For example, choice of the wick and case material eliminates many candidate working fluids often including water due to. A loop heat pipe lhp is a passive twophase transfer device related to the heat pipe. When to use a threepipe buffer tank configuration the designer proceeds to sketch out the loop, and puts in a primary loop circulator. The design is not straightforward and requires sound engineering judgment. Heat pipe design handbook, volume 1 internet archive. Heat pipe design guidance for heat sink integration. The need for an expansion loop in underground piping may be unnecessary if most of the expansion will be taken up by the pipes snaking in a ditch. This allows the wick in a loop heat pipe to be required only in the evaporator and. The ground itself is not a perfect heat sinksource because the energy added to the ground by the loop can change its temperature over time.
This entry was posted in heat pipe and tagged advanced thermal solutions, air flow, ats, electronics cooling, engineering, heat pipe, heat transfer, loop heat pipes, thermal design, thermal management. Heat pipes, 6th edition, takes a highly practical approach to the design and selection of heat pipes, making it an essential guide for practicing engineers and an. The designer must balance the wick pumping capability against the wick permeability when designing a heat pipe or loop heat pipe. Heat pipe manufacturers generally provide data sheets. The loop heat pipe lhp was invented in russia in the early 1980s. A miniature loop heat pipe lhp has been designed, built and tested at dynatherm corp. The design and test results for a capillary pumped loop cpl for thermal management of up to 210 w at the source and heat transfer over a distance of 1 m are discussed. The heat sources will inject heat into this loop, and the load circuits will extract heat from it. Functionality, advancements and industrial applications of heat pipes introduces heat pipe technologies and highlights a variety of applications for passive thermal control. It is a twophase heat transfer device that utilizes the evaporation and condensation of a working fluid to. Esa satellite cooling system makes paris metro more. Loop heat pipe design flexible heating pipe tech two.
The loop heat pipe is a variant of the ordinary heat pipe, and is a twophase flow loop type heat pipe, which is a unidirectional heat conduction element similar to a diode. Loop heat pipe lhp 3, 4, 5 is a twophase liquidvapour heat transfer. The research will enable design, optimisation and analysis of such a new galhp. The previous, approximately 10 mm thick evaporator of the loop heat pipe can now be reduced to 0. It utilizes boiling and condensation of the working fluid to transfer heat, and the surface tension forces of menisci formed at the liquidvapor interfaces on the porous wick to. Loop heat pipe with coherent porous wick since the porous material used for current heat pipes is usually stochastic structure, it is hard to apply analytical or numerical methods for design optimization. On the other hand, the new, more expensive books dont cover this information either you must. The loop heat pipe is composed of evaporator, reservoir, capillary. These studies highlight the influence of various design parameters of php on its performance. Lhps are high thermal conductance devices that are selfcontained and passive.
Design optimization of a loop heat pipe to cool a lithium ion battery onboard a military aircraft 18 february 2010 journal of mechanical science and technology, vol. This book introduces operational and design principles for heat pipes. This will impact pipe dimensions and the circulating pump that you size to. There is no connection whatsoever to the domestic water supply. This small, 229 mm by 127 mm, ammoniacharged lhp is intended to provide thermal management and temperature control for electronic components. Design tools based on computational fluid dynamics simulation and hshptm heat sinkheat. Design and testing of an ammonia loop heat pipe sciencedirect. This book is intended to explore some of the recent advances in heat pipes and their applications in thermal systems. With the increase in electric heat dissipation and miniaturization, we need advanced cooling systems to solve the high temperature problems. Loop heat pipe design flexible heating pipe tech two phase.
Most of the art of lhp fabrication is in the primary and secondary wick. When somebody first explained to me how they work, i was like, no way. For this article, well focus on a singlefamily residential building. Heat pipe technology is pertinent to the design and application of selfcontrolled. Loop design theory loop types a ground loop is a heat exchanger that either extracts or adds heat to the ground. In a heat pipe, the wick extends along the entire length so there are long lengths and large pressure drops for the liquid flow in the wick. Functionality, advancements and industrial applications of. Understanding loop heat pipes advanced thermal solutions. Heat pipes are used in a wide range of applications, including electronics cooling, diecasting and injection moulding, heat recovery and energy conservation, deicing and manufacturing process temperature control, and in domestic appliances. If the inner diameter of the capillary tube is small enough.
