Transcript Exergy budget of the earth

Exergy and Possible Applications
Zhang Lixiao
Email:[email protected]
4/10/2016
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Questions?

What is real resource or wealthy ?
-Available energy

How to interpret the concept of scarcity ?
-Irreversibility
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Past Memory


Let there be a series of thermal reservoirs.
WR is the reversible (maximum) obtainable work
between any two temperatures.
Temperature
T*
T1
QH
WR
QC
T2
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Maximum attainable work
 TC 
WR  QH 1  
 TH 
WR  max QH
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The general concept of exergy

In 1953 the term exergy was suggested by Z. Rant to denote
“technical working capacity”.

A complete definition was given by H.D.Baehr in 1965Exergy is that part of energy that is convertible into all other forms of
energy.

Exergy is a measurement of how far a certain system deviates from
a state of equilibrium with its environment (Wall,1977).

According to Szargut et al. (1988) "exergy is the amount of work
obtainable when some matter is brought to a state of
thermodynamic equilibrium with the common components of the
natural surroundings’’.
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Some remarks

Contrast is the source of action and depletion of contrast is
the creator of time. Exergy is the physical value of contrast.

Contrast is everywhere: Dark/Light, Cold/Hot,
Woman/Man, Yin/Yang, Mother Earth/Father Sun,
Good/Evil, God/Satan, Life/Death, ...

Energy and matter cannot be created, destroyed, produced
or consumed.
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Possible applications
Resource
Exergy
Buffering
capacity
Environmental
impact
Exergy as the trinity of resource, buffering capacity and environmental impact
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Second Law analysis of a real process
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Resource accounting-wall School

On global scale
-G. Wall & M. Gong(2000), "On Exergetics, Economics and Desalination",
Encyclopedia of Desalination and Water Resources (DESWARE), EOLSS
Publishers, Oxford
-CHEN, G. Q.(2005). Exergy consumption of the earth. Ecological
Modelling184(2-4), 363-380.
-HERMANN, W. A.(2006). Quantifying global exergy resources.
Energy31(12), 1685-1702.
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Exergy budget of the earth
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On state scale
County
USA
Sweden
Japan
Italy
Norway
China
Associated years
1970
1980
1985
1990
1995
1993
Authors and published year
Methodology
(Reisad, 1975)
(Wall, 1987)
(Wall, 1990)
(Wall et al., 1994)
(Ertesvag & Mielnik, 2000)
(Chen & Chen, 2006)
Reistad’s approach
Wall’s approach
Wall’s approach
Wall’s approach
Wall’s approach
Wall’s approach
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On sectoral scale
County
Associated years
Authors and published year
Saudi Arabia
Saudi Arabia
Saudi Arabia
Turkey
Turkey
1990-2001
1990-2001
1990-2001
1990-2001
2000-2020
(Dincer et al., 2004)
(Dincer et al., 2005)
(Dincer et al., 2004)
(Utlu & Hepbasli, 2006)
(Utlu & Hepbasli, 2005)
China
1978-2002
(Ji & Chen, 2006)
Sectors
public and private sector
agricultural sector
transportation sector
agricultural sector
residential–commercial
sector
transportation sector
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Exergy as ecological indicator-Jorgenson School

The biggest asset of ecosystem exergy analysis is that it can
measure the increase in disorder in ecosystems associated with
human environmental impact.

Wagendorp et al. (2001) proposed to use the ecosystem exergy
concept as the theoretical basis for selecting indicators of the land
use impact category in Life Cycle Assessment (LCA).
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Ecosystem exergy concept

Four key elements:

Ecosystems are open systems that receive external exergy fluxes
(mainly solar exergy);

Ecosystems use part of that external exergy to increase their internal
exergy level in terms of biomass, structure and information (order
from disorder)

Ecosystems increase and maintain their capability to build up order
through a process of learning and memorizing by genetic selection
and transfer (order from order)

Ecosystems with high exergy level are more successful in dissipating
external exergy flows; it means that they are better buffered and thus
have higher stability
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Exergy analysis of waste emissions- Rosen School
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How to calculate the exergy?
Is not so important compared to how to define a
system boundary!
Not very difficulty but very complicated!
Vast references can help you finish your work once
you catch the philosophy of exergy!
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Thanks for your attentions!
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