thermal design of a heat pipe

8/13/2019 Thermal Design of a Heat Pipe

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SUBMITTEDBYV

INEETK

UMARM

ISHRA( 134103051)

THERMAL DESIGN OF A HEAT PIPESYSTEM FOR REMOVAL OF SNOW

FROM ROOF TOP

ME655

ENERGYCONSERVATIONANDHEATRECOVERY


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Introduction

A heat pipe is a heat-transfer device that combines the principles of both thermal

conductivity and phase transition to efficiently manage the transfer of heat between two

interfaces.

The most popular snow treatment method is removal and transportation, but snow melting

methods such as road heating systems (hot water circulation type) have recently become

popular in Japan. Also snow melting system using Thermal Energy Storage without waterheating equipment using primary energy have been installed.

Snow melting and Deicing are the recent area of application of heat pipe, one in which work

in Japan has been particularly intense.


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Motivation

With all these, accumulation of snow on the roof tops of the domestic and commercialbuilding has been one of the worrying issues of the people and their governments. Heavy

snow and ice accumulation coupled with the roof collapse due to its heavy weight keeps

the residents in constant worry. What complicates the matter more is the melting of this

mass cause water seepage, which can rot roofs, destroy insulation, flood attics, stain the

ceiling, ruin gutters and damage the interior of the residents home.

Snow removal and disposal are expensive winter activities that affect the quality of life

and the environment in cities throughout the world. Over the years people have found out

many solutions to deal with the roof snow. A few of them are;

Fig 1. Snow covered roof tops and

exteriors


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For the long term solutions and especially in larger commercial buildings, the roofs are

normally covered with the anti-water repellent membrane, also insulating their attic

firmly.

It is also known that, people use de-icing agents to melt the snow and snow blowers.

Other than these solutions, people also opt for electronic and electrical heating of the

roofs, using newer and improved materials for the roof tops.

Fig 3. Ice dam formation and effects Fig 4. De-Icing tapes, heating coils to melt ice


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Literature Survey

Liu et.al, [1] claim the improvised version of Hydronic or electric heating ofsurfaces used in the prevention of ice formation and snow deposition by heating

pipe system.

Wang et.al, [2, 3] come up with a novel idea of road ice and snow melting basedin low temperature geo-thermal tail water and Industrial waste water. They findout that it is feasible to utilize geothermal tail water about 40*C for melting of

ice and snow on winter roads. Adachi [4] proposes a sprinkerless snow control system where water is lifted

from a well using a pump from the subsurface of the water having a temperaturegreater than freezing from the earth and delivering the relatively warm water into the conduit heat exchanger system positioned beneath an exterior surface to

be protected from snow build-up.

Sack et.al [5] studied a probabilistic model for roof snow loads and hasdeveloped a conditional probability of snow ice sliding through the roof as thefunction of temperature


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Danny Harvey [6] who studies about the cost information and energy efficiency states a

provision of a high performance envelope as the most important in reducing heating

loads and also as it permits alternative system for the crisis.

Van Wagoner [7] proposes a protected membrane roofing system for insulating the

interior of a building from ambient thermal cycling and for insuring water impermeable

integrity of the roofing membrane.

Jelle [8] suggests self-cleaning surfaces with origin in photocatalytic hydrophilic

surfaces, super hydrophobic or ultra hydrophobic surfaces and coarse microstructure or

nanostructured surfaces which can deal with snow accumulations.

Groll [9] gives a review on the status of heat pipe technology in Western Europe withspecial emphasis on its research work and applications.


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References

[1] Xiaobing Liu, Simon J. Rees, Jeffrey D. Spitler, Modeling snow melting on heatedpavement surfaces. Part I: Model development. Applied Thermal Engineering, 27 (2007)

11151124.

[2] Huajun Wang, Jun Zhao, Zhihao Chen, Experimental investigation of ice and snow

melting process on pavement utilizing geothermal tail water. Energy Conversion and

Management, 49 (2008) 15381546.

[3] Huajun Wang, Zhihao Chen., Study of critical free-area ratio during the snow-meltingprocess on pavement using low-temperature heating fluids. Energy Conversion and

Management, 50 (2009) 157165.

[4] Adachi, Method and apparatus for Sprinklerless snow control. Patent Number:

4,693,300.

[5] Sack R L., Arnholtz D., Simulating uniform roof snow loads. Computers & Structures,

Vol. 30. No 3. pp. 503-510, 1988.

[6] L. D. Danny Harvey, Reducing energy use in the buildings sector: measures, costs, and

examples. Energy Efficiency, 2 (2009) 139163.


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[7] John D. Van Wagoner, Thermally efficient, protected membrane roofing system.

Patent number: 4,719,723.

[8] Bjorn Petter Jelle., The challenge of removing snow downfall on photovoltaic solarcell roofs in order to maximize solar energy efficiencyResearch opportunities for the

future. Energy and Buildings, 67 (2013) 334351.

[9] Groll M., Heat pipe research and development in Western Europe Heat Recovery

Systems & CHP Vol. 9. No 1. pp. 19-66. 1989.

thermal design of a heat pipe

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