applications ◽  
Design And Optimization ◽  
Flow And Heat Transfer ◽  
Micro Heat Pipes

The paper presents a lubrication-type model of liquid flow and heat transfer in different groove structures in micro heat pipes under negligible gravity and small capillary number. In the adiabatic region the flow rate can be controlled by changing the shape of the cross-section. We have computed the flow rate as a function of geometric parameters. Determination of the vapor-liquid interface shape in the grooves requires coupling of fluid flow and heat transfer. We examined the shape of the interface when thermocapillary effect is insignificant and then consider the effect of thermocapilarity. Practical applications of our results are discussed in relation to the design and optimization of micro heat pipes.

scholarly journals Research on the Performance and Enlightenment of New York Storm Surge Adaptive Landscape Infrastructure

2019 ◽  
Vol 118 ◽  
pp. 03026
Author(s):  
Feng Lu
Keyword(s):  
New York ◽  
Global Warming ◽  
Spatial Distribution ◽  
Data Integration ◽  
Storm Surge ◽  
Field Research ◽  
Storm Surges ◽  
Adaptive Landscape ◽  
Practical Applications ◽  
City Construction

In the context of global warming, the study of the resilient city and resilient landscape has received more and more attention. In this work, New York is used as an example to explore the practical applications of storm surge adaptive landscape infrastructure. The vulnerability of New York in storm surges and New York’s plans for resilient city construction are introduced. Then according to the spatial distribution, through field research, questionnaires and data integration, the landscape infrastructure cases of beaches, waterfront parks, inland parks, nature areas and streets are studied, and their performance in Sandy is analysed. After that, under the guidance of resilient city theories and storm surge adaptation strategies, the experience that can be learned from these cases is summarized.

scholarly journals A Review of Recent Developments and Advances in Eco-Friendly Geopolymer Concrete

2020 ◽  
Vol 10 (21) ◽  
pp. 7838
Author(s):  
Lahiba Imtiaz ◽  
Sardar Kashif Ur Rehman ◽  
Shazim Ali Memon ◽  
Muhammad Khizar Khan ◽  
Muhammad Faisal Javed
Keyword(s):  
Global Warming ◽  
Construction Industry ◽  
Energy Requirement ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Practical Applications ◽  
Factors Influencing ◽  
Recent Developments ◽  
Flow Charts ◽  
Hardened Properties

The emission of CO2 and energy requirement in the production of Ordinary Portland Cement (OPC) causes the continuous depletion of ozone layer and global warming. The introduction of geopolymer concrete (GPC) technology in the construction industry leads to sustainable development and cleaner environment by reducing environmental pollution. In this article, constituents of GPC and their influence on properties of GPC has been reviewed critically. Fresh and hardened properties of GPC as well as the factors influencing these properties are discussed in detail. Flow charts have been proposed to show which factors have higher/lower impact on the fresh and hardened properties of GPC. A comprehensive review on the mix design of GPC, nanomaterial-based GPC, 3D printing using GPC, reinforced GPC and Global warming potential (GWP) assessment was conducted. Finally, the practical applications of GPC in the construction industry are provided.

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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