Abstract: This paper is aliterature review focusing on the embodied energy and the operating energy of buildingswith case studies located in different countries and lifetimes.
The aim is tounderstand the significance of embodied energy, especially in low energybuildings. Buildings demand energy as operating and embodied energy throughout theirlife cycle. Studies showed that the building’s life cycle demand is contributedby almost 80-90% of operating energy and 10-20% of embodied energy in mostcases.
1 2 Definitions: InitialEmbodied Energy: The amount of energy used to acquire materials, manufacture,transport and install the building assemblies in the initial stage of thebuilding. 3RecurringEmbodied Energy: Energy used to maintain and replace the components duringthe life of the building. 2OperatingEnergy: Energy used by the buildings for heating, cooling, lighting, and otherelectrical equipment. This is expressed as either end-use or primary energy.LowEnergy Buildings: The type of buildings designed aiming at minimizing theoperating energy of the building.
Examples include Solar house, passive house etc.TotalEnergy: 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 ofpaper, definitions for reuse, material recycling in open and closed loops,combustion should be mentioned. Introduction:Buildings contributeto significant amount of energy usage globally as well as to social economicdevelopment of the nation. Another factor they contribute to is, environmentalimpacts like waste generation and emissions. These factors have motivated thebuilding industry to concentrate on pursuing more environmentally sustainablebuilding design and construction techniques.
The operational energy can be significantlyreduced by designing low-energy building. This is done using passive and activetechnologies. This includes improved insulation of the building, better windows,technical solutions like biomass burners, solar panels etc. However, commonlythe reduction of operating energy is done by increasing the use of energyintensive materials. It is argued that the benefit of reduced operating energycomes with the effect of increased embodied energy 4.Several studies oflow energy buildings show that embodied energy accounts for 40-60% of totalenergy use 5. Studies have shownthat even though the operational energy is very low in a building, total energyusage was higher than the building having higher need for operating energy 1. This is the resultof using materials with intense energy requirement for their manufacture.
Theauthor feels that it is important to take materials into consideration when tryingto design an energy efficient building. A structure is only truly energyefficient when both embodied and operating energies are optimized. For example,passive houses certification does not consider the amount of energy used for manufacturingthe excessive amount of insulation required for its high efficiencyoperationally 6. Life Cycle Assessment (LCA) LCA is aprocess of attempting to provide the measure of overall environmental impactthat includes material and energy flows of a system. ISO 14040 (1997) definesit as “LCA is a technique for assessing the potential environmental aspectsassociated with a product (or service) by compiling an inventory of relevantinputs and outputs, evaluating the potential environmental impacts associatedwith these inputs and outputs, and interpreting the results of the inventoryand impact phases in relation to the objectives of the study” 7 LCAconsists of four phases – Defining the goal & scope, inventory analysis,impact assessment and result interpretation. Goals and scope definitionconsists of determining the system boundaries, broadness of study. Inventory analysisinvolves collecting the data to quantify the materials and input/output of asystem. Impact assessment deals with evaluation of potential environmentalimpacts by adopting qualitative and quantitative approach.
2. Method (tables of summary of literature review) -check for pointersin the papers (purple pen) Reference Case study no. country Type of building Area (m2) Lifetime (years) C. Thormark 1 1 Sweden Residential 120*20 50 C. Scheuer 8 2 USA University (other) 7300 75 Winther and Hestnes 3-7 Norway Residential it is important to mention all thescenarios and the possibilities and if they are considered in this review. Results:Factors affecting embodied energy: use of recycled materials anduse of materials that require less energy during manufacture is shown to reducethe embodied energy.
Conclusion: Make sure to add something like howthe embodied energy can be reduced. Recycling might be a good point to add.(search some papers on that). Also, using materials that require less energywhile manufacturing will be a good point. References 1 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.
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3 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. 4 I.
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387-393, 1999. 6 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.
7 ISO, “ISO 14040, Environmental Management-Life Cycle Assessment- Principles and Framework,” International Organization for Standardization, 1997. 8 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.