It covers all of the basics, which havent changed since the book was written. Emphasis in this test program is to examine the turnkey startup of the nrl lhp and its. Steady state model of a loop heat pipe lhp with coherent porous silicon cps wick in the evaporator mohammed hamdan, frank m. The ic industry of taiwan, roc is one of the most competitive industries in the world. A loop heat pipe lhp is a twophase heat transfer device that uses capillary action to remove heat from a source and passively move it to a condenser or radiator. Heat pipes capabilities also include loop heat pipes and high temperature heat pipes. Steady state model of a loop heat pipe lhp with coherent. Fluids used with loop heat pipes titanium loop heat pipe wick most current lhps use ammonia as the working fluid and operate at temperatures between 40 and 70c. Pdf this book provides a practical study of modern heat pipe. It is equally important for the geothermal heat pump, earth loop, and air ducting or radiant heat piping to be designed correctly.
This handbook provides all aspects of piping design starting from fluid properties, stress analysis, construction and fabrication details, compensating methods for thermal expansion, erection etc. Calyos sa after being adapted for earth, the heat pipes were added to new trains built for the one metro line. Working of closed loop pulsating heat pipe the tube is first evacuated and then filled partially with a working fluid. A book written by peterson 10 illustrated the performance limit approach for the. Loop heat pipes lhps are twophase heattransfer devices with capillary pumping of a working fluid. Study of a novel liquidvapour separatorincorporated.
The paper presents an overview of heat pipes, especially those used in different space missions. When heat pipes are used to move heat vs spread heat this is a twostep process. Closed loop open loop ground source water source pipe sizing design energy savings efficiency cop. This new edition has been revised to include new information on the underlying theory of heat pipes and heat transfer, and features fully updated applications, new data sections, and updated. Mathematical modeling of loop heat pipes and experimental. There are several limits that govern heat pipe theory. Piping layouts to avoid in hydronic systems hpac magazine.
The loop heat pipe lhp is a passive twophase heat transport device that is gaining importance as a part of spacecraft thermal control systems and also in applications such as in avionics cooling. This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale. Heat pipes, i am obliged to point out, are awesome. Twophase flow, heat transfer, dimensionless, loop heat pipe, thermal control, figure of merit. Lhps are similar to heat pipes but have the advantage of being able to provide reliable operation over long distance and the ability to operate against gravity. In a heat pipe wick, heat enters from the liquid side of the wick. The paper proposes the fabrication and test of flat plate loop heat pipe fplhp with a novel evaporator structure. Loop heat pipes lhps are twophase devices that can passively transport. Henderson department of mechanical, industrial, and nuclear engineering department of electrical and computer engineering and computer science university of cincinnati. For lhp design and fabrication, preliminary analysis on the basis of dimensionless criteria is necessary due to complicated phenomena, which take place in. Once the correct heat pipes have been identified the next step is integration into the heat sink. The most common variants are discussed here, including variable conductance heat pipes, oscillating and loop units, rotating and microheat pipes. The design idea of the worlds first lhp system was proposed by scientists in 1971. It can carry higher power over longer distances by having cocurrent liquid and vapor flow, in contrast to the countercurrent flow in a heat pipe.
It doesnt cover newer heat pipe variations, such as pressure controlled heat pipes and variable conductance heat pipes, or loop heat pipes lhps. An essential guide for practicing engineers and an ideal text for postgraduate students, the book takes a highly practical approach to the design and. Heat pipes, 6th edition, takes a highly practical approach to the design and selection of heat pipes, making it an essential guide for practicing engineers and an ideal text for postgraduate students. Loop heat pipe design, manufacturing and testing an industrial. Single and multiple loop php studies are widely reported in the literature. Overallan excellent book that covers the subject in great depth for the benefit of heat pipe designers and usersengineers will no doubt continue to stretch. Act designs and manufactures loop heat pipes for your industry. Introduction to loop heat pipes introduction to lhp ku 2015 tfaws 10. Aavid has been performing heat pipe and loop heat pipe life testing on a variety of material systems and heat rejection conditions for over 40 years.
