Page 212 - Materials Chemistry, Second Edition

198 LIFE CYCLE ASSESSMENT HANDBOOK

"closed loop" of considerations that relates exergy, environment and econom-
ics in an operationally usefully methodology.
Lombardi (2001) perform an exergetic life cycle assessment and a classical
environmental life cycle assessment for a low carbon dioxide emission power
cycle which is a semi-closed gas turbine combined cycle. An 85% reduction in

C0 2 emissions is achieved by means of chemical absorption with a blended
solution of amines. The ExLCA is performed to assess the cost over the life
cycle of the plant in terms of exergy losses, which are calculated using the
Aspen Plus software package. The results show that the major irreversibilities
over the life cycle of the system are associated with the operating phase of the
power system.
Carrado et al. (2006) analyze the performance of an innovative high-efficiency
steam power plant by means of two "life cycle-based" methodologies: tradi-
tional LCAand extended exergy analysis (EEA). EE A considers material exergy
(the sum of physical exergy contents of all the materials used in fabrication),
physical exergy (the sum of the physical exergy fluxes entering the fabrication
process), capital exergy (the total monetary cost of the equipment, expressed in
terms of its equivalent exergetic content), labour exergy (the sum of the labour
contribution expressed in terms of its equivalent exergetic input), and environ-
mental remediation (the total exergetic "expense" required to bring the efflu-
ents to a state of equilibrium with the surroundings). The plant considered
is a hydrogen-fed steam power plant in which the H 2 is produced by a "zero
C0 2 emission" coal gasification process. The C0 2 capture system is a standard
humid-CaO absorbing process. Accounting for external costs with EEA shows
that the real exergy efficiency of the system decreases from 41.8% to about 17%
if one includes C0 2 capture and sequestration.
De Meester et at. (2009) report an exergetic life cycle assessment that quanti-
fies all energy and material needs for a family dwelling, in terms of both con-
struction aspects ("embodied energy and materials") and usage aspects. The
case study covers 65 optimized Belgian family dwelling types with low energy
3
inputs (556 MJ/(m year)). For the cavity wall and external insulation building
type, non-renewable inputs are dominant for the construction, with 85-86% of
the total exergy extracted from the environment. For the wooden frame, non-
renewable resource intake for construction, the corresponding value is 62%.
Despite the low-energy building type, heating requirements during the use
phase are dominant in the overall resource intake, accounting for 60% of the
total annual exergy consumption. The authors suggest that a reduction of heat-
ing requirements should be envisaged to make family dwellings less fossil fuel
resource dependant.
Dewulf et al. (2001) focus on the sustainability of different technological
options for the treatment of waste gases from a waste water treatment plant
containing volatile organic compounds. The treatment options considered are
biofiltration, catalytic and thermal oxidation and active carbon adsorption.
The amount of resources and utilities to construct and operate each system
is investigated from the point of view of the second law of thermodynamics.
It is concluded that biofiltration is the most exergetically efficient system.