This paper is a
literature review focusing on the embodied energy and the operating energy of buildings
with case studies located in different countries and lifetimes. The aim is to
understand the significance of embodied energy, especially in low energy
buildings. Buildings demand energy as operating and embodied energy throughout their
life cycle. Studies showed that the building’s life cycle demand is contributed
by almost 80-90% of operating energy and 10-20% of embodied energy in most
cases. 1 2
Embodied Energy: The amount of energy used to acquire materials, manufacture,
transport and install the building assemblies in the initial stage of the
Embodied Energy: Energy used to maintain and replace the components during
the life of the building. 2
Energy: Energy used by the buildings for heating, cooling, lighting, and other
electrical equipment. This is expressed as either end-use or primary energy.
Energy Buildings: The type of buildings designed aiming at minimizing the
operating energy of the building. Examples include Solar house, passive house etc.
Energy: The sum of all the energy used for the whole building’s life cycle.
(Embodied energy plus Operating Energy).
if using recycling as a part of
paper, definitions for reuse, material recycling in open and closed loops,
combustion should be mentioned.
to significant amount of energy usage globally as well as to social economic
development of the nation. Another factor they contribute to is, environmental
impacts like waste generation and emissions. These factors have motivated the
building industry to concentrate on pursuing more environmentally sustainable
building design and construction techniques. The operational energy can be significantly
reduced by designing low-energy building. This is done using passive and active
technologies. This includes improved insulation of the building, better windows,
technical solutions like biomass burners, solar panels etc. However, commonly
the reduction of operating energy is done by increasing the use of energy
intensive materials. It is argued that the benefit of reduced operating energy
comes with the effect of increased embodied energy 4.
Several studies of
low energy buildings show that embodied energy accounts for 40-60% of total
energy use 5. Studies have shown
that even though the operational energy is very low in a building, total energy
usage was higher than the building having higher need for operating energy 1. This is the result
of using materials with intense energy requirement for their manufacture. The
author feels that it is important to take materials into consideration when trying
to design an energy efficient building. A structure is only truly energy
efficient when both embodied and operating energies are optimized. For example,
passive houses certification does not consider the amount of energy used for manufacturing
the excessive amount of insulation required for its high efficiency
Life Cycle Assessment (LCA)
LCA is a
process of attempting to provide the measure of overall environmental impact
that includes material and energy flows of a system. ISO 14040 (1997) defines
it as “LCA is a technique for assessing the potential environmental aspects
associated with a product (or service) by compiling an inventory of relevant
inputs and outputs, evaluating the potential environmental impacts associated
with these inputs and outputs, and interpreting the results of the inventory
and impact phases in relation to the objectives of the study” 7
consists of four phases – Defining the goal & scope, inventory analysis,
impact assessment and result interpretation. Goals and scope definition
consists of determining the system boundaries, broadness of study. Inventory analysis
involves collecting the data to quantify the materials and input/output of a
system. Impact assessment deals with evaluation of potential environmental
impacts by adopting qualitative and quantitative approach. 2.
Method (tables of summary of literature review) -check for pointers
in the papers (purple pen)
Case study no.
Type of building
C. Thormark 1
C. Scheuer 8
Winther and Hestnes
it is important to mention all the
scenarios and the possibilities and if they are considered in this review.
Factors affecting embodied energy: use of recycled materials and
use of materials that require less energy during manufacture is shown to reduce
the embodied energy.
Make sure to add something like how
the embodied energy can be reduced. Recycling might be a good point to add.
(search some papers on that). Also, using materials that require less energy
while manufacturing will be a good point.
C. . Thormark,
“A low energy building in a life cycle—its embodied energy, energy
need for operation and recycling potential,” Building and
Environment, vol. 37, no. 4, pp. 429-435, 2002.
T. . Ramesh, R. .
Prakash and K. K. Shukla, “Life cycle energy analysis of buildings: An
overview,” Energy and Buildings, vol. 42, no. 10, pp.
R. J. Cole and P.
C. Kernan, “Life-cycle energy use in office buildings,” Building
and Environment, vol. 31, no. 4, pp. 307-317, 1996.
I. . Sartori and A.
G. Hestnes, “Energy use in the life cycle of conventional and
low-energy buildings: A review article,” Energy and Buildings, vol.
39, no. 3, pp. 249-257, 2007.
B. . Winther and A.
G. Hestnes, “Solar versus green : The analysis of a Norwegian row
house,” Solar Energy, vol. 66, no. 6, pp. 387-393, 1999.
R. H. K. M. André
Stephan, “A comprehensive assessment of the life cycle energy demand
of passive houses,” Applied Energy, vol. 112, pp. 23-34, 2013.
14040, Environmental Management-Life Cycle Assessment- Principles and
Framework,” International Organization for Standardization, 1997.
C. . Scheuer, G. A.
Keoleian and P. . Reppe, “Life cycle energy and environmental
performance of a new university building: modeling challenges and design
implications,” Energy and Buildings, vol. 35, no. 10, pp.