Heat pipe product reliability guide water heat pipe parameters and limitations. A loop heat pipe lhp with a heat transport capacity of 500 w, for high powered spacecraft thermal management is being developed by the. Figure 7 shows a flat pipe design, they can be used as heat spreaders. The principles of this interaction are common in all loop types and will be discussed here. They can transport a large heat load over a long distance with a small. Top american libraries canadian libraries universal library community texts project gutenberg biodiversity heritage library childrens library. The main advantage to this system lies in the fact that, being closed, antifreeze instead of water can be used as the heat transfer medium. They possess all the main advantages of conventional heat pipes, but owing to the original design and special properties of the capillary structure are capable of transferring heat efficiency for distances up to several meters at any orientation in the gravity field, or to several tens of. Loop heat pipe design, manufacturing and testing an. Operating characteristics of loop heat pipes jentung ku.
Heatspring magazine 4step guide to designing geothermal. They possess all the main advantages of conventional heat pipes, but owing to the original design and special properties of the capillary structure are capable of transferring heat efficiency for distances up to several meters. As with any design process, many of the decisions that must be taken are interrelated and the process is iterative. Ats engineering ebook advanced thermal solutions, inc. Historical perspectives, principles of operations, types of heat pipes are discussed. Here are the four basic steps to geothermal heat pump design. Vapor grooves liquid line a section aa condenser main design features. Home loop heat pipe design, manufacturing and testing an industrial perspective. In this paper, results of the nrl lhp experimental studies, conducted by naval research laboratory nrl and nasa goddard space flight center, will be presented. Thermal control with low power, miniature loop heat pipes. The life tests results investigation have generated important data that has been applied on the design and construction of loop heat.
This book presents current research and development related to the design, applications and technology of various heat pipes, including conventional heat pipes and thermosyphon, pulsating heat pipes, loop heat pipes, and variable conductance heat pipes. To maintenance of all pipeworks whether underground or overhead, carrying any fluid like water, oil, air, industrial gases like oxygen, nitrogen, acetylene etc. Such considerations lead to successful operation for the design life of the unit. The book begins with a thorough analysis of heat pipe infrastructure, including principles of operation, temperature limits, reliability and lessons learned from worked examples and case studies.
Data bases for standard pipe size and wall thickness and expansion characteristics may be accessed, or user data entered. Loop heat pipes lhps are twophase devices that can passively transport heat over long distances relative to other passive two phase systems such as heat pipes. The total heat load a heat pipe can carry is a function of total length, evaporator and condenser length, diameter, and orientation with respect to gravity. From heat pipe to loop heat pipe and capillary pumped loop. Thermal performance and operational characteristics of. When the heat source is much smaller than the heat sink base, a flat.
The working medium is mainly composed of a gas phase and a liquid phase in the steam pipe and the liquid pipe respectively. If you are just getting interested in heat pipes, dunn and reay is an excellent starting point. Several factors have contributed to the science and technology of the present stateofart heat pipe leading to the development of loop heat pipes, micro and miniature heat pipes and micro loop heat pipes. Loop heat pipe for electronics western michigan university. Schematic of an lhp primary wick compensation arteries chamber evaporator. Loop heat pipe design, manufacturing and testing an industrial perspective. Heat pipes are considered as an effective thermal solution, particularly in high heat flux applications and in situations where there is a combination of nonuniform heat loading, limited airflow over the heatgenerating components, and space or weight constraints. Thinner loop heat pipe this loop heat pipe uses copper sheets that are only 0. Heat pipes are not new, but many variants and applications are. Thermal expansion of the carrier pipe during operation is. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig.
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